HIV-1 and other retroviruses exit infected cells by budding from the plasma membrane, a process requiring membrane fission. The primary late assembly (L) domain in the p6 region of HIV-1 Gag mediates the detachment of the virion by recruiting host Tsg101, a component of the class E vacuolar protein sorting (Vps) machinery. We now show that HIV Gag p6 contains a second region involved in L domain function that binds AIP1, a homolog of the yeast class E Vps protein Bro1. Further, AIP1 interacts with Tsg101 and homologs of a subunit of the yeast class E Vps protein complex ESCRT-III. AIP1 also binds to the L domain in EIAV p9, and this binding correlates perfectly with L domain function. These observations identify AIP1 as a component of the viral budding machinery, which serves to link a distinct region in the L domain of HIV-1 p6 and EIAV p9 to ESCRT-III.
Strack, B., Calistri, A., Craig, S., Popova, E., & Göttlinger, H. G. (2003). AIP1/ALIX is a binding partner for HIV-1 p6 and EIAV p9 functioning in virus budding. Cell, 114(6), 689–699. https://doi.org/10.1016/S0092-8674(03)00653-6