P31609 (NCAP_I54A0) Reviewed, UniProtKB/Swiss-Prot
Last modified October 16, 2013. Version 51. History...
Names and origin
|Protein names||Recommended name:|
Short name=Protein N
|Organism||Influenza A virus (strain A/Leningrad/1/1954 H1N1)|
|Taxonomic identifier||393557 [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||498 AA.|
|Protein existence||Inferred from homology|
General annotation (Comments)
Encapsidates the negative strand viral RNA, protecting it from nucleases. The encapsidated genomic RNA is termed the ribonucleoprotein (RNP) and serves as template for transcription and replication. The RNP needs to be localized in the nucleus to start an infectious cycle, but is too large to diffuse through the nuclear pore complex. NP comprises at least 2 nuclear localization signals and is responsible of the active RNP import into the nucleus through the cellular importin alpha/beta pathway. Later in the infection, nucleus export of RNP are mediated through viral proteins NEP interacting with M1 which binds nucleoproteins. It is possible that the nucleoprotein binds directly exportin-1 (XPO1) and plays an active role in RNP nuclear export. M1 interaction with RNP seems to hide nucleoprotein's nuclear localization signals. Soon after a virion infects a new cell, M1 dissociates from the RNP under acidification of the virion driven by M2 protein. Dissociation of M1 from RNP unmask nucleoprotein's nuclear localization signals, targeting the RNP to the nucleus By similarity.
Homomultimerizes to form the nucleocapsid. May bind human exportin-1. Binds to viral genomic RNA. Protein-RNA contacts are mediated by a combination of electrostatic interactions between positively charged residues and the phosphate backbone and planar interactions between aromatic side chains and bases By similarity.
Late in virus-infected cells, may be cleaved from a 56-kDa protein to a 53-kDa protein by a cellular caspase. This cleavage might be a marker for the onset of apoptosis in infected cells or have a specific function in virus host interaction By similarity.
Belongs to the influenza viruses nucleoprotein family.
Sequence annotation (Features)
|||"Synthesis, cloning and determination of the primary structure of a full-size DNA copy of the NP protein gene from influenza virus type A."|
Beklemishev A.B., Blinov V.M., Vassilenko S.K., Golovin S.Y., Karginov V.A., Mamayev L.V., Mikriukov N.N., Netesov S.V., Petrenko V.A., Petrov N.A., Frolov I.V.
Bioorg. Khim. 11:636-640(1985) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC RNA].
|M38279 Genomic RNA. Translation: AAA43459.1.|
3D structure databases
|SMR||P31609. Positions 22-496. |
Protocols and materials databases
Family and domain databases
|InterPro||IPR002141. Flu_NP. |
|Pfam||PF00506. Flu_NP. 1 hit. |
|Accession||Primary (citable) accession number: P31609|
|Entry status||Reviewed (UniProtKB/Swiss-Prot)|
|Annotation program||Viral Protein Annotation Program|
Index of protein domains and families