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Q77375 (VPR_HV1AN) Reviewed, UniProtKB/Swiss-Prot

Last modified February 19, 2014. Version 66. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (1) | Third-party data text xml rdf/xml gff fasta
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Names and origin

Protein namesRecommended name:
Protein Vpr
Alternative name(s):
R ORF protein
Viral protein R
Gene names
OrganismHuman immunodeficiency virus type 1 group O (isolate ANT70) (HIV-1) [Complete proteome]
Taxonomic identifier327105 [NCBI]
Taxonomic lineageVirusesRetro-transcribing virusesRetroviridaeOrthoretrovirinaeLentivirusPrimate lentivirus group
Virus hostHomo sapiens (Human) [TaxID: 9606]

Protein attributes

Sequence length97 AA.
Sequence statusComplete.
Protein existenceInferred from homology

General annotation (Comments)


Involved in the transport of the viral pre-integration (PIC) complex to the nucleus during the early stages of the infection. This function is crucial for viral infection of non-dividing macrophages. May interact with karyopherin alpha/KPNA1 and KPNA2 to increase their affinity for proteins containing basic-type nuclear localization signal, including the viral matrix protein MA, thus facilitating the translocation of the viral genome into the nucleus. May also act directly at the nuclear pore complex, by binding nucleoporins phenylalanine-glycine (FG)-repeat regions By similarity.

May target specific host proteins for degradation by the 26S proteasome. Acts by associating with the cellular CUL4A-DDB1 E3 ligase complex through direct interaction with host VPRPB/DCAF-1. This change in the E3 ligase substrate specificity would result in cell cycle arrest or apoptosis in infected cells. Prevents infected cells from undergoing mitosis and proliferating, by inducing arrest or delay in the G2 phase of the cell cycle. This arrest creates a favorable environment for maximizing viral expression and production by rendering the HIV-1 LTR transcriptionally more active. In this context, Vpr stimulates gene expression driven by the HIV-1 LTR by interacting with human SP1, TFIIB and TFIID. Cell cycle arrest reportedly occurs within hours of infection and is not blocked by antiviral agents, suggesting that it is initiated by the Vpr carried into the virion. Additionally, Vpr induces apoptosis in a cell cycle dependent manner suggesting that these two effects are mechanistically linked. Interacts with mitochondrial permeability transition pore complex (PTPC). This interaction induces a rapid dissipation of the mitochondrial transmembrane potential, and mitochondrial release of apoptogenic proteins such as cytochrome C or apoptosis inducing factors. Detected in the serum and cerebrospinal fluid of AIDS patient, Vpr may also induce cell death to bystander cells By similarity.

Subunit structure

Homooligomer, may form homodimer. Interacts with p6-gag region of the Pr55 Gag precursor protein through a (Leu-X-X)4 motif near the C terminus of the P6gag protein. Interacts with host SLC25A4/ANT1, SLC25A5/ANT2, SLC25A6/ANT3, SP1, CDC25C, RAD23A/HHR23A, COPS6/HVIP, TFIIB, UNG, SF3B2/SAP145, KPNA1 and KPNA2. Interacts with host VPRBP/DCAF1, leading to hijack the CUL4A-RBX1-DDB1-DCAF1/VPRBP complex, mediate ubiquitination of host proteins such as TERT and ZGPAT and arrest the cell cycle in G2 phase. Interacts with ANKHD1 By similarity.

Subcellular location

Virion. Host nucleus. Host extracellular space. Note: Incorporation into virion is dependent on p6 GAG sequences. Lacks a canonical nuclear localization signal, thus import into nucleus may function independently of the human importin pathway. Detected in high quantity in the serum and cerebrospinal fluid of AIDS patient By similarity.


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).

Sequence similarities

Belongs to the HIV-1 VPR protein family.


   Biological processApoptosis
Cell cycle
Host G2/M cell cycle arrest by virus
Host-virus interaction
Ion transport
Modulation of host cell cycle by virus
Transcription regulation
Viral penetration into host nucleus
Virus entry into host cell
   Cellular componentHost nucleus
   Molecular functionActivator
Ion channel
   Technical termComplete proteome
Gene Ontology (GO)
   Biological_processapoptotic process

Inferred from electronic annotation. Source: UniProtKB-KW

cell cycle

Inferred from electronic annotation. Source: UniProtKB-KW

ion transport

Inferred from electronic annotation. Source: UniProtKB-KW

regulation of transcription, DNA-templated

Inferred from electronic annotation. Source: UniProtKB-KW

suppression by virus of G2/M transition of host mitotic cell cycle

Inferred from electronic annotation. Source: UniProtKB-KW

transcription, DNA-templated

Inferred from electronic annotation. Source: UniProtKB-KW

viral entry into host cell

Inferred from electronic annotation. Source: UniProtKB-KW

viral penetration into host nucleus

Inferred from electronic annotation. Source: UniProtKB-KW

   Cellular_componentextracellular space of host

Inferred from electronic annotation. Source: UniProtKB-SubCell

host cell nucleus

Inferred from electronic annotation. Source: UniProtKB-SubCell


Inferred from electronic annotation. Source: GOC


Inferred from electronic annotation. Source: UniProtKB-SubCell

Complete GO annotation...

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 9797Protein Vpr


Region1 – 4242Homooligomerization By similarity

Amino acid modifications

Modified residue791Phosphoserine; by host By similarity
Modified residue951Phosphoserine; by host By similarity
Modified residue971Phosphoserine; by host By similarity


Sequence LengthMass (Da)Tools
Q77375 [UniParc].

Last modified November 1, 1996. Version 1.
Checksum: 0E118346DB4B4EA7

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[1]"Genomic cloning and complete sequence analysis of a highly divergent African human immunodeficiency virus isolate."
Vanden Haesevelde M., Decourt J.L., De Leys R.J., Vanderborght B., van der Groen G., van Heuverswijn H., Saman E.
J. Virol. 68:1586-1596(1994) [PubMed] [Europe PMC] [Abstract]


Sequence databases

L20587 Genomic RNA. Translation: AAA99881.1.

3D structure databases

SMRQ77375. Positions 1-97.

Protocols and materials databases


Family and domain databases

InterProIPR000012. RetroV_VpR/X.
[Graphical view]
PfamPF00522. VPR. 1 hit.
[Graphical view]

Entry information

Entry nameVPR_HV1AN
AccessionPrimary (citable) accession number: Q77375
Entry history
Integrated into UniProtKB/Swiss-Prot: July 25, 2006
Last sequence update: November 1, 1996
Last modified: February 19, 2014
This is version 66 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Relevant documents


Index of protein domains and families