Skip Header

You are using a version of browser that may not display all the features of this website. Please consider upgrading your browser.

Virion infectivity factor



Human immunodeficiency virus type 1 group M subtype B (isolate HXB2) (HIV-1)
Reviewed-Annotation score: -Experimental evidence at protein leveli


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.UniRule annotation5 Publications


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.UniRule annotation
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).UniRule annotation
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.UniRule annotation

GO - Molecular functioni

  • identical protein binding Source: IntAct
  • RNA binding Source: UniProtKB-KW

GO - Biological processi


Molecular functionRNA-binding
Biological processHost-virus interaction, Ubl conjugation pathway

Enzyme and pathway databases

ReactomeiR-HSA-162585 Uncoating of the HIV Virion
R-HSA-162588 Budding and maturation of HIV virion
R-HSA-162592 Integration of provirus
R-HSA-162594 Early Phase of HIV Life Cycle
R-HSA-164516 Minus-strand DNA synthesis
R-HSA-164525 Plus-strand DNA synthesis
R-HSA-164843 2-LTR circle formation
R-HSA-173107 Binding and entry of HIV virion
R-HSA-175474 Assembly Of The HIV Virion
R-HSA-175567 Integration of viral DNA into host genomic DNA
R-HSA-177539 Autointegration results in viral DNA circles
R-HSA-180585 Vif-mediated degradation of APOBEC3G
R-HSA-180689 APOBEC3G mediated resistance to HIV-1 infection
R-HSA-180910 Vpr-mediated nuclear import of PICs

Names & Taxonomyi

Protein namesi
Recommended name:
Virion infectivity factorUniRule annotation
Short name:
VifUniRule annotation
Alternative name(s):
SOR proteinUniRule annotation
Cleaved into the following 2 chains:
p17UniRule annotation
p7UniRule annotation
Gene namesi
Name:vifUniRule annotation
OrganismiHuman immunodeficiency virus type 1 group M subtype B (isolate HXB2) (HIV-1)
Taxonomic identifieri11706 [NCBI]
Taxonomic lineageiVirusesRetro-transcribing virusesRetroviridaeOrthoretrovirinaeLentivirusPrimate lentivirus group
Virus hostiHomo sapiens (Human) [TaxID: 9606]
  • UP000002241 Componenti: Genome

Subcellular locationi

  • Host cytoplasm UniRule annotation
  • Host cell membrane UniRule annotation; Peripheral membrane protein UniRule annotation; Cytoplasmic side UniRule annotation
  • Virion UniRule annotation
  • Note: 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.UniRule annotation

GO - Cellular componenti

Keywords - Cellular componenti

Host cell membrane, Host cytoplasm, Host membrane, Membrane, Virion

Pathology & Biotechi


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi96T → A: 90% loss of reverse transcriptase activity in virions; no effect on the ability to decrease APOBEC3G level. 1 Publication1
Mutagenesisi96T → E: Complete loss of viral infectivity in non permissive cells; no effect on the ability to decrease APOBEC3G level. 1 Publication1
Mutagenesisi114C → S: Reduces the ability to decrease APOBEC3G level; when associated with S-133. 1 Publication1
Mutagenesisi133C → S: Reduces the ability to decrease APOBEC3G level; when associated with S-114. 1 Publication1
Mutagenesisi144S → A: 90% loss of viral infectivity in non permissive cells; no effect on the ability to decrease APOBEC3G level. 1 Publication1
Mutagenesisi157 – 160KKIK → AAIA: 75% loss of membrane binding; decrease Pr55Gag binding. 1 Publication4
Mutagenesisi173 – 179RWNKPQK → AWNAPQA: 40% loss of membrane binding; decrease Pr55Gag binding. 7
Mutagenesisi179 – 184KTKGHR → ATAGHA: 25% loss of membrane binding; decrease Pr55Gag binding. 6
Mutagenesisi188T → A: No effect on the ability to decrease APOBEC3G level. 1 Publication1

Keywords - Diseasei


PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000427591 – 192Virion infectivity factorUniRule annotationAdd BLAST192
ChainiPRO_00000427601 – 150p17UniRule annotationAdd BLAST150
ChainiPRO_0000042761151 – 192p7UniRule annotationAdd BLAST42

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei96Phosphothreonine; by host MAP4K1UniRule annotation1 Publication1
Modified residuei144Phosphoserine; by hostUniRule annotation1 Publication1
Modified residuei155Phosphothreonine; by hostUniRule annotation1 Publication1
Modified residuei165Phosphoserine; by host MAP4K1UniRule annotation1 Publication1
Modified residuei188Phosphothreonine; by hostUniRule annotation1 Publication1

Post-translational modificationi

Highly phosphorylated on serine and threonine residues (By similarity). 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.UniRule annotation2 Publications
Processed in virion by the viral protease.UniRule annotation
Polyubiquitinated and degraded by the proteasome in the presence of APOBEC3G.UniRule annotation


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei150 – 151Cleavage in virion (by viral protease)UniRule annotation2

Keywords - PTMi

Phosphoprotein, Ubl conjugation

Proteomic databases


PTM databases




Expressed late during infection in a Rev-dependent manner.UniRule annotation


Subunit structurei

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.UniRule annotation6 Publications

Binary interactionsi

Show more details

GO - Molecular functioni

  • identical protein binding Source: IntAct

Protein-protein interaction databases

BioGridi1205539, 59 interactors
IntActiP69723, 5 interactors


3D structure databases


Family & Domainsi


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni14 – 17Interaction with host APOBEC3F; F1-boxUniRule annotation4
Regioni40 – 44Interaction with host APOBEC3G; G-boxUniRule annotation5
Regioni54 – 72Interaction with host APOBEC3F and APOBEC3G; FG-boxUniRule annotationAdd BLAST19
Regioni74 – 79Interaction with host APOBEC3F; F2-boxUniRule annotation6
Regioni75 – 114RNA-bindingUniRule annotationAdd BLAST40
Regioni151 – 164MultimerizationUniRule annotationAdd BLAST14
Regioni171 – 172Membrane associationUniRule annotation2


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Motifi108 – 139HCCH motifUniRule annotationAdd BLAST32
Motifi144 – 153BC-box-like motifUniRule annotation10


The BC-like-box motif mediates the interaction with elongin BC complex.UniRule annotation
The HCCH motif (H-x5-C-x(18)-C-x5-H) mediates the interaction with CUL5.UniRule annotation

Sequence similaritiesi

Belongs to the primate lentivirus group Vif protein family.UniRule annotationCurated

Phylogenomic databases


Family and domain databases

HAMAPiMF_04081 HIV_VIF, 1 hit
InterProiView protein in InterPro
IPR000475 Viral_infect
PfamiView protein in Pfam
PF00559 Vif, 1 hit


Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P69723-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
60 70 80 90 100
110 120 130 140 150
160 170 180 190
Mass (Da):22,513
Last modified:August 13, 1987 - v1

Sequence databases

Select the link destinations:
Links Updated
K03455 Genomic RNA Translation: AAB50260.1
RefSeqiNP_057851.1, NC_001802.1

Genome annotation databases


Similar proteinsi

Entry informationi

Entry nameiVIF_HV1H2
AccessioniPrimary (citable) accession number: P69723
Secondary accession number(s): P03401
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: August 13, 1987
Last modified: May 23, 2018
This is version 90 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program


Keywords - Technical termi

Complete proteome, Direct protein sequencing, Reference proteome


  1. SIMILARITY comments
    Index of protein domains and families

We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.

Do not show this banner again
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health