Isoforms: p23 (192 amino acids)

Localization: cytoplasm (cytosol / membrane) virion (Ref. #4)

Function: accessory protein 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

Reference Sequences:

HIV-1 (HXB2):

          10         20         30         40         50         60         70 
           |          |          |          |          |          |          | 
  MENRWQVMIV WQVDRMRIRT WKSLVKHHMY VSGKARGWFY RHHYESPHPR ISSEVHIPLG DARLVITTYW
          80         90        100        110        120        130        140
           |          |          |          |          |          |          |
  GLHTGERDWH LGQGVSIEWR KKRYSTQVDP ELADQLIHLY YFDCFSDSAI RKALLGHIVS PRCEYQAGHN
         150        160        170        180        190 
           |          |          |          |          |
  KVGSLQYLAL AALITPKKIK PPLPSVTKLT EDRWNKPQKT KGHRGSHTMN GH 
      [download in fasta format]

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

InterPro signature for Retroviral Vif protein - IPR000475

• 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

Identifiers:

PDB/MMDB: Search for HIV-1 & VIF

SwissProt: P03401 (HIV-1 HXB2 Vif)
EMBL: K03455; AAB50260.1; [EMBL/GenBank/DDBJ]

PIR: A04002; ASLJS3
HIV: K03455; VIF$HXB2
InterPro: IPR000475
Pfam: PF00559
Prints: PR00349; VIRIONINFECT
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
PRESAGE: 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

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]