ID   SIGM1_REOVD             Reviewed;         455 AA.
AC   P03528; A4ZY26; Q85668;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   22-JUL-2008, sequence version 3.
DT   02-SEP-2026, entry version 136.
DE   RecName: Full=Outer capsid protein sigma-1;
DE            Short=Sigma1;
DE   AltName: Full=Cell attachment protein;
DE   AltName: Full=Hemagglutinin;
GN   Name=S1;
OS   Reovirus type 3 (strain Dearing) (T3D) (Mammalian orthoreovirus 3).
OC   Viruses; Riboviria; Orthornavirae; Duplornaviricota; Resentoviricetes;
OC   Reovirales; Spinareoviridae; Orthoreovirus; Orthoreovirus mammalis;
OC   Mammalian orthoreovirus.
OX   NCBI_TaxID=10886;
OH   NCBI_TaxID=40674; Mammalia.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=6095208; DOI=10.1093/nar/12.22.8699;
RA   Nagata L., Masri S.A., Mah D.C.W., Lee P.W.K.;
RT   "Molecular cloning and sequencing of the reovirus (serotype 3) S1 gene
RT   which encodes the viral cell attachment protein sigma 1.";
RL   Nucleic Acids Res. 12:8699-8710(1984).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3855545; DOI=10.1073/pnas.82.1.24;
RA   Cashdollar L.W., Chmelo R.A., Wiener J.R., Joklik W.K.;
RT   "Sequences of the S1 genes of the three serotypes of reovirus.";
RL   Proc. Natl. Acad. Sci. U.S.A. 82:24-28(1985).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=4000269; DOI=10.1038/315421a0;
RA   Bassel-Duby R., Jayasuriya A.K., Chatterjee D., Sonenberg N.,
RA   Maizel J.V. Jr., Fields B.N.;
RT   "Sequence of reovirus haemagglutinin predicts a coiled-coil structure.";
RL   Nature 315:421-423(1985).
RN   [4]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=2305549; DOI=10.1016/0042-6822(90)90093-7;
RA   Duncan R., Horne D., Cashdollar L.W., Joklik W.K., Lee P.W.K.;
RT   "Identification of conserved domains in the cell attachment proteins of the
RT   three serotypes of reovirus.";
RL   Virology 174:399-409(1990).
RN   [5]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RC   STRAIN=Infectious clone;
RX   PubMed=18005692; DOI=10.1016/j.chom.2007.03.003;
RA   Kobayashi T., Antar A.A., Boehme K.W., Danthi P., Eby E.A., Guglielmi K.M.,
RA   Holm G.H., Johnson E.M., Maginnis M.S., Naik S., Skelton W.B., Wetzel J.D.,
RA   Wilson G.J., Chappell J.D., Dermody T.S.;
RT   "A plasmid-based reverse genetics system for animal double-stranded RNA
RT   viruses.";
RL   Cell Host Microbe 1:147-157(2007).
RN   [6]
RP   INTERACTION WITH HUMAN F11R/JAM1, AND FUNCTION.
RX   PubMed=11239401; DOI=10.1016/s0092-8674(01)00231-8;
RA   Barton E.S., Forrest J.C., Connolly J.L., Chappell J.D., Liu Y.,
RA   Schnell F.J., Nusrat A., Parkos C.A., Dermody T.S.;
RT   "Junction adhesion molecule is a receptor for reovirus.";
RL   Cell 104:441-451(2001).
RN   [7]
RP   STRUCTURE BY ELECTRON MICROSCOPY OF THE VIRION, AND SUBCELLULAR LOCATION.
RX   PubMed=11333914; DOI=10.1128/jvi.75.11.5335-5342.2001;
RA   Chandran K., Zhang X., Olson N.H., Walker S.B., Chappell J.D.,
RA   Dermody T.S., Baker T.S., Nibert M.L.;
RT   "Complete in vitro assembly of the reovirus outer capsid produces highly
RT   infectious particles suitable for genetic studies of the receptor-binding
RT   protein.";
RL   J. Virol. 75:5335-5342(2001).
RN   [8]
RP   X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS) OF 246-455.
RX   PubMed=11782420; DOI=10.1093/emboj/21.1.1;
RA   Chappell J.D., Prota A.E., Dermody T.S., Stehle T.;
RT   "Crystal structure of reovirus attachment protein sigma1 reveals
RT   evolutionary relationship to adenovirus fiber.";
RL   EMBO J. 21:1-11(2002).
