1pd3
From Proteopedia
Influenza A NEP M1-binding domain
Structural highlights
Function[NEP_I34A1] Mediates the nuclear export of encapsidated genomic RNAs (ribonucleoproteins, RNPs). Acts as an adapter between viral RNPs complexes and the nuclear export machinery of the cell. Possesses no intrinsic RNA-binding activity, but includes a C-terminal M1-binding domain. This domain is believed to allow recognition of RNPs to which the M1 protein is bound. Because the M1 protein is not available in large quantities until the later stages of infection, such an indirect recognition mechanism probably ensures that genomic RNPs are not exported from the nucleus before sufficient quantities of viral mRNA and progeny genomic RNA have been synthesized. Furthermore, the RNPs enters the cytoplasm only when they have associated with the M1 protein that is necessary to guide them to the plasma membrane. May down-regulate viral RNA synthesis when overproduced. Publication Abstract from PubMedDuring influenza virus infection, viral ribonucleoproteins (vRNPs) are replicated in the nucleus and must be exported to the cytoplasm before assembling into mature viral particles. Nuclear export is mediated by the cellular protein Crm1 and putatively by the viral protein NEP/NS2. Proteolytic cleavage of NEP defines an N-terminal domain which mediates RanGTP-dependent binding to Crm1 and a C-terminal domain which binds to the viral matrix protein M1. The 2.6 A crystal structure of the C-terminal domain reveals an amphipathic helical hairpin which dimerizes as a four-helix bundle. The NEP-M1 interaction involves two critical epitopes: an exposed tryptophan (Trp78) surrounded by a cluster of glutamate residues on NEP, and the basic nuclear localization signal (NLS) of M1. Implications for vRNP export are discussed. Crystal structure of the M1 protein-binding domain of the influenza A virus nuclear export protein (NEP/NS2).,Akarsu H, Burmeister WP, Petosa C, Petit I, Muller CW, Ruigrok RW, Baudin F EMBO J. 2003 Sep 15;22(18):4646-55. PMID:12970177[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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