VIF - Virion Infectivity Factor

HIV VIF promotes virion maturation and infectivity.

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PDB: not available
SwissProt: P69723 (HIV-1 HXB2 Vif)
Chime Tutorial: not available
Los Alamos HIV structure DB: not available
EMBL: K03455 [EMBL/GenBank/DDBJ]
BioAfrica: Vif Protein Data Mining Tool


  • p23 (192 amino acids)


  • Virion (Ref. #4)
  • Cell cytoplasm (cytosol / membrane)


  • Counteracts the innate antiviral activity of human APOBEC3F and APOBEC3G. Forms a complex with host APOBEC3F and APOBEC3G thus preventing the entry of these lethally hypermutating enzymes into progeny virions
  • Enhances infectivity of virus particles
  • Inhibits T cell intracellular antiviral defences
  • Prevents T cell intracellular antiviral proteins from being incorporated in viral particles
  • Functions during virus particle assembly
  • Binds to viral genomic RNA in the cytoplasm to form
    a 40 S messenger ribonucleoprotein (mRNP) complex
  • Regulates protease activity

Additional Information:

  • 7 to 20 Vif molecules are incorporated into each virion (Ref. #8)
  • Vif requires phosphorylation in order to function
  • essential for replication of HIV in lymphocytes and macrophages (Ref. #3)
  • Vif mutants result in improperly packed nucleoprotein cores (Ref. #5)
  • Vif interacts with viral genomic RNA, and is package into the nucleoprotein complex (Ref. #6)
  • Vif activity is influenced by multimerization (Ref. #7)
  • When involved in mRNP complexes, Vif may mediate viral RNA interactions with HIV-1 Gag precursors during the formation of the viral particle
  • CEM15 is a human cytoplasmic protein that provides an intracellular defence against HIV replication in T cells by binding to viral RNA
  • CEM15 expression is sufficient to prevent HIV infection
  • Viruses lacking Vif are only able to replicate in cells lacking CEM15
  • CEM15 is homologous to cytidine deaminase, an enzyme that edits RNA

Genomic Location: [TOP]

Reference Sequences:

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:

Protein-Protein Interactions: [TOP]

  • Viruses lacking Vif are only able to replicate in cells lacking CEM15 (also known as apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G, APOBEC3G).
  • Vif prevents CEM15/APOBEC3G from being incorporated into viral particles. If CEM15/APOBEC3G is incorporated with the HIV core, it will induce G-to-A hypermutation of nascent viral DNA. Many viral mRNA transcripts would get degradated by host factors, while remaining viral mRNA will result in proteins with excessive polymorphisms
  • Vif interacts with HIV-1 Protease to prevent it from cleaving Gag and Gag-Pol polyproteins at the wrong stage of the replication cycle

Primary and Secondary Database Entries: [TOP]


ViralZone: HIV-1
PDB/MMDB: Search for HIV-1 & VIF

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

PIR: A04002; ASLJS3
HIV: K03455; VIF$HXB2
InterPro: IPR000475
Pfam: PF00559
ProDom: PD590614 (residues 1 - 32) / PD579704 (residues 2 - 89) / PD042902 (residues 17 - 145)
PD596211 (residues 32 - 69) / PD460564 (residues 38 - 152) / PD595841 (residues 70 - 93)
PD000063 (residues 94 - 132) / PD554398 (residues 133 - 152) / PD595446 (residues 165 - 186)
SCOP: SSF50331 MOP-like protein
BLOCKS: P03401
Prosite: P03401
ProtoNet: P03401
ProtoMap: P03401
Database of Interacting Proteins: P03401
ModBase: P03401
Swiss-2DPAGE: 2D gel

BioAfrica Tools:
- Vif Protein Data Mining Tool provides real-time analysis of HIV-1 Vif isolates
- HIV Structure BLAST searches for similar HIV sequences that have known structures
- HIV Proteomics Resource contains protein sequence and structure analysis tools

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]

Page last updated by Tulio de Oliveira.