ID   ENV_HTLV2               Reviewed;         486 AA.
AC   P03383; P03382;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   02-SEP-2026, entry version 133.
DE   RecName: Full=Envelope glycoprotein gp63;
DE   AltName: Full=Env polyprotein;
DE   Contains:
DE     RecName: Full=Surface protein;
DE              Short=SU;
DE     AltName: Full=Glycoprotein 46;
DE              Short=gp46;
DE   Contains:
DE     RecName: Full=Transmembrane protein;
DE              Short=TM;
DE     AltName: Full=Glycoprotein 21;
DE              Short=gp21;
DE   Flags: Precursor;
GN   Name=env;
OS   Human T-cell leukemia virus 2 (HTLV-2).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Orthoretrovirinae; Deltaretrovirus;
OC   Deltaretrovirus priTlym2; Primate T-lymphotropic virus 2.
OX   NCBI_TaxID=11909;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=2582407; DOI=10.1073/pnas.82.10.3101;
RA   Shimotohno K., Takahashi Y., Shimizu N., Gojobori T., Golde D.W.,
RA   Chen I.S.Y., Miwa M., Sugimura T.;
RT   "Complete nucleotide sequence of an infectious clone of human T-cell
RT   leukemia virus type II: an open reading frame for the protease gene.";
RL   Proc. Natl. Acad. Sci. U.S.A. 82:3101-3105(1985).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=6204380; DOI=10.1126/science.6204380;
RA   Sodroski J., Patarca R., Perkins D., Briggs D., Lee T.-H., Essex M.,
RA   Coligan J., Wong-Staal F., Gallo R.C., Haseltine W.A.;
RT   "Sequence of the envelope glycoprotein gene of type II human T lymphotropic
RT   virus.";
RL   Science 225:421-424(1984).
RN   [3]
RP   PROTEOLYTIC PROCESSING OF POLYPROTEIN BY FURIN.
RX   PubMed=12487813; DOI=10.1089/088922202320886299;
RA   Hasegawa H., Tatsumi M., Ogawa-Goto K., Takahashi H., Kojima A.,
RA   Iwasaki T., Kurata T., Sata T., Takeuchi T., Sheehy N., Sawa H.,
RA   Nagashima K., Hall W.W.;
RT   "Processing of the HTLV-II envelope precursor glycoprotein gp62 by furin is
RT   essential for cell fusion activity.";
RL   AIDS Res. Hum. Retroviruses 18:1253-1260(2002).
CC   -!- FUNCTION: The surface protein (SU) attaches the virus to the host cell
CC       by binding to its receptor. This interaction triggers the refolding of
CC       the transmembrane protein (TM) and is thought to activate its fusogenic
CC       potential by unmasking its fusion peptide. Fusion occurs at the host
CC       cell plasma membrane (By similarity). {ECO:0000250}.
CC   -!- FUNCTION: The transmembrane protein (TM) acts as a class I viral fusion
CC       protein. Under the current model, the protein has at least 3
CC       conformational states: pre-fusion native state, pre-hairpin
CC       intermediate state, and post-fusion hairpin state. During viral and
CC       target cell membrane fusion, the coiled coil regions (heptad repeats)
CC       assume a trimer-of-hairpins structure, positioning the fusion peptide
CC       in close proximity to the C-terminal region of the ectodomain. The
CC       formation of this structure appears to drive apposition and subsequent
CC       fusion of viral and target cell membranes. Membranes fusion leads to
CC       delivery of the nucleocapsid into the cytoplasm (By similarity).
CC       {ECO:0000250}.
CC   -!- SUBUNIT: The mature envelope protein (Env) consists of a trimer of SU-
CC       TM heterodimers attached by a labile interchain disulfide bond.
CC       {ECO:0000250}.
