ID   K7YXX1_9INFA            Unreviewed;        97 AA.
AC   K7YXX1;
DT   06-FEB-2013, integrated into UniProtKB/TrEMBL.
DT   06-FEB-2013, sequence version 1.
DT   29-MAY-2024, entry version 56.
DE   RecName: Full=Matrix protein 2 {ECO:0000256|HAMAP-Rule:MF_04069, ECO:0000256|RuleBase:RU361247};
DE   AltName: Full=Proton channel protein M2 {ECO:0000256|HAMAP-Rule:MF_04069};
GN   Name=M2 {ECO:0000313|EMBL:AFX88542.1};
GN   Synonyms=M {ECO:0000256|HAMAP-Rule:MF_04069};
OS   Influenza A virus (A/pintail/Alberta/352/1986(H6N2)).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus;
OC   Alphainfluenzavirus influenzae; Influenza A virus.
OX   NCBI_TaxID=1261960 {ECO:0000313|EMBL:AFX88542.1};
RN   [1] {ECO:0000313|EMBL:AFX88542.1}
RP   NUCLEOTIDE SEQUENCE.
RC   STRAIN=A/pintail/Alberta/352/1986 {ECO:0000313|EMBL:AFX88542.1};
RA   Wentworth D.E., Dugan V., Halpin R., Lin X., Bera J., Ghedin E.,
RA   Fedorova N., Tsitrin T., Stockwell T., Amedeo P., Bishop B., Edworthy P.,
RA   Gupta N., Katzel D., Li K., Schobel S., Shrivastava S., Thovarai V.,
RA   Wang S., van Doorn R., Mai L.Q., Hang N.L., Phuong H.V., Cuong V.D.,
RA   Thanh L., Thach N.C., Quyen P.D., Bao Y., Sanders R., Dernovoy D.,
RA   Kiryutin B., Lipman D.J., Tatusova T.;
RT   "The NIAID Influenza Genome Sequencing Project.";
RL   Submitted (NOV-2012) to the EMBL/GenBank/DDBJ databases.
RN   [2] {ECO:0000313|EMBL:AFX88542.1}
RP   NUCLEOTIDE SEQUENCE.
RC   STRAIN=A/pintail/Alberta/352/1986 {ECO:0000313|EMBL:AFX88542.1};
RG   The NIAID Influenza Genome Sequencing Consortium;
RL   Submitted (NOV-2012) to the EMBL/GenBank/DDBJ databases.
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:0000256|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. {ECO:0000256|RuleBase:RU361247}.
CC   -!- SUBUNIT: Homotetramer; composed of two disulfide-linked dimers held
CC       together by non-covalent interactions. May interact with matrix protein
CC       1. {ECO:0000256|HAMAP-Rule:MF_04069, ECO:0000256|RuleBase:RU361247}.
CC   -!- SUBCELLULAR LOCATION: Virion membrane {ECO:0000256|HAMAP-
CC       Rule:MF_04069}. Host apical cell membrane {ECO:0000256|HAMAP-
CC       Rule:MF_04069}; Single-pass type III membrane protein
CC       {ECO:0000256|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:0000256|HAMAP-Rule:MF_04069}.
CC   -!- DOMAIN: Cytoplasmic tail plays an important role in virion assembly and
CC       morphogenesis. {ECO:0000256|HAMAP-Rule:MF_04069,
CC       ECO:0000256|RuleBase:RU361247}.
CC   -!- MISCELLANEOUS: When the channel is activated, one or more imidazole
CC       moities of His-37 probably become bi-protonated. {ECO:0000256|HAMAP-
CC       Rule:MF_04069}.
CC   -!- SIMILARITY: Belongs to the influenza viruses matrix protein M2 family.
CC       {ECO:0000256|HAMAP-Rule:MF_04069, ECO:0000256|RuleBase:RU361247}.
CC   -!- CAUTION: Lacks conserved residue(s) required for the propagation of
CC       feature annotation. {ECO:0000256|HAMAP-Rule:MF_04069}.
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DR   EMBL; CY126385; AFX88542.1; -; Viral_cRNA.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016020; C:membrane; IEA:UniProtKB-UniRule.
