P63232 · M2_I73A5

Function

function

Forms a proton-selective ion channel that is necessary for the efficient release of the viral genome during virus entry. After attaching to the cell surface, the virion enters the cell by endocytosis. Acidification of the endosome triggers M2 ion channel activity. The influx of protons into virion interior is believed to disrupt interactions between the viral ribonucleoprotein (RNP), matrix protein 1 (M1), and lipid bilayers, thereby freeing the viral genome from interaction with viral proteins and enabling RNA segments to migrate to the host cell nucleus, where influenza virus RNA transcription and replication occur. Also plays a role in viral proteins secretory pathway. Elevates the intravesicular pH of normally acidic compartments, such as trans-Golgi network, preventing newly formed hemagglutinin from premature switching to the fusion-active conformation.

Miscellaneous

When the channel is activated, one or more imidazole moieties of His-37 probably become bi-protonated.

Activity regulation

The M2 protein from most influenza A strains is inhibited by amantadine and rimantadine, resulting in viral uncoating incapacity. Emergence of amantadine-resistant variants is usually rapid.

Features

Showing features for site.

TypeIDPosition(s)Description
Site37Essential for channel activity, possibly by being protonated during channel activation, and by forming the channel gate and the selective filter
Site41Seems to be involved in pH gating

GO annotations

AspectTerm
Cellular Componenthost cell plasma membrane
Cellular Componentmembrane
Cellular Componentvirion membrane
Molecular Functionmonoatomic ion channel activity
Molecular Functionproton transmembrane transporter activity
Biological Processprotein complex oligomerization
Biological Processsuppression by virus of host autophagy
Biological Processsymbiont genome entry into host cell via pore formation in plasma membrane

Keywords

Names & Taxonomy

Protein names

  • Recommended name
    Matrix protein 2
  • Alternative names
    • Proton channel protein M2

Gene names

    • Name
      M

Organism names

Accessions

  • Primary accession
    P63232
  • Secondary accessions
    • P03490
    • Q1PUD8

Proteomes

Subcellular Location

Virion membrane
Host apical cell membrane
; Single-pass type III membrane protein
Note: Abundantly expressed at the apical plasma membrane in infected polarized epithelial cells, in close proximity to budding and assembled virions. Minor component of virions (only 16-20 molecules/virion).

Features

Showing features for topological domain, transmembrane.

TypeIDPosition(s)Description
Topological domain1-22Virion surface
Transmembrane23-43Helical; Signal-anchor for type III membrane protein
Topological domain44-97Intravirion

Keywords

PTM/Processing

Features

Showing features for chain, disulfide bond, glycosylation, lipidation, modified residue.

TypeIDPosition(s)Description
ChainPRO_00000788891-97Matrix protein 2
Disulfide bond17Interchain (with C-17)
Disulfide bond19Interchain (with C-19)
Glycosylation20N-linked (GlcNAc...) asparagine; by host
Lipidation50S-palmitoyl cysteine; by host
Modified residue64Phosphoserine; by host
Modified residue82Phosphoserine; by host
Modified residue93Phosphoserine; by host

Keywords

PTM databases

Interaction

Subunit

Homotetramer; composed of two disulfide-linked dimers held together by non-covalent interactions. May interact with matrix protein 1.

Protein-protein interaction databases

Structure

3D structure databases

Family & Domains

Features

Showing features for region, compositional bias.

TypeIDPosition(s)Description
Region60-88Disordered
Compositional bias67-88Basic and acidic residues

Domain

Cytoplasmic tail plays an important role in virion assembly and morphogenesis.

Sequence similarities

Belongs to the influenza viruses matrix protein M2 family.

Keywords

Family and domain databases

Sequence & Isoform

Align isoforms (2)
  • Sequence status
    Complete

This entry describes 2 isoforms produced by Alternative splicing. Only the first 9 residues are shared by the 2 isoforms.

P63232-1

This isoform has been chosen as the canonical sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

  • Length
    97
  • Mass (Da)
    11,186
  • Last updated
    1986-07-21 v1
  • Checksum
    3CDD4DE90D7B16A4
MSLLTEVETPIRNEWGCRCNDSSDPLVVAASIIGILHLILWILDRLFFKCIYRFFEHGLKRGPSTEGVPESMREEYRKEQQSAVDADDSHFVSIELE

P63234-1

The sequence of this isoform can be found in the external entry linked below. Isoforms of the same protein are often annotated in two different entries if their sequences differ significantly.

View isoform

Features

Showing features for compositional bias.

TypeIDPosition(s)Description
Compositional bias67-88Basic and acidic residues

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
X08090
EMBL· GenBank· DDBJ
CAA30887.1
EMBL· GenBank· DDBJ
Genomic RNA
X08092
EMBL· GenBank· DDBJ
CAA30891.1
EMBL· GenBank· DDBJ
Genomic RNA
CY009349
EMBL· GenBank· DDBJ
ABE12541.1
EMBL· GenBank· DDBJ
Genomic RNA

Similar Proteins

Disclaimer

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