VIF - Virion Infectivity Factor

HIV VIF counteracts the innate antiviral activity of host cytidine deaminase nucleic acid editing enzymes and increases infectivity.

Vif Life cycle

Key web links:
ViralZone: HIV-1, HIV replication cycle, HIV resource
PDB: not available
UniProt: P69723 (HIV-1 HXB2 Vif)
Chime Tutorial: not available
HIV-1/Human Protein Interaction DB: HIV-1 Vif
Los Alamos HIV structure DB: not available
EMBL: K03455 [EMBL/GenBank/DDBJ]


  • p23 (192 amino acids)


  • Counteracts the innate antiviral activity of host cytidine deaminase nucleic acid editing enzymes APOBEC3D (A3D), APOBEC3G (A3G), APOBEC3F (A3F) and APOBEC3H (A3H) by degrading these lethally hypermutating enzymes and preventing their incorporation into progeny virions .
  • Enhances infectivity of virus particles.


  • Virion
  • Cell cytoplasm
  • Host cell membrane

Additional Information:

  • Late timing of expression.
  • 7 to 20 Vif molecules are incorporated into each virion .
  • Vif requires phosphorylation in order to function.
  • Essential for the replication of HIV in lymphocytes and macrophages .
  • Vif interacts with viral genomic RNA, and is packaged into the nucleoprotein complex .
  • Vif mutants result in improperly packaged nucleoprotein cores .
  • Vif activity is influenced by multimerization .
  • When involved in mRNP complexes, Vif may mediate viral RNA interactions with HIV-1 Gag precursors during the formation of the viral particle.
  • APOBEC3G is a human cytoplasmic protein that provides an intracellular defence against HIV replication in T cells by binding to viral RNA.
  • APOBEC3G expression is sufficient to prevent HIV infection.
  • Viruses lacking Vif are only able to replicate in cells lacking APOBEC3G.
  • APOBEC3G is homologous to cytidine deaminase, an enzyme that edits RNA.
  • Vif functions during virus particle assembly.

Vif Function & Host-Virus Protein Interactions:[TOP]

Interactions highlighted in the image:

Potential interactions (not in the image):

Genomic Location & Protein Sequence: [TOP]

HIV-1 (HXB2):

          10         20         30         40         50         60         70         80         90        100
| | | | | | | | | |
110 120 130 140 150 160 170 180 190
| | | | | | | | |
[download in fasta format]

Length: 192 amino acids
Molecular Weight: 22513 Da
Theoretical pI: 9.89

Protein Domains/Folds/Motifs: [TOP]

InterPro signature for Retroviral Vif protein - IPR000475

Secondary Structure prediction:

Low Complexity Regions - seg:

Antigenic sites - EMBOSS:

DOMON domain:

Predicted Motifs: Printer-friendly version

Protein kinase C:
Casein kinase II:
Tyrosine kinase:
cAMP / cGMP kinase:
Cell attachment motif:
Asp Protease motif:
Asp Prot Retro motif:
Arginine-rich Region:
Cysteine-rich Region:
Tryptophan-rich Region:
Zinc-finger CCHC motif:
Leucine Zipper motif:

Primary and Secondary Database Entries: [TOP]


ViralZone: HIV-1, HIV replication cycle, HIV resource
PDB/MMDB: Search for HIV-1 & VIF

UniProt: P69723 (HIV-1 HXB2 Vif)
EMBL: K03455; AAB50260.1; [EMBL/GenBank/DDBJ]

InterPro: IPR000475
Pfam: PF00559
SCOP: SSF50331 MOP-like protein
BLOCKS: P03401
Prosite: P03401
ProtoNet: P03401
Database of Interacting Proteins: P03401
ModBase: P03401
HIV-1/Human Protein Interaction DB: HIV-1 Vif
HIV-1 Sequence Database Los Alamos HIV Sequence Database


Reviews and References: [TOP]

Cite the resource by citing the following paper:
Doherty R et al. BioAfrica's HIV-1 Proteomics Resource: Combining protein data with bioinformatics tools. Retrovirology (2005), 9;2(1):18.

