Anti-FluA NP (4F8)

The influenza A virus is the leading cause of annual influenza epidemics and occasional influenza pandemics. NP of influenza A virus plays a central role in viral replication. As a structural protein with no intrinsic enzymatic activity, it is the most abundant viral protein in infected cells. Monomeric NP is a 56 kDa protein with a patch of basic residues capable of binding to a single-strand RNA. NP also contains nuclear localization signals (NLS) and nuclear export signals (NES). The Influenza A virus nucleoprotein (NP) is the major protein component of the genomic viral ribonucleoprotein (vRNP) complexes, which are the replication- and transcription-competent units of Influenza viruses. Early during infection, NP mediates import of vRNPs into the host cell nucleus where viral replication and transcription take place, also newly synthesized NP molecules are targeted into the nucleus, enabling coreplicational assembly of progeny vRNPs. Protein function: 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 host 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 that are responsible for the active RNP import into the nucleus through cellular importin alpha/beta pathway. Later in the infection, nclear export of RNPs are mediated through viral proteins NEP interacting with M1 which binds nucleoproteins. It is possible that nucleoprotein binds directly host exportin-1/XPO1 and plays an active role in RNPs 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 unmasks nucleoprotein's nuclear localization signals, targeting the RNP to the nucleus. [The UniProt Consortium]