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<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">Self assembly of HIV-1 Gag protein on lipid membranes generates PI(4,5)P<sub>2</sub>
/Cholesterol nanoclusters</title>
<author><name sortKey="Yandrapalli, Naresh" sort="Yandrapalli, Naresh" uniqKey="Yandrapalli N" first="Naresh" last="Yandrapalli">Naresh Yandrapalli</name>
<affiliation><nlm:aff id="a1"><institution>CNRS-Université Montpellier, Centre d’études d’agents Pathogenes et de Biotechnologies pour la Santé</institution>
, Montpellier,<country>France</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Lubart, Quentin" sort="Lubart, Quentin" uniqKey="Lubart Q" first="Quentin" last="Lubart">Quentin Lubart</name>
<affiliation><nlm:aff id="a2"><institution>CNRS-Université Grenoble, Institut National de Physique</institution>
, Grenoble,<country>France</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Tanwar, Hanumant S" sort="Tanwar, Hanumant S" uniqKey="Tanwar H" first="Hanumant S." last="Tanwar">Hanumant S. Tanwar</name>
<affiliation><nlm:aff id="a3"><institution>Deakin University, School of Medicine</institution>
, Melbourne,<country>Australia</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Picart, Catherine" sort="Picart, Catherine" uniqKey="Picart C" first="Catherine" last="Picart">Catherine Picart</name>
<affiliation><nlm:aff id="a2"><institution>CNRS-Université Grenoble, Institut National de Physique</institution>
, Grenoble,<country>France</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Mak, Johnson" sort="Mak, Johnson" uniqKey="Mak J" first="Johnson" last="Mak">Johnson Mak</name>
<affiliation><nlm:aff id="a3"><institution>Deakin University, School of Medicine</institution>
, Melbourne,<country>Australia</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Muriaux, Delphine" sort="Muriaux, Delphine" uniqKey="Muriaux D" first="Delphine" last="Muriaux">Delphine Muriaux</name>
<affiliation><nlm:aff id="a1"><institution>CNRS-Université Montpellier, Centre d’études d’agents Pathogenes et de Biotechnologies pour la Santé</institution>
, Montpellier,<country>France</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Favard, Cyril" sort="Favard, Cyril" uniqKey="Favard C" first="Cyril" last="Favard">Cyril Favard</name>
<affiliation><nlm:aff id="a1"><institution>CNRS-Université Montpellier, Centre d’études d’agents Pathogenes et de Biotechnologies pour la Santé</institution>
, Montpellier,<country>France</country>
</nlm:aff>
</affiliation>
</author>
</titleStmt>
<publicationStmt><idno type="wicri:source">PMC</idno>
<idno type="pmid">28008947</idno>
<idno type="pmc">5180241</idno>
<idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5180241</idno>
<idno type="RBID">PMC:5180241</idno>
<idno type="doi">10.1038/srep39332</idno>
<date when="2016">2016</date>
<idno type="wicri:Area/Pmc/Corpus">000859</idno>
<idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Corpus" wicri:corpus="PMC">000859</idno>
</publicationStmt>
<sourceDesc><biblStruct><analytic><title xml:lang="en" level="a" type="main">Self assembly of HIV-1 Gag protein on lipid membranes generates PI(4,5)P<sub>2</sub>
/Cholesterol nanoclusters</title>
<author><name sortKey="Yandrapalli, Naresh" sort="Yandrapalli, Naresh" uniqKey="Yandrapalli N" first="Naresh" last="Yandrapalli">Naresh Yandrapalli</name>
<affiliation><nlm:aff id="a1"><institution>CNRS-Université Montpellier, Centre d’études d’agents Pathogenes et de Biotechnologies pour la Santé</institution>
, Montpellier,<country>France</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Lubart, Quentin" sort="Lubart, Quentin" uniqKey="Lubart Q" first="Quentin" last="Lubart">Quentin Lubart</name>
<affiliation><nlm:aff id="a2"><institution>CNRS-Université Grenoble, Institut National de Physique</institution>
, Grenoble,<country>France</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Tanwar, Hanumant S" sort="Tanwar, Hanumant S" uniqKey="Tanwar H" first="Hanumant S." last="Tanwar">Hanumant S. Tanwar</name>
<affiliation><nlm:aff id="a3"><institution>Deakin University, School of Medicine</institution>
, Melbourne,<country>Australia</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Picart, Catherine" sort="Picart, Catherine" uniqKey="Picart C" first="Catherine" last="Picart">Catherine Picart</name>
<affiliation><nlm:aff id="a2"><institution>CNRS-Université Grenoble, Institut National de Physique</institution>
, Grenoble,<country>France</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Mak, Johnson" sort="Mak, Johnson" uniqKey="Mak J" first="Johnson" last="Mak">Johnson Mak</name>
<affiliation><nlm:aff id="a3"><institution>Deakin University, School of Medicine</institution>
, Melbourne,<country>Australia</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Muriaux, Delphine" sort="Muriaux, Delphine" uniqKey="Muriaux D" first="Delphine" last="Muriaux">Delphine Muriaux</name>
<affiliation><nlm:aff id="a1"><institution>CNRS-Université Montpellier, Centre d’études d’agents Pathogenes et de Biotechnologies pour la Santé</institution>
, Montpellier,<country>France</country>
</nlm:aff>
</affiliation>
</author>
<author><name sortKey="Favard, Cyril" sort="Favard, Cyril" uniqKey="Favard C" first="Cyril" last="Favard">Cyril Favard</name>
<affiliation><nlm:aff id="a1"><institution>CNRS-Université Montpellier, Centre d’études d’agents Pathogenes et de Biotechnologies pour la Santé</institution>
, Montpellier,<country>France</country>
</nlm:aff>
</affiliation>
</author>
</analytic>
<series><title level="j">Scientific Reports</title>
<idno type="eISSN">2045-2322</idno>
<imprint><date when="2016">2016</date>
</imprint>
</series>
</biblStruct>
</sourceDesc>
</fileDesc>
<profileDesc><textClass></textClass>
</profileDesc>
</teiHeader>
<front><div type="abstract" xml:lang="en"><p>The self-assembly of HIV-1 Gag polyprotein at the inner leaflet of the cell host plasma membrane is the key orchestrator of virus assembly. The binding between Gag and the plasma membrane is mediated by specific interaction of the Gag matrix domain and the PI(4,5)P<sub>2</sub>
lipid (PIP<sub>2</sub>
). It is unknown whether this interaction could lead to local reorganization of the plasma membrane lipids. In this study, using model membranes, we examined the ability of Gag to segregate specific lipids upon self-assembly. We show for the first time that Gag self-assembly is responsible for the formation of PIP<sub>2</sub>
lipid nanoclusters, enriched in cholesterol but not in sphingomyelin. We also show that Gag mainly partition into liquid-disordered domains of these lipid membranes. Our work strongly suggests that, instead of targeting pre-existing plasma membrane lipid domains, Gag is more prone to generate PIP<sub>2</sub>
/Cholesterol lipid nanodomains at the inner leaflet of the plasma membrane during early events of virus assembly.</p>
</div>
</front>
<back><div1 type="bibliography"><listBibl><biblStruct><analytic><author><name sortKey="Balasubramaniam, M" uniqKey="Balasubramaniam M">M. Balasubramaniam</name>
</author>
<author><name sortKey="Freed, E O" uniqKey="Freed E">E. O. Freed</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Bieniasz, P D" uniqKey="Bieniasz P">P. D. Bieniasz</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Muriaux, D" uniqKey="Muriaux D">D. Muriaux</name>
</author>
<author><name sortKey="Darlix, J L" uniqKey="Darlix J">J.-L. Darlix</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Hendrix, J" uniqKey="Hendrix J">J. Hendrix</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Saad, J S" uniqKey="Saad J">J. S. Saad</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Ono, A" uniqKey="Ono A">A. Ono</name>
</author>
<author><name sortKey="Ablan, S D" uniqKey="Ablan S">S. D. Ablan</name>
</author>
<author><name sortKey="Lockett, S J" uniqKey="Lockett S">S. J. Lockett</name>
</author>
<author><name sortKey="Nagashima, K" uniqKey="Nagashima K">K. Nagashima</name>
</author>
<author><name sortKey="Freed, E O" uniqKey="Freed E">E. O. Freed</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Chan, R" uniqKey="Chan R">R. Chan</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Ono, A" uniqKey="Ono A">A. Ono</name>
</author>
<author><name sortKey="Freed, E O" uniqKey="Freed E">E. O. Freed</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Callahan, E M" uniqKey="Callahan E">E. M. Callahan</name>
</author>
<author><name sortKey="Wills, J W" uniqKey="Wills J">J. W. Wills</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Holm, K" uniqKey="Holm K">K. Holm</name>
</author>
<author><name sortKey="Weclewicz, K" uniqKey="Weclewicz K">K. Weclewicz</name>
</author>
<author><name sortKey="Hewson, R" uniqKey="Hewson R">R. Hewson</name>
</author>
<author><name sortKey="Suomalainen, M" uniqKey="Suomalainen M">M. Suomalainen</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Campbell, S" uniqKey="Campbell S">S. Campbell</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Pike, L J" uniqKey="Pike L">L. J. Pike</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Sengupta, P" uniqKey="Sengupta P">P. Sengupta</name>
</author>
<author><name sortKey="Hammond, A" uniqKey="Hammond A">A. Hammond</name>
</author>
<author><name sortKey="Holowka, D" uniqKey="Holowka D">D. Holowka</name>
</author>
<author><name sortKey="Baird, B" uniqKey="Baird B">B. Baird</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Charlier, L" uniqKey="Charlier L">L. Charlier</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Mercredi, P Y" uniqKey="Mercredi P">P. Y. Mercredi</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Keller, H" uniqKey="Keller H">H. Keller</name>
</author>
<author><name sortKey="Kr Usslich, H G" uniqKey="Kr Usslich H">H.-G. Kräusslich</name>
</author>
<author><name sortKey="Schwille, P" uniqKey="Schwille P">P. Schwille</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Wen, Y" uniqKey="Wen Y">Y. Wen</name>
</author>
<author><name sortKey="Dick, R" uniqKey="Dick R">R. Dick</name>
</author>
<author><name sortKey="Feigenson, G" uniqKey="Feigenson G">G. Feigenson</name>
</author>
<author><name sortKey="Vogt, V" uniqKey="Vogt V">V. Vogt</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Kerviel, A" uniqKey="Kerviel A">A. Kerviel</name>
</author>
<author><name sortKey="Thomas, A" uniqKey="Thomas A">A. Thomas</name>
</author>
<author><name sortKey="Chaloin, L" uniqKey="Chaloin L">L. Chaloin</name>
</author>
<author><name sortKey="Favard, C" uniqKey="Favard C">C. Favard</name>
</author>
<author><name sortKey="Muriaux, D" uniqKey="Muriaux D">D. Muriaux</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Wawrezinieck, L" uniqKey="Wawrezinieck L">L. Wawrezinieck</name>
</author>
<author><name sortKey="Rigneault, H" uniqKey="Rigneault H">H. Rigneault</name>
</author>
<author><name sortKey="Marguet, D" uniqKey="Marguet D">D. Marguet</name>
</author>
<author><name sortKey="Lenne, P F" uniqKey="Lenne P">P.-F. Lenne</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Favard, C" uniqKey="Favard C">C. Favard</name>
</author>
<author><name sortKey="Wenger, J" uniqKey="Wenger J">J. Wenger</name>
</author>
<author><name sortKey="Lenne, P F" uniqKey="Lenne P">P.-F. Lenne</name>
</author>
<author><name sortKey="Rigneault, H" uniqKey="Rigneault H">H. Rigneault</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Eggeling, C" uniqKey="Eggeling C">C. Eggeling</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Andrade, D M" uniqKey="Andrade D">D. M. Andrade</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Wu, H M" uniqKey="Wu H">H.-M. Wu</name>
</author>
<author><name sortKey="Lin, Y H" uniqKey="Lin Y">Y.-H. Lin</name>
</author>
<author><name sortKey="Yen, T C" uniqKey="Yen T">T.-C. Yen</name>
</author>
<author><name sortKey="Hsieh, C L" uniqKey="Hsieh C">C.-L. Hsieh</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Gambhir, A" uniqKey="Gambhir A">A. Gambhir</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Puff, N" uniqKey="Puff N">N. Puff</name>
</author>
<author><name sortKey="Watanabe, C" uniqKey="Watanabe C">C. Watanabe</name>
</author>
<author><name sortKey="Seigneuret, M" uniqKey="Seigneuret M">M. Seigneuret</name>
</author>
<author><name sortKey="Angelova, M I" uniqKey="Angelova M">M. I. Angelova</name>
</author>
<author><name sortKey="Staneva, G" uniqKey="Staneva G">G. Staneva</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Heberle, F A" uniqKey="Heberle F">F. A. Heberle</name>
</author>
<author><name sortKey="Wu, J" uniqKey="Wu J">J. Wu</name>
</author>
<author><name sortKey="Goh, S L" uniqKey="Goh S">S. L. Goh</name>
</author>
<author><name sortKey="Petruzielo, R S" uniqKey="Petruzielo R">R. S. Petruzielo</name>
</author>
<author><name sortKey="Feigenson, G W" uniqKey="Feigenson G">G. W. Feigenson</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Chukkapalli, V" uniqKey="Chukkapalli V">V. Chukkapalli</name>
</author>
<author><name sortKey="Hogue, I B" uniqKey="Hogue I">I. B. Hogue</name>
</author>
<author><name sortKey="Boyko, V" uniqKey="Boyko V">V. Boyko</name>
</author>
<author><name sortKey="Hu, W S" uniqKey="Hu W">W.-S. Hu</name>
</author>
<author><name sortKey="Ono, A" uniqKey="Ono A">A. Ono</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Ing Lfsson, H I" uniqKey="Ing Lfsson H">H. I. Ingólfsson</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Datta, S A K" uniqKey="Datta S">S. A. K. Datta</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Macia, E" uniqKey="Macia E">E. Macia</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Momany, C" uniqKey="Momany C">C. Momany</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Fung, B K" uniqKey="Fung B">B. K. Fung</name>
</author>
<author><name sortKey="Stryer, L" uniqKey="Stryer L">L. Stryer</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Kempf, N" uniqKey="Kempf N">N. Kempf</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Dalton, A K" uniqKey="Dalton A">A. K. Dalton</name>
</author>
<author><name sortKey="Ako Adjei, D" uniqKey="Ako Adjei D">D. Ako-Adjei</name>
</author>
<author><name sortKey="Murray, P S" uniqKey="Murray P">P. S. Murray</name>
</author>
<author><name sortKey="Murray, D" uniqKey="Murray D">D. Murray</name>
</author>
<author><name sortKey="Vogt, V M" uniqKey="Vogt V">V. M. Vogt</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Lindwasser, O W" uniqKey="Lindwasser O">O. W. Lindwasser</name>
</author>
<author><name sortKey="Resh, M D" uniqKey="Resh M">M. D. Resh</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Hawkes, D" uniqKey="Hawkes D">D. Hawkes</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Campbell, S M" uniqKey="Campbell S">S. M. Campbell</name>
</author>
<author><name sortKey="Crowe, S M" uniqKey="Crowe S">S. M. Crowe</name>
</author>
