ID   Q99D92_9HIV1            Unreviewed;        85 AA.
AC   Q99D92;
DT   01-JUN-2001, integrated into UniProtKB/TrEMBL.
DT   01-JUN-2001, sequence version 1.
DT   08-NOV-2023, entry version 44.
DE   RecName: Full=Protein Vpu {ECO:0000256|RuleBase:RU364058};
DE   AltName: Full=U ORF protein {ECO:0000256|RuleBase:RU364058};
DE   AltName: Full=Viral protein U {ECO:0000256|RuleBase:RU364058};
GN   Name=rev {ECO:0000313|EMBL:AAK14223.1};
GN   Synonyms=vpu {ECO:0000256|RuleBase:RU364058};
OS   Human immunodeficiency virus 1.
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Lentivirus.
OX   NCBI_TaxID=11676 {ECO:0000313|EMBL:AAK14223.1};
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1] {ECO:0000313|EMBL:AAK14223.1}
RP   NUCLEOTIDE SEQUENCE.
RC   STRAIN=4354 {ECO:0000313|EMBL:AAK14223.1};
RA   Vallejo A., Gurtler L., Zekeng L., Hewlett I.K.;
RT   "Nucleotide sequence analysis of the accessory genes of HIV-1 group O
RT   isolates.";
RL   Submitted (OCT-2000) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Enhances virion budding, by targeting human CD4 and
CC       Tetherin/BST2 to proteasome degradation. Degradation of CD4 prevents
CC       any unwanted premature interactions between viral Env and its receptor
CC       human CD4 in the endoplasmic reticulum. Degradation of antiretroviral
CC       protein Tetherin/BST2 is important for virion budding, as BST2 tethers
CC       new viral particles to the host cell membrane. Mechanistically, Vpu
CC       bridges either CD4 or BST2 to BTRC, a substrate recognition subunit of
CC       the Skp1/Cullin/F-box protein E3 ubiquitin ligase, induces their
CC       ubiquitination and subsequent proteasomal degradation. The alteration
CC       of the E3 ligase specificity by Vpu seems to interfere with the
CC       degradation of host IKBKB, leading to NF-kappa-B down-regulation and
CC       subsequent apoptosis. Acts as a viroporin that forms an oligomeric ion
CC       channel in membranes. Modulates the host DNA repair mechanisms to
CC       promote degradation of nuclear viral cDNA in cells that are already
CC       productively infected in order to suppress immune sensing and proviral
CC       hyper-integration (superinfection). Manipulates PML-NBs and modulates
CC       SUMOylation of host BLM protein thereby enhancing its DNA-end
CC       processing activity toward viral unintegrated linear DNA. Also inhibits
CC       RAD52-mediated homologous repair of viral cDNA, preventing the
CC       generation of dead-end circular forms of single copies of the long
CC       terminal repeat and permitting sustained nucleolytic attack.
CC       {ECO:0000256|RuleBase:RU364058}.
CC   -!- SUBCELLULAR LOCATION: Host membrane {ECO:0000256|RuleBase:RU364058};
CC       Single-pass type I membrane protein {ECO:0000256|RuleBase:RU364058}.
CC   -!- SIMILARITY: Belongs to the HIV-1 VPU protein family.
CC       {ECO:0000256|RuleBase:RU364058}.
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DR   EMBL; AF316862; AAK14223.1; -; Genomic_DNA.
DR   GO; GO:0033644; C:host cell membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016020; C:membrane; IEA:UniProtKB-KW.
DR   GO; GO:0005261; F:monoatomic cation channel activity; IEA:InterPro.
DR   GO; GO:0032801; P:receptor catabolic process; IEA:InterPro.
DR   GO; GO:0019076; P:viral release from host cell; IEA:UniProtKB-UniRule.
DR   InterPro; IPR008187; Vpu.
DR   Pfam; PF00558; Vpu; 1.
PE   3: Inferred from homology;
KW   Apoptosis {ECO:0000256|RuleBase:RU364058};
KW   Host membrane {ECO:0000256|RuleBase:RU364058};
KW   Host-virus interaction {ECO:0000256|RuleBase:RU364058};
KW   Ion channel {ECO:0000256|RuleBase:RU364058};
KW   Ion transport {ECO:0000256|RuleBase:RU364058};
KW   Membrane {ECO:0000256|RuleBase:RU364058};
KW   Transmembrane {ECO:0000256|RuleBase:RU364058};
KW   Transmembrane helix {ECO:0000256|RuleBase:RU364058};
KW   Transport {ECO:0000256|RuleBase:RU364058}.
FT   TRANSMEM        6..31
FT                   /note="Helical"
FT                   /evidence="ECO:0000256|RuleBase:RU364058"
SQ   SEQUENCE   85 AA;  10395 MW;  6BE3E43A02CC8BEA CRC64;
     MNHKDLIVLI VIVALLLINV LLWTFNLRAY LEDRKQDRRE REILKRLRRI REIREDSDYE
     SNGEEEQEVR DLVFDYGFAN PMFEL
//