CC   -!- INTERACTION:
CC       P03383; O43513: MED7; Xeno; NbExp=3; IntAct=EBI-9676086, EBI-394632;
CC   -!- SUBCELLULAR LOCATION: [Transmembrane protein]: Virion membrane
CC       {ECO:0000250}; Single-pass type I membrane protein {ECO:0000250}. Host
CC       cell membrane {ECO:0000250}; Single-pass type I membrane protein
CC       {ECO:0000250}. Note=It is probably concentrated at the site of budding
CC       and incorporated into the virions possibly by contacts between the
CC       cytoplasmic tail of Env and the N-terminus of Gag. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: [Surface protein]: Virion membrane {ECO:0000250};
CC       Peripheral membrane protein {ECO:0000250}. Host cell membrane
CC       {ECO:0000250}; Peripheral membrane protein {ECO:0000250}. Note=The
CC       surface protein is not anchored to the viral envelope, but associates
CC       with the extravirion surface through its binding to TM. It is probably
CC       concentrated at the site of budding and incorporated into the virions
CC       possibly by contacts between the cytoplasmic tail of Env and the N-
CC       terminus of Gag (By similarity). {ECO:0000250}.
CC   -!- DOMAIN: The 17 amino acids long immunosuppressive region is present in
CC       many retroviral envelope proteins. Synthetic peptides derived from this
CC       relatively conserved sequence inhibit immune function in vitro and in
CC       vivo (By similarity). {ECO:0000250}.
CC   -!- PTM: Specific enzymatic cleavages in vivo yield mature proteins.
CC       Envelope glycoproteins are synthesized as an inactive precursor that is
CC       N-glycosylated and processed likely by host cell furin or by a furin-
CC       like protease in the Golgi to yield the mature SU and TM proteins. The
CC       cleavage site between SU and TM requires the minimal sequence [KR]-X-
CC       [KR]-R (By similarity). {ECO:0000250}.
CC   -!- PTM: The CXXC motif is highly conserved across a broad range of
CC       retroviral envelope proteins. It is thought to participate in the
CC       formation of a labile disulfide bond possibly with the CX6CC motif
CC       present in the transmembrane protein. Isomerization of the intersubunit
CC       disulfide bond to an SU intrachain disulfide bond is thought to occur
CC       upon receptor recognition in order to allow membrane fusion (By
CC       similarity). {ECO:0000250}.
CC   -!- PTM: The transmembrane protein is palmitoylated. {ECO:0000250}.
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DR   EMBL; M10060; AAB59887.1; -; Genomic_DNA.
DR   EMBL; K02024; AAA45410.1; -; Genomic_RNA.
DR   PIR; A03980; VCLJT2.
DR   PIR; A03981; VCLJH2.
DR   RefSeq; NP_041006.1; NC_001488.1.
DR   AlphaFoldDB; P03383; -.
DR   SMR; P03383; -.
DR   ELM; P03383; -.
DR   IntAct; P03383; 1.
DR   MINT; P03383; -.
DR   GlyCosmos; P03383; 5 sites, No reported glycans.
DR   GeneID; 1491942; -.
DR   KEGG; vg:1491942; -.
DR   OrthoDB; 4817at10239; -.
DR   PRO; PR:P03383; -.
DR   Proteomes; UP000009254; Segment.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0019031; C:viral envelope; IEA:UniProtKB-KW.
DR   GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0019064; P:fusion of virus membrane with host plasma membrane; IEA:UniProtKB-KW.
DR   GO; GO:0046718; P:symbiont entry into host cell; IEA:UniProtKB-KW.
DR   GO; GO:0019062; P:virion attachment to host cell; IEA:UniProtKB-KW.
DR   CDD; cd09851; HTLV-1-like_HR1-HR2; 1.
DR   Gene3D; 1.10.287.210; -; 1.
DR   InterPro; IPR018154; TLV/ENV_coat_polyprotein.
DR   PANTHER; PTHR10424:SF81; ERVV2 PROTEIN; 1.
DR   PANTHER; PTHR10424; VIRAL ENVELOPE PROTEIN; 1.
DR   Pfam; PF00429; TLV_coat; 2.
