P08383 · BM2_INBSI

Function

function

Forms presumably a highly low-pH gated proton-selective channel. Trp-23 may function as a minimalistic gate that opens and closes the pore. When the environmental pH is lower than a threshold, the BM2 channel would be activated and selectively transport protons across the membrane from the extracellular side to the cytoplasmic side. Crucial for the uncoating process. When the virion is internalized into the endosome, the channel acidifies the virion's interior, promoting the dissociation of matrix protein 1 (M1) from the ribonucleoprotein (RNP) thus allowing the transport of the RNP from the virion into the cell's nucleus. Also plays a role in viral protein 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 (By similarity).
Plays a crucial role in virion assembly. Expressed in the late phase of the infection (By similarity).

Miscellaneous

Influenza B virus genome RNA segment 7 encodes the M1 (AC P06816) and BM2 proteins. Normal translation produces the M1 protein. The M1 termination codon overlaps the BM2 initiation codon in an overlapping stop-start pentanucleotide 5'-UAAUG-3'. Termination of M1 translation triggers reinitiation on the BM2 AUG in the +2 open reading frame.

Features

Showing features for site.

1109102030405060708090100
TypeIDPosition(s)Description
Site19Essential for channel activity, possibly by being protonated during channel activation, and by forming the channel gate and the selective filter
Site23Seems to be involved in pH gating

GO annotations

AspectTerm
Cellular Componenthost cell plasma membrane
Cellular Componentmembrane
Cellular Componentvirion membrane
Molecular Functionchannel activity
Biological Processproton transmembrane transport

Keywords

Names & Taxonomy

Protein names

  • Recommended name
    Matrix protein 2
  • Alternative names
    • BM2

Gene names

    • Name
      M

Organism names

Accessions

  • Primary accession
    P08383

Proteomes

Subcellular Location

Virion membrane
; Single-pass type III membrane protein
Host cell membrane
; Single-pass type III membrane protein
Note: Transported to the plasma membrane through the trans Golgi network.

Features

Showing features for topological domain, transmembrane.

Type
IDPosition(s)Description
Topological domain1-4Virion surface
Transmembrane5-27Helical; Signal-anchor for type III membrane protein
Topological domain28-109Intravirion

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00000789001-109Matrix protein 2

Post-translational modification

Phosphorylated by host.

Keywords

Interaction

Subunit

Homotetramer.

Structure

3D structure databases

Sequence

  • Sequence status
    Complete
  • Length
    109
  • Mass (Da)
    12,625
  • Last updated
    2006-01-10 v2
  • Checksum
    8B230F38F37F8978
MLEPFQILSICSFILSALHFMAWTIGHLNQIKRGVNLKIRIRNPNKETINREVSILRHSYQKEIQAKETMKEVLSDNMEILSDHIVIEGLSAEEIIKMGETVLEVEELH

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
M14909
EMBL· GenBank· DDBJ
AAA67101.1
EMBL· GenBank· DDBJ
Genomic RNA

Similar Proteins

Disclaimer

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