P03485 (M1_I34A1) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Matrix protein 1
Short name=M1

Gene names

Name:

M

Organism

Influenza A virus (strain A/Puerto Rico/8/1934 H1N1) [Reference proteome]

Taxonomic identifier

211044 [NCBI]

Taxonomic lineage

Viruses › ssRNA viruses › ssRNA negative-strand viruses › Orthomyxoviridae › Influenzavirus A › Influenza A virus › H1N1 subtype

Virus host

Aves [TaxID: 8782]
Homo sapiens (Human) [TaxID: 9606]
Sus scrofa (Pig) [TaxID: 9823]

Protein attributes

Sequence length	252 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	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.9 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.9
Subunit structure	Homodimer and homomultimer. Interacts with NEP. 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.6 Ref.7 Ref.8
Subcellular location	Virion membrane; Peripheral membrane protein; Cytoplasmic side. Host nucleus.
Miscellaneous	Most abundant protein in virion. When expressed alone can form virus-like particles in transfected cells.
Sequence similarities	Belongs to the influenza viruses Matrix protein M1 family.

Ontologies

Keywords
Biological process	Host-virus interaction Inhibition of host complement factors by virus Viral immunoevasion
Cellular component	Host nucleus Membrane Viral matrix protein Virion
Coding sequence diversity	Alternative splicing
Ligand	RNA-binding
Technical term	3D-structure Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	suppression by virus of host complement activation Inferred from electronic annotation. Source: UniProtKB-KW uncoating of virus Traceable author statement. Source: Reactome viral entry into host cell via membrane fusion with the plasma membrane Traceable author statement. Source: Reactome viral entry into host cell via receptor-mediated endocytosis Traceable author statement. Source: Reactome viral genome maturation Traceable author statement. Source: Reactome viral genome packaging Traceable author statement. Source: Reactome viral release from host cell Traceable author statement. Source: Reactome viral transcription Traceable author statement. Source: Reactome
Cellular_component	cytosol Traceable author statement. Source: Reactome endocytic vesicle membrane Traceable author statement. Source: Reactome endosome lumen Traceable author statement. Source: Reactome extracellular region Traceable author statement. Source: Reactome host cell nucleus Inferred from electronic annotation. Source: UniProtKB-SubCell nucleoplasm Traceable author statement. Source: Reactome plasma membrane Traceable author statement. Source: Reactome virion membrane Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular_function	RNA binding Inferred from electronic annotation. Source: UniProtKB-KW structural molecule activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Alternative products

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: P03485-1)

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: P06821-1)

The sequence of this isoform can be found in the external entry P06821.
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

Molecule processing

Chain

1 – 252

252

Matrix protein 1

PRO_0000078864

Regions

Region

1 – 164

164

Membrane-binding

Region

165 – 252

88

RNP-binding

Motif

101 – 105

5

Nuclear localization signal

Experimental info

Sequence conflict

207 – 208

2

SQ → IR in ABD77676. Ref.4

Secondary structure

1

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252

Helix Strand Turn

Details...

Helix

3 – 12

10

Helix

19 – 32

14

Helix

39 – 47

9

Beta strand

50 – 52

3

Helix

54 – 67

14

Helix

78 – 83

6

Helix

86 – 88

3

Helix

90 – 103

14

Helix

109 – 116

8

Helix

121 – 132

12

Helix

134 – 137

4

Helix

140 – 157

18

Sequences

	Sequence		Length	Mass (Da)
	Isoform M1 [UniParc]. Last modified July 21, 1986. Version 1. Checksum: 2A54EEC87C3D4638	FASTA	252	27,893
	10 20 30 40 50 60 MSLLTEVETY VLSIIPSGPL KAEIAQRLED VFAGKNTDLE VLMEWLKTRP ILSPLTKGIL 70 80 90 100 110 120 GFVFTLTVPS ERGLQRRRFV QNALNGNGDP NNMDKAVKLY RKLKREITFH GAKEISLSYS 130 140 150 160 170 180 AGALASCMGL IYNRMGAVTT EVAFGLVCAT CEQIADSQHR SHRQMVTTTN PLIRHENRMV 190 200 210 220 230 240 LASTTAKAME QMAGSSEQAA EAMEVASQAR QMVQAMRTIG THPSSSAGLK NDLLENLQAY 250 QKRMGVQMQR FK
	Isoform M2 [UniParc]. See P06821.		–	–

