ID   SIGM3_REOVJ             Reviewed;         365 AA.
AC   P30211;
DT   01-APR-1993, integrated into UniProtKB/Swiss-Prot.
DT   01-APR-1993, sequence version 1.
DT   25-MAY-2022, entry version 86.
DE   RecName: Full=Outer capsid protein sigma-3;
DE            Short=Sigma3;
GN   Name=S4;
OS   Reovirus type 2 (strain D5/Jones) (T2J) (Mammalian orthoreovirus 2).
OC   Viruses; Riboviria; Orthornavirae; Duplornaviricota; Resentoviricetes;
OC   Reovirales; Reoviridae; Spinareovirinae; Orthoreovirus.
OX   NCBI_TaxID=10885;
OH   NCBI_TaxID=40674; Mammalia.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=1736524; DOI=10.1016/0042-6822(92)90308-c;
RA   Seliger L.S., Giantini M., Shatkin A.J.;
RT   "Translational effects and sequence comparisons of the three serotypes of
RT   the reovirus S4 gene.";
RL   Virology 187:202-210(1992).
CC   -!- FUNCTION: Stimulates translation by blocking the activation of the
CC       dsRNA-dependent protein kinase EIF2AK2/PKR, thereby inhibiting the host
CC       interferon response. Sigma3 prevents the activation of EIF2AK2 by
CC       competing with the kinase for dsRNA-binding (By similarity).
CC       {ECO:0000250}.
CC   -!- FUNCTION: The viral outer shell polypeptides, of which sigma-3 is one,
CC       impose structural constraints that prevent elongation of nascent
CC       transcripts by the RNA-dependent RNA polymerase lambda-3.
CC       {ECO:0000250}.
CC   -!- SUBUNIT: Heterohexamer of three sigma-3 and three Mu-1 proteins. The
CC       RNA-binding form is probably a homodimer (By similarity).
CC       {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Virion {ECO:0000250}. Note=Found in the outer
CC       capsid. Each subunit is positioned with the small lobe anchoring it to
CC       the protein mu1 on the surface of the virion, and the large lobe, the
CC       site of initial cleavages during entry-related proteolytic disassembly,
CC       protruding outwards (By similarity). {ECO:0000250}.
CC   -!- PTM: Cleaved during virus the endosomal proteolytic disassembly of the
CC       outer capsid. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the orthoreovirus sigma-3 protein family.
CC       {ECO:0000305}.
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DR   EMBL; X60066; CAA42670.1; -; mRNA.
DR   PIR; B42192; MNXRSJ.
DR   SMR; P30211; -.
DR   Proteomes; UP000006370; Genome.
DR   GO; GO:0039624; C:viral outer capsid; IEA:UniProtKB-KW.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0030291; F:protein serine/threonine kinase inhibitor activity; IEA:UniProtKB-KW.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0005198; F:structural molecule activity; IEA:InterPro.
DR   GO; GO:0039580; P:suppression by virus of host PKR signaling; IEA:UniProtKB-KW.
DR   GO; GO:0039502; P:suppression by virus of host type I interferon-mediated signaling pathway; IEA:UniProtKB-KW.
DR   GO; GO:0019058; P:viral life cycle; IEA:InterPro.
DR   InterPro; IPR000153; Reo_capsid_sigma3.
DR   InterPro; IPR023634; Reovirus_capsid_sigma-3_dom_sf.
DR   Pfam; PF00979; Reovirus_cap; 1.
DR   SUPFAM; SSF64465; SSF64465; 1.
PE   2: Evidence at transcript level;
KW   Capsid protein; 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 PKR by virus; Interferon antiviral system evasion;
KW   Metal-binding; Outer capsid protein; RNA-binding; Transcription;
KW   Transcription regulation; Translation regulation; Viral immunoevasion;
KW   Virion; Zinc; Zinc-finger.
FT   CHAIN           1..365
FT                   /note="Outer capsid protein sigma-3"
FT                   /id="PRO_0000222753"
FT   ZN_FING         51..73
FT                   /note="CCHC-type"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   365 AA;  41226 MW;  574350AEDFE04478 CRC64;
     MEVCLPNGHQ IVDWINNAFE GRVSIYSAQQ GWDKTISAQP DMMVCGGAVV CMHCLGVVGS
     LQRKLKHLPH HKCNQQLRQQ DYVDVQFADR VTAHWKRGML SFVSQMHAIM NDVTPEELER
     VRTDGGSLAE LNWLQVDPGS MFRSIHSSWT DPLQVVEDLD TQLDRYWTAL NLMIDSSDLV
     PNFMMRDPSH AFNGVKLEGE ARQTQFSRTF DSRSNLEWGV MIYDYSELER DPLKGRAYRK
     EVVTPARDFG HFGLSHYSRA TTPILGKMPA VFSGMLTGNC KMYPFIKGTA KLRTVKKLVD
     AVNHTWGSEK IRYALGPGGM TGWYNRTMQQ APIVLTPAAL TMFPDMTKFG DLQYPIMIGD
     PAVLG