DR   GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0005216; F:monoatomic ion channel activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0015078; F:proton transmembrane transporter activity; 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   Gene3D; 6.10.250.1640; -; 1.
DR   HAMAP; MF_04069; INFV_M2; 1.
DR   InterPro; IPR002089; Flu_M2.
DR   Pfam; PF00599; Flu_M2; 1.
PE   3: Inferred from homology;
KW   Disulfide bond {ECO:0000256|HAMAP-Rule:MF_04069};
KW   Host cell membrane {ECO:0000256|HAMAP-Rule:MF_04069,
KW   ECO:0000256|RuleBase:RU361247};
KW   Host membrane {ECO:0000256|HAMAP-Rule:MF_04069,
KW   ECO:0000256|RuleBase:RU361247};
KW   Host-virus interaction {ECO:0000256|HAMAP-Rule:MF_04069};
KW   Hydrogen ion transport {ECO:0000256|ARBA:ARBA00022781, ECO:0000256|HAMAP-
KW   Rule:MF_04069};
KW   Inhibition of host autophagy by virus {ECO:0000256|HAMAP-Rule:MF_04069};
KW   Ion channel {ECO:0000256|ARBA:ARBA00023303, ECO:0000256|HAMAP-
KW   Rule:MF_04069};
KW   Ion transport {ECO:0000256|ARBA:ARBA00023065, ECO:0000256|HAMAP-
KW   Rule:MF_04069};
KW   Lipoprotein {ECO:0000256|ARBA:ARBA00023288, ECO:0000256|HAMAP-
KW   Rule:MF_04069};
KW   Membrane {ECO:0000256|ARBA:ARBA00023136, ECO:0000256|HAMAP-Rule:MF_04069};
KW   Palmitate {ECO:0000256|ARBA:ARBA00023139, ECO:0000256|HAMAP-Rule:MF_04069};
KW   Phosphoprotein {ECO:0000256|ARBA:ARBA00022553, ECO:0000256|HAMAP-
KW   Rule:MF_04069};
KW   Signal-anchor {ECO:0000256|HAMAP-Rule:MF_04069,
KW   ECO:0000256|RuleBase:RU361247};
KW   Transmembrane {ECO:0000256|HAMAP-Rule:MF_04069,
KW   ECO:0000256|RuleBase:RU361247};
KW   Transmembrane helix {ECO:0000256|HAMAP-Rule:MF_04069,
KW   ECO:0000256|RuleBase:RU361247};
KW   Transport {ECO:0000256|ARBA:ARBA00022448, ECO:0000256|HAMAP-Rule:MF_04069};
KW   Viral ion channel {ECO:0000256|ARBA:ARBA00023039, ECO:0000256|HAMAP-
KW   Rule:MF_04069};
KW   Virion {ECO:0000256|ARBA:ARBA00022844, ECO:0000256|HAMAP-Rule:MF_04069}.
FT   TOPO_DOM        1..22
FT                   /note="Virion surface"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04069"
FT   TRANSMEM        26..48
FT                   /note="Helical"
FT                   /evidence="ECO:0000256|SAM:Phobius"
FT   TOPO_DOM        44..97
FT                   /note="Intravirion"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04069"
FT   REGION          60..89
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            37
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:0000256|HAMAP-Rule:MF_04069"
FT   SITE            41
FT                   /note="Seems to be involved in pH gating"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04069"
FT   MOD_RES         64
FT                   /note="Phosphoserine; by host"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04069"
FT   MOD_RES         82
FT                   /note="Phosphoserine; by host"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04069"
FT   DISULFID        17
FT                   /note="Interchain (with Cys-17)"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04069"
FT   DISULFID        19
FT                   /note="Interchain (with Cys-19)"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_04069"
SQ   SEQUENCE   97 AA;  11210 MW;  AB3216314372F2B2 CRC64;
     MSLLTEVETP TRSGWECKCS DSSDPLIFAA SIIGILHLIL WILDRLFFKY IYRRLKYGLK
     RGPSTEGVPK SMREEYQQEQ QSAVDVDDGH FVNIELE
//