Cellular cofactors involved in HIV assembly and budding

Remarkable discoveries in recent years have transformed the field of HIV assembly and budding. The present review highlights major recent advances in the field, with a focus on the cellular cofactors that have been shown to play key roles in HIV assembly and budding.

The identification of the interaction of Gag with TSG101 and other components of the endosomal sorting complex required for transport first revealed the important role of endosomal sorting pathways in HIV particle production. The classical model of HIV particle assembly at the plasma membrane has been modified by studies demonstrating particle assembly and budding into the lumen of the multivesicular body. Gag traffics to the multivesicular body through a direct interaction with the AP-3 complex, even in cell types in which particle budding into the lumen of the multivesicular body is not apparent. The profound role played by endosomal trafficking pathways in assembly and budding events has been emphasized by recent studies examining the subcellular localization of retroviral genomic RNA and of Vpu.

A number of important discoveries in recent years have resulted in a complex model of HIV assembly and budding in which endosomal sorting and trafficking pathways play a central role.