<author><name sortKey="Mak, J" uniqKey="Mak J">J. Mak</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Dick, R A" uniqKey="Dick R">R. A. Dick</name>
</author>
<author><name sortKey="Goh, S L" uniqKey="Goh S">S. L. Goh</name>
</author>
<author><name sortKey="Feigenson, G W" uniqKey="Feigenson G">G. W. Feigenson</name>
</author>
<author><name sortKey="Vogt, V M" uniqKey="Vogt V">V. M. Vogt</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Barros, M" uniqKey="Barros M">M. Barros</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Jiang, Z" uniqKey="Jiang Z">Z. Jiang</name>
</author>
<author><name sortKey="Redfern, R E" uniqKey="Redfern R">R. E. Redfern</name>
</author>
<author><name sortKey="Isler, Y" uniqKey="Isler Y">Y. Isler</name>
</author>
<author><name sortKey="Ross, A H" uniqKey="Ross A">A. H. Ross</name>
</author>
<author><name sortKey="Gericke, A" uniqKey="Gericke A">A. Gericke</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Chen, X" uniqKey="Chen X">X. Chen</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Al Momany, A" uniqKey="Al Momany A">A. Al-Momany</name>
</author>
<author><name sortKey="Li, L" uniqKey="Li L">L. Li</name>
</author>
<author><name sortKey="Alexander, R T" uniqKey="Alexander R">R. T. Alexander</name>
</author>
<author><name sortKey="Ballermann, B J" uniqKey="Ballermann B">B. J. Ballermann</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Honigmann, A" uniqKey="Honigmann A">A. Honigmann</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Van Den Bogaart, G" uniqKey="Van Den Bogaart G">G. van den Bogaart</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Mclaughlin, S" uniqKey="Mclaughlin S">S. McLaughlin</name>
</author>
<author><name sortKey="Murray, D" uniqKey="Murray D">D. Murray</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Golebiewska, U" uniqKey="Golebiewska U">U. Golebiewska</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Goswami, D" uniqKey="Goswami D">D. Goswami</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Thomas, A" uniqKey="Thomas A">A. Thomas</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Blosser, M C" uniqKey="Blosser M">M. C. Blosser</name>
</author>
<author><name sortKey="Honerkamp Smith, A R" uniqKey="Honerkamp Smith A">A. R. Honerkamp-Smith</name>
</author>
<author><name sortKey="Han, T" uniqKey="Han T">T. Han</name>
</author>
<author><name sortKey="Haataja, M" uniqKey="Haataja M">M. Haataja</name>
</author>
<author><name sortKey="Keller, S" uniqKey="Keller S">S. Keller</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Raghupathy, R" uniqKey="Raghupathy R">R. Raghupathy</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Honigmann, A" uniqKey="Honigmann A">A. Honigmann</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Spillane, K M" uniqKey="Spillane K">K. M. Spillane</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Hamard Peron, E" uniqKey="Hamard Peron E">E. Hamard-Peron</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Escoffre, J M" uniqKey="Escoffre J">J. M. Escoffre</name>
</author>
<author><name sortKey="Hubert, M" uniqKey="Hubert M">M. Hubert</name>
</author>
<author><name sortKey="Teissie, J" uniqKey="Teissie J">J. Teissié</name>
</author>
<author><name sortKey="Rols, M P" uniqKey="Rols M">M. P. Rols</name>
</author>
<author><name sortKey="Favard, C" uniqKey="Favard C">C. Favard</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Ehrlich, L S" uniqKey="Ehrlich L">L. S. Ehrlich</name>
</author>
<author><name sortKey="Fong, S" uniqKey="Fong S">S. Fong</name>
</author>
<author><name sortKey="Scarlata, S" uniqKey="Scarlata S">S. Scarlata</name>
</author>
<author><name sortKey="Zybarth, G" uniqKey="Zybarth G">G. Zybarth</name>
</author>
<author><name sortKey="Carter, C" uniqKey="Carter C">C. Carter</name>
</author>
</analytic>
</biblStruct>
<biblStruct><analytic><author><name sortKey="Wang, J" uniqKey="Wang J">J. Wang</name>
</author>
</analytic>
</biblStruct>
</listBibl>
</div1>
</back>
</TEI>
<pmc article-type="research-article"><pmc-dir>properties open_access</pmc-dir>
<front><journal-meta><journal-id journal-id-type="nlm-ta">Sci Rep</journal-id>
<journal-id journal-id-type="iso-abbrev">Sci Rep</journal-id>
<journal-title-group><journal-title>Scientific Reports</journal-title>
</journal-title-group>
<issn pub-type="epub">2045-2322</issn>
<publisher><publisher-name>Nature Publishing Group</publisher-name>
</publisher>
</journal-meta>
<article-meta><article-id pub-id-type="pmid">28008947</article-id>
<article-id pub-id-type="pmc">5180241</article-id>
<article-id pub-id-type="pii">srep39332</article-id>
<article-id pub-id-type="doi">10.1038/srep39332</article-id>
<article-categories><subj-group subj-group-type="heading"><subject>Article</subject>
</subj-group>
</article-categories>
<title-group><article-title>Self assembly of HIV-1 Gag protein on lipid membranes generates PI(4,5)P<sub>2</sub>
/Cholesterol nanoclusters</article-title>
</title-group>
<contrib-group><contrib contrib-type="author"><name><surname>Yandrapalli</surname>
<given-names>Naresh</given-names>
</name>
<xref ref-type="aff" rid="a1">1</xref>
</contrib>
<contrib contrib-type="author"><name><surname>Lubart</surname>
<given-names>Quentin</given-names>
</name>
<xref ref-type="aff" rid="a2">2</xref>
</contrib>
<contrib contrib-type="author"><name><surname>Tanwar</surname>
<given-names>Hanumant S.</given-names>
</name>
<xref ref-type="aff" rid="a3">3</xref>
</contrib>
<contrib contrib-type="author"><name><surname>Picart</surname>
<given-names>Catherine</given-names>
</name>
<xref ref-type="aff" rid="a2">2</xref>
</contrib>
<contrib contrib-type="author"><name><surname>Mak</surname>
<given-names>Johnson</given-names>
</name>
<xref ref-type="aff" rid="a3">3</xref>
</contrib>
<contrib contrib-type="author"><name><surname>Muriaux</surname>
<given-names>Delphine</given-names>
</name>
<xref ref-type="corresp" rid="c1">a</xref>
<xref ref-type="aff" rid="a1">1</xref>
</contrib>
<contrib contrib-type="author"><name><surname>Favard</surname>
<given-names>Cyril</given-names>
</name>
<xref ref-type="corresp" rid="c2">b</xref>
<xref ref-type="aff" rid="a1">1</xref>
</contrib>
<aff id="a1"><label>1</label>
<institution>CNRS-Université Montpellier, Centre d’études d’agents Pathogenes et de Biotechnologies pour la Santé</institution>
, Montpellier,<country>France</country>
</aff>
<aff id="a2"><label>2</label>
<institution>CNRS-Université Grenoble, Institut National de Physique</institution>
, Grenoble,<country>France</country>
</aff>
<aff id="a3"><label>3</label>
<institution>Deakin University, School of Medicine</institution>
, Melbourne,<country>Australia</country>
</aff>
</contrib-group>
<author-notes><corresp id="c1"><label>a</label>
<email>delphine.muriaux@cpbs.cnrs.fr</email>
</corresp>
<corresp id="c2"><label>b</label>
<email>cyril.favard@cpbs.cnrs.fr</email>
</corresp>
</author-notes>
<pub-date pub-type="epub"><day>23</day>
<month>12</month>
<year>2016</year>
</pub-date>
<pub-date pub-type="collection"><year>2016</year>
</pub-date>
<volume>6</volume>
<elocation-id>39332</elocation-id>
<history><date date-type="received"><day>18</day>
<month>08</month>
<year>2016</year>
</date>
<date date-type="accepted"><day>22</day>
<month>11</month>
<year>2016</year>
</date>
</history>
<permissions><copyright-statement>Copyright © 2016, The Author(s)</copyright-statement>
<copyright-year>2016</copyright-year>
<copyright-holder>The Author(s)</copyright-holder>
<license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by/4.0/"><pmc-comment>author-paid</pmc-comment>
<license-p>This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit <ext-link ext-link-type="uri" xlink:href="http://creativecommons.org/licenses/by/4.0/">http://creativecommons.org/licenses/by/4.0/</ext-link>
</license-p>
</license>
</permissions>
<abstract><p>The self-assembly of HIV-1 Gag polyprotein at the inner leaflet of the cell host plasma membrane is the key orchestrator of virus assembly. The binding between Gag and the plasma membrane is mediated by specific interaction of the Gag matrix domain and the PI(4,5)P<sub>2</sub>
lipid (PIP<sub>2</sub>
). It is unknown whether this interaction could lead to local reorganization of the plasma membrane lipids. In this study, using model membranes, we examined the ability of Gag to segregate specific lipids upon self-assembly. We show for the first time that Gag self-assembly is responsible for the formation of PIP<sub>2</sub>
lipid nanoclusters, enriched in cholesterol but not in sphingomyelin. We also show that Gag mainly partition into liquid-disordered domains of these lipid membranes. Our work strongly suggests that, instead of targeting pre-existing plasma membrane lipid domains, Gag is more prone to generate PIP<sub>2</sub>
/Cholesterol lipid nanodomains at the inner leaflet of the plasma membrane during early events of virus assembly.</p>
</abstract>
</article-meta>
</front>
<body><p>The retroviral Gag protein drives the assembly process of the Human Immunodeficiency Virus type 1(HIV-1) particles<xref ref-type="bibr" rid="b1">1</xref>
<xref ref-type="bibr" rid="b2">2</xref>
. This protein is synthesized as a polyprotein Pr55 Gag, which contains three major structural domains, namely matrix (MA), capsid (CA) and nucleocapsid (NC), as well as two spacer peptides, sp1 and sp2 and an unstructured C-terminus p6 peptide. Each of these domains are known to have a specific and distinct function during the viral assembly process. Importantly, the N-terminal MA domain targets Gag to the plasma membrane and mediates membrane binding, the CA domain is responsible for Gag-Gag interaction and self-assembly and the NC domain recruits the viral RNA that also acts as a scaffold for viral particle assembly<xref ref-type="bibr" rid="b3">3</xref>
. Although it has recently been shown that HIV assembly may be initiated in the cytosol<xref ref-type="bibr" rid="b4">4</xref>
, it is commonly accepted that the formation of large HIV-1 assembly complex mainly occurs at the plasma membrane (PM) of the virus producing cells. Two main features of the N-terminal MA domain of Gag govern the HIV-1 Gag inner leaflet PM binding: the N-terminal myristate and the highly basic region (HBR) that contains a specific binding pocket for the phosphatidyl inositol (4,5) bisphosphate lipid (PI(4,5)P<sub>2</sub>
or PIP<sub>2</sub>
)<xref ref-type="bibr" rid="b5">5</xref>
. PIP<sub>2</sub>
has been shown to play a major role in HIV-1 assembly in cells since cellular depletion of PIP<sub>2</sub>
decrease the efficiency of viral particle release<xref ref-type="bibr" rid="b6">6</xref>
. In addition, PIP<sub>2</sub>
is also enriched in the virus envelope relative to the PM of the virus-producing cells<xref ref-type="bibr" rid="b7">7</xref>
. This lipidomic analysis also shows that HIV particles are enriched in sphingolipids and cholesterol<xref ref-type="bibr" rid="b7">7</xref>
supporting the idea that the viral particles are released from the so called “rafts” domains. Historically, Gag has been shown to associate with detergent resistant membrane (DRM) by cell membrane fraction assays<xref ref-type="bibr" rid="b8">8</xref>
<xref ref-type="bibr" rid="b9">9</xref>
. Nevertheless, the exact composition of these “rafts” or DRM is controversial<xref ref-type="bibr" rid="b10">10</xref>
<xref ref-type="bibr" rid="b11">11</xref>
. Indeed, many different types of “rafts” may exist within the plasma membrane as long as they are enriched in cholesterol and sphingolipids<xref ref-type="bibr" rid="b12">12</xref>
. However, Gag self-assembly occurs at the inner leaflet of the cellular PM where sphingolipids are poorly present. Moreover, natural PIP<sub>2</sub>
, the main interacting partner of Gag, has a polyunsaturated fatty acyl residue at the sn-2 position of the glycerol backbone. This acyl chain polyunsaturation is not in favour of PIP<sub>2</sub>
partitioning into rafts<xref ref-type="bibr" rid="b13">13</xref>
. To circumvent such a constrain, Saad <italic>et al</italic>
. suggested a model based on NMR data using truncated acyl chains PIP<sub>2</sub>
<xref ref-type="bibr" rid="b5">5</xref>
. In this model, the sn-2 acyl chain of the PIP<sub>2</sub>
is removed from the plane of the membrane and trapped into an hydrophobic pocket of MA. However, coarse grained dynamics studies<xref ref-type="bibr" rid="b14">14</xref>
and new NMR experiments using full length acyl chain PIP<sub>2</sub>
<xref ref-type="bibr" rid="b15">15</xref>
showed the opposite. Finally, recent experiments using either a multimerizable matrix domain of HIV-1 Gag<xref ref-type="bibr" rid="b16">16</xref>
or RSV Gag<xref ref-type="bibr" rid="b17">17</xref>
also exhibited contradictory results regarding their partitioning in lipid domains of giant unilamellar vesicles (GUVs).</p>
<p>Therefore, the ability of the Gag/PIP<sub>2</sub>
complex to partition preferentially into “raft” domains or more generally into PM pre-existing domains to enhance virus assembly is still a matter of controversy<xref ref-type="bibr" rid="b18">18</xref>
. In order to elucidate whether Gag would bind to pre-existing “rafts” or lipid domains in the PM or generate its own lipid domains for assembling, we first decided to monitor its binding and partitioning to single or dual-phase model membranes made with simple and complex lipid compositions (see <xref ref-type="table" rid="t1">Table 1</xref>
for detailed composition of lipid mixtures). On GUVs, we observed that Gag was mainly partitioning into liquid-disordered (<italic>L</italic>
<sub><italic>d</italic>
</sub>
) phase, i.e. more likely out of “rafts” microdomains in the dual-phase model membrane and that Gag was not generating micrometer range lipid phase separation in single phase model membranes.</p>
<p>We therefore monitored, at the nanoscale level, a possible PIP<sub>2</sub>
, cholesterol (Chol) and sphingomyelin (SPM) reorganization during Gag self-assembly. Unfortunately, direct imaging of lipid nanodomains generation is not an easy task. Even the presence of pre-existing lipid nanodomains has indirectly been revealed by monitoring lipid diffusion<xref ref-type="bibr" rid="b19">19</xref>
<xref ref-type="bibr" rid="b20">20</xref>
<xref ref-type="bibr" rid="b21">21</xref>
<xref ref-type="bibr" rid="b22">22</xref>
<xref ref-type="bibr" rid="b23">23</xref>
. Although accurate in detecting and measuring the size of pre-existing nanodomains, direct imaging is not fast enough to follow the generation of nanodomains. Therefore, we decided to use indirect approaches such as fluorescence quenching<xref ref-type="bibr" rid="b24">24</xref>
<xref ref-type="bibr" rid="b25">25</xref>
or Forster Resonant Energy Transfer (FRET)<xref ref-type="bibr" rid="b26">26</xref>
. FRET or self-quenching occurs when two (similar or different) fluorescent molecules are found together within a 3 to 10 nm radius.</p>
