ID POLS_SAGV Reviewed; 1253 AA. AC Q9JGK8; Q80S33; DT 30-MAY-2006, integrated into UniProtKB/Swiss-Prot. DT 01-OCT-2000, sequence version 1. DT 05-DEC-2018, entry version 95. DE RecName: Full=Structural polyprotein; DE AltName: Full=p130; DE Contains: DE RecName: Full=Capsid protein; DE EC=3.4.21.90; DE AltName: Full=Coat protein; DE Short=C; DE Contains: DE RecName: Full=Precursor of protein E3/E2; DE AltName: Full=p62; DE AltName: Full=pE2; DE Contains: DE RecName: Full=Assembly protein E3; DE Contains: DE RecName: Full=Spike glycoprotein E2; DE AltName: Full=E2 envelope glycoprotein; DE Contains: DE RecName: Full=6K protein; DE Contains: DE RecName: Full=Spike glycoprotein E1; DE AltName: Full=E1 envelope glycoprotein; OS Sagiyama virus (SAGV). OC Viruses; ssRNA viruses; ssRNA positive-strand viruses, no DNA stage; OC Togaviridae; Alphavirus. OX NCBI_TaxID=59303; OH NCBI_TaxID=7158; Aedes. OH NCBI_TaxID=7178; Culex tritaeniorhynchus (Mosquito). OH NCBI_TaxID=9796; Equus caballus (Horse). OH NCBI_TaxID=9606; Homo sapiens (Human). OH NCBI_TaxID=9823; Sus scrofa (Pig). RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC RNA]. RX PubMed=10769079; RA Shirako Y., Yamaguchi Y.; RT "Genome structure of Sagiyama virus and its relatedness to other RT alphaviruses."; RL J. Gen. Virol. 81:1353-1360(2000). RN [2] RP NUCLEOTIDE SEQUENCE [GENOMIC RNA]. RA Kinney R.M., Pfeffer M.; RT "Nucleotide sequence analyses of the 26S mRNAs of viruses of the genus RT Alphavirus."; RL Submitted (JAN-2001) to the EMBL/GenBank/DDBJ databases. CC -!- FUNCTION: Capsid protein: Possesses a protease activity that CC results in its autocatalytic cleavage from the nascent structural CC protein. Following its self-cleavage, the capsid protein CC transiently associates with ribosomes, and within several minutes CC the protein binds to viral RNA and rapidly assembles into CC icosahedric core particles. The resulting nucleocapsid eventually CC associates with the cytoplasmic domain of the spike glycoprotein CC E2 at the cell membrane, leading to budding and formation of CC mature virions. In case of infection, new virions attach to target CC cells and after clathrin-mediated endocytosis their membrane fuses CC with the host endosomal membrane. This leads to the release of the CC nucleocapsid into the cytoplasm, followed by an uncoating event CC necessary for the genomic RNA to become accessible. The uncoating CC might be triggered by the interaction of capsid proteins with CC ribosomes. Binding of ribosomes would release the genomic RNA CC since the same region is genomic RNA-binding and ribosome-binding. CC {ECO:0000250|UniProtKB:P03315}. CC -!- FUNCTION: Assembly protein E3: Provides the signal sequence for CC the translocation of the precursor of protein E3/E2 to the host CC endoplasmic reticulum. Mediates pH protection of spike CC glycoprotein E1 during the transport via the secretory pathway. CC {ECO:0000250|UniProtKB:P03315}. CC -!