Belongs to the primate lentivirus group Vif protein family.
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.
Expressed late during infection in a Rev-dependent manner.
HIV-1 lineages are divided in three main groups, M (for Major), O (for Outlier), and N (for New, or Non-M, Non-O). The vast majority of strains found worldwide belong to the group M. Group O seems to be endemic to and largely confined to Cameroon and neighboring countries in West Central Africa, where these viruses represent a small minority of HIV-1 strains. The group N is represented by a limited number of isolates from Cameroonian persons. The group M is further subdivided in 9 clades or subtypes (A to D, F to H, J and K).
Highly phosphorylated on serine and threonine residues.
Homomultimer; in vitro and presumably in vivo. Interacts with viral RNA and Pr55Gag precursor; these interactions mediate Vif incorporation into the virion. Interacts with the viral reverse transcriptase. Interacts with human APOBEC3F and APOBEC3G. Interacts with host UBCE7IP1 isoform 3/ZIN and possibly with SAT. Interacts with host tyrosine kinases HCK and FYN; these interactions may decrease level of phosphorylated APOBEC3G incorporation into virions. Interacts with host ABCE1; this interaction may play a role in protecting viral RNA from damage during viral assembly. Forms an E3 ligase complex by interacting with host CUL5 and elongin BC complex (ELOB and ELOC). Interacts with host MDM2; this interaction targets Vif for degradation by the proteasome.
Polyubiquitinated and degraded by the proteasome in the presence of APOBEC3G.
Processed in virion by the viral protease.
Required for replication in 'nonpermissive' cells, including primary T-cells, macrophages and certain T-cell lines, but is dispensable for replication in 'permissive' cell lines, such as 293T cells. In nonpermissive cells, Vif-defective viruses can produce virions, but they fail to complete reverse transcription and cannot successfully infect new cells.
The BC-like-box motif mediates the interaction with elongin BC complex.
The HCCH motif (H-x(5)-C-x(18)-C-x(5)-H) mediates the interaction with CUL5.
Vif-defective viruses show catastrophic failure in reverse transcription due to APOBEC-induced mutations that initiate a DNA base repair pathway and compromise the structural integrity of the ssDNA. In the absence of Vif, the virion is morphologically abnormal.
Belongs to the primate lentivirus group gag polyprotein family.
Specific enzymatic cleavages by the viral protease yield mature proteins.