Human Immunodeficiency Virus Type 1 Vpr Mediates Degradation of APC1, a Scaffolding Component of the Anaphase-Promoting Complex/Cyclosome

Abstract

HIV-1 encodes several accessory proteins: Nef, Vif, Vpr and Vpu, whose functions are to modulate the cellular environment to favor immune evasion and viral replication. While Vpr was shown to mediate a G2/M cell cycle arrest and provide a replicative advantage during infection of myeloid cells, the mechanisms underlying these functions remain unclear. In this study, we defined HIV-1 Vpr proximity interaction network using the BioID proximity labelling approach and identified 352 potential Vpr partners/targets, including several complexes such as the cell cycle regulatory anaphase promoting complex/cyclosome (APC/C). Herein, we demonstrate that both wild-type and cell cycle-defective mutants of Vpr induce the degradation of APC1, an essential APC/C scaffolding protein, and show that this activity relies on the recruitment of DCAF1 by Vpr and the presence of a functional proteasome. Vpr forms a complex with APC1 and the APC/C coactivators Cdh1 and Cdc20 are found associated with these complexes. Interestingly, we find that Vpr encoded by the prototypic HIV-1 NL4.3 does not interact efficiently with APC1 and is unable to mediate its degradation as a result of a N28S-G41N amino acid substitution. In contrast, we show that APC1 degradation is a conserved feature of several primary Vpr variants from transmitted/founder virus. Functionally, Vpr-mediated APC1 degradation did not impact the ability of the protein to induce a G2 cell cycle arrest during infection of CD4+ T cells nor enhance HIV-1 replication in macrophages, suggesting that this conserved activity may be important for other aspects of HIV-1 pathogenesis. IMPORTANCE The function of the Vpr accessory protein during HIV-1 infection remains poorly defined. Several cellular targets of Vpr were previously identified but their individual degradation does not fully explain the ability of Vpr to impair the cell cycle or promote HIV-1 replication in macrophages. Here, we used the unbiased proximity labelling approach, called BioID, to further define the Vpr proximity interaction network and identified several potentially new Vpr partners/targets. We validated our approach by focusing on a cell cycle master-regulator, the APC/C complex, and demonstrated that Vpr mediated the degradation of a critical scaffolding component of APC/C called APC1. Furthermore, we showed that targeting of APC/C by Vpr did not impact the known activity of Vpr. Since degradation of APC1 is a conserved feature of several primary variants of Vpr, it is likely that the interplay between Vpr and APC/C governs other aspects of HIV-1 pathogenesis.

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“…CDIPT also interacts with proteins of numerous HPV serotypes 39,56 , EBV 39 and HIV-1 57 . Scyllo-inositol is listed as an inhibitor of CDIPT 58 and was proposed as a potential drug to prevent Alzheimer's disease 59 .…”

HIV-1 Vpr Functions in Primary CD4+ T Cells

“…Likewise, Vpr has been implicated in disrupting multiple other structures crucial for cell cycle progression, including the anaphase promoting complex/cyclosome, the centrosome, the replisome, as well as chromosomal centromeres and telomeres. Barbosa and colleagues recently showcased in CD4 + T cells how transmitter/founder Vpr variants coopt the DCAF1-DDB1 E3 Ligase complex to target APC1 for proteasomal degradation, potentially disabling the vital role it plays in the metaphase-to-anaphase transition [ 71 ]. Park and colleagues’ work on primary T cells evidenced that a similar mechanism is followed by Vpr in subverting centrosome activity, sequestering the kinase PLK4 and leading to centriole duplication [ 72 ].…”

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“…It interacts with SARS-CoV-2 as well as influenza A and is reported in three CRISPR-Cas9 studies as a relevant host factor during SARS-CoV-2 infection (Daniloski et al, 2021;Wang et al, 2021;Wei et al, 2021). CDIPT also interacts with proteins of numerous HPV serotypes (Muller et al, 2012;Rozenblatt-Rosen et al, 2012), EBV (Rozenblatt-Rosen et al, 2012), and HIV-1 (Barbosa et al, 2021). Scyllo-inositol is listed as an inhibitor of CDIPT (Chen et al, 2002) and was proposed as a potential drug to prevent Alzheimer's disease (Michon et al, 2020).…”