Antagonism of tetherin restriction of HIV-1 release by Vpu involves binding and sequestration of the restriction factor in a perinuclear compartment.
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.
Dubé
Mathieu
M
Laboratory of Human Retrovirology, Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada.
Roy
Bibhuti Bhusan
BB
Guiot-Guillain
Pierre
P
Binette
Julie
J
Mercier
Johanne
J
Chiasson
Antoine
A
Cohen
Eric A
EA
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
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
PLoS Pathog. 2009 May;5(5):e1000429
19436700
PLoS Pathog. 2006 May;2(5):e39
16699598
Nature. 2008 Jan 24;451(7177):425-30
18200009
Cell Host Microbe. 2007 Sep 13;2(3):193-203
18005734
Virology. 2007 Dec 20;369(2):299-308
17822732
Cell. 2009 Oct 30;139(3):499-511
19879838
PLoS Pathog. 2009 May;5(5):e1000450
19478868
Traffic. 2003 Oct;4(10):694-709
12956872
Cell Host Microbe. 2008 Apr 17;3(4):245-52
18342597
Cell Host Microbe. 2008 Jun 12;3(6):388-98
18541215
J Virol. 1988 Oct;62(10):3779-88
3047430
Virology. 1995 Nov 10;213(2):639-49
7491787
PLoS Pathog. 2009 Feb;5(2):e1000300
19214216
J Virol. 2009 Aug;83(15):7536-46
19474106
J Immunol. 1989 May 1;142(9):3070-5
2540236
J Virol. 1992 Dec;66(12):7193-200
1433512
Cell Immunol. 2005 Jul-Aug;236(1-2):6-16
16157322
J Cell Biol. 1993 Dec;123(5):1107-17
8245121
Cell Host Microbe. 2009 Jul 23;6(1):54-67
19501037
J Biol Chem. 2009 Dec 11;284(50):35060-72
19837671
J Acquir Immune Defic Syndr Hum Retrovirol. 1995 Jan 1;8(1):10-22
8548340
J Virol. 1998 Mar;72(3):2280-8
9499087
J Virol. 1995 Dec;69(12):7699-711
7494279
Proc Natl Acad Sci U S A. 2003 Dec 9;100(25):15154-9
14657387
Proc Natl Acad Sci U S A. 2009 Feb 24;106(8):2886-91
19179289
Virology. 1998 Nov 10;251(1):96-107
9813206
J Virol. 1995 Mar;69(3):1510-20
7853484
J Virol. 1996 Feb;70(2):809-19
8551619
Mol Cell. 1998 Mar;1(4):565-74
9660940
PLoS Pathog. 2009 Sep;5(9):e1000574
19730691
Genomics. 1995 Apr 10;26(3):527-34
7607676
Proc Natl Acad Sci U S A. 2009 Dec 8;106(49):20889-94
19864625
Retrovirology. 2009 Sep 08;6:80
19737401
J Virol. 1994 Apr;68(4):2260-71
8139011
J Virol. 1998 Jun;72(6):4686-93
9573232
Traffic. 2006 Mar;7(3):298-307
16497224
J Virol. 2009 May;83(9):4574-90
19244337
J Virol. 2009 Oct;83(19):9672-81
19605472
J Virol. 2009 Aug;83(16):7931-47
19515779
J Virol. 2009 Feb;83(4):1837-44
19036818
J Exp Med. 2009 Jul 6;206(7):1603-14
19564354
Cell Host Microbe. 2009 Mar 19;5(3):285-97
19286137
J Virol. 1998 Apr;72(4):2577-88
9525574
J Virol. 2009 Nov;83(22):11966-78
19740980
Retrovirology. 2007 Oct 15;4:75
17937819
J Immunol. 2006 Sep 1;177(5):3260-5
16920966
Trends Microbiol. 2008 Dec;16(12):588-95
18964021
J Virol. 1990 Nov;64(11):5448-56
2214021
J Cell Sci. 2007 Nov 1;120(Pt 21):3850-8
17940069
PLoS Pathog. 2009 May;5(5):e1000443
19461879
Proc Natl Acad Sci U S A. 2009 Feb 24;106(8):2868-73
19196977
Annu Rev Genet. 2008;42:143-63
18624631
J Virol. 2009 Mar;83(5):2382-5
19091864
Proc Natl Acad Sci U S A. 1989 Jul;86(13):5163-7
2472639