- FUNCTION: Spike glycoprotein E2: Plays a role in viral attachment CC to target host cell, by binding to the cell receptor. Synthesized CC as a p62 precursor which is processed by furin at the cell CC membrane just before virion budding, giving rise to E2-E1 CC heterodimer. The p62-E1 heterodimer is stable, whereas E2-E1 is CC unstable and dissociate at low pH. p62 is processed at the last CC step, presumably to avoid E1 fusion activation before its final CC export to cell surface. E2 C-terminus contains a transitory CC transmembrane that would be disrupted by palmitoylation, resulting CC in reorientation of the C-terminal tail from lumenal to CC cytoplasmic side. This step is critical since E2 C-terminus is CC involved in budding by interacting with capsid proteins. This CC release of E2 C-terminus in cytoplasm occurs lately in protein CC export, and precludes premature assembly of particles at the CC endoplasmic reticulum membrane. {ECO:0000250|UniProtKB:P03315}. CC -!- FUNCTION: 6K protein: Constitutive membrane protein involved in CC virus glycoprotein processing, cell permeabilization, and the CC budding of viral particles. Disrupts the calcium homeostasis of CC the cell, probably at the endoplasmic reticulum level. This leads CC to cytoplasmic calcium elevation. Because of its lipophilic CC properties, the 6K protein is postulated to influence the CC selection of lipids that interact with the transmembrane domains CC of the glycoproteins, which, in turn, affects the deformability of CC the bilayer required for the extreme curvature that occurs as CC budding proceeds. Present in low amount in virions, about 3% CC compared to viral glycoproteins. {ECO:0000250|UniProtKB:P03315}. CC -!- FUNCTION: Spike glycoprotein E1: Class II viral fusion protein. CC Fusion activity is inactive as long as E1 is bound to E2 in mature CC virion. After virus attachment to target cell and endocytosis, CC acidification of the endosome would induce dissociation of E1/E2 CC heterodimer and concomitant trimerization of the E1 subunits. This CC E1 trimer is fusion active, and promotes release of viral CC nucleocapsid in cytoplasm after endosome and viral membrane CC fusion. Efficient fusion requires the presence of cholesterol and CC sphingolipid in the target membrane. Fusion is optimal at levels CC of about 1 molecule of cholesterol per 2 molecules of CC phospholipids, and is specific for sterols containing a 3-beta- CC hydroxyl group. {ECO:0000250|UniProtKB:P03315}. CC -!- CATALYTIC ACTIVITY: CC Reaction=Autocatalytic release of the core protein from the N- CC terminus of the togavirus structural polyprotein by hydrolysis CC of a -Trp-|-Ser- bond.; EC=3.4.21.90; CC Evidence={ECO:0000250|UniProtKB:P03316}; CC -!- SUBUNIT: Precursor of protein E3/E2: The precursor of protein CC E3/E2 and E1 form a heterodimer shortly after synthesis. Spike CC glycoprotein E1: The precursor of protein E3/E2 and E1 form a CC heterodimer shortly after synthesis. Spike glycoprotein E1: CC Processing of the precursor of protein E3/E2 into E2 and E3 CC results in a heterodimer of the spike glycoproteins E2 and E1. CC Spike glycoprotein E2: Processing of the precursor of protein CC E3/E2 into E2 and E3 results in a heterodimer of the spike CC glycoproteins E2 and E1. Spike glycoprotein E1: Spike at virion CC surface are constituted of three E2-E1 heterodimers. Spike CC glycoprotein E2: Spike at virion surface are constituted of three CC E2-E1 heterodimers. Spike glycoprotein E1: After target cell CC attachment and endocytosis, E1 change conformation to form CC homotrimers. 