RN   [9]
RP   X-RAY CRYSTALLOGRAPHY (1.75 ANGSTROMS) OF 292-455.
RX   PubMed=17303562; DOI=10.1074/jbc.m610805200;
RA   Schelling P., Guglielmi K.M., Kirchner E., Paetzold B., Dermody T.S.,
RA   Stehle T.;
RT   "The reovirus sigma1 aspartic acid sandwich: a trimerization motif poised
RT   for conformational change.";
RL   J. Biol. Chem. 282:11582-11589(2007).
RN   [10] {ECO:0007744|PDB:3EOY}
RP   X-RAY CRYSTALLOGRAPHY (3.40 ANGSTROMS) OF 293-455 IN COMPLEX WITH THE HOST
RP   RECEPTOR F11R/JAM1, INTERACTION WITH HOST F11R/JAM1, MUTAGENESIS OF
RP   GLU-384, AND FUNCTION.
RX   PubMed=19079583; DOI=10.1371/journal.ppat.1000235;
RA   Kirchner E., Guglielmi K.M., Strauss H.M., Dermody T.S., Stehle T.;
RT   "Structure of reovirus sigma1 in complex with its receptor junctional
RT   adhesion molecule-A.";
RL   PLoS Pathog. 4:e1000235-e1000235(2008).
RN   [11] {ECO:0007744|PDB:3S6X, ECO:0007744|PDB:3S6Y, ECO:0007744|PDB:3S6Z}
RP   X-RAY CRYSTALLOGRAPHY (2.25 ANGSTROMS) OF 170-455 IN COMPLEX WITH
RP   SIALYLATED OLIGOSACCHARIDES, SUBUNIT, FUNCTION, MUTAGENESIS OF ASN-189;
RP   SER-195; ASN-198; ARG-202; LEU-203; PRO-204; GLY-205 AND ASN-210, AND
RP   DOMAIN.
RX   PubMed=21829363; DOI=10.1371/journal.ppat.1002166;
RA   Reiter D.M., Frierson J.M., Halvorson E.E., Kobayashi T., Dermody T.S.,
RA   Stehle T.;
RT   "Crystal structure of reovirus attachment protein sigma1 in complex with
RT   sialylated oligosaccharides.";
RL   PLoS Pathog. 7:e1002166-e1002166(2011).
RN   [12] {ECO:0007744|PDB:6GAP}
RP   X-RAY CRYSTALLOGRAPHY (2.15 ANGSTROMS) OF 25-262, DOMAIN, MUTAGENESIS OF
RP   ARG-161 AND ASN-182, AND SUBUNIT.
RX   PubMed=29695426; DOI=10.1128/jvi.00336-18;
RA   Dietrich M.H., Ogden K.M., Long J.M., Ebenhoch R., Thor A., Dermody T.S.,
RA   Stehle T.;
RT   "Structural and Functional Features of the Reovirus sigma1 Tail.";
RL   J. Virol. 92:0-0(2018).
CC   -!- FUNCTION: Fiber-like molecule of about 30 nm that attaches the virion
CC       to the host cell membrane by binding with initial low affinity to
CC       sialic acid containing proteins, followed by high-affinity bindingto
CC       the entry receptor F11R/JAM-A (PubMed:11239401, PubMed:19079583,
CC       PubMed:21829363). The interaction of sigma-1 with F11R is required for
CC       NF-kB activation and apoptosis. Binding to both sialic acid and F11R is
CC       required to induce maximal levels of apoptosis.
CC       {ECO:0000269|PubMed:11239401, ECO:0000269|PubMed:19079583,
CC       ECO:0000269|PubMed:21829363}.
CC   -!- SUBUNIT: Homotrimer (PubMed:29695426). Interacts (via the head region)
CC       with host receptor F11R/JAM1; this interaction leads to viral entry
CC       into host cell and to the disruption of F11R/JAM1 homodimers by sigma-1
CC       (PubMed:11239401). {ECO:0000269|PubMed:11239401,
CC       ECO:0000269|PubMed:29695426}.
CC   -!- SUBCELLULAR LOCATION: Virion {ECO:0000269|PubMed:11333914}. Note=Found
CC       in the outer capsid (36 copies). {ECO:0000269|PubMed:11333914}.
CC   -!- DOMAIN: The N-terminus anchors the molecule into the viral capsid. The
CC       coiled-coil domain is involved in oligomerization (PubMed:29695426).