<p>Starting from a simple lipid mixture and using self-quenching experiments of respectively PIP<sub>2</sub>
, Chol and SPM, we monitored the generation of Gag induced lipid nanodomains. We then performed the same type of experiments with dual labelling of the lipids (Chol and PIP<sub>2</sub>
, or SPM and PIP<sub>2</sub>
) followed up by FRET experiments to analyse how Gag was differently sorting these lipids during its self-assembly. We finally extended this study to more complex lipid compositions mimicking either lipid “rafts” or inner leaflet of the PM.</p>
<p>Our results show that Gag self-assembly is able to generate PIP<sub>2</sub>
nanodomains on model membranes with any of the composition we tested here. Importantly, these nanodomains contain Chol but not SPM.</p>
<sec disp-level="1"><title>Results</title>
<p>Since PIP<sub>2</sub>
, Chol and SPM have been shown to be enriched in the virus envelope<xref ref-type="bibr" rid="b7">7</xref>
, the impact of Gag self-assembly on their lateral distribution was tested in different types of model membranes (<xref ref-type="fig" rid="f1">Fig. 1A</xref>
) exhibiting different lipid compositions. Large unilamellar vesicles (LUVs) were firstly used in order to easily control the protein over lipid molecular ratio. Given that the plasma membrane of HIV producing cells (~10 <italic>μm</italic>
in diameter) has reduced level of curvature compared to these LUVs (100 nm in diameter), we have also used supported lipid bilayers (SLBs) as membrane models for analyses. Gag is known to bind specifically PIP<sub>2</sub>
<xref ref-type="bibr" rid="b27">27</xref>
. We then started with a simple PIP<sub>2</sub>
containing lipid mixture (PC/PS/PIP<sub>2</sub>
hereafter called “basic”) in which we introduced Chol or SPM (hereafter called “substituted basic”). Obviously, cellular PM have more complex lipid compositions. We therefore decided to extend our study to compositions mimicking either the inner leaflet cellular plasma membrane<xref ref-type="bibr" rid="b28">28</xref>
(hereafter called “inner leaflet”) or the “lipid rafts” domains (i.e. two separated phases, a liquid disordered (L<sub><italic>d</italic>
</sub>
) and a liquid ordered (L<sub><italic>o</italic>
</sub>
) enriched in cholesterol and sphingomyelin, hereafter called “rafts-mimicking”<xref ref-type="bibr" rid="b16">16</xref>
). <xref ref-type="table" rid="t1">Table 1</xref>
gives the exact compositions of the lipid mixtures used in this study. To assess a potential reorganisation of these lipids during Gag self-assembly, we used full-length Gag (FL-Gag) and different mutants. Theses mutants include: (1) a mutant of CA involved in CA-CA interaction and Gag self-assembly (WM)<xref ref-type="bibr" rid="b29">29</xref>
(2) Gag lacking the C-terminus NC-sp2-p6 domains that is involved in NC-RNA association (P39). The membrane binding domain alone of Gag (MA) was also tested (see <xref ref-type="fig" rid="f1">Fig. 1B</xref>
). Finally, a cellular PM PIP<sub>2</sub>
binding protein, the PH domain of EFA6 (PH-EFA6)<xref ref-type="bibr" rid="b30">30</xref>
and a peptide, MARCKS (151–175) that is known to laterally redistribute PIP<sub>2</sub>
<xref ref-type="bibr" rid="b24">24</xref>
were used as controls.</p>
<sec disp-level="2"><title>HIV-1 Gag efficiently binds model membranes containing PIP<sub>2</sub>
</title>
<p>The ability of the different proteins and peptide to bind LUVs and SLBs was analysed using membranes of “basic” composition. For this purpose, we monitored protein binding with two different techniques. On one hand, we performed LUV cosedimentation assays at fixed protein concentration (1 <italic>μ</italic>
M) and increasing PIP<sub>2</sub>
concentrations. After 15 min of incubation, LUV bound proteins were separated from unbound proteins by ultra-centrifugation. The pellet (P) and the supeRNAtant (S) were deposited on a denaturating gel to quantify the amount of bound (P) and unbound (S) proteins (<xref ref-type="fig" rid="f2">Fig. 2A</xref>
). On the other hand, we used Quartz Crystal Microbalance (QCM) to monitor the association of proteins to SLBs containing a fixed PIP<sub>2</sub>
concentration. SLBs were formed onto the quartz crystal. Proteins were then injected at increasing concentrations (from 10<sup>−2</sup>
to 10 <italic>μ</italic>
M) and the change in the resonance frequency of the quartz crystal was monitored (<xref ref-type="fig" rid="f2">Fig. 2B</xref>
). This change in frequency is directly connected to the mass increase at the surface of the quartz crystal.</p>
<p>The ratio of membrane bound to unbound protein is linked to an apparent partition coefficients (<italic>K</italic>
<sub><italic>p</italic>
</sub>
). <italic>K</italic>
<sub><italic>p</italic>
</sub>
were determined by fitting, with <xref ref-type="disp-formula" rid="eq3">eq. 1</xref>
, the plots of membrane bound protein with either increasing concentrations of lipids (<xref ref-type="fig" rid="f2">Fig. 2C</xref>
) or increasing concentration of protein (<xref ref-type="fig" rid="f2">Fig. 2D</xref>
). Except for MA, <italic>K</italic>
<sub><italic>p</italic>
</sub>
obtained for other proteins were less than 1 <italic>μM</italic>
. The results, summarized in <xref ref-type="table" rid="t2">Table 2</xref>
, are in good agreement with the previously obtained <italic>K</italic>
<sub><italic>p</italic>
</sub>
values for some of the different proteins used in this study. Interestingly, the <italic>K</italic>
<sub><italic>p</italic>
</sub>
values of MARCKS and PH-EFA6 (0.7 < <italic>K</italic>
<sub><italic>p</italic>
</sub>
< 0.8 <italic>μM</italic>
) were found to be in the range of the one obtained for Gag (FL) and its mutants (0.2 < <italic>K</italic>
<sub><italic>p</italic>
</sub>
< 0.8 <italic>μM</italic>
). This shows that the ratio of membrane bound over total protein will be equivalent for all these proteins, allowing, therefore, direct comparisons of their respective role on the lateral sorting of PIP<sub>2</sub>
after membrane binding.</p>
</sec>
<sec disp-level="2"><title>FL-Gag is mainly partitioning to L<sub><italic>d</italic>
</sub>
phases and does not induce micrometer phase separation</title>
<p>We firstly monitored the possible existence of Gag induced micrometer-range PIP<sub>2</sub>
domains by imaging the surface distribution of a fluorescently labelled PIP<sub>2</sub>
(namely Top-Fluor PIP<sub>2</sub>
or TF-PIP<sub>2</sub>
) and a fluorescently labeled FL-Gag (FL-Gag Alexa 549 or A549-FL-Gag) in “basic” GUVs. As expected, both TF-PIP<sub>2</sub>
and A549-FL-Gag showed a uniform distribution over the surface of the GUV (<xref ref-type="fig" rid="f3">Fig. 3A</xref>
). The same uniform distribution was also observed with “inner leaflet” GUVs (<xref ref-type="fig" rid="f3">Fig. 3A</xref>
). Spatial auto-correlation of the fluorescence of either PIP<sub>2</sub>
or FL-Gag (<xref ref-type="fig" rid="f3">Fig. 3B</xref>
) both exhibited fast decorrelation showing that the fluorescent labelling of PIP<sub>2</sub>
is not inducing micrometer partitioning <italic>per se</italic>
and that, if they exist, the PIP<sub>2</sub>
clusters are less than 200 nm size (i.e. below the diffraction limit). Interestingly, labelled FL-Gag was essentially restricted to L<sub><italic>d</italic>
</sub>
phases in the “rafts-mimicking” GUVs (<xref ref-type="fig" rid="f3">Fig. 3C</xref>
and D), confirming what was already observed by Keller <italic>et al</italic>
.<xref ref-type="bibr" rid="b16">16</xref>
with a multimerized derivative of MA. This strongly suggested that FL-Gag preferentially binds and remains in non “rafts”/L<sub><italic>o</italic>
</sub>
lipid phases.</p>
</sec>
<sec disp-level="2"><title>HIV-1 Gag self-assembly induces PIP<sub>2</sub>
nanoclustering</title>
<p>The lack of micrometer scale PIP<sub>2</sub>
induced domains lead us to monitor, using self-quenching experiments, a possible PIP<sub>2</sub>
lateral redistribution upon Gag self-assemby on LUVs or SLBs. As stated in the introduction, self-quenching occurs when two fluorescent molecules are close to each other (3 < r < 10 nm). To perform these experiments, we first controlled that increasing concentrations of MARCKS induced an increasing quenching of the TF-PIP<sub>2</sub>
as it was reported before with Bodipy TMR-PIP<sub>2</sub>
(BT-PIP<sub>2</sub>
)<xref ref-type="bibr" rid="b24">24</xref>
(<xref ref-type="supplementary-material" rid="S1">See SI</xref>
<xref ref-type="supplementary-material" rid="S1">Fig. S1</xref>
). We then monitored the change in TF-PIP<sub>2</sub>
fluorescence after addition of Gag or its mutants on “basic” LUVs in order to correctly control the protein to accessible PIP<sub>2</sub>
ratio (<inline-formula id="d32e553"><inline-graphic id="d32e554" xlink:href="srep39332-m1.jpg"></inline-graphic>
</inline-formula>
). We observed an increase in TF-PIP<sub>2</sub>
fluorescence (<xref ref-type="fig" rid="f4">Fig. 4A</xref>
) opposite to MARCKS. From <xref ref-type="fig" rid="f4">Fig. 4B</xref>
it was evidenced that addition of increasing concentrations of FL-Gag, P39 and WM induced an increasing fluorescence unquenching of TF-PIP<sub>2</sub>
. On the other hand, adding increasing concentrations of MA did not generate any change in the fluorescence of TF-PIP<sub>2</sub>
. Identically, PH-EFA6, known to specifically bind PIP<sub>2</sub>
without reorganizing its lateral distribution, did not produce any effect either (<xref ref-type="fig" rid="f4">Fig. 4A</xref>
and B). A major difference between the Gag matured protein MA and the precursor proteins (FL-Gag, P39 and WM) is their capacity to form large oligomer complexes via the CA-CA interactions<xref ref-type="bibr" rid="b31">31</xref>
, although WM is less efficient (two orders of magnitudes in solution) in supporting the formation of large Gag lattice, due to its inability to dimerize with nearby CA hexamer<xref ref-type="bibr" rid="b29">29</xref>
. Interestingly, this fluorescence unquenching was always less efficient in the case of WM compared to FL-Gag (from 3 to 5 times), indicating that this fluorescence variation depended on the capacity of Gag to multimerize. To support this hypothesis, FL-Gag and WM were incubated with “basic” LUVs for 15 minutes followed by ultracentrifugation. The self-assembly states of WM and FL-Gag bound to LUVs were analysed by performing a non denaturating gel electrophoresis to preserve existing multimers, followed by immunoblot. <xref ref-type="fig" rid="f4">Figure 4C</xref>
showed that, in the two <inline-formula id="d32e586"><inline-graphic id="d32e587" xlink:href="srep39332-m2.jpg"></inline-graphic>
</inline-formula>
ratio tested, WM was at least two times less efficient than FL-Gag in multimerizing on membranes (<xref ref-type="fig" rid="f4">Fig. 4B</xref>
). This ratio was in the range of the relative efficiency of TF-PIP<sub>2</sub>
unquenching observed between FL-Gag and WM. This confirmed the role of Gag self-assembly in the observed TF-PIP<sub>2</sub>
fluorescence changes. Although LUVs provide a simple, reliable and easy to control (in terms of protein to lipid ratios) model membranes, Gag self-assembly usually occurs on membranes with higher radius of curvature. Therefore, time course fluorescence self-quenching of TF-PIP<sub>2</sub>
were also conducted on “basic” SLBs. For FL-Gag and P39 the TF-PIP<sub>2</sub>
fluorescence intensity of SLBs decreased (<xref ref-type="fig" rid="f4">Fig. 4D</xref>
). This change in intensity was opposite to the one observed with LUVs (<xref ref-type="fig" rid="f4">Fig. 4A</xref>
) while still being a function of the protein concentration (<xref ref-type="fig" rid="f4">Fig. 4E</xref>
for FL-Gag). As it was the case for LUVs, the TF-PIP<sub>2</sub>
quenching induced by addition of the WM mutant was less efficient than in the case of FL-Gag. PH-EFA6 and MA did not induced changes in TF-PIP<sub>2</sub>
fluorescence (<xref ref-type="fig" rid="f4">Fig. 4D</xref>
). Interestingly, <xref ref-type="fig" rid="f4">Fig. 4D</xref>
shows that MARCKS addition induced the same TF-PIP2 quenching on SLBs and LUVs (see <xref ref-type="fig" rid="f4">Fig. 4A</xref>
). This suggest that model membrane curvature (curved LUV vs flat SLBs) is responsible for the opposite quenching observed with Gag and its mutants on SLBs and LUVs (<xref ref-type="supplementary-material" rid="S1">see SI</xref>
<xref ref-type="supplementary-material" rid="S1">Fig. S2</xref>
for detailed explanation). Altogether these results show that the self-assembly of HIV-1 Gag is generating TF-PIP<sub>2</sub>
clusters.</p>
<p>Diffusion of Gag is expected to slow down upon self-assembly. Hendrix <italic>et al</italic>
.<xref ref-type="bibr" rid="b4">4</xref>
already observed that Gag multimers exhibited a diffusion coefficient(D) of 0.01 <italic>μm</italic>
<sup>2</sup>
.<italic>s</italic>
<sup>−1</sup>
at maximum. If PIP<sub>2</sub>
s are tightly trapped in Gag multimers they will diffuse with similar coefficient as that of these Gag multimers. Consequently, the fluorescence of a 1 <italic>μ</italic>
m radius area containing these multimers and labelled PIP<sub>2</sub>
, should not totally return to its initial level 15s after photobleaching (<xref ref-type="fig" rid="f4">Fig. 4F</xref>
). This will lead the normalized fluorescence recovery value (NFR, defined in <xref ref-type="disp-formula" rid="eq6">eq. 4</xref>
, 0 < <italic>NFR</italic>
< 1) to be less than 1. We monitored this change in normalized fluorescence recovery in the absence or presence of FL-Gag. For that purpose, in the time course of quenching experiments, we performed Fluorescence Recovery After Photobleaching (FRAP) experiments before (start of the quenching experiment) and after (end of the quenching experiment) addition of FL-Gag on SLBs. In the absence of FL-Gag, normalized fluorescence recovered to 1, as expected for freely diffusing lipids (<xref ref-type="fig" rid="f4">Fig. 4G</xref>
, right). On the opposite, addition of increasing FL-Gag concentrations induced a decrease in PIP<sub>2</sub>
normalized fluorescence recovery as well as an increase in fluorescence quenching (previously shown in <xref ref-type="fig" rid="f4">Fig. 4E</xref>
). We controlled that the decrease in normalized fluorescence recovery was specific of PIP<sub>2</sub>
. Indeed, we did not observe any change in the normalized fluorescence recovery of a lipid analogue fluorescent dye (diIC18, see materials in SI) in the presence or in the absence of Gag (<xref ref-type="fig" rid="f4">Fig. 4G</xref>
, left).</p>
<p>Our data clearly show that HIV-1 Gag is sorting PIP<sub>2</sub>
in the lipid membrane and that Gag self-assembly generates PIP<sub>2</sub>
nanoclusters in model membranes.</p>
</sec>
<sec disp-level="2"><title>Cholesterol but not sphingomyelin is sensitive to HIV-1 Gag self-assembly</title>
