Virion infectivity factor

UniProtKB accession:  P69723

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UniProtKB description:  Counteracts the innate antiviral activity of host APOBEC3F and APOBEC3G by promoting their ubiquitination and degradation. Acts as a substrate recognition component of an E3 ubiquitin-protein ligase complex: mechanistically, Vif hijacks a host cullin-5-RING E3 ubiquitin-protein ligase complex (ECS complex) and the transcription coactivator CBFB/CBF-beta to form an active E3 ubiquitin-protein ligase complex that targets APOBEC3G and APOBEC3F for polyubiquitination, leading to their degradation by the proteasome. 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. Association with CBFB/CBF-beta also inhibits the transcription coactivator activity of CBFB/CBF-beta. 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.