title: Antagonism of tetherin restriction of HIV-1 release by Vpu involves binding and sequestration of the restriction factor in a perinuclear compartment.
abstract: The Vpu accessory protein promotes HIV-1 release by counteracting Tetherin/BST-2, an interferon-regulated restriction factor, which retains virions at the cell-surface. Recent reports proposed beta-TrCP-dependent proteasomal and/or endo-lysosomal degradation of Tetherin as potential mechanisms by which Vpu could down-regulate Tetherin cell-surface expression and antagonize this restriction. In all of these studies, Tetherin degradation did not, however, entirely account for Vpu anti-Tetherin activity. Here, we show that Vpu can promote HIV-1 release without detectably affecting Tetherin steady-state levels or turnover, suggesting that Tetherin degradation may not be necessary and/or sufficient for Vpu anti-Tetherin activity. Even though Vpu did not enhance Tetherin internalization from the plasma membrane (PM), it did significantly slow-down the overall transport of the protein towards the cell-surface. Accordingly, Vpu expression caused a specific removal of cell-surface Tetherin and a re-localization of the residual pool of Tetherin in a perinuclear compartment that co-stained with the TGN marker TGN46 and Vpu itself. This re-localization of Tetherin was also observed with a Vpu mutant unable to recruit beta-TrCP, suggesting that this activity is taking place independently from beta-TrCP-mediated trafficking and/or degradation processes. We also show that Vpu co-immunoprecipitates with Tetherin and that this interaction involves the transmembrane domains of the two proteins. Importantly, this association was found to be critical for reducing cell-surface Tetherin expression, re-localizing the restriction factor in the TGN and promoting HIV-1 release. Overall, our results suggest that association of Vpu to Tetherin affects the outward trafficking and/or recycling of the restriction factor from the TGN and as a result promotes its sequestration away from the PM where productive HIV-1 assembly takes place. This mechanism of antagonism that results in TGN trapping is likely to be augmented by beta-TrCP-dependent degradation, underlining the need for complementary and perhaps synergistic strategies to effectively counteract the powerful restrictive effects of human Tetherin.
authors.affiliation: Laboratory of Human Retrovirology, Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Dubé
authors.forename: Bibhuti Bhusan
authors.initials: BB
authors.lastname: Roy
authors.forename: Pierre
authors.initials: P
authors.lastname: Guiot-Guillain
authors.forename: Julie
authors.initials: J
authors.lastname: Binette
authors.forename: Johanne
authors.initials: J
authors.lastname: Mercier
authors.forename: Antoine
authors.initials: A
authors.lastname: Chiasson
authors.forename: Eric A
authors.initials: EA
authors.lastname: Cohen
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D004705:Endocytosis / Q000502:physiology; D005434:Flow Cytometry; D058851:GPI-Linked Proteins; D015497:HIV-1 / Q000378:metabolism*; D006367:HeLa Cells; D054298:Human Immunodeficiency Virus Proteins / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D008562:Membrane Glycoproteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D021381:Protein Transport / Q000502:physiology; D054334:Viral Regulatory and Accessory Proteins / Q000378:metabolism*; D057074:Virus Release / Q000502:physiology*; D000074010:Bone Marrow Stromal Antigen 2; D000086082:Viroporin Proteins
chemical_list: D015703:Antigens, CD; D058851:GPI-Linked Proteins; D054298:Human Immunodeficiency Virus Proteins; D008562:Membrane Glycoproteins; D054334:Viral Regulatory and Accessory Proteins; C094572:BST2 protein, human; D000074010:Bone Marrow Stromal Antigen 2; C514859:vpu protein, Human immunodeficiency virus 1; D000086082:Viroporin Proteins
references.citation: PLoS Pathog. 2009 May;5(5):e1000429
references.pmid: 19436700
references.citation: PLoS Pathog. 2006 May;2(5):e39
references.pmid: 16699598
references.citation: Nature. 2008 Jan 24;451(7177):425-30
references.pmid: 18200009
references.citation: Cell Host Microbe. 2007 Sep 13;2(3):193-203