<p>Since Chol and SPM are supposed to be the main lipid components of “raft” domains, their enrichment into the Gag self-assembly induced PIP<sub>2</sub>
nanoclusters was also assessed. 2% mol of egg phosphatidyl choline (EPC) present in our “basic” lipid composition, were substituted either by SPM or by Chol with half of them being labelled with TF derivatives (see <xref ref-type="table" rid="t1">Table 1</xref>
for detailed composition). This substitution allowed the net surface charge and the PIP<sub>2</sub>
content to be maintained, limiting any drastic change in the partitioning constant <italic>K</italic>
<sub><italic>p</italic>
</sub>
. Time course fluorescence change of either TF-SPM or TF-Chol were then monitored after FL-Gag addition. <xref ref-type="fig" rid="f5">Figure 5A</xref>
shows that FL-Gag addition had no effect on TF-SPM fluorescence whereas <xref ref-type="fig" rid="f5">Fig. 5B</xref>
shows that increasing concentrations of FL-Gag induced increasing quenching of TF-Chol, as it was the case for TF-PIP<sub>2</sub>
(<xref ref-type="fig" rid="f4">Fig. 4E</xref>
). This shows that FL-Gag self- assembly is able to generate Chol-enriched lipid nanodomains whereas it is not changing the SPM lateral distribution. Co-clustering of these molecules was also assessed by simultaneously monitoring the change in fluorescence upon addition of FL-Gag with either TF-SPM and BT-PIP<sub>2</sub>
(<xref ref-type="fig" rid="f5">Fig. 5C</xref>
) or TF-Chol and BT-PIP<sub>2</sub>
(<xref ref-type="fig" rid="f5">Fig. 5D</xref>
) labelled SLBs (<xref ref-type="supplementary-material" rid="S1">see SI</xref>
<xref ref-type="table" rid="t1">Table 1</xref>
for exact dual labelled lipid membranes compositions). TF-Chol and BT-PIP<sub>2</sub>
exhibited simultaneous quenching after addition of various concentration of FL-Gag, suggesting that TF-Chol and BT-PIP<sub>2</sub>
are co-clustered in Gag self-assembly induced nanodomains. In contrast, while BT-PIP<sub>2</sub>
was quenched as previously, TF-SPM exhibited a surprising apparent fluorescence unquenching after Gag addition. This was an unexpected result regarding the TF-SPM quenching induced by FL-Gag self-assembly in the presence of unlabelled PIP<sub>2</sub>
(<xref ref-type="fig" rid="f5">Fig. 5A</xref>
). Since this apparent unquenching of TF-SPM upon addition of FL-Gag only occurred when BT-PIP<sub>2</sub>
was present (see <xref ref-type="fig" rid="f5">Fig. 5A</xref>
vs <xref ref-type="fig" rid="f5">Fig. 5C</xref>
), we checked if TF-SPM (as a donor) and BT-PIP<sub>2</sub>
(as an acceptor) were able to exhibit FRET. Donor FRET efficiency has been shown to be a function of acceptor concentration in a lipid bilayer<xref ref-type="bibr" rid="b32">32</xref>
. This means that the FRET efficiency will decrease if acceptor (BT-PIP<sub>2</sub>
) local concentration decreases and that, as a consequence, the fluorescence of the donor (TF-SPM) will increase. We tested this by performing acceptor photobleaching experiments in order to decrease the acceptor concentration, locally and reversibly. We observed that, in the area where the acceptor (BT-PIP<sub>2</sub>
) was bleached, the fluorescence of the donor (TF-SPM) increased. This effect was abolished when concentrations were re-equilibrated by diffusion (<xref ref-type="supplementary-material" rid="S1">see SI</xref>
<xref ref-type="fig" rid="f3">Fig. 3</xref>
). In our TF-SPM/BT-PIP<sub>2</sub>
co-clustering assay, we observed a decrease in BT-PIP<sub>2</sub>
due to Gag self-assembly induced quenching and concomitantly, a non reversible TF-SPM fluorescence increase due to loss in FRET efficiency induced by decreasing concentration of acceptor (TF-PIP<sub>2</sub>
). This can only be explained by considering that Gag self-assembly clusters BT-PIP<sub>2</sub>
without TF-SPM.</p>
<p>Altogether, these results show that HIV-1 Gag self-assembly is generating common PIP<sub>2</sub>
and cholesterol nanodomains while excluding sphingomyelin.</p>
</sec>
<sec disp-level="2"><title>HIV-1 Gag is driving PIP<sub>2</sub>
and cholesterol nanoclustering independently of surrounding lipids</title>
<p>Because cellular PMs are complex lipid mixtures, we examined a possible role of this complexity on the lateral sorting of PIP<sub>2</sub>
, Chol and SPM during HIV-1 Gag self-assembly. For that purpose, we used the two other different lipid mixture mimicking either the inner leaflet of cells PM (“inner-leaflet”) or the “rafts” lipid mixture (“raft-mimicking”) (see <xref ref-type="table" rid="t1">Table 1</xref>
and SI Table 1 for detailed lipid composition). We first compared the effect of FL-Gag self-assembly on PIP<sub>2</sub>
clustering for these three lipid compositions. No characteristic change in TF-PIP<sub>2</sub>
fluorescence unquenching with increasing concentrations of FL-Gag (LUVs, <xref ref-type="fig" rid="f6">Fig. 6A</xref>
) or fluorescence quenching (SLBs, <xref ref-type="fig" rid="f6">Fig. 6B</xref>
) could be clearly detected amongst the three different lipid compositions. We then tested again Chol and SPM ability to partition into these FL-Gag induced PIP<sub>2</sub>
nanoclusters in the complex lipid mixtures. <xref ref-type="fig" rid="f6">Figure 6C</xref>
(TF-SPM/BT-PIP<sub>2</sub>
) and 6D (TF-Chol/BT-PIP<sub>2</sub>
) exhibited the same tendency for the fluorescence time courses of labelled lipid upon FL-Gag addition on SLBs, independently of the lipid composition.</p>
<p>These results show that, as in the “basic” composition, in complex lipid mixtures the PIP<sub>2</sub>
nanoclusters induced by Gag self assembly are enriched in Chol but not in SPM. This clearly suggest that Gag is sorting these lipids during self-assembly independently of the surrounding lipids chemical nature and acts as the driving force for lipid reorganization during HIV-1 assembly.</p>
</sec>
</sec>
<sec disp-level="1"><title>Discussion</title>
<p>Although the MA domain is primary responsible for HIV-1 Gag binding to the PM, the ten times higher apparent affinity for membrane models observed here in the case of FL-Gag, P39 and WM confirms that the NC domains and CA-CA self-assembly of Gag are involved in membrane binding efficiency. Indeed, the NC domain of Gag alone has recently been described to bind to PIP<sub>2</sub>
containing lipid membranes with an apparent <italic>K</italic>
<sub><italic>p</italic>
</sub>
as high as 7 <italic>μM</italic>
<xref ref-type="bibr" rid="b33">33</xref>
. It has also already been shown that the driving force for membrane association stems largely from ionic interactions between multimerized Gag and negatively charged phospholipids<xref ref-type="bibr" rid="b34">34</xref>
.</p>
<p>Using micrometer scale phase separated GUVs, we have observed that Gag was mainly partitioning in L<sub><italic>d</italic>
</sub>
phases, i.e., more likely outside of lipid “rafts” (namely Chol and SPM enriched) domains. The lack of myristate in the different Gag variants tested here could explain the Gag L<sub><italic>d</italic>
</sub>
phase localization<xref ref-type="bibr" rid="b35">35</xref>
. Nevertheless, our results are consistent with the L<sub><italic>d</italic>
</sub>
phase GUV localization of multimerizable myr(+)MA protein observed by Keller <italic>et al</italic>
.<xref ref-type="bibr" rid="b16">16</xref>
.</p>
<p>However, it is known that cholesterol is crucial for virus infectivity<xref ref-type="bibr" rid="b36">36</xref>
<xref ref-type="bibr" rid="b37">37</xref>
and that Gag can sense cholesterol<xref ref-type="bibr" rid="b38">38</xref>
<xref ref-type="bibr" rid="b39">39</xref>
. It was recently described that PIP<sub>2</sub>
could form clusters in the presence of cholesterol alone<xref ref-type="bibr" rid="b40">40</xref>
. Here we show that PIP<sub>2</sub>
and cholesterol are laterally redistributed upon Gag self-assembly on membranes and participate to the formation of cholesterol/PIP<sub>2</sub>
/Gag enriched nanodomains. Importantly, we also show that sphingomyelin is not sorted during HIV-1 Gag self-assembly and is excluded from the Gag/PIP<sub>2</sub>
/Chol nanoclusters. Taken together, these results suggest that binding and self-assembly of Gag protein does not occur in pre-existing lipid domains (such as “rafts”) but that this self-assembly is more likely to induce lipid nanodomains.</p>
<p>It is known that plasma membrane lipid organization is not only driven by lipid-lipid interactions. For example, cytoplasmic proteins such as ezrin<xref ref-type="bibr" rid="b41">41</xref>
<xref ref-type="bibr" rid="b42">42</xref>
, syntaxin-1<xref ref-type="bibr" rid="b43">43</xref>
have also been described to induce or interact with PIP<sub>2</sub>
nanoclusters. As a general mechanism, proteins with basic interfaces can recruit acidic lipids that, in turn, can facilitate recruitment and clustering of these proteins into nanodomains<xref ref-type="bibr" rid="b44">44</xref>
<xref ref-type="bibr" rid="b45">45</xref>
. A similar cooperative mechanism could also happen when HIV-1 Gag binds to PIP<sub>2</sub>
during viral assembly at the plasma membrane. Interestingly, mesoscale organized structures such as cortical actin network has also been shown to play an important role in the lateral organization of not only transmembrane proteins, but inner leaflet plasma membrane lipids such as PIP<sub>2</sub>
<xref ref-type="bibr" rid="b46">46</xref>
and more interestingly outer leaflet components such as GPi-anchored proteins<xref ref-type="bibr" rid="b47">47</xref>
. Moreover, this cortical actin network has also been shown to play a role in HIV-1 Gag assembly at the PM of Jurkat T-cells<xref ref-type="bibr" rid="b48">48</xref>
.</p>
<p>Since HIV-1 Gag has been often found in DRMs<xref ref-type="bibr" rid="b8">8</xref>
, pre-existing outer leaflet “rafts” could be trapped by these nascent PI(4,5)P<sub>2</sub>
-Gag nanodomains through transbilayer coupling - as we already proposed<xref ref-type="bibr" rid="b18">18</xref>
or as it has been recently shown for lipid domains<xref ref-type="bibr" rid="b49">49</xref>
and for outer leaflet GPi anchored proteins<xref ref-type="bibr" rid="b50">50</xref>
. Moreover, a recent study of the SPM dynamic in the cellular PM revealed that instead of clearly partitioning into nanodomains, SPM was mainly transiently trapped<xref ref-type="bibr" rid="b51">51</xref>
. In the case of the ganglioside GM1, another lipid described as partitioning into L<sub><italic>o</italic>
</sub>
phases, its transient trapping was shown to depend on molecular pinning and interleaflet coupling between lipid tail domains<xref ref-type="bibr" rid="b52">52</xref>
. This suggest that Gag could not only generates his own lipid nano-domains at the inner leaflet of the cellular PM but also induce the formation of domains in the outer leaflet of the cellular PM by transiently trapping SPM or other components.</p>
<p>Finally, we also observed that the matrix domain of Gag is not able to induce this PIP<sub>2</sub>
clustering, suggesting that, after maturation and particle release, the inner leaflet lipids of the virus envelope might be free to diffuse again.</p>
</sec>
<sec disp-level="1"><title>Conclusion</title>
<p>We have shown using simple and cell mimicking lipid composition model membranes that Gag self-assembly is inducing nano-clusters enriched in PIP<sub>2</sub>
and cholesterol, instead of partitioning to pre-existing ones. This lipid nano-clustering does not require sphingomyelin and mainly occurs out of the L<sub><italic>o</italic>
</sub>
phases in GUVs. Further, the different lipid composition tested here does not strikingly affect the capacity of Gag to induce these lipid nano-clusters suggesting that Gag is able to sort its own lipids independently of the surrounding lipids.</p>
</sec>
<sec disp-level="1"><title>Methods</title>
<p>All experiments were performed at room temperature (RT). Experimental buffer was Hepes 10 mM, pH = 7.4, KCl 150 mM, EDTA 2 mM except for QCM-D binding experiments. All images were acquired with a Zeiss LSM 780 microscope (Carl Zeiss, Inc.) using a 63x NA 1.4 oil objective and quantified using Image J software (NIH, MD, USA). Detailed materials, methods for model membranes (LUV, GUV, SLB) preparation and for protein purification are in SI.</p>
<sec disp-level="2"><title>Binding experiments</title>
<p>K<sub><italic>p</italic>
</sub>
were determined on basic lipid composition (EPC 68%, BPS 30% & PI(4,5)P<sub>2</sub>
2% for LUVs or POPC 68%, POPS 30% & PI(4,5)P<sub>2</sub>
2% for SLBs). Methods used were either cosedimentation assays for LUVs or QCM-D experiments on SLBs. Co-sedimentation assays were made at 1 <italic>μM</italic>
protein concentration with varying concentrations of total accessible lipids from 0.07 to 2250 <italic>μM</italic>
in 100 <italic>μl</italic>
of the same buffer that the one used in quenching experiments, according to the protocol in ref. <xref ref-type="bibr" rid="b53">53</xref>
. After 15 min of incubation at room temperature, samples were centrifuged at 220,000 g for 1 h at 4 °C using a Beckman Coulter’s TLA 100 rotor. The top 80 <italic>μl</italic>
was considered as supeRNAtant (S) and the remaining 20 <italic>μl</italic>
diluted with 60 <italic>μl</italic>
of working buffer as pellet (P). Pellet and supeRNAtant were analyzed on a 10% SDS-PAGE and stained using coomassie blue. Quantifications were made using Image J software (National Institutes of Health, MD, USA). SLBs were prepared with 0.1 mg.mL<sup>−1</sup>
liposomes flowing at 10 <italic>μ</italic>
L.min<sup>−1</sup>
for 10–20 min on a UV-treated SiO<sub>2</sub>
surface of Q-sensor fixed in a Q-Sense Flow module, QFM 401 Biolin Scientific, Sweden). Stable SLBs were rinsed with citrate buffer (NaCitrate 10 mM, 100 mM NaCl, and 0.5 mM EGTA, pH 4.6) and then with injection buffer (5 mM Tris & 100 mM NaCl pH 7.4). At equilibrium, 200 <italic>μ</italic>
L of increasing protein concentration was successively injected into the flow chamber followed by rinsing steps in between. The same was repeated with increasing protein concentrations until saturation. Sensorgrams were normalized to third harmonic in the case of varying harmonic curves. Δ<italic>F</italic>
(plateau values) were used to measure the lipid SLB surface fraction of protein bound. The fraction of protein bound is related to an apparent association constant <italic>K</italic>
(i.e, the reciprocal of the apparent partitioning constant, <italic>K</italic>
<sub><italic>p</italic>
</sub>
) following the equation:</p>
<p><disp-formula id="eq3"><inline-graphic id="d32e1055" xlink:href="srep39332-m3.jpg"></inline-graphic>
</disp-formula>
</p>
<p>where the percentage of protein bound is [<italic>PL</italic>
] = <italic>I</italic>
<sub><italic>Pellet</italic>
</sub>
/(<italic>I</italic>
