3gb8 | pdb_00003gb8
Crystal structure of CRM1/Snurportin-1 complex
Structural highlights
Function[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] [SPN1_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.[7] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCRM1 (also known as XPO1 and exportin 1) mediates nuclear export of hundreds of proteins through the recognition of the leucine-rich nuclear export signal (LR-NES). Here we present the 2.9 A structure of CRM1 bound to snurportin 1 (SNUPN). Snurportin 1 binds CRM1 in a bipartite manner by means of an amino-terminal LR-NES and its nucleotide-binding domain. The LR-NES is a combined alpha-helical-extended structure that occupies a hydrophobic groove between two CRM1 outer helices. The LR-NES interface explains the consensus hydrophobic pattern, preference for intervening electronegative residues and inhibition by leptomycin B. The second nuclear export signal epitope is a basic surface on the snurportin 1 nucleotide-binding domain, which binds an acidic patch on CRM1 adjacent to the LR-NES site. Multipartite recognition of individually weak nuclear export signal epitopes may be common to CRM1 substrates, enhancing CRM1 binding beyond the generally low affinity LR-NES. Similar energetic construction is also used in multipartite nuclear localization signals to provide broad substrate specificity and rapid evolution in nuclear transport. Structural basis for leucine-rich nuclear export signal recognition by CRM1.,Dong X, Biswas A, Suel KE, Jackson LK, Martinez R, Gu H, Chook YM Nature. 2009 Apr 30;458(7242):1136-41. Epub 2009 Apr 1. PMID:19339969[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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