ID   MU1_REOVJ               Reviewed;         708 AA.
AC   P12397; Q85659; Q89834;
DT   01-OCT-1989, integrated into UniProtKB/Swiss-Prot.
DT   23-JAN-2007, sequence version 3.
DT   27-MAR-2024, entry version 123.
DE   RecName: Full=Outer capsid protein mu-1;
DE            Short=Mu1;
DE   Contains:
DE     RecName: Full=Outer capsid protein mu-1N;
DE   Contains:
DE     RecName: Full=Outer capsid protein mu-1C;
GN   Name=M2;
OS   Reovirus type 2 (strain D5/Jones) (T2J) (Mammalian orthoreovirus 2).
OC   Viruses; Riboviria; Orthornavirae; Duplornaviricota; Resentoviricetes;
OC   Reovirales; Spinareoviridae; Orthoreovirus; Mammalian orthoreovirus.
OX   NCBI_TaxID=10885;
OH   NCBI_TaxID=40674; Mammalia.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=3354208; DOI=10.1016/0042-6822(88)90301-7;
RA   Wiener J.R., Joklik W.K.;
RT   "Evolution of reovirus genes: a comparison of serotype 1, 2, and 3 M2
RT   genome segments, which encode the major structural capsid protein mu 1C.";
RL   Virology 163:603-613(1988).
RN   [2]
RP   PROTEOLYTIC PROCESSING.
RX   PubMed=1328674; DOI=10.1128/jvi.66.11.6408-6418.1992;
RA   Nibert M.L., Fields B.N.;
RT   "A carboxy-terminal fragment of protein mu 1/mu 1C is present in infectious
RT   subvirion particles of mammalian reoviruses and is proposed to have a role
RT   in penetration.";
RL   J. Virol. 66:6408-6418(1992).
CC   -!- FUNCTION: Major outer capsid protein involved in host cell membrane
CC       penetration. In the endocytic compartment, outer-capsid protein sigma-3
CC       is removed by cathepsin proteases, which exposes the viral membrane-
CC       penetration protein mu-1. Both myristoylated peptides mu-1N and phi are
CC       released during infectious subvirion particles (ISVP) formation in the
CC       endosome. They associate with host membranes and mu-1N induces
CC       permeabilization and delivery of transcriptionally active viral
CC       particles into the host cell cytoplasm. Seems to induce apoptosis in
CC       the host cell (By similarity). {ECO:0000250}.
CC   -!- FUNCTION: The viral outer shell polypeptides, of which mu-1 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.
CC       {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: [Outer capsid protein mu-1]: Virion
CC       {ECO:0000250}. Host cell membrane {ECO:0000250}; Lipid-anchor
CC       {ECO:0000250}. Host endoplasmic reticulum {ECO:0000250}. Host
CC       mitochondrion {ECO:0000250}. Note=Found in the outer capsid. Seems to
CC       associate with cell membranes. This association is enhanced by
CC       myristoylation (By similarity). {ECO:0000250}.
CC   -!- DOMAIN: The C-terminal region, phi, determines both targeting to
CC       intracellular membranes and induction of apoptosis. {ECO:0000250}.
CC   -!- PTM: Cleaved during the endosomal proteolytic disassembly of the outer
CC       capsid. Mu-1 is proteolytically cleaved into mu-1N and mu-1C during the
CC       maturation step to generate the ISVP. Cleavage of mu-1 to mu-1C is
CC       dependent on myristoylation and binding to sigma-3 protein. Mu-1C is
CC       further cleaved into delta (59 kDa), and phi (13 kDa) segments during
CC       entry into the host cell cytoplasm. {ECO:0000269|PubMed:1328674}.
CC   -!- PTM: Mu-1 and mu-1N are N-terminally myristoylated. This acylation is
CC       essential for the membrane fusion activity (By similarity).
CC       {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the orthoreovirus mu-1 protein family.
CC       {ECO:0000305}.
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DR   EMBL; M19355; AAA47246.1; -; mRNA.
DR   PIR; B28607; M2XR2J.
DR   SMR; P12397; -.
DR   TCDB; 1.A.60.1.1; the mammalian reovirus pre-forming peptide, mu-1 (mu-1) family.
DR   GlyCosmos; P12397; 7 sites, No reported glycans.
DR   Proteomes; UP000006370; Genome.
DR   GO; GO:0044165; C:host cell endoplasmic reticulum; IEA:UniProtKB-SubCell.
DR   GO; GO:0033650; C:host cell mitochondrion; IEA:UniProtKB-SubCell.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016020; C:membrane; IEA:UniProtKB-KW.
