M2_I01A2
ID M2_I01A2 Reviewed; 100 AA.
AC P0C5T2;
DT 13-NOV-2007, integrated into UniProtKB/Swiss-Prot.
DT 13-NOV-2007, sequence version 1.
DT 02-JUN-2021, entry version 55.
DE RecName: Full=Matrix protein 2 {ECO:0000255|HAMAP-Rule:MF_04069};
DE AltName: Full=Proton channel protein M2 {ECO:0000255|HAMAP-Rule:MF_04069};
GN Name=M {ECO:0000255|HAMAP-Rule:MF_04069};
OS Influenza A virus (strain A/Chicken/Hong Kong/FY150/2001 H5N1 genotype D).
OC Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus.
OX NCBI_TaxID=222142;
OH NCBI_TaxID=8782; Aves.
OH NCBI_TaxID=9685; Felis catus (Cat) (Felis silvestris catus).
OH NCBI_TaxID=9606; Homo sapiens (Human).
OH NCBI_TaxID=9691; Panthera pardus (Leopard) (Felis pardus).
OH NCBI_TaxID=9694; Panthera tigris (Tiger).
OH NCBI_TaxID=9823; Sus scrofa (Pig).
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX PubMed=12077307; DOI=10.1073/pnas.132268999;
RA Guan Y., Peiris J.S.M., Lipatov A.S., Ellis T.M., Dyrting K.C., Krauss S.,
RA Zhang L.J., Webster R.G., Shortridge K.F.;
RT "Emergence of multiple genotypes of H5N1 avian influenza viruses in Hong
RT Kong SAR.";
RL Proc. Natl. Acad. Sci. U.S.A. 99:8950-8955(2002).
CC -!- FUNCTION: Forms a proton-selective ion channel that is necessary for
CC the efficient release of the viral genome during virus entry. After
CC attaching to the cell surface, the virion enters the cell by
CC endocytosis. Acidification of the endosome triggers M2 ion channel
CC activity. The influx of protons into virion interior is believed to
CC disrupt interactions between the viral ribonucleoprotein (RNP), matrix
CC protein 1 (M1), and lipid bilayers, thereby freeing the viral genome
CC from interaction with viral proteins and enabling RNA segments to
CC migrate to the host cell nucleus, where influenza virus RNA
CC transcription and replication occur. Also plays a role in viral
CC proteins secretory pathway. Elevates the intravesicular pH of normally
CC acidic compartments, such as trans-Golgi network, preventing newly
CC formed hemagglutinin from premature switching to the fusion-active
CC conformation. {ECO:0000255|HAMAP-Rule:MF_04069}.
CC -!- ACTIVITY REGULATION: The M2 protein from most influenza A strains is
CC inhibited by amantadine and rimantadine, resulting in viral uncoating
CC incapacity. Emergence of amantadine-resistant variants is usually
CC rapid.
CC -!- SUBUNIT: Homotetramer; composed of two disulfide-linked dimers held
CC together by non-covalent interactions. May interact with matrix protein
CC 1. {ECO:0000255|HAMAP-Rule:MF_04069}.
CC -!- SUBCELLULAR LOCATION: Virion membrane {ECO:0000255|HAMAP-
CC Rule:MF_04069}. Host apical cell membrane {ECO:0000255|HAMAP-
CC Rule:MF_04069}; Single-pass type III membrane protein
CC {ECO:0000255|HAMAP-Rule:MF_04069}. Note=Abundantly expressed at the
CC apical plasma membrane in infected polarized epithelial cells, in close
CC proximity to budding and assembled virions. Minor component of virions
CC (only 16-20 molecules/virion). {ECO:0000255|HAMAP-Rule:MF_04069}.
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=M2;
CC IsoId=P0C5T2-1; Sequence=Displayed;
CC Name=M1;
CC IsoId=Q80A04-1; Sequence=External;
CC -!- DOMAIN: Cytoplasmic tail plays an important role in virion assembly and
CC morphogenesis. {ECO:0000255|HAMAP-Rule:MF_04069}.
CC -!- MISCELLANEOUS: When the channel is activated, one or more imidazole
CC moieties of His-40 probably become bi-protonated. {ECO:0000255|HAMAP-
CC Rule:MF_04069}.
CC -!- SIMILARITY: Belongs to the influenza viruses matrix protein M2 family.
CC {ECO:0000255|HAMAP-Rule:MF_04069}.
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DR EMBL; AF509043; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR SMR; P0C5T2; -.
DR GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-UniRule.
DR GO; GO:0044385; C:integral to membrane of host cell; IEA:UniProtKB-UniRule.
DR GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0005216; F:ion channel activity; IEA:UniProtKB-UniRule.
DR GO; GO:0015078; F:proton transmembrane transporter activity; IEA:UniProtKB-UniRule.
DR GO; GO:0039707; P:pore formation by virus in membrane of host cell; IEA:UniProtKB-UniRule.
DR GO; GO:0051259; P:protein complex oligomerization; IEA:UniProtKB-UniRule.
DR GO; GO:0039521; P:suppression by virus of host autophagy; IEA:UniProtKB-UniRule.
DR HAMAP; MF_04069; INFV_M2; 1.
DR InterPro; IPR002089; Flu_M2.
DR Pfam; PF00599; Flu_M2; 1.
PE 3: Inferred from homology;
KW Alternative splicing; Disulfide bond; Host cell membrane; Host membrane;
KW Host-virus interaction; Hydrogen ion transport;
KW Inhibition of host autophagy by virus; Ion channel; Ion transport;
KW Lipoprotein; Membrane; Palmitate; Phosphoprotein; Signal-anchor;
KW Transmembrane; Transmembrane helix; Transport; Viral ion channel; Virion.
FT CHAIN 1..100
FT /note="Matrix protein 2"
FT /id="PRO_0000311624"
FT TOPO_DOM 1..25
FT /note="Virion surface"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT TRANSMEM 26..46
FT /note="Helical; Signal-anchor for type III membrane
FT protein"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT TOPO_DOM 47..100
FT /note="Intravirion"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT REGION 63..86
FT /note="Disordered"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT COMPBIAS 70..86
FT /note="Basic and acidic residues"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT SITE 40
FT /note="Essential for channel activity, possibly by being
FT protonated during channel activation, and by forming the
FT channel gate and the selective filter"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT SITE 44
FT /note="Seems to be involved in pH gating"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT MOD_RES 67
FT /note="Phosphoserine; by host"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT MOD_RES 85
FT /note="Phosphoserine; by host"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT LIPID 53
FT /note="S-palmitoyl cysteine; by host"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT DISULFID 20
FT /note="Interchain (with C-20)"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
FT DISULFID 22
FT /note="Interchain (with C-22)"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_04069"
SQ SEQUENCE 100 AA; 11577 MW; 4A5CE94EF2325828 CRC64;
MSLLTEVETY VLPTRNEWEC RCSGSSDPLV VASSIIGILH LILWILDRLF FKCIYRRLKY
GLKRGPSTEG VPESMREEYR QEQQSAVDVD DGHFVNIELE
