Structural highlights
FunctionSPN1_HUMAN Functions as an U snRNP-specific nuclear import adapter. Involved in the trimethylguanosine (m3G)-cap-dependent nuclear import of U snRNPs. Binds specifically to the terminal m3G-cap U snRNAs.[1] Publication Abstract from PubMedClassic nuclear export signals (NESs) confer CRM1-dependent nuclear export. Here we present crystal structures of the RanGTP-CRM1 complex alone and bound to the prototypic PKI or HIV-1 Rev NESs. These NESs differ markedly in the spacing of their key hydrophobic (Phi) residues, yet CRM1 recognizes them with the same rigid set of five Phi pockets. The different Phi spacings are compensated for by different conformations of the bound NESs: in the case of PKI, an alpha-helical conformation, and in the case of Rev, an extended conformation with a critical proline docking into a Phi pocket. NMR analyses of CRM1-bound and CRM1-free PKI NES suggest that CRM1 selects NES conformers that pre-exist in solution. Our data lead to a new structure-based NES consensus, and explain why NESs differ in their affinities for CRM1 and why supraphysiological NESs bind the exportin so tightly. NES consensus redefined by structures of PKI-type and Rev-type nuclear export signals bound to CRM1.,Guttler T, Madl T, Neumann P, Deichsel D, Corsini L, Monecke T, Ficner R, Sattler M, Gorlich D Nat Struct Mol Biol. 2010 Oct 24. PMID:20972448[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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