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Q8BAC3 (M1_I18A0) Reviewed, UniProtKB/Swiss-Prot

Last modified October 16, 2013. Version 47. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (1) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Alt products·Sequence annotation·Sequences·References·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein attributes

Sequence length252 AA.
Sequence statusComplete.
Protein existenceInferred from homology

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 By similarity.

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 By similarity.

Subunit structure

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.

Subcellular location

Virion membrane; Peripheral membrane protein; Cytoplasmic side By similarity. Host nucleus By similarity.

Miscellaneous

Most abundant protein in virion. When expressed alone can form virus-like particles in transfected cells.

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.

Sequence similarities

Belongs to the influenza viruses Matrix protein M1 family.

Ontologies

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: Q8BAC3-1)

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: Q8BAC4-1)

The sequence of this isoform can be found in the external entry Q8BAC4.
Isoforms of the same protein are often annotated in two different entries if their sequences differ significantly.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 252252Matrix protein 1
PRO_0000310565

Regions

Region1 – 164164Membrane-binding By similarity
Region165 – 25288RNP-binding By similarity
Motif101 – 1055Nuclear localization signal By similarity

Sequences

Sequence LengthMass (Da)Tools
Isoform M1 [UniParc].

Last modified March 1, 2003. Version 1.
Checksum: 9FDCEDBCE50FD96F

FASTA25227,880
        10         20         30         40         50         60 
MSLLTEVETY VLSIVPSGPL KAEIAQRLED VFAGKNTDLE ALMEWLKTRP ILSPLTKGIL 

        70         80         90        100        110        120 
GFVFTLTVPS ERGLQRRRFV QNALNGNGDP NNMDRAVKLY RKLKREITFH GAKEVALSYS 

       130        140        150        160        170        180 
AGALASCMGL IYNRMGTVTT EVAFGLVCAT CEQIADSQHR SHRQMVTTTN PLIRHENRMV 

       190        200        210        220        230        240 
LASTTAKAME QMAGSSEQAA EAMEVASQAR QMVQAMRTIG THPSSSAGLK DDLIENLQAY 

       250 
QKRMGVQMQR FK 

« Hide

Isoform M2 [UniParc].

See Q8BAC4.

References

[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 47-69.
Strain: A/South Carolina/1/18.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
AY130766 Genomic RNA. Translation: AAN06597.1.
U94896 Genomic RNA. Translation: AAC57066.1.

3D structure databases

ProteinModelPortalQ8BAC3.
SMRQ8BAC3. Positions 1-158.
ModBaseSearch...
MobiDBSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Family and domain databases

Gene3D1.10.10.180. 1 hit.
1.20.91.10. 1 hit.
InterProIPR013188. Flu_matrix_M1_C.
IPR001561. Flu_matrix_M1_N.
IPR015423. Flu_matrix_M1_N_sub1.
IPR015799. Flu_matrix_M1_N_sub2.
[Graphical view]
PfamPF00598. Flu_M1. 1 hit.
PF08289. Flu_M1_C. 1 hit.
[Graphical view]
ProDomPD596253. Flu_matrix_M1_C. 1 hit.
PD001061. Flu_matrix_M1_N. 1 hit.
[Graphical view] [Entries sharing at least one domain]
SMARTSM00759. Flu_M1_C. 1 hit.
[Graphical view]
SUPFAMSSF48145. SSF48145. 1 hit.
ProtoNetSearch...

Entry information

Entry nameM1_I18A0
AccessionPrimary (citable) accession number: Q8BAC3
Secondary accession number(s): O10427
Entry history
Integrated into UniProtKB/Swiss-Prot: November 13, 2007
Last sequence update: March 1, 2003
Last modified: October 16, 2013
This is version 47 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programViral Protein Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families