DR   SUPFAM; SSF58069; Virus ectodomain; 1.
PE   1: Evidence at protein level;
KW   Cleavage on pair of basic residues; Coiled coil; Disulfide bond;
KW   Fusion of virus membrane with host cell membrane;
KW   Fusion of virus membrane with host membrane; Glycoprotein;
KW   Host cell membrane; Host membrane; Host-virus interaction; Lipoprotein;
KW   Membrane; Palmitate; Reference proteome; Signal; Transmembrane;
KW   Transmembrane helix; Viral attachment to host cell; Viral envelope protein;
KW   Viral penetration into host cytoplasm; Virion; Virus entry into host cell.
FT   SIGNAL          1..18
FT                   /evidence="ECO:0000255"
FT   CHAIN           19..486
FT                   /note="Envelope glycoprotein gp63"
FT                   /id="PRO_0000239544"
FT   CHAIN           19..308
FT                   /note="Surface protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000038761"
FT   CHAIN           309..486
FT                   /note="Transmembrane protein"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000038762"
FT   TOPO_DOM        19..438
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        439..459
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        460..486
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   REGION          309..329
FT                   /note="Fusion peptide"
FT                   /evidence="ECO:0000255"
FT   REGION          372..388
FT                   /note="Immunosuppression"
FT                   /evidence="ECO:0000250"
FT   COILED          337..383
FT                   /evidence="ECO:0000255"
FT   COILED          393..425
FT                   /evidence="ECO:0000255"
FT   MOTIF           221..224
FT                   /note="CXXC"
FT   MOTIF           389..397
FT                   /note="CX6CC"
FT   SITE            308..309
FT                   /note="Cleavage; by host furin"
FT   LIPID           458
FT                   /note="S-palmitoyl cysteine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        136
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        218
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        240
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        286
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        400
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   DISULFID        221..397
FT                   /note="Interchain (between SU and TM chains, or C-224 with
FT                   C-397); in linked form"
FT                   /evidence="ECO:0000250"
FT   DISULFID        221..224
FT                   /evidence="ECO:0000250"
FT   DISULFID        389..396
FT                   /evidence="ECO:0000250"
FT   CONFLICT        27
FT                   /note="I -> V (in Ref. 2; AAA45410)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        56
FT                   /note="D -> H (in Ref. 2; AAA45410)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        115
FT                   /note="A -> S (in Ref. 2; AAA45410)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        118..119
FT                   /note="SA -> CP (in Ref. 2; AAA45410)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        267
FT                   /note="F -> P (in Ref. 2)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        302
FT                   /note="P -> L (in Ref. 2; AAA45410)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        318
FT                   /note="S -> P (in Ref. 2; AAA45410)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   486 AA;  54158 MW;  60D70B9CE8986CE5 CRC64;
     MGNVFFLLLF SLTHFPLAQQ SRCTLTIGIS SYHSSPCSPT QPVCTWNLDL NSLTTDQRLH
     PPCPNLITYS GFHKTYSLYL FPHWIKKPNR QGLGYYSPSY NDPCSLQCPY LGCQAWTSAY
     TGPVSSPSWK FHSDVNFTQE VSQVSLRLHF SKCGSSMTLL VDAPGYDPLW FITSEPTQPP
     PTSPPLVHDS DLEHVLTPST SWTTKILKFI QLTLQSTNYS CMVCVDRSSL SSWHVLYTPN
     ISIPQQTSSR TILFPSLALP APPSQPFPWT HCYQPRLQAI TTDNCNNSII LPPFSLAPVP
     PPATRRRRAV PIAVWLVSAL AAGTGIAGGV TGSLSLASSK SLLLEVDKDI SHLTQAIVKN
     HQNILRVAQY AAQNRRGLDL LFWEQGGLCK AIQEQCCFLN ISNTHVSVLQ ERPPLEKRVI
     TGWGLNWDLG LSQWAREALQ TGITILALLL LVILFGPCIL RQIQALPQRL QNRHNQYSLI
     NPETML
//