HIV-1 diverts actin debranching mechanismsfor particle assembly and release in CD4 Tlymphocytes.

Abstract

Enveloped viruses assemble and bud from the host cell membranes. Possible roles of cortical actin in these processes have often been a source of controversy. Here, we assessed the involvement of the Arp2/3 mediated branched actin in HIV-1 assembly at the membrane of infected CD4 T lymphocytes. Our results show that actin debranching not only increases HIV-1 release but also the number of individual HIV-1 assembly clusters present at the cell plasma membrane unravelling new mechanisms. Indeed, we showed that, in infected T lymphocytes, HIV-1 Gag prefers areas deficient in F-actin for assembly. In vitro, we could reproduce and quantify this mechanism using model systems. Finally, we found that the actin debranching factor, Arpin, an Arp2/3 inhibitor, is recruited by Gag at the cell membrane to promote virus assembly. Altogether, our data show that HIV-1 favors local actin debranching for assembly and release by subverting the host factor Arpin.