VPR - Viral Protein R
HIV VPR is involved in targeting the nuclear localization of
preintegration complexes, arrests infected cells at G2 phase of cell
cycle, and inhibits cell division.
[animated gif: 320x240 ]
Isoforms:
Localization:
Virion
Cell internal membranes
Cell nucleus
Function:
blocks cell division (Ref. #6)
promotes nuclear localization of preintegration complex (Ref. #3)
arrests cell in G2 phase of cell cycle (Ref. #4)
Additional
Information:
~100 copies of Vpr are associated with each virion (Ref. #5)
prevents
activation of p34cdc2/cyclin B complex, which is a regulator of the
cell cycle that important for entry into mitosis (Ref. #7 & #8)
genetically modified p34cdc2 prevents the cell cycle inhibitory activity of Vpr
incorporation of Vpr into virions is mediated by interactions with carboxyl-terminal region of p55 Gag
reduces mutation rate of HIV during replication
Genomic Location: [TOP ]
Reference
Sequences:
HIV-1
(HXB2):
10 20 30 40 50 60 70 | | | | | | | MEQAPEDQGP QREPHNEWTL ELLEELKNEA VRHFPRIWLH GLGQHIYETY GDTWAGVEAI IRILQQLLFI 78 | HFQNWVST [download in fasta format ]
Length:
78 amino acids
Molecular Weight: 9305 Da
Theoretical pI: 4.99
Protein Domains/Folds/Motifs: [TOP ]
InterPro signature for Retroviral VpR/VpX protein - IPR000012
Secondary Structure prediction:
Antigenic Sites - EMBOSS:
N-glycosylation:
none
N-myristoylation:
none
Amidation:
none
Protein kinase C:
none
Casein kinase II:
1 potential site
TygD (49 - 52)
Tyrosine kinase:
none
cAMP / cGMP kinase:
none
Cell attachment motif:
none
Asp Protease motif:
none
Asp Prot Retro motif:
none
Arginine-rich Region:
none
Cysteine-rich Region:
none
Tryptophan-rich Region:
none
Zinc-finger CCHC motif:
none
Leucine Zipper motif:
none
Protein-Protein Interactions: [TOP ]
interacts with carboxyl-terminal (p6 & NCp7 ) region of the N-myristoylated Gag polyprotein
cdc25c is a phosphatase that regulates the cell cycle by activating the p34cdc2 /cyclin B complex through the removal of phosphates from p34cdc2
Vpr induces cell cycle arrest by interacting with cdc25c .
Interactions between Vpr and cdc25c prevent p34cdc2 /cyclin B activation (Ref. #7 & #8)
Vpr interacts with HHR23A and mov34
interacts with Human cellular protein uracil-DNA glycosylase (UNG ) (Ref. #9)
stabilizes the interaction between karyopherin heterodimers and the nuclear localization signal of HIV-1 Matrix
karyopherin mediates nuclear import
Vpr interacts directly with nucleoporin , which make up the nuclear pore complexes and regulate the movement of molecules in and out of the nucleus
Primary and Secondary Database Entries: [TOP ]
Identifiers:
ViralZone: HIV-1 PDB/MMDB: Search for HIV-1 & VPR
SwissProt: P69726 (HIV-1 HXB2 Vpr)
EMBL: K03455; AAB50261.1; [EMBL /GenBank /DDBJ ]
PIR: UNKNOWN
HIV: K03455; VPR$HXB2
InterPro: IPR000012
Pfam: PF00522
Prints: PR00444 ; HIVVPRVPX
ProDom: PD000233 (residues 1 - 36) / PD000213 (residues 38 - 71)
SCOP: none
BLOCKS: P05926
Prosite: P05926 ProtoNet: P05926
ProtoMap: P05926
PRESAGE: P05926
Database of Interacting Proteins: P05926
ModBase: P05926
Swiss-2DPAGE: 2D gel
BioAfrica Tools:
- Vpr Protein Data Mining Tool provides real-time analysis of HIV-1 Vpr 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 ]
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 Vpr protein of human immunodeficiency virus type 1 influences nuclear localization of viral
nucleic acids in nondividing host cells.
Heinzinger NK, Bukinsky MI, Haggerty SA.
Proc Natl Acad Sci USA 91: 7311-7315 (1994) [pubmed: 8041786 ]
4 - The human immunodeficiency virus type 1 vpr gene arrests infected T cells in the G2 + M phase
of the cell cycle.
Jowett JB, Planelles V, Poon B.
J Virol 69: 6304-6313 (1995) [pubmed: 7666531 ]
5 - Human immunodeficiency virus vpr product is a virion-associated regulatory protein.
Cohen EA, Dehni G, Sodroski JG.
J Virol 64: 3097-3099 (1990) [pubmed: 2139896 ]
6 - The human immunodeficiency virus type 1 vpr gene prevents cell proliferation during
chronic infection.
Rogel ME, Wu LI, Emerman M.
J Virol 69: 882-888 (1995) [pubmed: 7815556 ]
7 - Human immunodeficiency virus type 1 Vpr arrests the cell cycle in G2 by inhibiting
the activation of p34cdc2-cyclin B.
Braaten D, Franke EK, Luban J.
J Virol 69: 6859-6864 (1995) [pubmed: 7474100 ]
8 - Human immunodeficiency virus type 1 viral protein R (Vpr) arrests cells in the G2 phase of
the cell cycle by inhibiting p34cdc2 activity.
He J, Choe S, Walker R.
J Virol 69: 6705-6711 (1995) [pubmed: 7474080 ]
9 - Human immunodeficiency virus type 1 Vpr protein binds to the uracil DNA glycosylase
DNA repair enzyme.
Bouhamdan M, Benichou S, Rey F.
J Virol 70: 697-704 (1996) [pubmed: 8551605 ]