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Q79669 (VPU_HV1MV) Reviewed, UniProtKB/Swiss-Prot

Last modified April 16, 2014. Version 56. 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 Vpu
Alternative name(s):
U ORF protein
Viral protein U
Gene names
OrganismHuman immunodeficiency virus type 1 group O (isolate MVP5180) (HIV-1) [Complete proteome]
Taxonomic identifier388816 [NCBI]
Taxonomic lineageVirusesRetro-transcribing virusesRetroviridaeOrthoretrovirinaeLentivirusPrimate lentivirus group
Virus hostHomo sapiens (Human) [TaxID: 9606]

Protein attributes

Sequence length85 AA.
Sequence statusComplete.
Protein existenceInferred from homology

General annotation (Comments)


Enhances virion budding, by targeting human CD4 and Tetherin/BST2 to proteasome degradation. Degradation of CD4 prevents any unwanted premature interactions between viral Env and its receptor human CD4 in the endoplasmic reticulum. Degradation of antiretroviral protein Tetherin/BST2 is important for virion budding, as BST2 tethers new viral particles to the host cell membrane. Mechanistically, Vpu bridges either CD4 or BST2 to BTRC, a substrate recognition subunit of the Skp1/Cullin/F-box protein E3 ubiquitin ligase, induces their ubiquitination and subsequent proteasomal degradation. The alteration of the E3 ligase specificity by Vpu seems to interfere with the degradation of host IKBKB, leading to NF-kappa-B down-regulation and subsequent apoptosis. Ion channel activity has also been suggested, however, formation of cation-selective channel has been reconstituted ex-vivo in lipid bilayers. It is thus unsure that this activity plays a role in vivo By similarity.

Enzyme regulation

Ion channel activity is inhibited by hexamethylene amiloride in vitro By similarity.

Subunit structure

May form pentamers or hexamers. Forms ternary complexes, by interacting with human CD4 and BTRC, and with human BST2 and BTRC By similarity.

Subcellular location

Host membrane; Single-pass type I membrane protein By similarity.


The N-terminal and transmembrane domains are required for proper virion budding, whereas the cytoplasmic domain is required for CD4 degradation. The cytoplasmic domain is composed of 2 amphipathic alpha helix By similarity.

Post-translational modification

Phosphorylated by host CK2. This phosphorylation is necessary for interaction with human BTRC and degradation of CD4 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 VPU protein family.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 8585Protein Vpu


Topological domain1 – 44Extracellular Potential
Transmembrane5 – 2521Helical; Potential
Topological domain26 – 8560Cytoplasmic Potential

Amino acid modifications

Modified residue571Phosphoserine; by host CK2 By similarity
Modified residue611Phosphoserine; by host CK2 By similarity


Sequence LengthMass (Da)Tools
Q79669 [UniParc].

Last modified November 1, 1996. Version 1.
Checksum: D9BD63BB4BC9F417

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[1]"A new subtype of human immunodeficiency virus type 1 (MVP-5180) from Cameroon."
Gurtler L.G., Hauser P.H., Eberle J., von Brunn A., Knapp S., Zekeng L., Tsague J.M., Kaptue L.
J. Virol. 68:1581-1585(1994) [PubMed] [Europe PMC] [Abstract]


Sequence databases

L20571 Genomic RNA. Translation: AAA44863.1.

3D structure databases


Protocols and materials databases


Family and domain databases

InterProIPR008187. Vpu.
[Graphical view]
PfamPF00558. Vpu. 1 hit.
[Graphical view]

Entry information

Entry nameVPU_HV1MV
AccessionPrimary (citable) accession number: Q79669
Entry history
Integrated into UniProtKB/Swiss-Prot: June 27, 2006
Last sequence update: November 1, 1996
Last modified: April 16, 2014
This is version 56 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