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Q8BAC4

- M2_I18A0

UniProt

Q8BAC4 - M2_I18A0

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Protein

Matrix protein 2

Gene

M

Organism
Influenza A virus (strain A/Brevig Mission/1/1918 H1N1) (Influenza A virus (strain A/South Carolina/1/1918 H1N1))
Status
Reviewed - Annotation score: 5 out of 5- Protein inferred from homologyi

Functioni

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 (By similarity).By similarity

Enzyme regulationi

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 (By similarity).By similarity

Sites

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sitei37 – 371Essential for channel activity, seems to be protonated during channel activation, and may play a role in the channel gating and selectivityBy similarity
Sitei41 – 411Seems to be involved in pH gatingBy similarity

GO - Molecular functioni

  1. hydrogen ion transmembrane transporter activity Source: InterPro
  2. ion channel activity Source: UniProtKB-KW

GO - Biological processi

  1. pore formation by virus in membrane of host cell Source: UniProtKB-KW
  2. protein oligomerization Source: UniProtKB-KW
  3. suppression by virus of host autophagy Source: UniProtKB-KW
Complete GO annotation...

Keywords - Molecular functioni

Ion channel, Viral ion channel

Keywords - Biological processi

Host-virus interaction, Hydrogen ion transport, Inhibition of host autophagy by virus, Ion transport, Transport

Names & Taxonomyi

Protein namesi
Recommended name:
Matrix protein 2
Alternative name(s):
Proton channel protein M2
Gene namesi
Name:M
OrganismiInfluenza A virus (strain A/Brevig Mission/1/1918 H1N1) (Influenza A virus (strain A/South Carolina/1/1918 H1N1))
Taxonomic identifieri88776 [NCBI]
Taxonomic lineageiVirusesssRNA negative-strand virusesOrthomyxoviridaeInfluenzavirus A
Virus hostiAves [TaxID: 8782]
Homo sapiens (Human) [TaxID: 9606]
Sus scrofa (Pig) [TaxID: 9823]
ProteomesiUP000008430: Genome

Subcellular locationi

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) (By similarity).By similarity

Topology

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Topological domaini1 – 2222Virion surfaceSequence AnalysisAdd
BLAST
Transmembranei23 – 4321HelicalSequence AnalysisAdd
BLAST
Topological domaini44 – 9754IntravirionSequence AnalysisAdd
BLAST

GO - Cellular componenti

  1. host cell plasma membrane Source: UniProtKB-KW
  2. integral component of membrane Source: UniProtKB-KW
  3. integral to membrane of host cell Source: UniProtKB-KW
  4. virion membrane Source: InterPro
Complete GO annotation...

Keywords - Cellular componenti

Host cell membrane, Host membrane, Membrane, Virion

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 9797Matrix protein 2PRO_0000310566Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Disulfide bondi17 – 17Interchain (with C-17)By similarity
Disulfide bondi19 – 19Interchain (with C-19)By similarity
Glycosylationi20 – 201N-linked (GlcNAc...); by hostSequence Analysis
Lipidationi50 – 501S-palmitoyl cysteine; by hostBy similarity
Modified residuei64 – 641Phosphoserine; by hostBy similarity

Keywords - PTMi

Disulfide bond, Glycoprotein, Lipoprotein, Palmitate, Phosphoprotein

Interactioni

Subunit structurei

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

Structurei

3D structure databases

ProteinModelPortaliQ8BAC4.
SMRiQ8BAC4. Positions 23-60.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domaini

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

Sequence similaritiesi

Keywords - Domaini

Signal-anchor, Transmembrane, Transmembrane helix

Family and domain databases

InterProiIPR002089. Flu_M2.
[Graphical view]
PfamiPF00599. Flu_M2. 1 hit.
[Graphical view]
ProDomiPD001031. Flu_M2. 1 hit.
[Graphical view] [Entries sharing at least one domain]

Sequences (2)i

Sequence statusi: Complete.

This entry describes 2 isoformsi produced by alternative splicing. Align

Note: Only the first 9 residues are shared by the 2 isoforms.

Isoform M2 (identifier: Q8BAC4-1) [UniParc]FASTAAdd to Basket

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.

« Hide

        10         20         30         40         50
MSLLTEVETP TRNEWGCRCN DSSDPLVIAA SIIGILHLIL WILDRLFFKC
60 70 80 90
IYRRLKYGLK RGPSTEGVPE SMREEYRKEQ QSAVDVDDGH FVNIELE
Length:97
Mass (Da):11,213
Last modified:March 1, 2003 - v1
Checksum:iADBB522C7F5E85FB
GO
Isoform M1 (identifier: Q8BAC3-1) [UniParc]FASTAAdd to Basket

The sequence of this isoform can be found in the external entry Q8BAC3.
Isoforms of the same protein are often annotated in two different entries if their sequences differ significantly.
Length:252
Mass (Da):27,880
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti61 – 633RGP → EGL in AAC57067. (PubMed:9065404)Curated

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY130766 Genomic RNA. Translation: AAN06598.1.
U94897 Genomic RNA. Translation: AAC57067.1.

Keywords - Coding sequence diversityi

Alternative splicing

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY130766 Genomic RNA. Translation: AAN06598.1 .
U94897 Genomic RNA. Translation: AAC57067.1 .

3D structure databases

ProteinModelPortali Q8BAC4.
SMRi Q8BAC4. Positions 23-60.
ModBasei Search...
MobiDBi Search...

Protocols and materials databases

Structural Biology Knowledgebase Search...

Family and domain databases

InterProi IPR002089. Flu_M2.
[Graphical view ]
Pfami PF00599. Flu_M2. 1 hit.
[Graphical view ]
ProDomi PD001031. Flu_M2. 1 hit.
[Graphical view ] [Entries sharing at least one domain ]
ProtoNeti Search...

Publicationsi

  1. "Characterization of the 1918 'Spanish' influenza virus matrix gene segment."
    Reid A.H., Fanning T.G., Janczewski T.A., McCall S., Taubenberger J.K.
    J. Virol. 76:10717-10723(2002) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
  2. "Initial genetic characterization of the 1918 'Spanish' influenza virus."
    Taubenberger J.K., Reid A.H., Krafft A.E., Bijwaard K.E., Fanning T.G.
    Science 275:1793-1796(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA] OF 38-63.
    Strain: A/South Carolina/1/18.

Entry informationi

Entry nameiM2_I18A0
AccessioniPrimary (citable) accession number: Q8BAC4
Secondary accession number(s): O10622
Entry historyi
Integrated into UniProtKB/Swiss-Prot: November 13, 2007
Last sequence update: March 1, 2003
Last modified: October 29, 2014
This is version 45 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Miscellaneousi

Miscellaneous

When the channel is activated, one or more imidazole moities of His-37 probably become bi-protonated.
South Carolina isolate has been sequenced from formalid fixed-lung tissues of a 21-year-old male which died in 1918 at Ft. Jackson, SC. Brevig Mission isolate has been sequenced from lung tissues of an Inuit woman buried in the permafrost in a gravesite near Brevig Mission, Alaska. This sample was recovered by John Hultin, retired pathologist.

Keywords - Technical termi

Complete proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families

External Data

Dasty 3