P05777 (M1_I33A0) Reviewed, UniProtKB/Swiss-Prot
Last modified April 3, 2013. Version 87. History...
Names and origin
|Protein names||Recommended name:|
Matrix protein 1
|Organism||Influenza A virus (strain A/Wilson-Smith/1933 H1N1) (Influenza A virus (strain A/WS/1933 H1N1)) [Complete proteome]|
|Taxonomic identifier||381518 [NCBI]|
|Taxonomic lineage||Viruses › ssRNA negative-strand viruses › Orthomyxoviridae › Influenzavirus A ›|
|Virus host||Aves [TaxID: 8782]|
Homo sapiens (Human) [TaxID: 9606]
Sus scrofa (Pig) [TaxID: 9823]
|Sequence length||252 AA.|
|Protein existence||Evidence at protein level|
General annotation (Comments)
Plays critical roles in virus replication, from virus entry and uncoating to assembly and budding of the virus particle. M1 binding to ribonucleocapsids (RNPs) in nucleus seems to inhibit viral transcription. Interaction of viral NEP with M1-RNP is thought to promote nuclear export of the complex, which is targeted to the virion assembly site at the apical plasma membrane in polarized epithelial cells. Interactions with NA and HA may bring M1, a non-raft-associated protein, into lipid rafts. Forms a continuous shell on the inner side of the lipid bilayer in virion, where it binds the RNP. During virus entry into cell, the M2 ion channel acidifies the internal virion core, inducing M1 dissociation from the RNP. M1-free RNPs are transported to the nucleus, where viral transcription and replication can take place. Ref.7
Determines the virion's shape: spherical or filamentous. Clinical isolates of influenza are characterized by the presence of significant proportion of filamentous virions, whereas after multiple passage on eggs or cell culture, virions have only spherical morphology. Filamentous virions are thought to be important to infect neighboring cells, and spherical virions more suited to spread through aerosol between hosts organisms. Ref.7
Homodimer and homomultimer. Interacts with NEP By similarity. Binds ribonucleocapsid by both interacting with genomic RNA and NP protein. May interact with HA and NA By similarity. Cannot bind NP without genomic RNA. Ref.5
Most abundant protein in virion. When expressed alone can form virus-like particles in transfected cells.
Belongs to the influenza viruses Matrix protein M1 family.
|Biological process||Host-virus interaction|
Inhibition of host complement factors by virus
|Cellular component||Host nucleus|
Viral matrix protein
|Coding sequence diversity||Alternative splicing|
|Technical term||Complete proteome|
|Gene Ontology (GO)|
|Biological_process||suppression by virus of host complement activation|
Inferred from electronic annotation. Source: UniProtKB-KW
|Cellular_component||host cell nucleus|
Inferred from electronic annotation. Source: UniProtKB-SubCellvirion membrane
Inferred from electronic annotation. Source: UniProtKB-SubCell
Inferred from electronic annotation. Source: UniProtKB-KWstructural molecule activity
Inferred from electronic annotation. Source: InterPro
|Complete GO annotation...|
|This entry describes 2 isoforms produced by alternative splicing. [Align] [Select]|
Note: Only the first 9 residues are shared by the 2 isoforms.
|Isoform M1 (identifier: P05777-1) |
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.
|Isoform M2 (identifier: P05780-1) |
The sequence of this isoform can be found in the external entry P05780.
Isoforms of the same protein are often annotated in two different entries if their sequences differ significantly.
Sequence annotation (Features)
|Feature key||Position(s)||Length||Description||Graphical view||Feature identifier|
|Chain||1 – 252||252||Matrix protein 1||PRO_0000078868|
|Region||1 – 164||164||Membrane-binding|
|Region||165 – 252||88||RNP-binding|
|Motif||101 – 105||5||Nuclear localization signal|
|Mutagenesis||41||1||V → A: Induces short filamentous virions. Ref.9|
|Mutagenesis||95||1||K → A or R: No effect. Ref.8 Ref.9|
|Mutagenesis||97||1||V → A: No effect. Ref.8|
|Mutagenesis||98||1||K → A or R: No effect. Ref.8|
|Mutagenesis||99||1||L → A: No effect. Ref.8|
|Mutagenesis||100 – 103||4||YRKL → AAAA or PPPY: Can't be rescued by reverse genetic. Ref.8|
|Mutagenesis||100 – 103||4||YRKL → PTAP: No effect. Ref.8|
|Mutagenesis||100||1||Y → A, F or S: No effect. Ref.8|
|Mutagenesis||101 – 105||5||RKLKR → SNLNS: 50% loss of RNA binding activity. Ref.4 Ref.8|
|Mutagenesis||101 – 102||2||RK → PD: No effect. Ref.8|
|Mutagenesis||101||1||R → A: Reduced growth and small-plaque morphology. Virions have an elongated filamentous morphology. Ref.8|
|Mutagenesis||101||1||R → K: No effect. Ref.8|
|Mutagenesis||102||1||K → A or R: No effect. Ref.8|
|Mutagenesis||103||1||L → A, I or V: No effect. Ref.8|
|Mutagenesis||104||1||K → A: Can't be rescued by reverse genetic. Ref.8|
|Mutagenesis||104||1||K → R: No effect. Ref.8|
|Mutagenesis||105||1||R → A: Can't be rescued by reverse genetic. Ref.8|
|Mutagenesis||105||1||R → K: Reduced growth and small-plaque morphology. Ref.8|
|Mutagenesis||106||1||E → A: Can't be rescued by reverse genetic. Ref.8|
|Mutagenesis||148||1||C → A: No effect. Ref.4 Ref.6|
|Mutagenesis||148||1||C → S: 31% loss of RNA binding activity. Ref.4 Ref.6|
|Mutagenesis||151||1||C → A: No effect. Ref.6|
|Mutagenesis||155||1||A → G: Complete loss of virus ability to be rescued in a reverse genetic system. Ref.6|
|Mutagenesis||159||1||H → A: No effect. Ref.6|
|Mutagenesis||162||1||H → A: No effect. Ref.6|
|Mutagenesis||218||1||T → A: No effect on virion morphology. Ref.9|
|Sequence conflict||117||1||L → F in AAA43352. Ref.3|
|Sequence conflict||219||1||I → V in AAA43352. Ref.3|
|Sequence conflict||231||1||D → S in AAA43252. Ref.2|
|||"Nucleotide sequences of influenza A virus RNA segment 7: a comparison of five isolates."|
Zebedee S.L., Lamb R.A.
