ID   D0FHX1_9INFA            Unreviewed;        62 AA.
AC   D0FHX1;
DT   24-NOV-2009, integrated into UniProtKB/TrEMBL.
DT   24-NOV-2009, sequence version 1.
DT   10-APR-2019, entry version 35.
DE   RecName: Full=Matrix protein 2 {ECO:0000256|SAAS:SAAS01040803};
DE   Flags: Fragment;
GN   Name=M2 {ECO:0000313|EMBL:ACX47411.1};
OS   Influenza A virus (A/Chengdu/03/2009(H1N1)).
OC   Viruses; ssRNA viruses; ssRNA negative-strand viruses;
OC   Negarnaviricota; Polyploviricotina; Insthoviricetes; Articulavirales;
OC   Orthomyxoviridae; Alphainfluenzavirus.
OX   NCBI_TaxID=681159 {ECO:0000313|EMBL:ACX47411.1};
RN   [1] {ECO:0000313|EMBL:ACX47411.1}
RP   NUCLEOTIDE SEQUENCE.
RC   STRAIN=A/Chengdu/03/2009 {ECO:0000313|EMBL:ACX47411.1};
RA   Jiang T., Qin C., Li X., Zhao H., Yu M., Deng Y., Yu X., Han J.,
RA   Qin E., Zhu Q.;
RT   "A community transmission of influenza A (H1N1) virus in a boarding
RT   school in China, 22-27 July 2009.";
RL   Submitted (OCT-2009) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Forms a proton-selective ion channel that is necessary
CC       for the efficient release of the viral genome during virus entry.
CC       After 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
CC       to disrupt interactions between the viral ribonucleoprotein (RNP),
CC       matrix protein 1 (M1), and lipid bilayers, thereby freeing the
CC       viral genome from interaction with viral proteins and enabling RNA
CC       segments to migrate to the host cell nucleus, where influenza
CC       virus RNA transcription and replication occur. Also plays a role
CC       in viral proteins secretory pathway. Elevates the intravesicular
CC       pH of normally acidic compartments, such as trans-Golgi network,
CC       preventing newly formed hemagglutinin from premature switching to
CC       the fusion-active conformation. {ECO:0000256|SAAS:SAAS01040783}.
CC   -!- ACTIVITY REGULATION: The M2 protein from most influenza A strains
CC       is inhibited by amantadine and rimantadine, resulting in viral
CC       uncoating incapacity. Emergence of amantadine-resistant variants
CC       is usually rapid. {ECO:0000256|SAAS:SAAS01073786}.
CC   -!- SUBUNIT: Homotetramer; composed of two disulfide-linked dimers
CC       held together by non-covalent interactions. May interact with
CC       matrix protein 1. {ECO:0000256|SAAS:SAAS01040791}.
CC   -!- SUBCELLULAR LOCATION: Host apical cell membrane
CC       {ECO:0000256|SAAS:SAAS01040793}; Single-pass type III membrane
CC       protein {ECO:0000256|SAAS:SAAS01040793}. Virion membrane
CC       {ECO:0000256|SAAS:SAAS01040800}.
CC   -!- SIMILARITY: Belongs to the influenza viruses matrix protein M2
CC       family. {ECO:0000256|SAAS:SAAS01040773}.
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DR   EMBL; GU056984; ACX47411.1; -; Viral_cRNA.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0044385; C:integral to membrane of host cell; IEA:UniProtKB-KW.
DR   GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0005216; F:ion channel activity; IEA:UniProtKB-KW.
DR   GO; GO:0015078; F:proton transmembrane transporter activity; IEA:InterPro.
DR   GO; GO:0039707; P:pore formation by virus in membrane of host cell; IEA:UniProtKB-KW.
DR   GO; GO:0051259; P:protein complex oligomerization; IEA:UniProtKB-KW.
DR   GO; GO:0039521; P:suppression by virus of host autophagy; IEA:UniProtKB-KW.
DR   InterPro; IPR002089; Flu_M2.
DR   Pfam; PF00599; Flu_M2; 1.
DR   ProDom; PD001031; Flu_M2; 1.
PE   3: Inferred from homology;
KW   Disulfide bond {ECO:0000256|SAAS:SAAS01040795};
KW   Host cell membrane {ECO:0000256|SAAS:SAAS01040804};
KW   Host membrane {ECO:0000256|SAAS:SAAS01040762};
KW   Host-virus interaction {ECO:0000256|SAAS:SAAS01040805};
KW   Hydrogen ion transport {ECO:0000256|SAAS:SAAS01040774};
KW   Inhibition of host autophagy by virus {ECO:0000256|SAAS:SAAS01040755};
KW   Ion channel {ECO:0000256|SAAS:SAAS01040776};
KW   Ion transport {ECO:0000256|SAAS:SAAS01040807};
KW   Membrane {ECO:0000256|SAAS:SAAS01040794, ECO:0000256|SAM:Phobius};
KW   Transmembrane {ECO:0000256|SAAS:SAAS01040784,
KW   ECO:0000256|SAM:Phobius};
KW   Transmembrane helix {ECO:0000256|SAAS:SAAS01040757,
KW   ECO:0000256|SAM:Phobius}; Transport {ECO:0000256|SAAS:SAAS01040788};
KW   Viral ion channel {ECO:0000256|SAAS:SAAS01040754};
KW   Virion {ECO:0000256|SAAS:SAAS01040766}.
FT   TRANSMEM     19     39       Helical. {ECO:0000256|SAM:Phobius}.
FT   NON_TER       1      1       {ECO:0000313|EMBL:ACX47411.1}.
FT   NON_TER      62     62       {ECO:0000313|EMBL:ACX47411.1}.
SQ   SEQUENCE   62 AA;  7156 MW;  28048D6BEEF42A1A CRC64;
     PTRSEWECRC SDSSDPLVIA ANIIGILHLI LWITDRLFFK CIYRRFKYGL KRGPSTEGVP
     ES
//