2l1l | pdb_00002l1l
NMR Solution Structure of the Phi0 PKI NES Peptide in Complex with CRM1-RanGTP
Structural highlights
Function[IPKA_HUMAN] Extremely potent competitive inhibitor of cAMP-dependent protein kinase activity, this protein interacts with the catalytic subunit of the enzyme after the cAMP-induced dissociation of its regulatory chains. [XPO1_HUMAN] Mediates the nuclear export of cellular proteins (cargos) bearing a leucine-rich nuclear export signal (NES) and of RNAs. In the nucleus, in association with RANBP3, binds cooperatively to the NES on its target protein and to the GTPase RAN in its active GTP-bound form (Ran-GTP). Docking of this complex to the nuclear pore complex (NPC) is mediated through binding to nucleoporins. Upon transit of a nuclear export complex into the cytoplasm, disassembling of the complex and hydrolysis of Ran-GTP to Ran-GDP (induced by RANBP1 and RANGAP1, respectively) cause release of the cargo from the export receptor. The directionality of nuclear export is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus. Involved in U3 snoRNA transport from Cajal bodies to nucleoli. Binds to late precursor U3 snoRNA bearing a TMG cap. Several viruses, among them HIV-1, HTLV-1 and influenza A use it to export their unspliced or incompletely spliced RNAs out of the nucleus. Interacts with, and mediates the nuclear export of HIV-1 Rev and HTLV-1 Rex proteins. Involved in HTLV-1 Rex multimerization.[1] [2] [3] [4] [5] [6] 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[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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