<sub><italic>P</italic>
</sub>
+ <italic>I</italic>
<sub><italic>S</italic>
</sub>
) in the case of the co-sedimentation experiments (<italic>I</italic>
<sub><italic>P</italic>
</sub>
& <italic>I</italic>
<sub><italic>S</italic>
</sub>
experimental intensities of pellet and supeRNAtant and <italic>I</italic>
<sub><italic>Pellet</italic>
</sub>
= <italic>I</italic>
<sub><italic>P</italic>
</sub>
− 0.2.<italic>I</italic>
<sub><italic>S</italic>
</sub>
, for dilution compensation). In the case of QCM-d experiments, apparent <italic>K</italic>
<sub><italic>p</italic>
</sub>
values were obtained using <xref ref-type="disp-formula" rid="eq3">Eq. 1</xref>
formulated as a function of [<italic>P</italic>
] instead of [<italic>L</italic>
].</p>
</sec>
<sec disp-level="2"><title>Image analysis of GUVs</title>
<p>GUVs were deposited on coverslips coated with casein (2 mg.mL<sup>−1</sup>
) fitted in an Attofluor cell chamber (Thermo Fisher Scientific, Inc.). Labeled FL-Gag was added to the buffer. Spectral images were acquired at constant excitation intensity at 488 nm, 561 nm and 633 nm using an emission spectral range between 499 and 690 nm with a 8 nm resolution. Linear unmixing of these images was done to avoid potential bleed-through due to fluorophore emission overlapping. To establish the spatial auto-correlation of the fluorescence intensity of TF-PIP<sub>2</sub>
or A594-FL-Gag on basic composition GUVs, the change in intensity was plotted along the GUV using the following integration:</p>
<p><disp-formula id="eq4"><inline-graphic id="d32e1139" xlink:href="srep39332-m4.jpg"></inline-graphic>
</disp-formula>
</p>
<p>Intensity was plotted with <italic>r</italic>
. sin <italic>θ</italic>
as the length unit. The obtained curves were autocorrelated using either the autocorr or the xcorr function of Matlab R2015 (Mathworks<sup>®</sup>
).</p>
<p>Intensity partition of each label in the case of raft GUVs was determined using the following equations:</p>
<p><disp-formula id="eq5"><inline-graphic id="d32e1155" xlink:href="srep39332-m5.jpg"></inline-graphic>
</disp-formula>
</p>
<p><italic>θ</italic>
<sub><italic>i</italic>
</sub>
and <italic>θ</italic>
<sub><italic>o</italic>
</sub>
were determined with the help of Alexa647-CtxB intensity circular profile.</p>
</sec>
<sec disp-level="2"><title>Fluorescence quenching measurements</title>
<p>For LUV experiments, fluorescence was monitored using a spectrometer (Photon Technologies InteRNAtional, Inc.) with <italic>λ</italic>
<sub><italic>exc</italic>
</sub>
= 485 ± 2 <italic>nm</italic>
and <italic>λ</italic>
<sub><italic>em</italic>
</sub>
= 520 ± 10 <italic>nm</italic>
. Excitation lamp intensity was calibrated using the Raman spectrum of pure water and its fluctuations corrected every second. For every interaction assay on LUVs, the obtained intensity curve was corrected for both bleaching and dilution effect and then normalized to the mean intensity before injection. In the case of SLBs, fluorescence was monitored by acquiring images using the Zeiss definite focus system to avoid any z-drift with a 2-photons excitation (930 nm) every 5 s (in order to strongly reduce photobleaching). TF-lipids fluorescence was acquired at 520 ± 30 nm and BT-PIP<sub>2</sub>
at 600 ± 40. Mean intensity of each image was normalized to the intensity before injection.</p>
</sec>
<sec disp-level="2"><title>Self-assembly assay on LUVs</title>
<p>100 <italic>μ</italic>
L of the basic LUVs was incubated at room temperature for 15 min with either 0.9 <italic>μ</italic>
M or 4.5 <italic>μ</italic>
M of FL-Gag or WM. After centrifugation at 10,000 g for 5 min at 4 C, 20 <italic>μ</italic>
L of the supeRNAtant was loaded on a 10% native-PAGE and proceed for immunoblot as in ref. <xref ref-type="bibr" rid="b53">53</xref>
. FL-Gag and WM were detected by a primary anti-capsid antibody (HIV-1 p24 NIH AIDS Reagents) followed by secondary antibody goat anti-mouse HRP conjugated. Membrane was revealed by Femto substrate (Thermo-scientific) and imaged by a G:Box (Syngene).</p>
</sec>
<sec disp-level="2"><title>Fluorescence Recovery After Photobleaching</title>
<p>The image sequence was acquired at 20 Hz using the 488 nm line of an Ar<sup>+</sup>
laser at a very low power to avoid photobleaching. After 2.5 s, 3 regions of interests (ROI), of 1 <italic>μ</italic>
m radius each, were rapidly photobleached (t < 60 ms) at maximal laser power. Fluorescence recovery was monitored for 15 s. The recovery curves were obtained as in ref. <xref ref-type="bibr" rid="b54">54</xref>
. In order to correctly estimate <italic>F</italic>
<sub>0</sub>
(the fluorescence intensity immediately after the end of the bleach) and <italic>F</italic>
<sub>15<italic>s</italic>
</sub>
, the curves were fitted as in ref. <xref ref-type="bibr" rid="b54">54</xref>
. The normalized fractional recovery (<italic>NFR</italic>
), is defined as:</p>
<p><disp-formula id="eq6"><inline-graphic id="d32e1251" xlink:href="srep39332-m6.jpg"></inline-graphic>
</disp-formula>
</p>
</sec>
</sec>
<sec disp-level="1"><title>Additional Information</title>
<p><bold>How to cite this article</bold>
: Yandrapalli, N. <italic>et al</italic>
. Self assembly of HIV-1 Gag protein on lipid membranes generates PI(4,5)P<sub>2</sub>
/Cholesterol nanoclusters. <italic>Sci. Rep.</italic>
<bold>6</bold>
, 39332; doi: 10.1038/srep39332 (2016).</p>
<p><bold>Publisher's note:</bold>
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.</p>
</sec>
<sec sec-type="supplementary-material" id="S1"><title>Supplementary Material</title>
<supplementary-material id="d32e36" content-type="local-data"><caption><title>Supplementary Information</title>
</caption>
<media xlink:href="srep39332-s1.pdf"></media>
</supplementary-material>
</sec>
</body>
<back><ack><p>We are thankful to Dr. Olivier Coux for his help with protein purification and Dr. Michel Franco for the gift of PH-EFA6 plasmid. We thank the Montpellier RIO Imaging (MRI) microscopy facilities. This work has been funded by ANR (ANR-13-BSV5-0006-01). C.P. acknowledges the European Commission (FP7) for a grant from the European Research Council (GA259370). N.Y. is a recipient of the European Community Erasmus Mundus PhD fellowship. C.F. and D.M. are part of the CNRS GDR MIV consortium.</p>
</ack>
<ref-list><ref id="b1"><mixed-citation publication-type="journal"><name><surname>Balasubramaniam</surname>
<given-names>M.</given-names>
</name>
& <name><surname>Freed</surname>
<given-names>E. O.</given-names>
</name>
<article-title>New insights into HIV assembly and trafficking</article-title>
. <source>Physiology (Bethesda)</source>
<volume>26</volume>
, <fpage>236</fpage>
–<lpage>251</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1152/physiol.00051.2010">http://dx.doi.org/10.1152/physiol.00051.2010</ext-link>
(<year>2011</year>
).<pub-id pub-id-type="pmid">21841072</pub-id>
</mixed-citation>
</ref>
<ref id="b2"><mixed-citation publication-type="journal"><name><surname>Bieniasz</surname>
<given-names>P. D.</given-names>
</name>
<article-title>The cell biology of HIV-1 virion genesis</article-title>
. <source>Cell Host Microbe</source>
<volume>5</volume>
, <fpage>550</fpage>
–<lpage>558</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.chom.2009.05.015">http://dx.doi.org/10.1016/j.chom.2009.05.015</ext-link>
(<year>2009</year>
).<pub-id pub-id-type="pmid">19527882</pub-id>
</mixed-citation>
</ref>
<ref id="b3"><mixed-citation publication-type="journal"><name><surname>Muriaux</surname>
<given-names>D.</given-names>
</name>
& <name><surname>Darlix</surname>
<given-names>J.-L.</given-names>
</name>
<article-title>Properties and functions of the nucleocapsid protein in virus assembly</article-title>
. <source>RNA Biol</source>
<volume>7</volume>
, <fpage>744</fpage>
–<lpage>753</lpage>
(<year>2010</year>
).<pub-id pub-id-type="pmid">21157181</pub-id>
</mixed-citation>
</ref>
<ref id="b4"><mixed-citation publication-type="journal"><name><surname>Hendrix</surname>
<given-names>J.</given-names>
</name>
<etal></etal>
. <article-title>Live-cell observation of cytosolic HIV-1 assembly onset reveals RNA-interacting Gag oligomers</article-title>
. <source>J Cell Biol</source>
<volume>210</volume>
, <fpage>629</fpage>
–<lpage>646</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1083/jcb.201504006">http://dx.doi.org/10.1083/jcb.201504006</ext-link>
(<year>2015</year>
).<pub-id pub-id-type="pmid">26283800</pub-id>
</mixed-citation>
</ref>
<ref id="b5"><mixed-citation publication-type="journal"><name><surname>Saad</surname>
<given-names>J. S.</given-names>
</name>
<etal></etal>
. <article-title>Structural basis for targeting HIV-1 Gag proteins to the plasma membrane for virus assembly</article-title>
. <source>Proc Natl Acad Sci USA</source>
<volume>103</volume>
, <fpage>11364</fpage>
–<lpage>11369</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1073/pnas.0602818103">http://dx.doi.org/10.1073/pnas.0602818103</ext-link>
(<year>2006</year>
).<pub-id pub-id-type="pmid">16840558</pub-id>
</mixed-citation>
</ref>
<ref id="b6"><mixed-citation publication-type="journal"><name><surname>Ono</surname>
<given-names>A.</given-names>
</name>
, <name><surname>Ablan</surname>
<given-names>S. D.</given-names>
</name>
, <name><surname>Lockett</surname>
<given-names>S. J.</given-names>
</name>
, <name><surname>Nagashima</surname>
<given-names>K.</given-names>
</name>
& <name><surname>Freed</surname>
<given-names>E. O.</given-names>
</name>
<article-title>Phosphatidylinositol (4,5) bisphosphate regulates HIV-1 Gag targeting to the plasma membrane</article-title>
. <source>Proc Natl Acad Sci USA</source>
<volume>101</volume>
, <fpage>14889</fpage>
–<lpage>14894</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1073/pnas.0405596101">http://dx.doi.org/10.1073/pnas.0405596101</ext-link>
(<year>2004</year>
).<pub-id pub-id-type="pmid">15465916</pub-id>
</mixed-citation>
</ref>
<ref id="b7"><mixed-citation publication-type="journal"><name><surname>Chan</surname>
<given-names>R.</given-names>
</name>
<etal></etal>
. <article-title>Retroviruses human immunodeficiency virus and murine leukemia virus are enriched in phosphoinositides</article-title>
. <source>J Virol</source>
<volume>82</volume>
, <fpage>11228</fpage>
–<lpage>11238</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.00981-08">http://dx.doi.org/10.1128/JVI.00981-08</ext-link>
(<year>2008</year>
).<pub-id pub-id-type="pmid">18799574</pub-id>
</mixed-citation>
</ref>
<ref id="b8"><mixed-citation publication-type="journal"><name><surname>Ono</surname>
<given-names>A.</given-names>
</name>
& <name><surname>Freed</surname>
<given-names>E. O.</given-names>
</name>
<article-title>Plasma membrane rafts play a critical role in HIV-1 assembly and release</article-title>
. <source>Proc Natl Acad Sci USA</source>
<volume>98</volume>
, <fpage>13925</fpage>
–<lpage>13930</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1073/pnas.241320298">http://dx.doi.org/10.1073/pnas.241320298</ext-link>
(<year>2001</year>
).<pub-id pub-id-type="pmid">11717449</pub-id>
</mixed-citation>
</ref>
<ref id="b9"><mixed-citation publication-type="journal"><name><surname>Callahan</surname>
<given-names>E. M.</given-names>
</name>
& <name><surname>Wills</surname>
<given-names>J. W.</given-names>
</name>
<article-title>Repositioning basic residues in the M domain of the rous sarcoma virus Gag protein</article-title>
. <source>J Virol</source>
<volume>74</volume>
, <fpage>11222</fpage>
–<lpage>11229</lpage>
(<year>2000</year>
).<pub-id pub-id-type="pmid">11070020</pub-id>
</mixed-citation>
</ref>
<ref id="b10"><mixed-citation publication-type="journal"><name><surname>Holm</surname>
<given-names>K.</given-names>
</name>
, <name><surname>Weclewicz</surname>
<given-names>K.</given-names>
</name>
, <name><surname>Hewson</surname>
<given-names>R.</given-names>
</name>
& <name><surname>Suomalainen</surname>
<given-names>M.</given-names>
</name>
<article-title>Human immunodeficiency virus type 1 assembly and lipid rafts: Pr55(Gag) associates with membrane domains that are largely resistant to brij98 but sensitive to triton x-100</article-title>
. <source>J Virol</source>
<volume>77</volume>
, <fpage>4805</fpage>
–<lpage>4817</lpage>
(<year>2003</year>
).<pub-id pub-id-type="pmid">12663787</pub-id>
</mixed-citation>
</ref>
<ref id="b11"><mixed-citation publication-type="journal"><name><surname>Campbell</surname>
<given-names>S.</given-names>
</name>
<etal></etal>
. <article-title>The raft-promoting property of virion-associated cholesterol, but not the presence of virion-associated brij 98 rafts, is a determinant of human immunodeficiency virus type 1 infectivity</article-title>
. <source>J Virol</source>
<volume>78</volume>
, <fpage>10556</fpage>
–<lpage>10565</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.78.19.10556-10565.2004">http://dx.doi.org/10.1128/JVI.78.19.10556-10565.2004</ext-link>
(<year>2004</year>
).<pub-id pub-id-type="pmid">15367622</pub-id>
</mixed-citation>
</ref>
<ref id="b12"><mixed-citation publication-type="journal"><name><surname>Pike</surname>
<given-names>L. J.</given-names>
</name>
<article-title>Rafts defined: a report on the keystone symposium on lipid rafts and cell function</article-title>
. <source>J Lipid Res</source>
<volume>47</volume>
, <fpage>1597</fpage>
–<lpage>1598</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1194/jlr.E600002-JLR200">http://dx.doi.org/10.1194/jlr.E600002-JLR200</ext-link>
(<year>2006</year>
).<pub-id pub-id-type="pmid">16645198</pub-id>
</mixed-citation>
</ref>
<ref id="b13"><mixed-citation publication-type="journal"><name><surname>Sengupta</surname>
<given-names>P.</given-names>
</name>
, <name><surname>Hammond</surname>
<given-names>A.</given-names>
</name>
, <name><surname>Holowka</surname>
<given-names>D.</given-names>
</name>
& <name><surname>Baird</surname>
<given-names>B.</given-names>
</name>
<article-title>Structural determinants for partitioning of lipids and proteins between coexisting fluid phases in giant plasma membrane vesicles</article-title>
. <source>Biochimica et Biophysica Acta (BBA) - Biomembranes</source>
<volume>1778</volume>
, <fpage>20</fpage>
–<lpage>32</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://www.sciencedirect.com/science/article/pii/S0005273607003240">http://www.sciencedirect.com/science/article/pii/S0005273607003240</ext-link>
(<year>2008</year>
).<pub-id pub-id-type="pmid">17936718</pub-id>
</mixed-citation>
</ref>
<ref id="b14"><mixed-citation publication-type="journal"><name><surname>Charlier</surname>
<given-names>L.</given-names>
</name>
<etal></etal>
. <article-title>Coarse-grained simulations of the HIV-1 matrix protein anchoring: revisiting its assembly on membrane domains</article-title>
. <source>Biophys J</source>
<volume>106</volume>
