The HIV-1 Vpu Viroporin Inhibitor BIT225 Does Not Affect Vpu-Mediated Tetherin Antagonism

ABSTRACT Tetherin (CD317/BST-2), an interferon-induced membrane protein, restricts the release of nascent retroviral particles from infected cell surfaces. While human immunodeficiency virus type 1 (HIV-1) encodes the accessory gene vpu to overcome the action of tetherin, the lineage of primate lentiviruses that gave rise to HIV-2 does not. It has been previously reported that the HIV-2 envelope glycoprotein has a Vpu-like function in promoting virus release. Here we demonstrate that the HIV-2 Rod envelope glycoprotein (HIV-2 Rod Env) is a tetherin antagonist. Expression of HIV-2 Rod Env, but not that of HIV-1 or the closely related simian immunodeficiency virus (SIV) SIVmac1A11, counteracts tetherin-mediated restriction of Vpu-defective HIV-1 in a cell-type-specific manner. This correlates with the ability of the HIV-2 Rod Env to mediate cell surface downregulation of tetherin. Antagonism requires an endocytic motif conserved across HIV/SIV lineages in the gp41 cytoplasmic tail, but specificity for tetherin is governed by extracellular determinants in the mature Env protein. Coimmunoprecipitation studies suggest an interaction between HIV-2 Rod Env and tetherin, but unlike studies with Vpu, we found no evidence of tetherin degradation. In the presence of HIV-2 Rod Env, tetherin localization is restricted to the trans-Golgi network, suggesting Env-mediated effects on tetherin trafficking sequester it from virus assembly sites on the plasma membrane. Finally, we recapitulated these observations in HIV-2-infected CD4+ T-cell lines, demonstrating that tetherin antagonism and sequestration occur at physiological levels of Env expression during virus replication.

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Determinants of Tetherin Antagonism in the Transmembrane Domain of the Human Immunodeficiency Virus Type 1 Vpu Protein

Journal of Virology ◽

10.1128/jvi.01699-10 ◽

2010 ◽

Vol 84 (24) ◽

pp. 12958-12970 ◽

Cited By ~ 97

Author(s):

Raphaël Vigan ◽

Stuart J. D. Neil

Keyword(s):

Human Immunodeficiency Virus ◽

Amino Acid ◽

Cell Surface ◽

Human Immunodeficiency Virus Type ◽

Transmembrane Domain ◽

Human Tetherin ◽

Immunodeficiency Virus ◽

Hiv 1 ◽

Tetherin Antagonism

ABSTRACT Tetherin (BST2/CD317) potently restricts the particle release of human immunodeficiency virus type 1 (HIV-1) mutants defective in the accessory gene vpu. Vpu antagonizes tetherin activity and induces its cell surface downregulation and degradation in a manner dependent on the transmembrane (TM) domains of both proteins. We have carried out extensive mutagenesis of the HIV-1 NL4.3 Vpu TM domain to identify three amino acid positions, A14, W22, and, to a lesser extent, A18, that are required for tetherin antagonism. Despite the mutants localizing indistinguishably from the wild-type (wt) protein and maintaining the ability to multimerize, mutation of these positions rendered Vpu incapable of coimmunoprecipitating tetherin or mediating its cell surface downregulation. Interestingly, these amino acid positions are predicted to form one face of the Vpu transmembrane alpha helix and therefore potentially contribute to an interacting surface with the transmembrane domain of tetherin either directly or by modulating the conformation of Vpu oligomers. While the equivalent of W22 is invariant in HIV-1/SIVcpz Vpu proteins, the positions of A14 and A18 are highly conserved among Vpu alleles from HIV-1 groups M and N, but not those from group O or SIVcpz that lack human tetherin (huTetherin)-antagonizing activity, suggesting that they may have contributed to the adaption of HIV-1 to human tetherin.

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Vpu-mediated tetherin antagonism of ongoing HIV-1 infection in CD4+ T-cells is not directly related to the extent of tetherin cell surface downmodulation

Virology ◽

10.1016/j.virol.2011.06.012 ◽

2011 ◽

Vol 417 (2) ◽

pp. 353-361 ◽

Cited By ~ 5

Author(s):

Björn D. Kuhl ◽

Richard D. Sloan ◽

Daniel A. Donahue ◽

Chen Liang ◽

Mark A. Wainberg

Keyword(s):

T Cells ◽

Cell Surface ◽

Cd4 T Cells ◽

Hiv 1 ◽

Tetherin Antagonism

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The Nef protein of the macrophage tropic HIV-1 strain AD8 counteracts human Bst-2/tetherin