CC       Stabilizing interactions at the coiled-coil-to-body domain transition
CC       site are crucial for sigma-1 folding and encapsidation
CC       (PubMed:29695426). Binds a range of sialylated glycans near the
CC       midpoint of its tail domain (PubMed:21829363).
CC       {ECO:0000269|PubMed:21829363, ECO:0000269|PubMed:29695426}.
CC   -!- PTM: Undergoes dramatic conformational rearrangements during viral
CC       disassembly in the endocytic pathway. {ECO:0000250|UniProtKB:P04506}.
CC   -!- SIMILARITY: Belongs to the orthoreovirus sigma-1 protein family.
CC       {ECO:0000305}.
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DR   EMBL; M10262; AAA47275.1; -; Genomic_DNA.
DR   EMBL; X01161; CAA25605.1; -; Genomic_RNA.
DR   EMBL; M32862; AAA47274.1; -; mRNA.
DR   EMBL; EF494441; ABP48919.1; -; Genomic_RNA.
DR   PIR; S25234; S25234.
DR   PDB; 1KKE; X-ray; 2.60 A; A/B/C=246-455.
DR   PDB; 2OJ5; X-ray; 1.75 A; A/B/C/D/E/F=292-455.
DR   PDB; 2OJ6; X-ray; 1.85 A; A/B/C/D/E/F=292-455.
DR   PDB; 3EOY; X-ray; 3.40 A; A/B/C/D/E/F=293-455.
DR   PDB; 3S6X; X-ray; 2.25 A; A/B/C=170-455.
DR   PDB; 3S6Y; X-ray; 2.79 A; A/B/C=170-455.
DR   PDB; 3S6Z; X-ray; 2.28 A; A/B/C=170-455.
DR   PDB; 6GAP; X-ray; 2.15 A; A/B/C=25-262.
DR   MDposit; P03528; -.
DR   SMR; P03528; -.
DR   BindingDB; P03528; -.
DR   GlyCosmos; P03528; 3 sites, No reported glycans.
DR   ABCD; P03528; 1 sequenced antibody.
DR   EvolutionaryTrace; P03528; -.
DR   GO; GO:0039624; C:viral outer capsid; IEA:UniProtKB-KW.
DR   GO; GO:0007155; P:cell adhesion; IEA:InterPro.
DR   GO; GO:0098670; P:entry receptor-mediated virion attachment to host cell; IEA:UniProtKB-KW.
DR   GO; GO:0046718; P:symbiont entry into host cell; IEA:UniProtKB-KW.
DR   Gene3D; 1.20.5.340; -; 1.
DR   Gene3D; 6.10.250.3380; -; 1.
DR   Gene3D; 6.20.10.20; -; 1.
DR   Gene3D; 2.10.25.20; reovirus attachment protein sigma1, domain 1; 1.
DR   Gene3D; 2.60.90.20; Virus attachment protein , globular domain; 1.
DR   InterPro; IPR008982; Adenovirus_pIV-like_att.
DR   InterPro; IPR009013; Attachment_protein_shaft_sf.
DR   InterPro; IPR002592; S1_C.
DR   Pfam; PF01664; Reo_sigma1; 1.
DR   SUPFAM; SSF51225; Fibre shaft of virus attachment proteins; 1.
DR   SUPFAM; SSF57997; Tropomyosin; 1.
DR   SUPFAM; SSF49835; Virus attachment protein globular domain; 1.
DR   PDBsum; 1KKE; -.
DR   PDBsum; 2OJ5; -.
DR   PDBsum; 2OJ6; -.
DR   PDBsum; 3EOY; -.
DR   PDBsum; 3S6X; -.
DR   PDBsum; 3S6Y; -.
DR   PDBsum; 3S6Z; -.
DR   PDBsum; 6GAP; -.
PE   1: Evidence at protein level;
KW   3D-structure; Capsid protein; Coiled coil; Glycoprotein; Hemagglutinin;
KW   Host-virus interaction; Outer capsid protein;
KW   Viral attachment to host cell; Viral attachment to host entry receptor;
KW   Virion; Virus entry into host cell.
FT   CHAIN           1..455
FT                   /note="Outer capsid protein sigma-1"
FT                   /id="PRO_0000040665"
FT   REGION          1..307
FT                   /note="Tail"
FT   REGION          198..205
FT                   /note="Binding to host receptor sialic acid"
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   REGION          308..455
FT                   /note="Head"
FT   COILED          116..148
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        231
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        264
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        282
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   MUTAGEN         161
FT                   /note="R->A: 30-fold reduced viral replication. 1000-fold
FT                   reduced viral replication; when associated with A-182."