, <fpage>577</fpage>
–<lpage>585</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.bpj.2013.12.019">http://dx.doi.org/10.1016/j.bpj.2013.12.019</ext-link>
(<year>2014</year>
).<pub-id pub-id-type="pmid">24507598</pub-id>
</mixed-citation>
</ref>
<ref id="b15"><mixed-citation publication-type="journal"><name><surname>Mercredi</surname>
<given-names>P. Y.</given-names>
</name>
<etal></etal>
. <article-title>Structural and molecular determinants of membrane binding by the HIV-1 matrix protein</article-title>
. <source>J Mol Biol</source>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.jmb.2016.03.005">http://dx.doi.org/10.1016/j.jmb.2016.03.005</ext-link>
(<year>2016</year>
).</mixed-citation>
</ref>
<ref id="b16"><mixed-citation publication-type="journal"><name><surname>Keller</surname>
<given-names>H.</given-names>
</name>
, <name><surname>Kräusslich</surname>
<given-names>H.-G.</given-names>
</name>
& <name><surname>Schwille</surname>
<given-names>P.</given-names>
</name>
<article-title>Multimerizable HIV Gag derivative binds to the liquid-disordered phase in model membranes</article-title>
. <source>Cell Microbiol</source>
<volume>15</volume>
, <fpage>237</fpage>
–<lpage>247</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1111/cmi.12064">http://dx.doi.org/10.1111/cmi.12064</ext-link>
(<year>2013</year>
).<pub-id pub-id-type="pmid">23121220</pub-id>
</mixed-citation>
</ref>
<ref id="b17"><mixed-citation publication-type="journal"><name><surname>Wen</surname>
<given-names>Y.</given-names>
</name>
, <name><surname>Dick</surname>
<given-names>R.</given-names>
</name>
, <name><surname>Feigenson</surname>
<given-names>G.</given-names>
</name>
& <name><surname>Vogt</surname>
<given-names>V.</given-names>
</name>
<article-title>Effects of membrane charge and order on membrane binding of the retroviral structural protein gag</article-title>
. <source>J Virol</source>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.01102-16">http://dx.doi.org/10.1128/JVI.01102-16</ext-link>
(<year>2016</year>
).</mixed-citation>
</ref>
<ref id="b18"><mixed-citation publication-type="journal"><name><surname>Kerviel</surname>
<given-names>A.</given-names>
</name>
, <name><surname>Thomas</surname>
<given-names>A.</given-names>
</name>
, <name><surname>Chaloin</surname>
<given-names>L.</given-names>
</name>
, <name><surname>Favard</surname>
<given-names>C.</given-names>
</name>
& <name><surname>Muriaux</surname>
<given-names>D.</given-names>
</name>
<article-title>Virus assembly and plasma membrane domains: which came first?</article-title>
<source>Virus Res</source>
<volume>171</volume>
, <fpage>332</fpage>
–<lpage>340</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.virusres.2012.08.014">http://dx.doi.org/10.1016/j.virusres.2012.08.014</ext-link>
(<year>2013</year>
).<pub-id pub-id-type="pmid">22989508</pub-id>
</mixed-citation>
</ref>
<ref id="b19"><mixed-citation publication-type="journal"><name><surname>Wawrezinieck</surname>
<given-names>L.</given-names>
</name>
, <name><surname>Rigneault</surname>
<given-names>H.</given-names>
</name>
, <name><surname>Marguet</surname>
<given-names>D.</given-names>
</name>
& <name><surname>Lenne</surname>
<given-names>P.-F.</given-names>
</name>
<article-title>Fluorescence correlation spectroscopy diffusion laws to probe the submicron cell membrane organization</article-title>
. <source>Biophys J</source>
<volume>89</volume>
, <fpage>4029</fpage>
–<lpage>4042</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1529/biophysj.105.067959">http://dx.doi.org/10.1529/biophysj.105.067959</ext-link>
(<year>2005</year>
).<pub-id pub-id-type="pmid">16199500</pub-id>
</mixed-citation>
</ref>
<ref id="b20"><mixed-citation publication-type="journal"><name><surname>Favard</surname>
<given-names>C.</given-names>
</name>
, <name><surname>Wenger</surname>
<given-names>J.</given-names>
</name>
, <name><surname>Lenne</surname>
<given-names>P.-F.</given-names>
</name>
& <name><surname>Rigneault</surname>
<given-names>H.</given-names>
</name>
<article-title>FCS diffusion laws in two-phase lipid membranes: determination of domain mean size by experiments and Monte Carlo simulations</article-title>
. <source>Biophys J</source>
<volume>100</volume>
, <fpage>1242</fpage>
–<lpage>1251</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.bpj.2010.12.3738">http://dx.doi.org/10.1016/j.bpj.2010.12.3738</ext-link>
(<year>2011</year>
).<pub-id pub-id-type="pmid">21354397</pub-id>
</mixed-citation>
</ref>
<ref id="b21"><mixed-citation publication-type="journal"><name><surname>Eggeling</surname>
<given-names>C.</given-names>
</name>
<etal></etal>
. <article-title>Direct observation of the nanoscale dynamics of membrane lipids in a living cell</article-title>
. <source>Nature</source>
<volume>457</volume>
, <fpage>1159</fpage>
–<lpage>1162</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1038/nature07596">http://dx.doi.org/10.1038/nature07596</ext-link>
(<year>2009</year>
).<pub-id pub-id-type="pmid">19098897</pub-id>
</mixed-citation>
</ref>
<ref id="b22"><mixed-citation publication-type="journal"><name><surname>Andrade</surname>
<given-names>D. M.</given-names>
</name>
<etal></etal>
. <article-title>Cortical actin networks induce spatio-temporal confinement of phospholipids in the plasma membrane-a minimally invasive investigation by STED-FCS</article-title>
. <source>Sci Rep</source>
<volume>5</volume>
, <fpage>11454</fpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1038/srep11454">http://dx.doi.org/10.1038/srep11454</ext-link>
(<year>2015</year>
).<pub-id pub-id-type="pmid">26118385</pub-id>
</mixed-citation>
</ref>
<ref id="b23"><mixed-citation publication-type="journal"><name><surname>Wu</surname>
<given-names>H.-M.</given-names>
</name>
, <name><surname>Lin</surname>
<given-names>Y.-H.</given-names>
</name>
, <name><surname>Yen</surname>
<given-names>T.-C.</given-names>
</name>
& <name><surname>Hsieh</surname>
<given-names>C.-L.</given-names>
</name>
<article-title>Nanoscopic substructures of raft-mimetic liquid-ordered membrane domains revealed by high-speed single-particle tracking</article-title>
. <source>Sci Rep</source>
<volume>6</volume>
, <fpage>20542</fpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1038/srep20542">http://dx.doi.org/10.1038/srep20542</ext-link>
(<year>2016</year>
).<pub-id pub-id-type="pmid">26861908</pub-id>
</mixed-citation>
</ref>
<ref id="b24"><mixed-citation publication-type="journal"><name><surname>Gambhir</surname>
<given-names>A.</given-names>
</name>
<etal></etal>
. <article-title>Electrostatic sequestration of PIP2 on phospholipid membranes by basic/aromatic regions of proteins</article-title>
. <source>Biophys J</source>
<volume>86</volume>
, <fpage>2188</fpage>
–<lpage>2207</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/S0006-3495(04)74278-2">http://dx.doi.org/10.1016/S0006-3495(04)74278-2</ext-link>
(<year>2004</year>
).<pub-id pub-id-type="pmid">15041659</pub-id>
</mixed-citation>
</ref>
<ref id="b25"><mixed-citation publication-type="journal"><name><surname>Puff</surname>
<given-names>N.</given-names>
</name>
, <name><surname>Watanabe</surname>
<given-names>C.</given-names>
</name>
, <name><surname>Seigneuret</surname>
<given-names>M.</given-names>
</name>
, <name><surname>Angelova</surname>
<given-names>M. I.</given-names>
</name>
& <name><surname>Staneva</surname>
<given-names>G.</given-names>
</name>
<article-title>Lo/Ld phase coexistence modulation induced by GM1</article-title>
. <source>Biochim Biophys Acta</source>
<volume>1838</volume>
, <fpage>2105</fpage>
–<lpage>2114</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.bbamem.2014.05.002">http://dx.doi.org/10.1016/j.bbamem.2014.05.002</ext-link>
(<year>2014</year>
).<pub-id pub-id-type="pmid">24835016</pub-id>
</mixed-citation>
</ref>
<ref id="b26"><mixed-citation publication-type="journal"><name><surname>Heberle</surname>
<given-names>F. A.</given-names>
</name>
, <name><surname>Wu</surname>
<given-names>J.</given-names>
</name>
, <name><surname>Goh</surname>
<given-names>S. L.</given-names>
</name>
, <name><surname>Petruzielo</surname>
<given-names>R. S.</given-names>
</name>
& <name><surname>Feigenson</surname>
<given-names>G. W.</given-names>
</name>
<article-title>Comparison of three teRNAry lipid bilayer mixtures: FRET and ESR reveal nanodomains</article-title>
. <source>Biophys J</source>
<volume>99</volume>
, <fpage>3309</fpage>
–<lpage>3318</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.bpj.2010.09.064">http://dx.doi.org/10.1016/j.bpj.2010.09.064</ext-link>
(<year>2010</year>
).<pub-id pub-id-type="pmid">21081079</pub-id>
</mixed-citation>
</ref>
<ref id="b27"><mixed-citation publication-type="journal"><name><surname>Chukkapalli</surname>
<given-names>V.</given-names>
</name>
, <name><surname>Hogue</surname>
<given-names>I. B.</given-names>
</name>
, <name><surname>Boyko</surname>
<given-names>V.</given-names>
</name>
, <name><surname>Hu</surname>
<given-names>W.-S.</given-names>
</name>
& <name><surname>Ono</surname>
<given-names>A.</given-names>
</name>
<article-title>Interaction between the human immunodeficiency virus type 1 Gag matrix domain and phosphatidylinositol-(4,5)-bisphosphate is essential for efficient Gag membrane binding</article-title>
. <source>J Virol</source>
<volume>82</volume>
, <fpage>2405</fpage>
–<lpage>2417</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.01614-07">http://dx.doi.org/10.1128/JVI.01614-07</ext-link>
(<year>2008</year>
).<pub-id pub-id-type="pmid">18094158</pub-id>
</mixed-citation>
</ref>
<ref id="b28"><mixed-citation publication-type="journal"><name><surname>Ingólfsson</surname>
<given-names>H. I.</given-names>
</name>
<etal></etal>
. <article-title>Lipid organization of the plasma membrane</article-title>
. <source>J Am Chem Soc</source>
<volume>136</volume>
, <fpage>14554</fpage>
–<lpage>14559</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1021/ja507832e">http://dx.doi.org/10.1021/ja507832e</ext-link>
(<year>2014</year>
).<pub-id pub-id-type="pmid">25229711</pub-id>
</mixed-citation>
</ref>
<ref id="b29"><mixed-citation publication-type="journal"><name><surname>Datta</surname>
<given-names>S. A. K.</given-names>
</name>
<etal></etal>
. <article-title>Conformation of the HIV-1 Gag protein in solution</article-title>
. <source>J Mol Biol</source>
<volume>365</volume>
, <fpage>812</fpage>
–<lpage>824</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.jmb.2006.10.073">http://dx.doi.org/10.1016/j.jmb.2006.10.073</ext-link>
. (<year>2007</year>
).<pub-id pub-id-type="pmid">17097677</pub-id>
</mixed-citation>
</ref>
<ref id="b30"><mixed-citation publication-type="journal"><name><surname>Macia</surname>
<given-names>E.</given-names>
</name>
<etal></etal>
. <article-title>The pleckstrin homology domain of the Arf6-specific exchange factor EFA6 localizes to the plasma membrane by interacting with phosphatidylinositol 4,5-bisphosphate and F-actin</article-title>
. <source>J Biol Chem</source>
<volume>283</volume>
, <fpage>19836</fpage>
–<lpage>19844</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1074/jbc.M800781200">http://dx.doi.org/10.1074/jbc.M800781200</ext-link>
(<year>2008</year>
).<pub-id pub-id-type="pmid">18490450</pub-id>
</mixed-citation>
</ref>
<ref id="b31"><mixed-citation publication-type="journal"><name><surname>Momany</surname>
<given-names>C.</given-names>
</name>
<etal></etal>
. <article-title>Crystal structure of dimeric HIV-1 capsid protein</article-title>
. <source>Nat Struct Biol</source>
<volume>3</volume>
, <fpage>763</fpage>
–<lpage>770</lpage>
(<year>1996</year>
).<pub-id pub-id-type="pmid">8784350</pub-id>
</mixed-citation>
</ref>
<ref id="b32"><mixed-citation publication-type="journal"><name><surname>Fung</surname>
<given-names>B. K.</given-names>
</name>
& <name><surname>Stryer</surname>
<given-names>L.</given-names>
</name>
<article-title>Surface density determination in membranes by fluorescence energy transfer</article-title>
. <source>Biochemistry</source>
<volume>17</volume>
, <fpage>5241</fpage>
–<lpage>5248</lpage>
(<year>1978</year>
).<pub-id pub-id-type="pmid">728398</pub-id>
</mixed-citation>
</ref>
<ref id="b33"><mixed-citation publication-type="journal"><name><surname>Kempf</surname>
<given-names>N.</given-names>
</name>
<etal></etal>
. <article-title>The HIV-1 nucleocapsid protein recruits negatively charged lipids to ensure its optimal binding to lipid membranes</article-title>
. <source>J Virol</source>
<volume>89</volume>
, <fpage>1756</fpage>
–<lpage>1767</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.02931-14">http://dx.doi.org/10.1128/JVI.02931-14</ext-link>
(<year>2015</year>
).<pub-id pub-id-type="pmid">25410868</pub-id>
</mixed-citation>
</ref>
<ref id="b34"><mixed-citation publication-type="journal"><name><surname>Dalton</surname>
<given-names>A. K.</given-names>
</name>
, <name><surname>Ako-Adjei</surname>
<given-names>D.</given-names>
</name>
, <name><surname>Murray</surname>
<given-names>P. S.</given-names>
</name>
, <name><surname>Murray</surname>
<given-names>D.</given-names>
</name>
& <name><surname>Vogt</surname>
<given-names>V. M.</given-names>
</name>
<article-title>Electrostatic interactions drive membrane association of the human immunodeficiency virus type 1 Gag MA domain</article-title>
. <source>J Virol</source>
<volume>81</volume>
, <fpage>6434</fpage>
–<lpage>6445</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.02757-06">http://dx.doi.org/10.1128/JVI.02757-06</ext-link>
(<year>2007</year>
).<pub-id pub-id-type="pmid">17392361</pub-id>
</mixed-citation>
</ref>
<ref id="b35"><mixed-citation publication-type="journal"><name><surname>Lindwasser</surname>
<given-names>O. W.</given-names>
</name>
& <name><surname>Resh</surname>
<given-names>M. D.</given-names>
</name>
<article-title>Myristoylation as a target for inhibiting HIV assembly: unsaturated fatty acids block viral budding</article-title>
. <source>Proc Natl Acad Sci USA</source>
<volume>99</volume>
, <fpage>13037</fpage>
–<lpage>13042</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1073/pnas.212409999">http://dx.doi.org/10.1073/pnas.212409999</ext-link>
(<year>2002</year>
).<pub-id pub-id-type="pmid">12244217</pub-id>
</mixed-citation>
</ref>
<ref id="b36"><mixed-citation publication-type="journal"><name><surname>Hawkes</surname>
<given-names>D.</given-names>
</name>
<etal></etal>
. <article-title>Properties of HIV-1 associated cholesterol in addition to raft formation are important for virus infection</article-title>
. <source>Virus Res</source>
<volume>210</volume>
, <fpage>18</fpage>
–<lpage>21</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.virusres.2015.06.023">http://dx.doi.org/10.1016/j.virusres.2015.06.023</ext-link>
(<year>2015</year>
).<pub-id pub-id-type="pmid">26191619</pub-id>
