Rayane Dibsy
Lauréat 2024

Role of F-actin cytoskeleton in HIV-1 assembly and release from infected CD4+ T lymphocytes

Institut

Institute of Research in Infectious Diseases of Montpellier IRIM-CNRS

Thesis Supervisor

Delphine MURIAUX and Cyril FAVARD

Summary of the work

Enveloped viruses assemble and bud from the host cell membranes. Any role of cortical actin in these processes have often been a source of debate.

Here, we assessed if cortical actin was involved in HIV-1 assembly in infected CD4 T lymphocytes. Our results show that preventing actin branching not only increases HIV-1 particle release but also the number of individual HIV-1 Gag assembly clusters at the T cell plasma membrane.

Indeed, in infected T lymphocytes and in in vitro quantitative model systems, we show that HIV-1 Gag protein prefers areas deficient in F-actin for assembling. Finally, we found that the host factor Arpin, an inhibitor of Arp2/3 branched actin, is recruited at the membrane of infected T cells and it can associate with the viral Gag protein.

Altogether, our data show that, for virus assembly and particle release, HIV-1 prefers low density of cortical actin and may favor local actin debranching by subverting Arpin.