Assembly of the HIV-1 core particle.

The core particle of HIV-1 assembles at the membrane of the host cell as the virus buds from the surface. The structural proteins and enzymes that comprise the core are translated as part of two polyprotein precursors, Gag and GagPol. The Gag precursor contains the structural proteins of the core and is both necessary and sufficient for directing particle assembly and budding. Over the past few years, significant progress has been made in our understanding of the interactions that drive particle assembly. Specifically, determinants within the Gag precursor that direct membrane association, Gag-Gag interactions and particle budding have been identified and partially characterized. Subdomains of the host cell membrane that favor particle assembly and budding have also been described. Finally, a potential role for cellular processes in mediating the final stages in particle release has recently been proposed and a cellular protein that appears to bind directly to the Gag precursor has been identified. Each of these observations helps to clarify previously obscure aspects of viral replication and points towards potential targets for the design of novel therapies.