AC   MF_04069;
DC   Protein; auto
TR   HAMAP; MF_04069; -; 1; level=0
XX
Names: INFV_M2
XX
ID   M2
DE   RecName: Full=Matrix protein 2;
DE   AltName: Full=Proton channel protein M2;
GN   Name=M;
XX
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.
CC   -!- SUBUNIT: Homotetramer; composed of two disulfide-linked dimers held
CC       together by non-covalent interactions. May interact with matrix protein
CC       1.
CC   -!- SUBCELLULAR LOCATION: Virion membrane. Host apical cell membrane;
CC       Single-pass type III membrane protein. 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).
CC   -!- DOMAIN: Cytoplasmic tail plays an important role in virion assembly and
CC       morphogenesis.
CC   -!- MISCELLANEOUS: When the channel is activated, one or more imidazole
CC       moities of #{His-37} probably become bi-protonated.
CC   -!- SIMILARITY: Belongs to the influenza viruses matrix protein M2 family.
XX
DR   Pfam; PF00599; Flu_M2; 1; trigger=no
DR   General; Transmembrane; -; 1; trigger=no
XX
KW   Disulfide bond
case <FTTag:Carbo>
KW   Glycoprotein
end case
KW   Host cell membrane
KW   Host membrane
KW   Host-virus interaction
KW   Hydrogen ion transport
KW   Inhibition of host autophagy by virus
KW   Ion channel
KW   Ion transport
KW   Lipoprotein
KW   Membrane
KW   Palmitate
KW   Phosphoprotein
KW   Signal-anchor
KW   Transmembrane
KW   Transmembrane helix
KW   Transport
KW   Viral ion channel
KW   Virion
XX
GO   GO:0020002; C:host cell plasma membrane
GO   GO:0016020; C:membrane
GO   GO:0055036; C:virion membrane
GO   GO:0015078; F:proton transmembrane transporter activity
GO   GO:0005216; F:monoatomic ion channel activity
GO   GO:0039707; P:virus-mediated pore formation in host cell membrane
GO   GO:0051259; P:protein complex oligomerization
GO   GO:0039521; P:suppression by virus of host autophagy
XX
FT   From: M2_I34A1 (P06821)
FT   TOPO_DOM        Nter..22
FT                   /note="Virion surface"
FT   TRANSMEM        23..43
FT                   /note="Helical; Signal-anchor for type III membrane
FT                   protein"
FT   TOPO_DOM        44..Cter
FT                   /note="Intravirion"
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   Condition: H
FT   SITE            41
FT                   /note="Seems to be involved in pH gating"
FT   Condition: W
FT   MOD_RES         64
FT                   /note="Phosphoserine; by host"
FT   Condition: S
FT   MOD_RES         82
FT                   /note="Phosphoserine; by host"
FT   Condition: S
FT   MOD_RES         93
FT                   /note="Phosphoserine; by host"
FT   Condition: S
FT   LIPID           50
FT                   /note="S-palmitoyl cysteine; by host"
FT   Condition: C
FT   CARBOHYD        20
FT                   /note="N-linked (GlcNAc...) asparagine; by host"
FT   Tag: Carbo; Optional; Condition: N
FT   DISULFID        17
FT                   /note="Interchain (with #{Cys-17})"
FT   Condition: C
FT   DISULFID        19
FT                   /note="Interchain (with #{Cys-19})"
FT   Condition: C
XX
Size: 96-100;
Related: None;
Template: P06821;
Scope:
 Viruses; Orthomyxoviridae
Fusion:
 Nter: None
 Cter: None
Duplicate: None
Plasmid: None
Comments: None
XX
# Revision 1.8 2023/10/13
//