ID   M1_I82A2                Reviewed;         109 AA.
AC   P26147;
DT   01-MAY-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-1992, sequence version 1.
DT   23-FEB-2022, entry version 81.
DE   RecName: Full=Matrix protein 1;
DE            Short=M1;
DE   Flags: Fragment;
GN   Name=M;
OS   Influenza A virus (strain A/Camel/Mongolia/1982 H1N1).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus.
OX   NCBI_TaxID=387191;
OH   NCBI_TaxID=8782; Aves.
OH   NCBI_TaxID=9606; Homo sapiens (Human).
OH   NCBI_TaxID=9823; Sus scrofa (Pig).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=8249279; DOI=10.1006/viro.1993.1629;
RA   Yamnikova S.S., Mandler J., Bekh-Ochir Z.H., Dachtzeren P., Ludwig S.,
RA   Lvov D.K., Scholtissek C.;
RT   "A reassortant H1N1 influenza A virus caused fatal epizootics among camels
RT   in Mongolia.";
RL   Virology 197:558-563(1993).
CC   -!- FUNCTION: Plays critical roles in virus replication, from virus entry
CC       and uncoating to assembly and budding of the virus particle. M1 binding
CC       to ribonucleocapsids (RNPs) in nucleus seems to inhibit viral
CC       transcription. Interaction of viral NEP with M1-RNP is thought to
CC       promote nuclear export of the complex, which is targeted to the virion
CC       assembly site at the apical plasma membrane in polarized epithelial
CC       cells. Interactions with NA and HA may bring M1, a non-raft-associated
CC       protein, into lipid rafts. Forms a continuous shell on the inner side
CC       of the lipid bilayer in virion, where it binds the RNP. During virus
CC       entry into cell, the M2 ion channel acidifies the internal virion core,
CC       inducing M1 dissociation from the RNP. M1-free RNPs are transported to
CC       the nucleus, where viral transcription and replication can take place
CC       (By similarity). {ECO:0000250}.
CC   -!- FUNCTION: Determines the virion's shape: spherical or filamentous.
CC       Clinical isolates of influenza are characterized by the presence of
CC       significant proportion of filamentous virions, whereas after multiple
CC       passage on eggs or cell culture, virions have only spherical
CC       morphology. Filamentous virions are thought to be important to infect
CC       neighboring cells, and spherical virions more suited to spread through
CC       aerosol between hosts organisms (By similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Homodimer and homomultimer. Interacts with NEP. Binds
CC       ribonucleocapsid by both interacting with genomic RNA and NP protein.
CC       May interact with HA and NA. Cannot bind NP without genomic RNA (By
CC       similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Virion membrane {ECO:0000250}; Multi-pass
CC       membrane protein {ECO:0000250}. Host nucleus {ECO:0000250}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative splicing; Named isoforms=2;
CC         Comment=Only the first 9 residues are shared by the 2 isoforms.;
CC       Name=M1;
CC         IsoId=P26147-1; Sequence=Displayed;
CC       Name=M2;
CC         IsoId=P26147-2; Sequence=Not described;
CC   -!- MISCELLANEOUS: Most abundant protein in virion. When expressed alone
CC       can form virus-like particles in transfected cells.
CC   -!- SIMILARITY: Belongs to the influenza viruses Matrix protein M1 family.
CC       {ECO:0000305}.
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; M73978; AAA16906.1; -; mRNA.
DR   SMR; P26147; -.
DR   GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0016020; C:membrane; IEA:UniProtKB-KW.
DR   GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0039660; F:structural constituent of virion; IEA:UniProtKB-KW.
DR   Gene3D; 1.10.10.180; -; 1.
DR   InterPro; IPR013188; Flu_matrix_M1_C.
DR   InterPro; IPR015799; Flu_matrix_M1_N_sub2.
DR   Pfam; PF08289; Flu_M1_C; 1.
DR   SMART; SM00759; Flu_M1_C; 1.
PE   2: Evidence at transcript level;
KW   Alternative splicing; Host nucleus; Membrane; RNA-binding;
KW   Viral matrix protein; Virion.
FT   CHAIN           <1..109
FT                   /note="Matrix protein 1"
FT                   /id="PRO_0000078852"
FT   REGION          22..109
FT                   /note="RNP-binding"
FT                   /evidence="ECO:0000250"
FT   NON_TER         1
SQ   SEQUENCE   109 AA;  12095 MW;  B4771E90CB82FE22 CRC64;
     FGLVCATCEQ IADSQHRSHR QMVTTTNPLI RHENRMVLAS TTAKAMEQMA GSSEQAAEAM
     EVASQARQMV QAMRTIGTHP SSSAGLKNDL LENLQAYQKR MGVQMQRFK