</mixed-citation>
</ref>
<ref id="b37"><mixed-citation publication-type="journal"><name><surname>Campbell</surname>
<given-names>S. M.</given-names>
</name>
, <name><surname>Crowe</surname>
<given-names>S. M.</given-names>
</name>
& <name><surname>Mak</surname>
<given-names>J.</given-names>
</name>
<article-title>Virion-associated cholesterol is critical for the maintenance of HIV-1 structure and infectivity</article-title>
. <source>AIDS</source>
<volume>16</volume>
, <fpage>2253</fpage>
–<lpage>2261</lpage>
(<year>2002</year>
).<pub-id pub-id-type="pmid">12441796</pub-id>
</mixed-citation>
</ref>
<ref id="b38"><mixed-citation publication-type="journal"><name><surname>Dick</surname>
<given-names>R. A.</given-names>
</name>
, <name><surname>Goh</surname>
<given-names>S. L.</given-names>
</name>
, <name><surname>Feigenson</surname>
<given-names>G. W.</given-names>
</name>
& <name><surname>Vogt</surname>
<given-names>V. M.</given-names>
</name>
<article-title>HIV-1 Gag protein can sense the cholesterol and acyl chain environment in model membranes</article-title>
. <source>Proc Natl Acad Sci USA</source>
<volume>109</volume>
, <fpage>18761</fpage>
–<lpage>18766</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1073/pnas.1209408109">http://dx.doi.org/10.1073/pnas.1209408109</ext-link>
(<year>2012</year>
).<pub-id pub-id-type="pmid">23010924</pub-id>
</mixed-citation>
</ref>
<ref id="b39"><mixed-citation publication-type="journal"><name><surname>Barros</surname>
<given-names>M.</given-names>
</name>
<etal></etal>
. <article-title>Membrane binding of HIV-1 matrix protein: Dependence on bilayer composition and protein lipidation</article-title>
. <source>J Virol</source>
<volume>90</volume>
, <fpage>4544</fpage>
–<lpage>4555</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.02820-15">http://dx.doi.org/10.1128/JVI.02820-15</ext-link>
(<year>2016</year>
).<pub-id pub-id-type="pmid">26912608</pub-id>
</mixed-citation>
</ref>
<ref id="b40"><mixed-citation publication-type="journal"><name><surname>Jiang</surname>
<given-names>Z.</given-names>
</name>
, <name><surname>Redfern</surname>
<given-names>R. E.</given-names>
</name>
, <name><surname>Isler</surname>
<given-names>Y.</given-names>
</name>
, <name><surname>Ross</surname>
<given-names>A. H.</given-names>
</name>
& <name><surname>Gericke</surname>
<given-names>A.</given-names>
</name>
<article-title>Cholesterol stabilizes fluid phosphoinositide domains</article-title>
. <source>Chem Phys Lipids</source>
<volume>182</volume>
, <fpage>52</fpage>
–<lpage>61</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.chemphyslip.2014.02.003">http://dx.doi.org/10.1016/j.chemphyslip.2014.02.003</ext-link>
(<year>2014</year>
).<pub-id pub-id-type="pmid">24556334</pub-id>
</mixed-citation>
</ref>
<ref id="b41"><mixed-citation publication-type="journal"><name><surname>Chen</surname>
<given-names>X.</given-names>
</name>
<etal></etal>
. <article-title>Phosphatidylinositol 4,5-bisphosphate clusters the cell adhesion molecule CD44 and assembles a specific CD44-Ezrin heterocomplex, as revealed by small angle neutron scattering</article-title>
. <source>J Biol Chem</source>
<volume>290</volume>
, <fpage>6639</fpage>
–<lpage>6652</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1074/jbc.M114.589523">http://dx.doi.org/10.1074/jbc.M114.589523</ext-link>
(<year>2015</year>
).<pub-id pub-id-type="pmid">25572402</pub-id>
</mixed-citation>
</ref>
<ref id="b42"><mixed-citation publication-type="journal"><name><surname>Al-Momany</surname>
<given-names>A.</given-names>
</name>
, <name><surname>Li</surname>
<given-names>L.</given-names>
</name>
, <name><surname>Alexander</surname>
<given-names>R. T.</given-names>
</name>
& <name><surname>Ballermann</surname>
<given-names>B. J.</given-names>
</name>
<article-title>Clustered PI(4,5)P2 accumulation and Ezrin phosphorylation in response to Clic5a</article-title>
. <source>J Cell Sci</source>
<volume>127</volume>
, <fpage>5164</fpage>
–<lpage>5178</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1242/jcs.147744">http://dx.doi.org/10.1242/jcs.147744</ext-link>
(<year>2014</year>
).<pub-id pub-id-type="pmid">25344252</pub-id>
</mixed-citation>
</ref>
<ref id="b43"><mixed-citation publication-type="journal"><name><surname>Honigmann</surname>
<given-names>A.</given-names>
</name>
<etal></etal>
. <article-title>Phosphatidylinositol 4,5-bisphosphate clusters act as molecular beacons for vesicle recruitment</article-title>
. <source>Nat Struct Mol Biol</source>
<volume>20</volume>
, <fpage>679</fpage>
–<lpage>686</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1038/nsmb.2570">http://dx.doi.org/10.1038/nsmb.2570</ext-link>
. (<year>2013</year>
).<pub-id pub-id-type="pmid">23665582</pub-id>
</mixed-citation>
</ref>
<ref id="b44"><mixed-citation publication-type="journal"><name><surname>van den Bogaart</surname>
<given-names>G.</given-names>
</name>
<etal></etal>
. <article-title>Membrane protein sequestering by ionic protein-lipid interactions</article-title>
. <source>Nature</source>
<volume>479</volume>
, <fpage>552</fpage>
–<lpage>555</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1038/nature10545">http://dx.doi.org/10.1038/nature10545</ext-link>
(<year>2011</year>
).<pub-id pub-id-type="pmid">22020284</pub-id>
</mixed-citation>
</ref>
<ref id="b45"><mixed-citation publication-type="journal"><name><surname>McLaughlin</surname>
<given-names>S.</given-names>
</name>
& <name><surname>Murray</surname>
<given-names>D.</given-names>
</name>
<article-title>Plasma membrane phosphoinositide organization by protein electrostatics</article-title>
. <source>Nature</source>
<volume>438</volume>
, <fpage>605</fpage>
–<lpage>611</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1038/nature04398">http://dx.doi.org/10.1038/nature04398</ext-link>
(<year>2005</year>
).<pub-id pub-id-type="pmid">16319880</pub-id>
</mixed-citation>
</ref>
<ref id="b46"><mixed-citation publication-type="journal"><name><surname>Golebiewska</surname>
<given-names>U.</given-names>
</name>
<etal></etal>
. <article-title>Evidence for a fence that impedes the diffusion of phosphatidylinositol 4,5-bisphosphate out of the forming phagosomes of macrophages</article-title>
. <source>Mol Biol Cell</source>
<volume>22</volume>
, <fpage>3498</fpage>
–<lpage>3507</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1091/mbc.E11-02-0114">http://dx.doi.org/10.1091/mbc.E11-02-0114</ext-link>
(<year>2011</year>
).<pub-id pub-id-type="pmid">21795401</pub-id>
</mixed-citation>
</ref>
<ref id="b47"><mixed-citation publication-type="journal"><name><surname>Goswami</surname>
<given-names>D.</given-names>
</name>
<etal></etal>
. <article-title>Nanoclusters of GPi-anchored proteins are formed by cortical actin-driven activity</article-title>
. <source>Cell</source>
<volume>135</volume>
, <fpage>1085</fpage>
–<lpage>1097</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.cell.2008.11.032">http://dx.doi.org/10.1016/j.cell.2008.11.032</ext-link>
(<year>2008</year>
).<pub-id pub-id-type="pmid">19070578</pub-id>
</mixed-citation>
</ref>
<ref id="b48"><mixed-citation publication-type="journal"><name><surname>Thomas</surname>
<given-names>A.</given-names>
</name>
<etal></etal>
. <article-title>Involvement of the Rac1-IRSp53-Wave2-Arp2/3 signaling pathway in HIV-1 Gag particle release in CD4 T cells</article-title>
. <source>J Virol</source>
<volume>89</volume>
, <fpage>8162</fpage>
–<lpage>8181</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.00469-15">http://dx.doi.org/10.1128/JVI.00469-15</ext-link>
(<year>2015</year>
).<pub-id pub-id-type="pmid">26018170</pub-id>
</mixed-citation>
</ref>
<ref id="b49"><mixed-citation publication-type="journal"><name><surname>Blosser</surname>
<given-names>M. C.</given-names>
</name>
, <name><surname>Honerkamp-Smith</surname>
<given-names>A. R.</given-names>
</name>
, <name><surname>Han</surname>
<given-names>T.</given-names>
</name>
, <name><surname>Haataja</surname>
<given-names>M.</given-names>
</name>
& <name><surname>Keller</surname>
<given-names>S.</given-names>
</name>
<article-title>Transbilayer colocalization of lipid domains explained via measurement of strong coupling parameters</article-title>
. <source>Biophysical JouRNAl</source>
<volume>109</volume>
, <fpage>2317</fpage>
–<lpage>2327</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://www.sciencedirect.com/science/article/pii/S0006349515011066">http://www.sciencedirect.com/science/article/pii/S0006349515011066</ext-link>
(<year>2015</year>
).<pub-id pub-id-type="pmid">26636943</pub-id>
</mixed-citation>
</ref>
<ref id="b50"><mixed-citation publication-type="journal"><name><surname>Raghupathy</surname>
<given-names>R.</given-names>
</name>
<etal></etal>
. <article-title>Transbilayer lipid interactions mediate nanoclustering of lipid-anchored proteins</article-title>
. <source>Cell</source>
<volume>161</volume>
, <fpage>581</fpage>
–<lpage>594</lpage>
URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1016/j.cell.2015.03.048">http://dx.doi.org/10.1016/j.cell.2015.03.048</ext-link>
(<year>2015</year>
).<pub-id pub-id-type="pmid">25910209</pub-id>
</mixed-citation>
</ref>
<ref id="b51"><mixed-citation publication-type="journal"><name><surname>Honigmann</surname>
<given-names>A.</given-names>
</name>
<etal></etal>
. <article-title>Scanning STED-FCS reveals spatiotemporal heterogeneity of lipid interaction in the plasma membrane of living cells</article-title>
. <source>Nat Commun</source>
<volume>5</volume>
, <fpage>5412</fpage>
, URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1038/ncomms6412">http://dx.doi.org/10.1038/ncomms6412</ext-link>
(<year>2014</year>
).<pub-id pub-id-type="pmid">25410140</pub-id>
</mixed-citation>
</ref>
<ref id="b52"><mixed-citation publication-type="journal"><name><surname>Spillane</surname>
<given-names>K. M.</given-names>
</name>
<etal></etal>
. <article-title>High-speed single-particle tracking of GM1 in model membranes reveals anomalous diffusion due to interleaflet coupling and molecular pinning</article-title>
. <source>Nano Lett</source>
<volume>14</volume>
, <fpage>5390</fpage>
–<lpage>5397</lpage>
, URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1021/nl502536u">http://dx.doi.org/10.1021/nl502536u</ext-link>
(<year>2014</year>
).<pub-id pub-id-type="pmid">25133992</pub-id>
</mixed-citation>
</ref>
<ref id="b53"><mixed-citation publication-type="journal"><name><surname>Hamard-Peron</surname>
<given-names>E.</given-names>
</name>
<etal></etal>
. <article-title>Targeting of murine leukemia virus Gag to the plasma membrane is mediated by PI(4,5)P2/PS and a polybasic region in the matrix</article-title>
. <source>J Virol</source>
<volume>84</volume>
, <fpage>503</fpage>
–<lpage>515</lpage>
, URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1128/JVI.01134-09">http://dx.doi.org/10.1128/JVI.01134-09</ext-link>
(<year>2010</year>
).<pub-id pub-id-type="pmid">19828619</pub-id>
</mixed-citation>
</ref>
<ref id="b54"><mixed-citation publication-type="journal"><name><surname>Escoffre</surname>
<given-names>J. M.</given-names>
</name>
, <name><surname>Hubert</surname>
<given-names>M.</given-names>
</name>
, <name><surname>Teissié</surname>
<given-names>J.</given-names>
</name>
, <name><surname>Rols</surname>
<given-names>M. P.</given-names>
</name>
& <name><surname>Favard</surname>
<given-names>C.</given-names>
</name>
<article-title>Evidence for electro-induced membrane defects assessed by lateral mobility measurement of a GPi anchored protein</article-title>
. <source>Eur Biophys J</source>
<volume>43</volume>
, <fpage>277</fpage>
–<lpage>286</lpage>
, URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1007/s00249-014-0961-1">http://dx.doi.org/10.1007/s00249-014-0961-1</ext-link>
(<year>2014</year>
).<pub-id pub-id-type="pmid">24781652</pub-id>
</mixed-citation>
</ref>
<ref id="b55"><mixed-citation publication-type="journal"><name><surname>Ehrlich</surname>
<given-names>L. S.</given-names>
</name>
, <name><surname>Fong</surname>
<given-names>S.</given-names>
</name>
, <name><surname>Scarlata</surname>
<given-names>S.</given-names>
</name>
, <name><surname>Zybarth</surname>
<given-names>G.</given-names>
</name>
& <name><surname>Carter</surname>
<given-names>C.</given-names>
</name>
<article-title>Partitioning of HIV-1 Gag and Gag-related proteins to membranes</article-title>
. <source>Biochemistry</source>
<volume>35</volume>
, <fpage>3933</fpage>
–<lpage>3943</lpage>
, URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1021/bi952337x">http://dx.doi.org/10.1021/bi952337x</ext-link>
(<year>1996</year>
).<pub-id pub-id-type="pmid">8672424</pub-id>
</mixed-citation>
</ref>
<ref id="b56"><mixed-citation publication-type="journal"><name><surname>Wang</surname>
<given-names>J.</given-names>
</name>
<etal></etal>
. <article-title>Lateral sequestration of phosphatidylinositol 4,5-bisphosphate by the basic effector domain of myristoylated alanine-rich c kinase substrate is due to nonspecific electrostatic interactions</article-title>
. <source>J Biol Chem</source>
<volume>277</volume>
, <fpage>34401</fpage>
–<lpage>34412</lpage>
, URL <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1074/jbc.M203954200">http://dx.doi.org/10.1074/jbc.M203954200</ext-link>
(<year>2002</year>
).<pub-id pub-id-type="pmid">12097325</pub-id>
</mixed-citation>
</ref>
</ref-list>
<fn-group><fn><p><bold>Author Contributions</bold>
D.M. and C.F. developed the concept of the study. N.Y., Q.L., H.T., C.F. conducted the experiments. N.Y., Q.L. and D.M. and C.F. conducted data interpretation. C.F., N.Y. and D.M. drafted the manuscript. J.M., C.P. contributed to data interpretation and manuscript drafting.</p>
</fn>
</fn-group>
</back>
<floats-group><fig id="f1"><label>Figure 1</label>
<caption><title>Scheme of the different lipid membranes and proteins used in this study.</title>
<p>(<bold>A</bold>
) Representation of the model lipid membranes and of an elongated FL-Gag protein used in this study (see <xref ref-type="table" rid="t1">Table 1</xref>
and <xref ref-type="supplementary-material" rid="S1">SI Table S1</xref>
for all the different lipid compositions used in this study). (<bold>B</bold>
) Schematic representation of the different Gag mutants used in this study, emphasizing the mutations and the differences in the domains present for each mutant.</p>
</caption>
<graphic xlink:href="srep39332-f1"></graphic>
</fig>
<fig id="f2"><label>Figure 2</label>
<caption><title>Binding of FL-Gag, its mutants and PH-EFA6 to “basic” lipid membranes.</title>
<p>(<bold>A</bold>
) Typical SDS-PAGE obtained after co-sedimentation assay for FL-Gag with increasing concentrations of LUV containing 2% mol PIP<sub>2</sub>
(P:Pellet, S:SupeRNAtant). (<bold>B</bold>
