VPU_HV1B9
ID VPU_HV1B9 Reviewed; 80 AA.
AC Q89843;
DT 03-OCT-2006, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1996, sequence version 1.
DT 25-MAY-2022, entry version 95.
DE RecName: Full=Protein Vpu {ECO:0000255|HAMAP-Rule:MF_04082};
DE AltName: Full=U ORF protein {ECO:0000255|HAMAP-Rule:MF_04082};
DE AltName: Full=Viral protein U {ECO:0000255|HAMAP-Rule:MF_04082};
GN Name=vpu {ECO:0000255|HAMAP-Rule:MF_04082};
OS Human immunodeficiency virus type 1 group M subtype B (strain 89.6)
OS (HIV-1).
OC Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC Ortervirales; Retroviridae; Orthoretrovirinae; Lentivirus.
OX NCBI_TaxID=401671;
OH NCBI_TaxID=9606; Homo sapiens (Human).
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=1433527; DOI=10.1128/jvi.66.12.7517-7521.1992;
RA Collman R., Balliet J.W., Gregory S.A., Friedman H., Kolson D.L.,
RA Nathanson N., Srinivasan A.;
RT "An infectious molecular clone of an unusual macrophage-tropic and highly
RT cytopathic strain of human immunodeficiency virus type 1.";
RL J. Virol. 66:7517-7521(1992).
CC -!- FUNCTION: Enhances virion budding by targeting host CD4 and
CC Tetherin/BST2 to proteasome degradation. Degradation of CD4 prevents
CC any unwanted premature interactions between viral Env and its host
CC receptor CD4 in the endoplasmic reticulum. Degradation of
CC antiretroviral protein Tetherin/BST2 is important for virion budding,
CC as BST2 tethers new viral particles to the host cell membrane.
CC Mechanistically, Vpu bridges either CD4 or BST2 to BTRC, a substrate
CC recognition subunit of the Skp1/Cullin/F-box protein E3 ubiquitin
CC ligase, induces their ubiquitination and subsequent proteasomal
CC degradation. The alteration of the E3 ligase specificity by Vpu seems
CC to promote the degradation of host IKBKB, leading to NF-kappa-B down-
CC regulation and subsequent apoptosis. Ion channel activity has also been
CC suggested, however, formation of cation-selective channel has been
CC reconstituted ex-vivo in lipid bilayers. It is thus unsure that this
CC activity plays a role in vivo. {ECO:0000255|HAMAP-Rule:MF_04082}.
CC -!- ACTIVITY REGULATION: Ion channel activity is inhibited by hexamethylene
CC amiloride in vitro. {ECO:0000255|HAMAP-Rule:MF_04082}.
CC -!- SUBUNIT: Forms pentamers or hexamers. Interacts with host CD4 and BRTC;
CC these interactions induce proteasomal degradation of CD4. Interacts
CC with host BST2; this interaction leads to the degradation of host BST2.
CC Interacts with host FBXW11. Interacts with host AP1M1; this interaction
CC plays a role in the mistrafficking and subsequent degradation of host
CC BST2. {ECO:0000255|HAMAP-Rule:MF_04082}.
CC -!- SUBCELLULAR LOCATION: Host membrane {ECO:0000255|HAMAP-Rule:MF_04082};
CC Single-pass type I membrane protein {ECO:0000255|HAMAP-Rule:MF_04082}.
CC -!- DOMAIN: The N-terminal and transmembrane domains are required for
CC proper virion budding, whereas the cytoplasmic domain is required for
CC CD4 degradation. The cytoplasmic domain is composed of 2 amphipathic
CC alpha helix. {ECO:0000255|HAMAP-Rule:MF_04082}.
CC -!- PTM: Phosphorylated by host CK2. This phosphorylation is necessary for
CC interaction with human BTRC and degradation of CD4. {ECO:0000255|HAMAP-
CC Rule:MF_04082}.
CC -!- MISCELLANEOUS: HIV-1 lineages are divided in three main groups, M (for
CC Major), O (for Outlier), and N (for New, or Non-M, Non-O). The vast
CC majority of strains found worldwide belong to the group M. Group O
CC seems to be endemic to and largely confined to Cameroon and neighboring
CC countries in West Central Africa, where these viruses represent a small
CC minority of HIV-1 strains. The group N is represented by a limited
CC number of isolates from Cameroonian persons. The group M is further
CC subdivided in 9 clades or subtypes (A to D, F to H, J and K).
CC {ECO:0000255|HAMAP-Rule:MF_04082}.
CC -!- SIMILARITY: Belongs to the HIV-1 VPU protein family.
CC {ECO:0000255|HAMAP-Rule:MF_04082}.
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DR EMBL; U39362; AAA81042.1; -; Genomic_DNA.
DR Proteomes; UP000007691; Genome.
DR GO; GO:0033644; C:host cell membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-UniRule.
DR GO; GO:0005261; F:cation channel activity; IEA:UniProtKB-UniRule.
DR GO; GO:0042609; F:CD4 receptor binding; IEA:UniProtKB-UniRule.
DR GO; GO:0032801; P:receptor catabolic process; IEA:UniProtKB-UniRule.
DR GO; GO:0039587; P:suppression by virus of host tetherin activity; IEA:UniProtKB-UniRule.
DR GO; GO:0039502; P:suppression by virus of host type I interferon-mediated signaling pathway; IEA:UniProtKB-UniRule.
DR GO; GO:0019076; P:viral release from host cell; IEA:UniProtKB-UniRule.
DR Gene3D; 1.10.195.10; -; 1.
DR HAMAP; MF_04082; HIV_VPU; 1.
DR InterPro; IPR008187; Vpu.
DR InterPro; IPR009032; Vpu_cyt_dom_sf.
DR Pfam; PF00558; Vpu; 1.
DR SUPFAM; SSF57647; SSF57647; 1.
PE 3: Inferred from homology;
KW AIDS; Apoptosis; Host membrane; Host-virus interaction;
KW Inhibition of host innate immune response by virus;
KW Inhibition of host interferon signaling pathway by virus;
KW Inhibition of host tetherin by virus; Ion channel; Ion transport; Membrane;
KW Phosphoprotein; Reference proteome; Transmembrane; Transmembrane helix;
KW Transport; Viral immunoevasion.
FT CHAIN 1..80
FT /note="Protein Vpu"
FT /id="PRO_0000250988"
FT TOPO_DOM 1..7
FT /note="Extracellular"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04082"
FT TRANSMEM 8..28
FT /note="Helical"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04082"
FT TOPO_DOM 29..80
FT /note="Cytoplasmic"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04082"
FT REGION 49..80
FT /note="Disordered"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT COMPBIAS 62..80
FT /note="Basic and acidic residues"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT MOD_RES 53
FT /note="Phosphoserine; by host CK2"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04082"
FT MOD_RES 57
FT /note="Phosphoserine; by host CK2"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04082"
SQ SEQUENCE 80 AA; 9197 MW; BB0CD229E0D2B39D CRC64;
MLSLQILAIV ALVVAAIIAI VVWSIVFIEY RKILRQRKID RLIDRIRERE EDSGNESEGD
QEELAALERG HLAPWDVDDL
