ID   M1_I85A4                Reviewed;         252 AA.
AC   Q67202;
DT   18-MAR-2008, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   08-NOV-2023, entry version 87.
DE   RecName: Full=Matrix protein 1 {ECO:0000255|HAMAP-Rule:MF_04068};
DE            Short=M1 {ECO:0000255|HAMAP-Rule:MF_04068};
GN   Name=M {ECO:0000255|HAMAP-Rule:MF_04068};
OS   Influenza A virus (strain A/Swine/Netherlands/12/1985 H1N1).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus;
OC   Alphainfluenzavirus influenzae; Influenza A virus.
OX   NCBI_TaxID=380347;
OH   NCBI_TaxID=8782; Aves.
OH   NCBI_TaxID=9606; Homo sapiens (Human).
OH   NCBI_TaxID=9823; Sus scrofa (Pig).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=1895397; DOI=10.1128/jvi.65.10.5491-5498.1991;
RA   Ito T., Gorman O.T., Kawaoka Y., Bean W.J., Webster R.G.;
RT   "Evolutionary analysis of the influenza A virus M gene with comparison of
RT   the M1 and M2 proteins.";
RL   J. Virol. 65:5491-5498(1991).
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       {ECO:0000255|HAMAP-Rule:MF_04068}.
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. {ECO:0000255|HAMAP-Rule:MF_04068}.
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.
CC       {ECO:0000255|HAMAP-Rule:MF_04068}.
CC   -!- SUBCELLULAR LOCATION: Virion membrane {ECO:0000255|HAMAP-
CC       Rule:MF_04068}; Peripheral membrane protein {ECO:0000255|HAMAP-
CC       Rule:MF_04068}; Cytoplasmic side {ECO:0000255|HAMAP-Rule:MF_04068}.
CC       Host nucleus {ECO:0000255|HAMAP-Rule:MF_04068}.
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=Q67202-1; Sequence=Displayed;
CC       Name=M2;
CC         IsoId=Q67201-1; Sequence=External;
CC   -!- MISCELLANEOUS: Most abundant protein in virion. When expressed alone
CC       can form virus-like particles in transfected cells. {ECO:0000255|HAMAP-
CC       Rule:MF_04068}.
CC   -!- SIMILARITY: Belongs to the influenza viruses Matrix protein M1 family.
CC       {ECO:0000255|HAMAP-Rule:MF_04068}.
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DR   EMBL; M63525; AAA43336.1; -; Genomic_RNA.
DR   SMR; Q67202; -.
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-UniRule.
DR   GO; GO:0039660; F:structural constituent of virion; IEA:UniProtKB-UniRule.
DR   GO; GO:0046761; P:viral budding from plasma membrane; IEA:UniProtKB-UniRule.
DR   Gene3D; 1.10.10.180; -; 1.
DR   Gene3D; 1.20.91.10; -; 1.
DR   HAMAP; MF_04068; INFV_M1; 1.
DR   InterPro; IPR036039; Flu_matrix_M1.
DR   InterPro; IPR013188; Flu_matrix_M1_C.
DR   InterPro; IPR001561; Flu_matrix_M1_N.
DR   InterPro; IPR015423; Flu_matrix_M1_N_sub1.
DR   InterPro; IPR015799; Flu_matrix_M1_N_sub2.
DR   InterPro; IPR037533; INFV_M1.
DR   Pfam; PF00598; Flu_M1; 1.
DR   Pfam; PF08289; Flu_M1_C; 1.
DR   SMART; SM00759; Flu_M1_C; 1.
DR   SUPFAM; SSF48145; Influenza virus matrix protein M1; 1.
PE   3: Inferred from homology;
KW   Alternative splicing; Host nucleus; Membrane; RNA-binding;
KW   Viral matrix protein; Virion.
FT   CHAIN           1..252
FT                   /note="Matrix protein 1"
FT                   /id="PRO_0000326324"
FT   REGION          1..164
FT                   /note="Membrane-binding"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04068"
FT   REGION          165..252
FT                   /note="RNP-binding"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04068"
FT   MOTIF           101..105
FT                   /note="Nuclear localization signal"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04068"
SQ   SEQUENCE   252 AA;  27915 MW;  843587B0F9B83865 CRC64;
     MSLLTEVETY VLSIIPSGPL KAEIAQRLED VFAGKNTDLE ALMEWLKTRP ILSPLTKGIL
     GFVFTLTVPS ERGLQRRRFV QNALNGNGDP NNMDRAVKLY RKLKREITFH GAKEVALSYS
     TGALASCMGL IYNRMGTVTT EVAFGLVCAT CEQIADSQHR SHRQMVTTTN PLIRHENRMV
     LASTTAKAME QMAGSSEQAA EAMEVASQAR QMVHAMRTIG THPSSSAGLK DDLLENLQAY
     QKRMGVQIQR FK
//