DR   GO; GO:0039624; C:viral outer capsid; IEA:UniProtKB-KW.
DR   GO; GO:0046812; F:host cell surface binding; IEA:InterPro.
DR   GO; GO:0039665; P:permeabilization of host organelle membrane involved in viral entry into host cell; IEA:UniProtKB-KW.
DR   GO; GO:0099008; P:viral entry via permeabilization of inner membrane; IEA:UniProtKB-KW.
DR   Gene3D; 2.60.120.420; Membrane penetration protein mu1, Chain B, domain 4; 1.
DR   Gene3D; 3.90.1370.10; Protein mu-1, chain B, domain 1; 1.
DR   Gene3D; 1.10.2040.10; Protein mu-1, chain B, domain 2; 1.
DR   Gene3D; 1.10.2050.10; Protein mu-1, chain B, domain 3; 1.
DR   InterPro; IPR009113; Mu1/VP4.
DR   InterPro; IPR036256; Mu1/VP4_sf.
DR   InterPro; IPR015961; Mu1_membr_pen_domI.
DR   InterPro; IPR015962; Mu1_membr_pen_domII.
DR   InterPro; IPR044937; Mu1_membr_pen_domIII.
DR   InterPro; IPR015960; Mu1_membr_pen_domIV.
DR   Pfam; PF05993; Reovirus_M2; 1.
DR   SUPFAM; SSF69908; Membrane penetration protein mu1; 1.
PE   1: Evidence at protein level;
KW   Apoptosis; Capsid protein; Glycoprotein; Host cell membrane;
KW   Host endoplasmic reticulum; Host membrane; Host mitochondrion; Lipoprotein;
KW   Membrane; Myristate; Outer capsid protein;
KW   Viral penetration into host cytoplasm;
KW   Viral penetration via permeabilization of host membrane; Virion;
KW   Virus entry into host cell.
FT   INIT_MET        1
FT                   /note="Removed; by host"
FT                   /evidence="ECO:0000250"
FT   CHAIN           2..708
FT                   /note="Outer capsid protein mu-1"
FT                   /id="PRO_0000040659"
FT   CHAIN           2..42
FT                   /note="Outer capsid protein mu-1N"
FT                   /id="PRO_0000344979"
FT   CHAIN           43..708
FT                   /note="Outer capsid protein mu-1C"
FT                   /id="PRO_0000040661"
FT   REGION          671..708
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            42..43
FT                   /note="Cleavage"
FT                   /evidence="ECO:0000250"
FT   LIPID           2
FT                   /note="N-myristoyl glycine; by host"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        3
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        12
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        81
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        110
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        458
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        482
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        528
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   708 AA;  76146 MW;  503DEE3053DEF422 CRC64;
     MGNASSIVQT INVTGDGNVF KPSAETSSTA VPSLSLSPGM LNPGGVPWIA IGDETSVTSP
     GALRRMTSKD IPETAIINTD NSSGAVPSES ALVPYNDEPL VVVTEHAIAN FTKAEMALEF
     NREFLDKLRV LSVSPKYSDL LTYVDCYVGV SARQALNNFQ KQVPVITPTR QTMYVDSIQA
     ALKALEKWEI DLRVAQTLLP TNVPIGEVSC PMQSVVKLLD DQLPDDSLIR RYPKEAAVAL
     AKRNGGIQWM DVSEGTVMNE AVNAVAASAL APSASAPPLE EKSKLTEQAM DLVTAAEPEI
     IASLVPVPAP VFAIPPKPAD YNVRTLKIDE ATWLRMIPKT MNTPFQIQVT DNTGTSWHMN
     LRGGTRVVNL DQIAPMRFVL DLGGKSYKET SWDPNGKKVG FIVFQSKIPF ELWTAASQIG
     QATVVNYVQL YAEDSSFTAQ SIIATTSLAY NYEPEQLNKT DPEMNYYLLA AFIDSAAIST
     SNMTQPDVWD ALLTMSPLSA GEVTVKGAVV SEVIPADLVG SYTPESLNAS LPNDAARCMI
     DRASKIAEAI KIDDDAGPDE YSPNSVPIQG QLAISQLETG YGVRIFNPKG ILSKIASRAM
     QAFIGDPSTI ITQAAPVLSD KNNWIALAQG VKTSLRTKSL SAGVKTAVSK LSSSESIQSW
     TQGFLDKVST HFPAPKPDCP QSGDSGDGSA RRLKRDSYAG VVKRGYTR
//