6K protein: Interacts with spike glycoprotein E1. 6K CC protein: Interacts with spike glycoprotein E2. Spike glycoprotein CC E1: Interacts with 6K protein. Spike glycoprotein E2: Interacts CC with 6K protein. {ECO:0000250|UniProtKB:P03315, CC ECO:0000250|UniProtKB:P03316}. CC -!- SUBCELLULAR LOCATION: Capsid protein: Virion CC {ECO:0000250|UniProtKB:P03316}. Host cytoplasm CC {ECO:0000250|UniProtKB:P03316}. Host cell membrane CC {ECO:0000250|UniProtKB:P03316}. CC -!- SUBCELLULAR LOCATION: Spike glycoprotein E2: Virion membrane CC {ECO:0000250|UniProtKB:Q8JUX5}; Single-pass type I membrane CC protein {ECO:0000255}. Host cell membrane CC {ECO:0000250|UniProtKB:P03316}; Single-pass type I membrane CC protein {ECO:0000250|UniProtKB:Q8JUX5}. CC -!- SUBCELLULAR LOCATION: 6K protein: Host cell membrane CC {ECO:0000250|UniProtKB:P03316}; Multi-pass membrane protein CC {ECO:0000255}. Virion membrane {ECO:0000250|UniProtKB:P03316}; CC Multi-pass membrane protein {ECO:0000255}. CC -!- SUBCELLULAR LOCATION: Spike glycoprotein E1: Virion membrane CC {ECO:0000250|UniProtKB:Q8JUX5}; Single-pass type I membrane CC protein {ECO:0000255}. Host cell membrane CC {ECO:0000250|UniProtKB:P03316, ECO:0000250|UniProtKB:Q8JUX5}; CC Single-pass type I membrane protein {ECO:0000255}. CC -!- DOMAIN: Structural polyprotein: As soon as the capsid protein has CC been autocleaved, an internal uncleaved signal peptide directs the CC remaining polyprotein to the endoplasmic reticulum. CC {ECO:0000250|UniProtKB:P03315}. CC -!- PTM: Structural polyprotein: Specific enzymatic cleavages in vivo CC yield mature proteins. Capsid protein is auto-cleaved during CC polyprotein translation, unmasking a signal peptide at the N- CC terminus of the precursor of E3/E2. The remaining polyprotein is CC then targeted to the host endoplasmic reticulum, where host signal CC peptidase cleaves it into pE2, 6K and E1 proteins. pE2 is further CC processed to mature E3 and E2 by host furin in trans-Golgi CC vesicle. {ECO:0000250|UniProtKB:P03315}. CC -!- PTM: Spike glycoprotein E2: Palmitoylated via thioester bonds. CC These palmitoylations may induce disruption of the C-terminus CC transmembrane. This would result in the reorientation of E2 C- CC terminus from lumenal to cytoplasmic side. CC {ECO:0000250|UniProtKB:P03315}. CC -!- PTM: Spike glycoprotein E1: N-glycosylated. CC {ECO:0000250|UniProtKB:P03315}. CC -!- PTM: Spike glycoprotein E2: N-glycosylated. CC {ECO:0000250|UniProtKB:P03315}. CC -!- PTM: Assembly protein E3: N-glycosylated. CC {ECO:0000250|UniProtKB:P03315}. CC -!- PTM: 6K protein: Palmitoylated via thioester bonds. CC {ECO:0000250|UniProtKB:P03315}. CC -!- MISCELLANEOUS: Structural polyprotein: Translated from a CC subgenomic RNA synthesized during togavirus replication. CC {ECO:0000250|UniProtKB:Q86925}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; AB032553; BAA92847.1; -; Genomic_RNA. DR EMBL; AF339483; AAO33337.1; -; Genomic_RNA. DR ProteinModelPortal; Q9JGK8; -. DR SMR; Q9JGK8; -. DR MEROPS; S03.001; -. DR OrthoDB; VOG0900008L; -. DR Proteomes; UP000007138; Genome. DR GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell. 