references.pmid: 18005734
references.citation: Virology. 2007 Dec 20;369(2):299-308
references.pmid: 17822732
references.citation: Cell. 2009 Oct 30;139(3):499-511
references.pmid: 19879838
references.citation: PLoS Pathog. 2009 May;5(5):e1000450
references.pmid: 19478868
references.citation: Traffic. 2003 Oct;4(10):694-709
references.pmid: 12956872
references.citation: Cell Host Microbe. 2008 Apr 17;3(4):245-52
references.pmid: 18342597
references.citation: Cell Host Microbe. 2008 Jun 12;3(6):388-98
references.pmid: 18541215
references.citation: J Virol. 1988 Oct;62(10):3779-88
references.pmid: 3047430
references.citation: Virology. 1995 Nov 10;213(2):639-49
references.pmid: 7491787
references.citation: PLoS Pathog. 2009 Feb;5(2):e1000300
references.pmid: 19214216
references.citation: J Virol. 2009 Aug;83(15):7536-46
references.pmid: 19474106
references.citation: J Immunol. 1989 May 1;142(9):3070-5
references.pmid: 2540236
references.citation: J Virol. 1992 Dec;66(12):7193-200
references.pmid: 1433512
references.citation: Cell Immunol. 2005 Jul-Aug;236(1-2):6-16
references.pmid: 16157322
references.citation: J Cell Biol. 1993 Dec;123(5):1107-17
references.pmid: 8245121
references.citation: Cell Host Microbe. 2009 Jul 23;6(1):54-67
references.pmid: 19501037
references.citation: J Biol Chem. 2009 Dec 11;284(50):35060-72
references.pmid: 19837671
references.citation: J Acquir Immune Defic Syndr Hum Retrovirol. 1995 Jan 1;8(1):10-22
references.pmid: 8548340
references.citation: J Virol. 1998 Mar;72(3):2280-8
references.pmid: 9499087
references.citation: J Virol. 1995 Dec;69(12):7699-711
references.pmid: 7494279
references.citation: Proc Natl Acad Sci U S A. 2003 Dec 9;100(25):15154-9
references.pmid: 14657387
references.citation: Proc Natl Acad Sci U S A. 2009 Feb 24;106(8):2886-91
references.pmid: 19179289
references.citation: Virology. 1998 Nov 10;251(1):96-107
references.pmid: 9813206
references.citation: J Virol. 1995 Mar;69(3):1510-20
references.pmid: 7853484
references.citation: J Virol. 1996 Feb;70(2):809-19
references.pmid: 8551619
references.citation: Mol Cell. 1998 Mar;1(4):565-74
references.pmid: 9660940
references.citation: PLoS Pathog. 2009 Sep;5(9):e1000574
references.pmid: 19730691
references.citation: Genomics. 1995 Apr 10;26(3):527-34
references.pmid: 7607676
references.citation: Proc Natl Acad Sci U S A. 2009 Dec 8;106(49):20889-94
references.pmid: 19864625
references.citation: Retrovirology. 2009 Sep 08;6:80
references.pmid: 19737401
references.citation: J Virol. 1994 Apr;68(4):2260-71
references.pmid: 8139011
references.citation: J Virol. 1998 Jun;72(6):4686-93
references.pmid: 9573232
references.citation: Traffic. 2006 Mar;7(3):298-307
references.pmid: 16497224
references.citation: J Virol. 2009 May;83(9):4574-90
references.pmid: 19244337
references.citation: J Virol. 2009 Oct;83(19):9672-81
references.pmid: 19605472
references.citation: J Virol. 2009 Aug;83(16):7931-47
references.pmid: 19515779
references.citation: J Virol. 2009 Feb;83(4):1837-44
references.pmid: 19036818
references.citation: J Exp Med. 2009 Jul 6;206(7):1603-14
references.pmid: 19564354
references.citation: Cell Host Microbe. 2009 Mar 19;5(3):285-97
references.pmid: 19286137
references.citation: J Virol. 1998 Apr;72(4):2577-88
references.pmid: 9525574
references.citation: J Virol. 2009 Nov;83(22):11966-78
references.pmid: 19740980
references.citation: Retrovirology. 2007 Oct 15;4:75
references.pmid: 17937819
references.citation: J Immunol. 2006 Sep 1;177(5):3260-5
references.pmid: 16920966
references.citation: Trends Microbiol. 2008 Dec;16(12):588-95
references.pmid: 18964021
references.citation: J Virol. 1990 Nov;64(11):5448-56
references.pmid: 2214021
references.citation: J Cell Sci. 2007 Nov 1;120(Pt 21):3850-8
references.pmid: 17940069
references.citation: PLoS Pathog. 2009 May;5(5):e1000443
references.pmid: 19461879
references.citation: Proc Natl Acad Sci U S A. 2009 Feb 24;106(8):2868-73
references.pmid: 19196977
references.citation: Annu Rev Genet. 2008;42:143-63
references.pmid: 18624631
references.citation: J Virol. 2009 Mar;83(5):2382-5
references.pmid: 19091864
references.citation: Proc Natl Acad Sci U S A. 1989 Jul;86(13):5163-7
references.pmid: 2472639