HIV-1 Vif

HIV-1 Vif (viral infectivity factor), supports productive viral replication in non-permissive cells, such as peripheral blood lymphocytes. It functions by inactivating a cellular anti-viral factor named APOBEC3G. Vif binds viral RNA and affects the stability of viral nucleoprotein core. May play a role in viral morphology. Interacts with host ABCE1, which seems to be involved in lentiviruses capsid formation and displays RNase L inhibitor activity. This interaction may play a role in protecting viral RNA from damage during viral assembly.

Human Immunodeficiency Virus Type 1 Viral Infectivity Factor

Counteracts the innate antiviral activity of host APOBEC3F and APOBEC3G. Forms a complex with host APOBEC3F and APOBEC3G thus preventing the entry of these lethally hypermutating enzymes into progeny virions. Recruits an active E3 ubiquitin ligase complex composed of elongin BC, CUL5, and RBX2 to induce polyubiquitination of APOBEC3G and APOBEC3F. In turn, they are directed to the 26S proteasome for degradation. Vif interaction with APOBEC3G also blocks its cytidine deaminase activity in a proteasome-independent manner, suggesting a dual inhibitory mechanism. May interact directly with APOBEC3G mRNA in order to inhibit its translation. Seems to play a role in viral morphology by affecting the stability of the viral nucleoprotein core. Finally, Vif also contributes to the G2 cell cycle arrest observed in HIV infected cells.

Viral life cycle Source: InterPro

Host cytoplasm; Host cell membrane; Virion. In the cytoplasm, seems to colocalize with intermediate filament vimentin. A fraction is associated with the cytoplasmic side of cellular membranes, presumably via the interaction with Pr55Gag precursor. Incorporated in virions at a ratio of approximately 7 to 20 molecules per virion.

Highly phosphorylated on serine and threonine residues. Thr-96 and Ser-165 are phosphorylated by the mitogen activated kinase MAP4K1. As the HIV-1 replication can be activated by stress and mitogens, these phosphorylations could be involved in this process. Ser-144 phosphorylation may inhibit elongin BC complex binding.
Processed in virion by the viral protease.
Highly phosphorylated on serine and threonine residues.
Polyubiquitinated and degraded by the proteasome in the presence of APOBEC3G.