5t94
From Proteopedia
Crystal structure of Kap60 bound to yeast RCC1 (Prp20)
Structural highlights
FunctionRCC1_YEAST Guanine nucleotide exchange factor that promotes the exchange of GSP1/GSP2-bound GDP by GTP and controls RNA metabolism and transport. Involved in yeast pheromone response pathway and in mRNA metabolism. Involved in nuclear pore complex (NPC) assembly and required for mRNA and ribosome nuclear export. Binds chromatin and is involved NPC-mediated transcriptional control.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] Publication Abstract from PubMedActive nuclear import of Ran exchange factor RCC1 is mediated by importin alpha3. This pathway is essential to generate a gradient of RanGTP on chromatin that directs nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope formation. Here we identify the mechanisms of importin alpha3 selectivity for RCC1. We find this isoform binds RCC1 with one order of magnitude higher affinity than the generic importin alpha1, although the two isoforms share an identical NLS-binding groove. Importin alpha3 uses its greater conformational flexibility to wedge the RCC1 beta-propeller flanking the NLS against its lateral surface, preventing steric clashes with its Armadillo-core. Removing the beta-propeller, or inserting a linker between NLS and beta-propeller, disrupts specificity for importin alpha3, demonstrating the structural context rather than NLS sequence determines selectivity for isoform 3. We propose importin alpha3 evolved to recognize topologically complex NLSs that lie next to bulky domains or are masked by quaternary structures.Importin alpha3 facilitates the nuclear transport of the Ran guanine nucleotide exchange factor RCC1. Here the authors reveal the molecular basis for the selectivity of RCC1 for importin alpha3 vs the generic importin alpha1 and discuss the evolution of importin alpha isoforms. Three-dimensional context rather than NLS amino acid sequence determines importin alpha subtype specificity for RCC1.,Sankhala RS, Lokareddy RK, Begum S, Pumroy RA, Gillilan RE, Cingolani G Nat Commun. 2017 Oct 17;8(1):979. doi: 10.1038/s41467-017-01057-7. PMID:29042532[15] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations 8 reviews cite this structure No citations found See AlsoReferences
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