1 - HIV Sequence Compendium 2000
Kuiken CL, Foley B, Hahn B, Korber B, Marx PA, McCutchan F, Mellors JW, Mullins JI, Sodroski J, Wolinksy S.
Theoretical Biol. & Biophys. Group, Los Alamos Nat Lab, LA-UR 01-3860 [Read it online: Compendium]
2 - Retroviruses
Coffin JM, Hughes SH, Varmus HE.
CD-ROM ed. (2002) Cold Spring Harbor Laboratory Press [Read it online: NCBI Bookshelf]
3 - The HIV 'A' (sor) gene product is essential for virus infectivity.
Strebel K, Daugherty D, Clouse K.
Nature 328: 728-730 (1987) [pubmed: 2441266]
4 - The Vif protein of human and simian immunodeficiency viruses is packaged into virions and
associates with viral core structures.
Liu H, Wu X, Newman M.
J Virol 69: 7630-7638 (1995) [pubmed: 7494271]
5 - Role of vif during packing of the core of HIV-1.
Hoglund S, Ohagen A, Lawrence K.
Virology 201(2): 349-355 (1994) [pubmed: 8184544]
6 - Human immunodeficiency virus type 1 Vif protein is packaged into the nucleoprotein complex
through an interaction with viral genomic RNA.
Khan MA.
J Virol 75(16): 7252-7265 (2001) [pubmed: 11461998]
7 - The multimerization of human immunodeficiency virus type I Vif protein: a requirement for Vif
function in the viral life cycle.
Yang S, Sun Y, Zhang H.
J Biol Chem 276(7): 4889-4893 (1994) [pubmed: 11071884]
8 - Characterization of human immunodeficiency virus type 1 Vif particle incorporation.
Camaur D, Trono D.
J Virol 70(9): 6106-6111 (1996) [pubmed: 8709234]
9 - Suppression of APOBEC3-mediated restriction of HIV-1 by Vif.
Feng Y, Baig TT, Love RP, Chelico L.
Front Microbiol. 5:450 (2014) [pubmed: 25206352]
10 - HIV-1 Vif: a guardian of the virus that opens up a new era in the research field of restriction factors.
Takaori-Kondo A, Shindo K.
Front Microbiol. 4:34 (2013) [pubmed: 23430691]
11 - HIV-1 Vif protein binds the editing enzyme APOBEC3G and induces its degradation.
Marin M, Rose KM, Kozak SL, Kabat D.
Nat Med. 9(11):1398-403 (2003) [pubmed: 14528301]
12 - The SOCS-box of HIV-1 Vif interacts with ElonginBC by induced-folding to recruit its Cul5-containing ubiquitin ligase complex.
Bergeron JR, Huthoff H, Veselkov DA, Beavil RL, Simpson PJ, Matthews SJ, Malim MH, Sanderson MR.
PLoS Pathog. 6(6):e1000925 (2010) [pubmed: 20532212]
13 - Structural analysis of viral infectivity factor of HIV type 1 and its interaction with A3G, EloC and EloB.
da Costa KS, Leal E, dos Santos AM, Lima e Lima AH, Alves CN, Lameira J.
PLoS One 9(2):e89116 (2014) [pubmed: 24586532]
14 - HIV-1 Vif N-terminal motif is required for recruitment of Cul5 to suppress APOBEC3.
Evans SL, Schön A, Gao Q, Han X, Zhou X, Freire E, Yu XF.
Retrovirology 11:4 (2014) [pubmed: 24422669]
15 - A second human antiretroviral factor, APOBEC3F, is suppressed by the HIV-1 and HIV-2 Vif proteins.
Wiegand HL, Doehle BP, Bogerd HP, Cullen BR.
EMBO J. 23(12):2451-8 (2004) [pubmed: 15152192]
16 - Defining HIV-1 Vif residues that interact with CBFβ by site-directed mutagenesis.
Matsui Y, Shindo K, Nagata K, Io K, Tada K, Iwai F, Kobayashi M, Kadowaki N, Harris RS, Takaori-Kondo A.
Virology 449:82-7 (2014) [pubmed: 24418540]
17 - Induction of APOBEC3G ubiquitination and degradation by an HIV-1 Vif-Cul5-SCF complex.
Yu X, Yu Y, Liu B, Luo K, Kong W, Mao P, Yu XF.
Science 302(5647):1056-60 (2003) [pubmed: 14564014]

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