FT                   /evidence="ECO:0000269|PubMed:29695426"
FT   MUTAGEN         182
FT                   /note="N->A: 100-fold reduced viral replication. 1000-fold
FT                   reduced viral replication; when associated with A-182."
FT                   /evidence="ECO:0000269|PubMed:29695426"
FT   MUTAGEN         189
FT                   /note="N->A: No effect on the binding to sialic acid."
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   MUTAGEN         195
FT                   /note="S->A: No effect on the binding to sialic acid."
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   MUTAGEN         198
FT                   /note="N->D: Complete loss of binding to sialic acid."
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   MUTAGEN         202
FT                   /note="R->A,W: Complete loss of binding to sialic acid."
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   MUTAGEN         203
FT                   /note="L->A: Complete loss of binding to sialic acid."
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   MUTAGEN         204
FT                   /note="P->A,L: Complete loss of binding to sialic acid."
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   MUTAGEN         205
FT                   /note="G->A: Partial loss of binding to sialic acid."
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   MUTAGEN         210
FT                   /note="N->A: No effect on the binding to sialic acid."
FT                   /evidence="ECO:0000269|PubMed:21829363"
FT   MUTAGEN         384
FT                   /note="E->A: Enhanced avidity for host F11R/JAM1."
FT                   /evidence="ECO:0000269|PubMed:19079583"
FT   CONFLICT        22
FT                   /note="A -> V (in Ref. 5; ABP48919)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        118..119
FT                   /note="EL -> DV (in Ref. 3; CAA25605 and 4; AAA47274)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        163
FT                   /note="S -> T (in Ref. 2; AAA47275)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        408
FT                   /note="A -> T (in Ref. 5; ABP48919)"
FT                   /evidence="ECO:0000305"
FT   HELIX           28..168
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          177..180
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          183..186
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          192..195
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          198..201
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          207..212
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          215..218
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   TURN            222..224
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          225..228
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          231..234
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   TURN            236..239
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   HELIX           240..243
FT                   /evidence="ECO:0007829|PDB:6GAP"
FT   STRAND          261..264
FT                   /evidence="ECO:0007829|PDB:3S6X"
FT   TURN            265..268
FT                   /evidence="ECO:0007829|PDB:3S6X"
FT   STRAND          269..272
FT                   /evidence="ECO:0007829|PDB:3S6X"
FT   TURN            276..278
FT                   /evidence="ECO:0007829|PDB:3S6X"
FT   STRAND          279..281
FT                   /evidence="ECO:0007829|PDB:3S6X"
FT   STRAND          287..289
FT                   /evidence="ECO:0007829|PDB:3S6X"
FT   HELIX           290..295
FT                   /evidence="ECO:0007829|PDB:1KKE"
FT   STRAND          300..303
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          306..309
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   HELIX           311..314
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          316..328
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          331..344
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          347..352
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          355..358
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          362..369
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          372..374
FT                   /evidence="ECO:0007829|PDB:1KKE"
FT   HELIX           380..383
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   TURN            386..389
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          394..408
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          410..422
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          425..431
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          439..443
FT                   /evidence="ECO:0007829|PDB:2OJ5"
FT   STRAND          446..452
FT                   /evidence="ECO:0007829|PDB:2OJ5"
SQ   SEQUENCE   455 AA;  49095 MW;  F376721B9F936A34 CRC64;
     MDPRLREEVV RLIIALTSDN GASLSKGLES RVSALEKTSQ IHSDTILRIT QGLDDANKRI
     IALEQSRDDL VASVSDAQLA ISRLESSIGA LQTVVNGLDS SVTQLGARVG QLETGLAELR
     VDHDNLVARV DTAERNIGSL TTELSTLTLR VTSIQADFES RISTLERTAV TSAGAPLSIR
     NNRMTMGLND GLTLSGNNLA IRLPGNTGLN IQNGGLQFRF NTDQFQIVNN NLTLKTTVFD
     SINSRIGATE QSYVASAVTP LRLNSSTKVL DMLIDSSTLE INSSGQLTVR STSPNLRYPI
     ADVSGGIGMS PNYRFRQSMW IGIVSYSGSG LNWRVQVNSD IFIVDDYIHI CLPAFDGFSI
     ADGGDLSLNF VTGLLPPLLT GDTEPAFHND VVTYGAQTVA IGLSSGGAPQ YMSKNLWVEQ
     WQDGVLRLRV EGGGSITHSN SKWPAMTVSY PRSFT
//