Nucleic Acids Res. 17:2870-2870(1989) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
|||"Nucleotide sequence of RNA segment 7 and the predicted amino sequence of M1 and M2 proteins of FPV/Weybridge (H7N7) and WSN (H1N1) influenza viruses."|
Markushin S., Ghiasi H., Sokolov N., Shilov A., Sinitsin B., Brown D., Klimov A., Nayak D.
Virus Res. 10:263-272(1988) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
|||"Transient expression and sequence of the matrix (M1) gene of WSN influenza A virus in a vaccinia vector."|
Baylor N.W., Zhiping Y.L., Wagner R.R.
Virology 163:618-621(1988) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
|||"Association of influenza virus matrix protein with ribonucleoproteins."|
Ye Z., Liu T., Offringa D.P., McInnis J., Levandowski R.A.
J. Virol. 73:7467-7473(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: MUTAGENESIS OF 101-ARG--ARG-105 AND CYS-148.
|||"Influenza virus assembly: effect of influenza virus glycoproteins on the membrane association of M1 protein."|
Ali A., Avalos R.T., Ponimaskin E., Nayak D.P.
J. Virol. 74:8709-8719(2000) [PubMed] [Europe PMC] [Abstract]
Cited for: INTERACTION WITH HA AND NA.
|||"Conserved cysteine and histidine residues in the putative zinc finger motif of the influenza A virus M1 protein are not critical for influenza virus replication."|
Hui E.K., Ralston K., Judd A.K., Nayak D.P.
J. Gen. Virol. 84:3105-3113(2003) [PubMed] [Europe PMC] [Abstract]
Cited for: MUTAGENESIS OF CYS-148; CYS-151; ALA-155; HIS-159 AND HIS-162.
|||"Reverse genetics studies on the filamentous morphology of influenza A virus."|
Bourmakina S.V., Garcia-Sastre A.
J. Gen. Virol. 84:517-527(2003) [PubMed] [Europe PMC] [Abstract]
Cited for: FUNCTION.
|||"Basic residues of the helix six domain of influenza virus M1 involved in nuclear translocation of M1 can be replaced by PTAP and YPDL late assembly domain motifs."|
Hui E.K., Barman S., Yang T.Y., Nayak D.P.
J. Virol. 77:7078-7092(2003) [PubMed] [Europe PMC] [Abstract]
Cited for: MUTAGENESIS OF LYS-95; VAL-97; LYS-98; LEU-99; TYR-100; ARG-101; LYS-102; LEU-103; LYS-104; ARG-105 AND GLU-106.
|||"The M1 matrix protein controls the filamentous phenotype of influenza A virus."|
Elleman C.J., Barclay W.S.
Virology 321:144-153(2004) [PubMed] [Europe PMC] [Abstract]
Cited for: MUTAGENESIS OF VAL-41; LYS-95 AND THR-218.
|X08088 Genomic RNA. Translation: CAA30882.1.|
M23920 Genomic RNA. Translation: AAA43252.1. Sequence problems.
M19374 Genomic RNA. Translation: AAA43352.1.
L25818 Genomic RNA. Translation: AAA91325.1.
|PIR||MFIVWS. A28608. |
3D structure databases
|SMR||P05777. Positions 1-158. |
Protocols and materials databases
Family and domain databases
|Gene3D||22.214.171.124. 1 hit. |
126.96.36.199. 1 hit.
|InterPro||IPR013188. Flu_matrix_M1_C. |
|Pfam||PF00598. Flu_M1. 1 hit. |
PF08289. Flu_M1_C. 1 hit.
|ProDom||PD596253. Flu_matrix_M1_C. 1 hit. |
PD001061. Flu_matrix_M1_N. 1 hit.
[Graphical view] [Entries sharing at least one domain]
|SMART||SM00759. Flu_M1_C. 1 hit. |
|SUPFAM||SSF48145. Flu_M1. 1 hit. |
|Accession||Primary (citable) accession number: P05777|
|Entry status||Reviewed (UniProtKB/Swiss-Prot)|
|Annotation program||Viral Protein Annotation Program|
Index of protein domains and families