) Typical change in resonance frequency observed during QCM-D experiments after addition of the different proteins at different concentrations on a basic composition SLB. (<bold>C</bold>
and <bold>D</bold>
) Binding isotherm curve obtained from co-sedimentation assays ((<bold>C</bold>
), n = 3) and QCM-D experiments ((<bold>D</bold>
), n = 2) for the different proteins used in this study. Experimental values were fitted using <xref ref-type="disp-formula" rid="eq3">equation 1</xref>
. <italic>K</italic>
<sub><italic>p</italic>
</sub>
obtained from these binding isotherms are summarized in <xref ref-type="table" rid="t1">Table 2</xref>
.</p>
</caption>
<graphic xlink:href="srep39332-f2"></graphic>
</fig>
<fig id="f3"><label>Figure 3</label>
<caption><title>Fluorescence distribution of TF-PIP<sub>2</sub>
and A594-FL-Gag on “Basic”, “Inner Leaflet” and “rafts-mimicking” GUVs.</title>
<p>(<bold>A</bold>
) Left, localization of TF-PIP<sub>2</sub>
(green) and A594-FL-Gag (red) in a “Basic” composition GUV. Right, localization of TF-PIP<sub>2</sub>
(green) and A594-FL-Gag (red) in an “Inner Leaflet” composition GUV, (scale bar 5 <italic>μ</italic>
m). (<bold>B</bold>
) Spatial autocorrelation of the fluorescence intensities of TF-PIP<sub>2</sub>
(in green) and A594-FL-Gag(in red) for the “Basic” composition calculated using <xref ref-type="disp-formula" rid="eq4">eq. 2</xref>
, (<italic>mean</italic>
± <italic>s.d., n </italic>
=<italic> 4</italic>
). (<bold>C</bold>
) Localization in “Raft” GUVs (<bold>F</bold>
) of TF-PIP<sub>2</sub>
(green), A594-FL-Gag (red) and GM1, a raft partitioning ganglioside, labeled with alexa 647 cholera toxin B (A647 Ctx-B)(blue), (scale bar 5 <italic>μ</italic>
m). (<bold>D</bold>
) Partitioning in <italic>L</italic>
<sub><italic>o</italic>
</sub>
and <italic>L</italic>
<sub><italic>d</italic>
</sub>
phase of “raft” GUVs for A-594 FL, TF-PIP<sub>2</sub>
and A647-CtxB (<italic>mean</italic>
± <italic>s.d., n</italic>
= <italic>25</italic>
) as determined using <xref ref-type="disp-formula" rid="eq5">eq. 3</xref>
.</p>
</caption>
<graphic xlink:href="srep39332-f3"></graphic>
</fig>
<fig id="f4"><label>Figure 4</label>
<caption><title>PIP<sub>2</sub>
nanoclustering induced by Gag self-assembly on basic composition lipid membranes.</title>
<p>(<bold>A</bold>
) Typical time course of TF-PIP<sub>2</sub>
fluorescence on LUVs after addition of the different proteins or peptide at a <inline-formula id="d32e1440"><inline-graphic id="d32e1441" xlink:href="srep39332-m7.jpg"></inline-graphic>
</inline-formula>
= 10. (<bold>B</bold>
) Relative quenching values observed for FL-Gag, its mutant, MA and PH-EFA6 on LUVs (<italic>mean</italic>
± <italic>s.d. values of n</italic>
≥ 3 <italic>for each</italic>
<inline-formula id="d32e1456"><inline-graphic id="d32e1457" xlink:href="srep39332-m8.jpg"></inline-graphic>
</inline-formula>
<italic>conditions, except P39</italic>
(2 ≤ <italic>n</italic>
≤ 3)). (<bold>C</bold>
) Differences in WM and FL-Gag self-assembly efficiency on LUV at two different <inline-formula id="d32e1469"><inline-graphic id="d32e1470" xlink:href="srep39332-m9.jpg"></inline-graphic>
</inline-formula>
ratio. Bar graph represents the mean signal observed for monomers dimers and trimers & multimers obtained from independent experiments (<italic>mean</italic>
± <italic>s.d.</italic>
, n = 3). (<bold>D</bold>
) Typical time course of TF-PIP<sub>2</sub>
fluorescence on SLBs after addition of 1 <italic>μ</italic>
M of the different proteins or peptide. (<bold>E</bold>
) Fluorescence time course of TF-PIP<sub>2</sub>
after addition of increasing FL-Gag concentrations. (<bold>F</bold>
) Schematic representation of the effect of an immobile fraction on the fractional recovery. Upper part, without Gag, fractional recovery = 1. Lower part, with Gag, self assembled Gag trapped PIP<sub>2</sub>
are still in the bleached area leading to a normalized fractional recovery < 1. (<bold>G</bold>
) Plot box of the fractional recoveries obtained from FRAP measurements before and after addition of increasing concentrations of FL-Gag on SLB containing either DiIC18 as a lipid analogue control (left) or TF-PIP<sub>2</sub>
(right). (Boxes are 25,75% with bars max and min values of n ≥ 15, ***p ≤ 10<sup>−3</sup>
for Student t-test at 0.01 confidence level).</p>
</caption>
<graphic xlink:href="srep39332-f4"></graphic>
</fig>
<fig id="f5"><label>Figure 5</label>
<caption><title>Gag self-assembly is sorting cholesterol but not sphingomyelin.</title>
<p>(<bold>A</bold>
and <bold>B</bold>
) Typical fluorescence time course after addition of increasing FL-Gag concentrations on subsituted basic SLBs labeled with TF-SPM (<bold>A</bold>
) or TF-Chol (<bold>B</bold>
). (<bold>C</bold>
and <bold>D</bold>
) Simultaneous fluorescence time course after addition of increasing concentrations of FL-Gag on substituted basic SLBs labelled with TF-SPM (in green) and BT-PIP<sub>2</sub>
(in red) (<bold>C</bold>
) or TF-Chol (in green) and BT-PIP<sub>2</sub>
(in red) (<bold>D</bold>
).</p>
</caption>
<graphic xlink:href="srep39332-f5"></graphic>
</fig>
<fig id="f6"><label>Figure 6</label>
<caption><title>Gag PIP<sub>2</sub>
and Chol nanoclustering in complex membrane models.</title>
<p>(<bold>A</bold>
and <bold>B</bold>
) TF-PIP<sub>2</sub>
fluorescence changes in lipid membranes of different composition (basic, Inner Leaflet, Raft) using LUVs (<bold>A</bold>
) relative quenching of at different <inline-formula id="d32e1568"><inline-graphic id="d32e1569" xlink:href="srep39332-m10.jpg"></inline-graphic>
</inline-formula>
ratio. <italic>mean</italic>
± <italic>s.d., n </italic>
≥ <italic>3</italic>
) or SLBs (<bold>B</bold>
) typical time course of TF-PIP<sub>2</sub>
fluorescence after addition of 1 <italic>μ</italic>
M FL-Gag.) (<bold>C</bold>
) Simultaneous fluorescence time course obtained on “inner leaflet” SLBs for BT-PIP<sub>2</sub>
(in red) and in green TF-SPM (left panel) or TF-Chol (right panel). (<bold>D</bold>
) Simultaneous fluorescence time course obtained on “raft” SLBs for BT-PIP<sub>2</sub>
(in red) and in green TF-SPM (left panel) or TF-Chol (right panel).</p>
</caption>
<graphic xlink:href="srep39332-f6"></graphic>
</fig>
<table-wrap position="float" id="t1"><label>Table 1</label>
<caption><title>Different lipid composition of LUV, SLB and GUV used in the single labeled lipid experiments.</title>
</caption>
<table frame="hsides" rules="groups" border="1"><colgroup><col align="left"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
</colgroup>
<thead valign="bottom"><tr><th rowspan="2" align="center" valign="top" charoff="50"> </th>
<th colspan="2" align="center" valign="top" charoff="50">Basic<hr></hr>
</th>
<th colspan="2" align="center" valign="top" charoff="50">Substituted Basic<hr></hr>
</th>
<th colspan="2" align="center" valign="top" charoff="50">Inner Leaflet<sup>#</sup>
<hr></hr>
</th>
<th colspan="2" align="center" valign="top" charoff="50">Rafts-mimicking<sup>#</sup>
<hr></hr>
</th>
</tr>
<tr><th align="center" valign="top" charoff="50">Lipid</th>
<th align="center" valign="top" charoff="50">Mol%</th>
<th align="center" valign="top" charoff="50">Lipid</th>
<th align="center" valign="top" charoff="50">Mol%</th>
<th align="center" valign="top" charoff="50">Lipid</th>
<th align="center" valign="top" charoff="50">Mol%</th>
<th align="center" valign="top" charoff="50">Lipid</th>
<th align="center" valign="top" charoff="50">Mol%</th>
</tr>
</thead>
<tbody valign="top"><tr><td rowspan="5" align="left" valign="top" charoff="50">EggPC</td>
<td align="center" valign="top" charoff="50">EggPC</td>
<td align="center" valign="top" charoff="50">68</td>
<td align="center" valign="top" charoff="50">Egg PC</td>
<td align="center" valign="top" charoff="50">66</td>
<td align="center" valign="top" charoff="50">Egg PC</td>
<td align="center" valign="top" charoff="50">17</td>
<td align="center" valign="top" charoff="50">DOPC</td>
<td align="center" valign="top" charoff="50">31</td>
</tr>
<tr><td align="center" valign="top" charoff="50">Brain PS</td>
<td align="center" valign="top" charoff="50">30</td>
<td align="center" valign="top" charoff="50">Brain PS</td>
<td align="center" valign="top" charoff="50">30</td>
<td align="center" valign="top" charoff="50">Brain PS</td>
<td align="center" valign="top" charoff="50">17</td>
<td align="center" valign="top" charoff="50">DOPS</td>
<td align="center" valign="top" charoff="50">6</td>
</tr>
<tr><td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">2</td>
<td align="center" valign="top" charoff="50">Brain SM</td>
<td align="center" valign="top" charoff="50">9</td>
<td align="center" valign="top" charoff="50">Brain SM</td>
<td align="center" valign="top" charoff="50">30</td>
</tr>
<tr><td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">Cholesterol</td>
<td align="center" valign="top" charoff="50">30</td>
<td align="center" valign="top" charoff="50">Cholesterol</td>
<td align="center" valign="top" charoff="50">25</td>
</tr>
<tr><td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">Liver PE</td>
<td align="center" valign="top" charoff="50">25</td>
<td align="center" valign="top" charoff="50">GM1</td>
<td align="center" valign="top" charoff="50">1</td>
</tr>
<tr><td rowspan="2" align="left" valign="top" charoff="50">LUV</td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">0 or 1.5</td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">0</td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">5</td>
</tr>
<tr><td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">2 or 0.5</td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">2</td>
<td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">2</td>
</tr>
<tr><td rowspan="2" align="left" valign="top" charoff="50">SLB</td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50">Brain SM or Chol.</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">6</td>
</tr>
<tr><td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50">TF-SM or TF-Chol</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
</tr>
<tr><td rowspan="2" align="left" valign="top" charoff="50">GUV</td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50">Brain PI(4,5)P<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">6</td>
</tr>
<tr><td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
<td align="center" valign="top" charoff="50">TF-PIP<sub>2</sub>
</td>
<td align="center" valign="top" charoff="50">1</td>
</tr>
</tbody>
</table>
<table-wrap-foot><fn id="t1-fn1"><p><sup>#</sup>
Adapted from ref. <xref ref-type="bibr" rid="b28">28</xref>
.</p>
</fn>
<fn id="t1-fn2"><p><sup>#</sup>
Adapted from ref. <xref ref-type="bibr" rid="b16">16</xref>
.</p>
</fn>
</table-wrap-foot>
</table-wrap>
<table-wrap position="float" id="t2"><label>Table 2</label>
<caption><title>Apparent K<sub><italic>p</italic>
</sub>
of the different proteins used in this study.</title>
</caption>
<table frame="hsides" rules="groups" border="1"><colgroup><col align="left"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
<col align="center"></col>
</colgroup>
<thead valign="bottom"><tr><th rowspan="2" align="center" valign="top" charoff="50">Protein</th>
<th align="center" valign="top" charoff="50"><italic>K</italic>
<sub><italic>p</italic>
</sub>
(<italic>μM</italic>
)</th>
<th align="center" valign="top" charoff="50"><italic>K</italic>
<sub><italic>p</italic>
</sub>
(<italic>μM</italic>
)</th>
<th rowspan="2" align="center" valign="top" charoff="50"><italic>K</italic>
<sub><italic>p</italic>
</sub>
(<italic>μM</italic>
)</th>
<th rowspan="2" align="center" valign="top" charoff="50">Lip. Comp (mol %)</th>
<th rowspan="2" align="center" valign="top" charoff="50">Ref.</th>
</tr>
<tr><th align="center" valign="top" charoff="50">LUV</th>
<th align="center" valign="top" charoff="50">SLB</th>
</tr>
</thead>
<tbody valign="top"><tr><td align="left" valign="top" charoff="50">FL</td>
<td align="center" valign="top" charoff="50">0.13 ± 0.05</td>
<td align="center" valign="top" charoff="50">0.40 ± 0.11</td>
<td align="center" valign="top" charoff="50">0.88 ± 0.20 (LUV)</td>
<td align="center" valign="top" charoff="50">POPS (100)</td>
<td align="center" valign="top" charoff="50"><xref ref-type="bibr" rid="b55">55</xref>
</td>
</tr>
<tr><td align="left" valign="top" charoff="50">P39</td>
<td align="center" valign="top" charoff="50">0.66 ± 0.44</td>
<td align="center" valign="top" charoff="50">0.47 ± 0.26</td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
</tr>
<tr><td align="left" valign="top" charoff="50">WM</td>
<td align="center" valign="top" charoff="50">0.56 ± 0.26</td>
<td align="center" valign="top" charoff="50">0.26 ± 0.13</td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50"> </td>
</tr>
<tr><td rowspan="2" align="left" valign="middle" charoff="50">MA</td>
<td align="center" valign="top" charoff="50">1.72 ± 1.05</td>
<td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">2.46 ± 1 (LUV)</td>
<td align="center" valign="top" charoff="50">POPS (100)</td>
<td align="center" valign="top" charoff="50"><xref ref-type="bibr" rid="b55">55</xref>
</td>
</tr>
<tr><td align="center" valign="top" charoff="50"> </td>
<td align="center" valign="top" charoff="50">7.16 ± 3.33</td>
<td align="center" valign="top" charoff="50">8.2 ± 0.7(SLB)</td>
<td align="center" valign="top" charoff="50">DOPC:DOPS:PI(4,5)P<sub>2</sub>
(80:15:5)</td>
<td align="center" valign="top" charoff="50"><xref ref-type="bibr" rid="b39">39</xref>
</td>
</tr>
<tr><td rowspan="2" align="left" valign="middle" charoff="50">PH-EFA6</td>
<td rowspan="2" align="center" valign="middle" charoff="50">0.88 ± 0.27</td>
<td rowspan="2" align="center" valign="middle" charoff="50">0.68 ± 0.03</td>
<td rowspan="2" align="center" valign="middle" charoff="50">0.5 (SLB)</td>
<td align="center" valign="top" charoff="50">PC:PE:PS:PI(4,5)P<sub>2</sub>
</td>
<td rowspan="2" align="center" valign="middle" charoff="50"><xref ref-type="bibr" rid="b30">30</xref>
</td>
</tr>
<tr><td align="center" valign="top" charoff="50">(34:34:30:2)</td>
</tr>
<tr><td rowspan="2" align="left" valign="middle" charoff="50">MARCKS</td>
<td rowspan="2" align="center" valign="middle" charoff="50">n.d.<sup>#</sup>
</td>
<td rowspan="2" align="center" valign="middle" charoff="50">0.65 ± 0.23</td>
<td rowspan="2" align="center" valign="middle" charoff="50">4.4 ± 1 (LUV)</td>
<td align="center" valign="top" charoff="50">PC:PI(4,5)P<sub>2</sub>
</td>
<td rowspan="2" align="center" valign="middle" charoff="50"><xref ref-type="bibr" rid="b56">56</xref>
</td>
</tr>
<tr><td align="center" valign="top" charoff="50">(99:1)</td>
</tr>
</tbody>
</table>
<table-wrap-foot><fn id="t2-fn1"><p><sup>#</sup>
Could not be determined by this method.</p>
</fn>
</table-wrap-foot>
</table-wrap>
</floats-group>
</pmc>
</record>
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