10.1101/2020.02.07.938464 ◽

2020 ◽

Author(s):

Sebastian Giese ◽

Scott P. Lawrence ◽

Michela Mazzon ◽

Bernadien M. Nijmeijer ◽

Mark Marsh

Keyword(s):

Cell Surface ◽

Virus Release ◽

Viral Budding ◽

Primary Monocyte ◽

Human Tetherin ◽

Human Immunodeficiency Viruses ◽

Infected Cells ◽

Translation Initiation Codon ◽

Hiv 1 ◽

Tetherin Antagonism

AbstractBst-2/tetherin inhibits the release of numerous enveloped viruses by physically attaching nascent particles to infected cells during the process of viral budding from the cell surface. Tetherin also restricts human immunodeficiency viruses (HIV), and pandemic main (M) group HIV-1s are thought to exclusively rely on their Vpu proteins to overcome tetherin-mediated restriction of virus release. However, at least one M group HIV-1 strain, the macrophage-tropic primary AD8 isolate, is unable to express vpu due to a mutation in its translation initiation codon. Here, using primary monocyte-derived macrophages (MDMs), we show that AD8 was able to use its Nef protein to compensate for the absence of Vpu and restore virus release to wild type levels. We demonstrate that HIV-1 AD8 Nef reduces endogenous tetherin levels from the cell surface, physically separating it from the site of viral budding and thus preventing HIV retention. Mechanistically, AD8 Nef enhances l-tetherin internalisation, leading to perinuclear accumulation of the restriction factor. Finally, we show that Nef proteins from other HIV strains also display varying degrees of tetherin antagonism. Overall, this is the first report showing that M group HIV-1s can use an accessory protein other than Vpu to antagonise human tetherin.

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HIV-1 Vpu Antagonizes CD317/Tetherin by Adaptor Protein-1-Mediated Exclusion from Virus Assembly Sites

Journal of Virology ◽

10.1128/jvi.00504-16 ◽

2016 ◽

Vol 90 (15) ◽

pp. 6709-6723 ◽

Cited By ~ 18

Author(s):

François M. Pujol ◽

Vibor Laketa ◽

Florian Schmidt ◽

Markus Mukenhirn ◽

Barbara Müller ◽

...

Keyword(s):

Plasma Membrane ◽

Cell Surface ◽

Virus Assembly ◽

Adaptor Protein ◽

Restriction Factor ◽

Dependent Manner ◽

Anterograde Transport ◽

Particle Release ◽

Hiv 1 ◽

Tetherin Antagonism

ABSTRACTThe host cell restriction factor CD317/tetherin traps virions at the surface of producer cells to prevent their release. The HIV-1 accessory protein Vpu antagonizes this restriction. Vpu reduces the cell surface density of the restriction factor and targets it for degradation; however, these activities are dispensable for enhancing particle release. Instead, Vpu has been suggested to antagonize CD317/tetherin by preventing recycling of internalized CD317/tetherin to the cell surface, blocking anterograde transport of newly synthesized CD317/tetherin, and/or displacing the restriction factor from virus assembly sites at the plasma membrane. At the molecular level, antagonism relies on the physical interaction of Vpu with CD317/tetherin. Recent findings suggested that phosphorylation of a diserine motif enables Vpu to bind to adaptor protein 1 (AP-1) trafficking complexes via two independent interaction motifs and to couple CD317/tetherin to the endocytic machinery. Here, we used a panel of Vpu proteins with specific mutations in individual interaction motifs to define which interactions are required for antagonism of CD317/tetherin. Impairing recycling or anterograde transport of CD317/tetherin to the plasma membrane was insufficient for antagonism. In contrast, excluding CD317/tetherin from HIV-1 assembly sites depended on Vpu motifs for interaction with AP-1 and CD317/tetherin and correlated with antagonism of the particle release restriction. Consistently, interference with AP-1 function or its expression blocked these Vpu activities. Our results define displacement from HIV-1 assembly sites as active principle of CD317/tetherin antagonism by Vpu and support a role of tripartite complexes between Vpu, AP-1, and CD317/tetherin in this process.IMPORTANCECD317/tetherin poses an intrinsic barrier to human immunodeficiency virus type 1 (HIV-1) replication in human cells by trapping virus particles at the surface of producer cells and thereby preventing their release. The viral protein Vpu antagonizes this restriction, and molecular interactions with the restriction factor and adaptor protein complex 1 (AP-1) were suggested to mediate this activity. Vpu modulates intracellular trafficking of CD317/tetherin and excludes the restriction factor from HIV-1 assembly sites at the plasma membrane, but the relative contribution of these effects to antagonism remain elusive. Using a panel of Vpu mutants, as well as interference with AP-1 function and expression, we show here that Vpu antagonizes CD317/tetherin by blocking its recruitment to viral assembly sites in an AP-1-dependent manner. These results refine our understanding of the molecular mechanisms of CD317/tetherin antagonism and suggest complexes of Vpu with the restriction factor and AP-1 as targets for potential therapeutic intervention.