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:0039619; C:T=4 icosahedral viral capsid; IEA:UniProtKB-KW. DR GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell. DR GO; GO:0004252; F:serine-type endopeptidase activity; IEA:InterPro. DR GO; GO:0005198; F:structural molecule activity; IEA:InterPro. DR GO; GO:0039654; P:fusion of virus membrane with host endosome membrane; IEA:UniProtKB-KW. DR GO; GO:0019062; P:virion attachment to host cell; IEA:UniProtKB-KW. DR Gene3D; 2.60.40.350; -; 1. DR Gene3D; 2.60.98.10; -; 3. DR InterPro; IPR002548; Alpha_E1_glycop. DR InterPro; IPR000936; Alpha_E2_glycop. DR InterPro; IPR002533; Alpha_E3_glycop. DR InterPro; IPR000336; Flavivir/Alphavir_Ig-like_sf. DR InterPro; IPR036253; Glycoprot_cen/dimer_sf. DR InterPro; IPR038055; Glycoprot_E_dimer_dom. DR InterPro; IPR014756; Ig_E-set. DR InterPro; IPR009003; Peptidase_S1_PA. DR InterPro; IPR000930; Peptidase_S3. DR Pfam; PF01589; Alpha_E1_glycop; 1. DR Pfam; PF00943; Alpha_E2_glycop; 1. DR Pfam; PF01563; Alpha_E3_glycop; 1. DR Pfam; PF00944; Peptidase_S3; 1. DR PRINTS; PR00798; TOGAVIRIN. DR SUPFAM; SSF50494; SSF50494; 1. DR SUPFAM; SSF56983; SSF56983; 1. DR SUPFAM; SSF81296; SSF81296; 1. DR PROSITE; PS51690; ALPHAVIRUS_CP; 1. PE 3: Inferred from homology; KW Capsid protein; Cleavage on pair of basic residues; Complete proteome; KW Disulfide bond; Fusion of virus membrane with host endosomal membrane; KW Fusion of virus membrane with host membrane; Glycoprotein; KW Host cell membrane; Host cytoplasm; Host membrane; KW Host-virus interaction; Hydrolase; Lipoprotein; Membrane; Palmitate; KW Protease; Serine protease; T=4 icosahedral capsid protein; KW Transmembrane; Transmembrane helix; Viral attachment to host cell; KW Viral penetration into host cytoplasm; Virion; KW Virus entry into host cell. FT CHAIN 1 268 Capsid protein. {ECO:0000250}. FT /FTId=PRO_0000238766. FT CHAIN 269 754 Precursor of protein E3/E2. FT {ECO:0000250}. FT /FTId=PRO_0000238767. FT CHAIN 269 332 Assembly protein E3. {ECO:0000250}. FT /FTId=PRO_0000238768. FT CHAIN 333 754 Spike glycoprotein E2. {ECO:0000250}. FT /FTId=PRO_0000238769. FT CHAIN 755 815 6K protein. {ECO:0000250}. FT /FTId=PRO_0000238770. FT CHAIN 816 1253 Spike glycoprotein E1. {ECO:0000250}. FT /FTId=PRO_0000238771. FT TOPO_DOM 333 694 Extracellular. {ECO:0000255}. FT TRANSMEM 695 715 Helical. {ECO:0000255}. FT TOPO_DOM 716 754 Cytoplasmic. {ECO:0000255}. FT TOPO_DOM 755 769 Extracellular. {ECO:0000255}. FT TRANSMEM 770 790 Helical. {ECO:0000255}. FT TOPO_DOM 791 792 Cytoplasmic. {ECO:0000255}. FT TRANSMEM 793 813 Helical. {ECO:0000255}. FT TOPO_DOM 814 1227 Extracellular. {ECO:0000255}. FT TRANSMEM 1228 1248 Helical. {ECO:0000255}. FT TOPO_DOM 1249 1253 Cytoplasmic. {ECO:0000255}. FT DOMAIN 120 268 Peptidase S3. {ECO:0000255|PROSITE- FT ProRule:PRU01027}. FT REGION 1 114 Intrinsically disordered, in contact with FT genomic RNA in nucleocapsid. FT {ECO:0000255}. FT REGION 94 107 Ribosome-binding. {ECO:0000250}. FT REGION 269 280 Functions as an uncleaved signal peptide FT for the precursor of protein E3/E2. FT {ECO:0000250|UniProtKB:P03315}. FT REGION 727 747 Transient transmembrane before p62-6K FT protein processing. {ECO:0000255}. FT REGION 899 916 E1 fusion peptide loop. FT {ECO:0000250|UniProtKB:Q8JUX5}. FT ACT_SITE 146 146 Charge relay system. FT {ECO:0000255|PROSITE-ProRule:PRU01027}. FT ACT_SITE 168 168 Charge relay system. FT {ECO:0000255|PROSITE-ProRule:PRU01027}. FT ACT_SITE 220 220 Charge relay system. FT {ECO:0000255|PROSITE-ProRule:PRU01027}. FT SITE 268 269 Cleavage; by autolysis. FT {ECO:0000250|UniProtKB:P03315}. FT SITE 332 333 Cleavage; by host furin. {ECO:0000250}. FT SITE 754 755 Cleavage; by host signal peptidase. FT {ECO:0000250}. FT SITE 815 816 Cleavage; by host signal peptidase. FT {ECO:0000250}. FT LIPID 727 727 S-palmitoyl cysteine; by host. FT {ECO:0000250}. FT LIPID 747 747 S-palmitoyl cysteine; by host. FT {ECO:0000250}. FT LIPID 748 748 S-palmitoyl cysteine; by host. FT {ECO:0000250}. FT CARBOHYD 279 279 N-linked (GlcNAc...) asparagine; by host. FT {ECO:0000255}. FT CARBOHYD 594 594 N-linked (GlcNAc...) asparagine; by host. FT {ECO:0000255}. FT CARBOHYD 956 956 N-linked (GlcNAc...) asparagine; by host. FT {ECO:0000255}. FT DISULFID 864 929 {ECO:0000250}. FT DISULFID 877 909 {ECO:0000250}. FT DISULFID 878 911 {ECO:0000250}. FT DISULFID 883 893 {ECO:0000250}. FT DISULFID 1074 1086 {ECO:0000250}. FT DISULFID 1116 1191 {ECO:0000250}. FT DISULFID 1121 1195 {ECO:0000250}. FT DISULFID 1143 1185 {ECO:0000250}. FT VARIANT 403 403 V -> A. FT VARIANT 519 519 D -> N. FT VARIANT 872 872 P -> S. FT VARIANT 1242 1242 A -> V. SQ SEQUENCE 1253 AA; 138060 MW; D8F11776CF2152F2 CRC64; MNYIPTQTFY GRRWRPRPAF RPWRVPMQPA PPMVIPELQT PIVQAQQMQQ LISAVSALTT KQNGKAPKKP KKKPQKAKAK KNEQQKKNEN KKPPPKQKNL AKKKKPGKRE RMCMKIENDC IFEVKLDGKV TGYACLVGDK VMKPAHVKGV IDNPDLAKLT YKKSSKYDLE CAQIPVHMKS DASKYTHEKP EGHYNWHHGA VQYSGGRFTI PTGAGKPGDS GRPIFDNKGR VVAIVLGGAN EGARTALSVV TWTKDMVTRY TPEGTEEWSA ALMMCVLANV TFPCSEPACA PCCYEKQPEQ TLRMLEDNVD RPGYYDLLEA TMTCNNSARH RRSVTEHFNV YKATKPYLAY CADCGDGQFC YSPVAIEKIR DEASDGMIKI QVAAQIGINK RGTHEHNKIR YIVGHYMKEA NRDSLQVHTS GVCAIRGTMG HFIVAYCPPG DELKVQFQDA ESHTQACKVQ YKHDPAPVGR EKFTVRPHFG IEVPCTTYQL TTAPTEEEID MHTPPDIPDI TLLSQQSGDV KITAGGKTIR YNCTCGSGNV GTTSSDKTIN SCKIAQCHAA VTNHDKWQYT SSFVPRADQL PRKGKVHVPF PLTNSTCRVP LARAPGVTYG KRELTVKLHP DHPTLLTYRS LGADPRPYEE WIDRYVERTI PVTEDGIEYR WGNNPPVRLW AQLTTEGKPH GWPHEIILYY YGLYPAATIA AVSAAGLAVV LSLLASCYMF ATARRKCLTP YALTPGAVVP VTLGVLCCAP RAHAASFAES MAYLWDENQT LFWLELATPL AAIIILVCCL KNLLCCCQPL SFLVLVSLGT PVVKSYEHTA TIPNVVGFPY KAHIERNGFS PMTLQLEVLG TSLEPTLNLE YITCEYKTVV PPPYIKCCGA SECRSMERPD YQCQVYTGVY PFMWGGAYCF CDTENTQLSE AYVDRSDVCK HDHAAAYKAH TAAMKATIRI SYGNLNQTTT AFVNGEHTVT VGGSRFTFGP ISTAWTPFDN KIVVYKNDVY NQDFPPYGSG QPGRFGDVQS RTVESKDLYA NTALKLSRPS SGTVHVPYTQ TPSGFKYWIK ERGTSLNDKA PFGCVIKTNP VRAENCAVGN IPVSMDIPDS AFTRVIDAPA VTNLECQVAV CTHSSDFGGI ATLTFKTDKP GKCAVHSHSN VATIQEAAVD IKTDGKITLH FSTASASPAF MVSVCSAKTT CMAACEPPKD HIVPYGASHN NQVFPDMSGT AMTWVQRVAG GLGGLTLAAV AALILVTCVT MRR //