Influenza A H1N1 NS, also known as Non-structural protein 1 or NS1A or NS1, is a 234 amino acid containing protein belonging to the Influenza A virus (strain A/Swine/Iowa/15/1930 H1N1) which has aves, human and pig as host. This protein belongs to the influenza A viruses NS1 family and is a homodimer located in the nucleus of uninfected, transfected cells, and in the cytoplasm of infected cells. The viral protein NS1 binds to and inhibits two cellular proteins that are required for the 3'-end processing of cellular pre-mRNAs which include the 30 kDa cleavage and polyadenylation specificity factor (CPSF4) and the poly(A)-binding protein 2 (PABPN1). Thus inhibiting post-transcriptional processing of cellular pre-mRNA and leading to accumulation of unprocessed 3' end pre-mRNAs in nucleus and loss of cellular protein synthesis. This helps the virus to escape interferon synthesis after activation of the IRF3 pathway, and therefore prevents establishment of cellular antiviral state. NS1 is also known to prevent human EIF2AK2/PKR activation, at the very beginning of the infection, when NS1 is mainly present in the cytoplasm and prevent antiviral response.
H1N1; H1N1 NS; Influenza H1N1