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Tetherin antagonism by HIV-1 and its SIV precursors

Retrovirology ◽

10.1186/1742-4690-8-s2-o8 ◽

2011 ◽

Vol 8 (S2) ◽

Author(s):

Frank Kirchhoff

Keyword(s):

Hiv 1 ◽

Tetherin Antagonism

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Reacquisition of Nef-Mediated Tetherin Antagonism in a Single In Vivo Passage of HIV-1 through Its Original Chimpanzee Host

Cell Host & Microbe ◽

10.1016/j.chom.2012.07.008 ◽

2012 ◽

Vol 12 (3) ◽

pp. 373-380 ◽

Cited By ~ 31

Author(s):

Nicola Götz ◽

Daniel Sauter ◽

Shariq M. Usmani ◽

Joëlle V. Fritz ◽

Christine Goffinet ◽

...

Keyword(s):

Hiv 1 ◽

Tetherin Antagonism

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The Nef Protein of the Macrophage Tropic HIV-1 Strain AD8 Counteracts Human BST-2/Tetherin

Viruses ◽

10.3390/v12040459 ◽

2020 ◽

Vol 12 (4) ◽

pp. 459 ◽

Cited By ~ 1

Author(s):

Sebastian Giese ◽

Scott P. Lawrence ◽

Michela Mazzon ◽

Bernadien M. Nijmeijer ◽

Mark Marsh

Keyword(s):

Cell Surface ◽

Virus Release ◽

Viral Budding ◽

Primary Monocyte ◽

Human Tetherin ◽

Immunodeficiency Virus ◽

Infected Cells ◽

Translation Initiation Codon ◽

Hiv 1 ◽

Tetherin Antagonism

Bone Marrow Stromal Cell Antigen 2 (BST-2)/tetherin inhibits the release of numerous enveloped viruses by physically tethering nascent particles to infected cells during the process of viral budding from the cell surface. Tetherin also restricts human immunodeficiency virus (HIV), and pandemic main (M) group HIV type 1s (HIV-1s) are thought to rely exclusively on their Vpu proteins to overcome tetherin-mediated restriction of virus release. However, at least one M group HIV-1 strain, the macrophage-tropic primary AD8 isolate, is unable to express Vpu due to a mutation in its translation initiation codon. Here, using primary monocyte-derived macrophages (MDMs), we show that AD8 Nef protein can compensate for the absence of Vpu and restore virus release to wild type levels. We demonstrate that HIV-1 AD8 Nef reduces endogenous cell surface tetherin levels, physically separating it from the site of viral budding, thus preventing HIV retention. Mechanistically, AD8 Nef enhances internalisation of the long isoform of human tetherin, leading to perinuclear accumulation of the restriction factor. Finally, we show that Nef proteins from other HIV strains also display varying degrees of tetherin antagonism. Overall, we show that M group HIV-1s can use an accessory protein other than Vpu to antagonise human tetherin.

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HIV-1 and HIV-2 differentially regulate NF-κB activity during the late stages of the replication cycle through BST-2/tetherin antagonism

10.1101/2020.05.11.088385 ◽

2020 ◽

Author(s):

