ID   FUS_PI3B                Reviewed;         540 AA.
AC   P09990;
DT   01-JUL-1989, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1996, sequence version 2.
DT   25-MAY-2022, entry version 105.
DE   RecName: Full=Fusion glycoprotein F0;
DE   Contains:
DE     RecName: Full=Fusion glycoprotein F2;
DE   Contains:
DE     RecName: Full=Fusion glycoprotein F1;
DE   Flags: Precursor;
GN   Name=F;
OS   Bovine parainfluenza 3 virus (BPIV-3).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Haploviricotina;
OC   Monjiviricetes; Mononegavirales; Paramyxoviridae; Orthoparamyxovirinae;
OC   Respirovirus.
OX   NCBI_TaxID=11215;
OH   NCBI_TaxID=9913; Bos taurus (Bovine).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=910N;
RX   PubMed=3031615; DOI=10.1093/nar/15.7.2945;
RA   Suzu S., Sakai Y., Shioda T., Shibuta H.;
RT   "Nucleotide sequence of the bovine parainfluenza 3 virus genome: the genes
RT   of the F and HN glycoproteins.";
RL   Nucleic Acids Res. 15:2945-2958(1987).
CC   -!- FUNCTION: Class I viral fusion protein. Under the current model, the
CC       protein has at least 3 conformational states: pre-fusion native state,
CC       pre-hairpin intermediate state, and post-fusion hairpin state. During
CC       viral and plasma cell membrane fusion, the heptad repeat (HR) regions
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 plasma cell membranes. Directs fusion of viral and
CC       cellular membranes leading to delivery of the nucleocapsid into the
CC       cytoplasm. This fusion is pH independent and occurs directly at the
CC       outer cell membrane. The trimer of F1-F2 (F protein) probably interacts
CC       with HN at the virion surface. Upon HN binding to its cellular
CC       receptor, the hydrophobic fusion peptide is unmasked and interacts with
CC       the cellular membrane, inducing the fusion between cell and virion
CC       membranes. Later in infection, F proteins expressed at the plasma
CC       membrane of infected cells could mediate fusion with adjacent cells to
CC       form syncytia, a cytopathic effect that could lead to tissue necrosis
CC       (By similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Homotrimer of disulfide-linked F1-F2. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Virion membrane {ECO:0000250}; Single-pass type I
CC       membrane protein {ECO:0000250}. Host cell membrane {ECO:0000250};
CC       Single-pass membrane protein {ECO:0000250}.
CC   -!- PTM: The inactive precursor F0 is glycosylated and proteolytically
CC       cleaved into F1 and F2 to be functionally active. The cleavage is
CC       mediated by cellular proteases during the transport and maturation of
CC       the polypeptide (By similarity). {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the paramyxoviruses fusion glycoprotein family.
CC       {ECO:0000305}.
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DR   EMBL; Y00114; CAA68297.1; -; Genomic_RNA.
DR   EMBL; D84095; BAA12217.1; -; Genomic_RNA.
DR   PIR; A27218; VGNZB3.
DR   SMR; P09990; -.
DR   Proteomes; UP000133413; Genome.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
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:viral entry into host cell; IEA:UniProtKB-KW.
DR   InterPro; IPR000776; Fusion_F0_Paramyxovir.
DR   Pfam; PF00523; Fusion_gly; 1.
PE   3: Inferred from homology;
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; Membrane; Signal; Transmembrane;
KW   Transmembrane helix; 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..540
FT                   /note="Fusion glycoprotein F0"
FT                   /id="PRO_0000039342"
FT   CHAIN           19..109
FT                   /note="Fusion glycoprotein F2"
FT                   /id="PRO_0000039343"
FT   CHAIN           110..540
FT                   /note="Fusion glycoprotein F1"
FT                   /id="PRO_0000039344"
FT   TOPO_DOM        19..495
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000250"
FT   TRANSMEM        496..516
FT                   /note="Helical"
FT                   /evidence="ECO:0000250"
FT   TOPO_DOM        517..540
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000250"
FT   REGION          110..134
FT                   /note="Fusion peptide"
FT                   /evidence="ECO:0000250"
FT   COILED          135..163
FT                   /evidence="ECO:0000255"
FT   COILED          459..484
FT                   /evidence="ECO:0000255"
FT   SITE            109..110
FT                   /note="Cleavage; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        101
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        238
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        359
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        446
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   DISULFID        63..192
FT                   /note="Interchain (between F2 and F1 chains)"
FT                   /evidence="ECO:0000250"
FT   DISULFID        331..340
FT                   /evidence="ECO:0000250"
FT   DISULFID        355..363
FT                   /evidence="ECO:0000250"
FT   DISULFID        387..392
FT                   /evidence="ECO:0000250"
FT   DISULFID        394..417
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   540 AA;  60007 MW;  D340D88302B9216E CRC64;
     MIITNTIIII LIISPSFCQI DITKLQRVGV LVNNPKGMKI SQNFETRYLI LSLIPKIENS
     HSCGDQQINQ YKKLLDRLII PLYDGLKLQK DVIVVSHETN NNTNSRTKRF FGEIIGTIAI
     GIATSAQITA AVALVEAKQA KSDIEKLKEA IRDTNKAVQS IQSSVGNLIV AVKSVQDYVN
     NEIVPSITRL GCEAAGLKLG IALTQHYSEL TNIFGDNIGT LKEKGIKLQG IASLYHTNIT
     EIFTTSTVDQ YDIYDLLFTE SIKMRVIDVD LSDYSITLQV RLPLLTKISN TQIYKVDSIS
     YNIQGKEWYI PLPNHIMTKG AFLGGADIKE CIEAFSSYIC PSDPGFTLNH EIENCLSGNI
     TQCPKTIVTS DVVPRYAFVN GGLIANCITT TCTCNGVDNR INQSPDQGIK IITHKECQVI
     GINGMLFSTN REGTLATYTF DDIILNNSVA LNPIDISMEL NKAKLELEES KEWIKKSNQK
     LDSVGSWYQS SATITIIIVM IVVLFIINIT IIVVIIRHHR IQGKNQNDKN SEPYVLTSRQ