Structural highlights
Function
[NS1_I34A1] Inhibits post-transcriptional processing of cellular pre-mRNA, by binding and inhibiting two cellular proteins that are required for the 3'-end processing of cellular pre-mRNAs: the 30 kDa cleavage and polyadenylation specificity factor (CPSF4) and the poly(A)-binding protein 2 (PABPN1). This results in the accumulation of unprocessed 3' end pre-mRNAs which can't be exported from the nucleus. Cellular protein synthesis is thereby shut off very early after virus infection. Viral protein synthesis is not affected by the inhibition of the cellular 3' end processing machinery because the poly(A) tails of viral mRNAs are produced by the viral polymerase through a stuttering mechanism (By similarity). Prevents the establishment of the cellular antiviral state by inhibiting TRIM25-mediated DDX58 ubiquitination, which normally triggers the antiviral transduction signal that leads to the activation of type I IFN genes by transcription factors like IRF3 and IRF7. Prevents human EIF2AK2/PKR activation, either by binding double-strand RNA, or by interacting directly with EIF2AK2/PKR. This function may be important at the very beginning of the infection, when NS1 is mainly present in the cytoplasm. Also binds poly(A) and U6 snRNA. Suppresses the RNA silencing-based antiviral response in Drosophila cells (By similarity).
Publication Abstract from PubMed
The nonstructural protein NS1 of influenza virus is an antagonist of host immune responses and is implicated in virulence. It has two domains, an N-terminal double-stranded RNA-binding domain (RBD) and an effector domain crucial for RBD function, for nuclear export and for sequestering messenger RNA-processing proteins. Here we present the crystallographic structure of the effector domain, which has a novel fold and suggests mechanisms for increased virulence in H5N1 strains.
X-ray structure of influenza virus NS1 effector domain.,Bornholdt ZA, Prasad BV Nat Struct Mol Biol. 2006 Jun;13(6):559-60. Epub 2006 May 21. PMID:16715094[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Bornholdt ZA, Prasad BV. X-ray structure of influenza virus NS1 effector domain. Nat Struct Mol Biol. 2006 Jun;13(6):559-60. Epub 2006 May 21. PMID:16715094 doi:nsmb1099