References

[1]	"Cloning of influenza cDNA into M13: the sequence of the RNA segment encoding the A/PR/8/34 matrix protein." Winter G., Fields S. Nucleic Acids Res. 8:1965-1974(1980) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
[2]	"Plasmid-only rescue of influenza A virus vaccine candidates." Schickli J.H., Flandorfer A., Nakaya T., Martinez-Sobrido L., Garcia-Sastre A., Palese P. Philos. Trans. R. Soc. Lond., B, Biol. Sci. 356:1965-1973(2001) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA]. Strain: A/Puerto Rico/8/34/Mount Sinai.
[3]	"Efficient generation and growth of influenza virus A/PR/8/34 from eight cDNA fragments." de Wit E., Spronken M.I.J., Bestebroer T.M., Rimmelzwaan G.F., Osterhaus A.D.M.E., Fouchier R.A.M. Virus Res. 103:155-161(2004) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA], REVERSE GENETICS.
[4]	"The NIAID influenza genome sequencing project." Ghedin E., Spiro D., Miller N., Zaborsky J., Feldblyum T., Subbu V., Shumway M., Sparenborg J., Groveman L., Halpin R., Sitz J., Koo H., Salzberg S.L., Webster R.G., Hoffmann E., Krauss S., Naeve C., Bao Y. , Bolotov P., Dernovoy D., Kiryutin B., Lipman D.J., Tatusova T. Submitted (MAR-2006) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
[5]	"Variation in nucleotide sequences coding for the N-terminal regions of the matrix and nonstructural proteins of influenza A viruses." Hall R.M., Air G.M. J. Virol. 38:1-7(1981) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] OF 1-106.
[6]	"Molecular assembly of influenza virus: association of the NS2 protein with virion matrix." Yasuda J., Nakada S., Kato A., Toyoda T., Ishihama A. Virology 196:249-255(1993) [PubMed] [Europe PMC] [Abstract] Cited for: INTERACTION WITH NEP PROTEIN.
[7]	"The M1 and NP proteins of influenza A virus form homo- but not heterooligomeric complexes when coexpressed in BHK-21 cells." Zhao H., Ekstrom M., Garoff H. J. Gen. Virol. 79:2435-2446(1998) [PubMed] [Europe PMC] [Abstract] Cited for: HOMOMULTIMERIZATION.
[8]	"In vitro dissection of the membrane and RNP binding activities of influenza virus M1 protein." Baudin F., Petit I., Weissenhorn W., Ruigrok R.W. Virology 281:102-108(2001) [PubMed] [Europe PMC] [Abstract] Cited for: INTERACTION WITH MEMBRANE AND VIRAL RNP.
[9]	"Effect of influenza virus matrix protein and viral RNA on ribonucleoprotein formation and nuclear export." Huang X., Liu T., Muller J., Levandowski R.A., Ye Z. Virology 287:405-416(2001) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[10]	"Assembly and budding of influenza virus." Nayak D.P., Hui E.K., Barman S. Virus Res. 106:147-165(2004) [PubMed] [Europe PMC] [Abstract] Cited for: REVIEW.
[11]	"HLA-A2-peptide complexes: refolding and crystallization of molecules expressed in Escherichia coli and complexed with single antigenic peptides." Garboczi D.N., Hung D.T., Wiley D.C. Proc. Natl. Acad. Sci. U.S.A. 89:3429-3433(1992) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.5 ANGSTROMS) OF 58-66.
[12]	"Structure of a bifunctional membrane-RNA binding protein, influenza virus matrix protein M1." Sha B., Luo M. Nat. Struct. Biol. 4:239-244(1997) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.08 ANGSTROMS) OF 1-158.
[13]	"Combined results from solution studies on intact influenza virus M1 protein and from a new crystal form of its N-terminal domain show that M1 is an elongated monomer." Arzt S., Baudin F., Barge A., Timmins P., Burmeister W.P., Ruigrok R.W. Virology 279:439-446(2001) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.3 ANGSTROMS) OF 1-164.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

V01099 Genomic RNA. Translation: CAA24282.1.
AF389121 Genomic RNA. Translation: AAM75161.1.
EF467824 Viral cRNA. Translation: ABO21712.1.
CY009445 Genomic RNA. Translation: ABD77676.1.

RefSeq

NP_040978.1. NC_002016.1.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1AA7	X-ray	2.08	A/B	1-158	[»]
1EA3	X-ray	2.30	A/B	1-164	[»]
1HHI	X-ray	2.50	C/F	58-66	[»]
3VDX	X-ray	3.00	A/B/C	3-164	[»]
4D9J	X-ray	3.92	A/B/C/D/E/F/G/H/I/J/K/L	3-164	[»]

ProteinModelPortal

P03485.

SMR

P03485. Positions 1-158.

ModBase

Search...

Protein-protein interaction databases

IntAct

P03485. 17 interactions.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

GeneID

956527.

Enzyme and pathway databases

Reactome

REACT_116125. Disease.

Family and domain databases

Gene3D

1.10.10.180. 1 hit.
1.20.91.10. 1 hit.

InterPro

IPR013188. Flu_matrix_M1_C.
IPR001561. Flu_matrix_M1_N.
IPR015423. Flu_matrix_M1_N_sub1.
IPR015799. Flu_matrix_M1_N_sub2.
[Graphical view]

Pfam

PF00598. Flu_M1. 1 hit.
PF08289. Flu_M1_C. 1 hit.
[Graphical view]

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.
[Graphical view]

SUPFAM

SSF48145. Flu_M1. 1 hit.

ProtoNet

Search...

Other

EvolutionaryTrace

P03485.

Entry information

Entry name

M1_I34A1

Accession

Primary (citable) accession number: P03485
Secondary accession number(s): A4GXH8, Q20N36, Q77HF4

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	July 21, 1986
Last modified:	April 3, 2013
This is version 102 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Viral Protein Annotation Program