HIV-1 Assembly Differentially Alters Dynamics and Partitioning of Tetraspanins and Raft Components

Authors

  • Dimitry N. Krementsov,

    1. Graduate Program in Cell and Molecular Biology, University of Vermont, Burlington, VT 05405, USA
    2. Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
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    • These authors contributed equally to this work.

  • Patrice Rassam,

    1. Institut National de la Santé et de la Recherche Medicale, Unité 554, 34090 Montpellier, France
    2. Université de Montpellier, Centre National de la Recherche Scientifique, Unité Mixte Recherche 5048, Centre de Biochimie Structurale, 34090 Montpellier, France
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    • These authors contributed equally to this work.

  • Emmanuel Margeat,

    1. Institut National de la Santé et de la Recherche Medicale, Unité 554, 34090 Montpellier, France
    2. Université de Montpellier, Centre National de la Recherche Scientifique, Unité Mixte Recherche 5048, Centre de Biochimie Structurale, 34090 Montpellier, France
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  • Nathan H. Roy,

    1. Graduate Program in Cell and Molecular Biology, University of Vermont, Burlington, VT 05405, USA
    2. Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
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  • Jürgen Schneider-Schaulies,

    1. Institute for Virology and Immunobiology, University of Würzburg, Versbacher Street 7, D-97078 Würzburg, Germany
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  • Pierre-Emmanuel Milhiet,

    Corresponding author
    1. Institut National de la Santé et de la Recherche Medicale, Unité 554, 34090 Montpellier, France
    2. Université de Montpellier, Centre National de la Recherche Scientifique, Unité Mixte Recherche 5048, Centre de Biochimie Structurale, 34090 Montpellier, France
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  • Markus Thali

    Corresponding author
    1. Graduate Program in Cell and Molecular Biology, University of Vermont, Burlington, VT 05405, USA
    2. Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
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Markus Thali, Markus.Thali@uvm.edu;

Pierre-Emmanuel Milhiet, pem@cbs.cnrs.fr

Abstract

Partitioning of membrane proteins into various types of microdomains is crucial for many cellular functions. Tetraspanin-enriched microdomains (TEMs) are a unique type of protein-based microdomain, clearly distinct from membrane rafts, and important for several cellular processes such as fusion, migration and signaling. Paradoxically, HIV-1 assembly/egress occurs at TEMs, yet the viral particles also incorporate raft lipids.

Using different quantitative microscopy approaches, we investigated the dynamic relationship between TEMs, membrane rafts and HIV-1 exit sites, focusing mainly on the tetraspanin CD9. Our results show that clustering of CD9 correlates with multimerization of the major viral structural component, Gag, at the plasma membrane. CD9 exhibited confined behavior and reduced lateral mobility at viral assembly sites, suggesting that Gag locally traps tetraspanins. In contrast, the raft lipid GM1 and the raft-associated protein CD55, while also recruited to assembly/budding sites, were only transiently trapped in these membrane areas. CD9 recruitment and confinement were found to be partially dependent on cholesterol, while those of CD55 were completely dependent on cholesterol. Importantly, our findings support the emerging concept that cellular and viral components, instead of clustering at preexisting microdomain platforms, direct the formation of distinct domains for the execution of specific functions.

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