François E. Dufrasne ◽

Géraldine Dessilly ◽

Mara Lucchetti ◽

Kate Soumillion ◽

Eléonore Ngyuvula ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

Viral Replication ◽

Signaling Pathway ◽

Replication Cycle ◽

Immune Control ◽

Antiviral Immune Response ◽

Late Stages ◽

Hiv 1 ◽

Tetherin Antagonism

ABSTRACTHIV-2 is the second causative agent of AIDS and is commonly considered as an attenuated form of retroviral infection. Most of HIV-2-infected individuals display a slow-progressing disease, lower viral loads and a stronger immunological control of viral infection as compared with HIV-1-infected patients. The main hypothesis that could explain the difference of disease progression between HIV-1 and HIV-2 implies a more efficient T cell–mediated immunity in the control of HIV-2 infection. Herein, we investigate the effects of the HIV-2 envelope glycoprotein (Env) and its antitetherin function in the NF-κB signaling pathway during single-round infection of CD4+ T cells. First, we report an essential role of the Env cytoplasmic tail (CT) in the activation of this signaling pathway and we also demonstrate that the HIV-2 Env CT activates NF-κB in a TRAF6-dependent but TAK1-independent manner. Further, we show that HIV-2 reference strains and clinical isolates are unable to completely inhibit NF-κB mainly via the Env-mediated BST-2/tetherin antagonism in the late stages of the viral replication cycle in CD4+ T cells, in striking contrast to the HIV-1 Vpu-mediated counteraction of tetherin. We observe that this inability of HIV-2 to suppress NF-κB signaling pathway promotes stimulation of numerous genes involved in the antiviral immune response, such as il-6, il-21 and ifn-β genes. Therefore, HIV-1 and HIV-2 differentially regulate the NF-κB-induced antiviral immune response mainly through the BST-2/tetherin antagonism. These new insights highlight molecular mechanisms determining, at least partly, the distinct immune control and disease outcomes of HIV-1 and HIV-2 infections.IMPORTANCEThis study explores how HIV-1 and HIV-2 diverge in their regulation of the NF-κB signaling pathway. We revealed that HIV-2 fails to completely inhibit NF-κB activity, thereby inducing a stronger antiviral response than HIV-1. We demonstrated that the ability to antagonize the cellular restriction factor BST-2/tetherin largely governs the regulation of the NF-κB pathway: at the late stages of the viral replication cycle, HIV-1 Vpu blocks this pathway whereas HIV-2 Env does not. We also demonstrated that several NF-κB-targeted genes are upregulated in CD4+ T cells infected with HIV-2, but not with HIV-1. This stronger NF-κB-induced antiviral response may explain the better immune control of HIV-2 infection and the differences between HIV-1 and HIV-2 pathogenesis. Moreover, we observed in this study that non-pathogenic isolates of HIV-2 have an impaired NF-κB inhibitory capacity compared to pathogenic ones.

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Tetherin Antagonism by HIV-1 Group M Nef Proteins

Journal of Virology ◽

10.1128/jvi.01465-16 ◽

2016 ◽

Vol 90 (23) ◽

pp. 10701-10714 ◽

Cited By ~ 13

Author(s):

Juan F. Arias ◽

Marta Colomer-Lluch ◽

Benjamin von Bredow ◽

Justin M. Greene ◽

Julie MacDonald ◽

...

Keyword(s):

Transmembrane Protein ◽

Viral Gene ◽

Significant Activity ◽

Virus Release ◽

Aids Pandemic ◽

Human Tetherin ◽

Dependent Cell ◽

Infected Cells ◽

Hiv 1 ◽

Tetherin Antagonism

ABSTRACTAlthough Nef is the viral gene product used by most simian immunodeficiency viruses to overcome restriction by tetherin, this activity was acquired by the Vpu protein of HIV-1 group M due to the absence of sequences in human tetherin that confer susceptibility to Nef. Thus, it is widely accepted that HIV-1 group M uses Vpu instead of Nef to counteract tetherin. Challenging this paradigm, we identified Nef alleles of HIV-1 group M isolates with significant activity against human tetherin. These Nef proteins promoted virus release and tetherin downmodulation from the cell surface and, in the context ofvpu-deleted HIV-1 recombinants, enhanced virus replication and resistance to antibody-dependent cell-mediated cytotoxicity (ADCC). Further analysis revealed that the Vpu proteins from several of these viruses lack antitetherin activity, suggesting that under certain circumstances, HIV-1 group M Nef may acquire the ability to counteract tetherin to compensate for the loss of this function by Vpu. These observations illustrate the remarkable plasticity of HIV-1 in overcoming restriction by tetherin and challenge the prevailing view that all HIV-1 group M isolates use Vpu to counteract tetherin.IMPORTANCEMost viruses of HIV-1 group M, the main group of HIV-1 responsible for the global AIDS pandemic, use their Vpu proteins to overcome restriction by tetherin (BST-2 or CD317), which is a transmembrane protein that inhibits virus release from infected cells. Here we show that the Nef proteins of certain HIV-1 group M isolates can acquire the ability to counteract tetherin. These results challenge the current paradigm that HIV-1 group M exclusively uses Vpu to counteract tetherin and underscore the importance of tetherin antagonism for efficient viral replication.

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