CRM1 is an export receptor mediating rapid nuclear exit of proteins and RNAs to the cytoplasm. CRM1 export cargoes include proteins with a leucine-rich nuclear export signal (NES) that bind directly to CRM1 in a trimeric complex with RanGTP. Using a quantitative CRM1-NES cargo binding assay, significant differences in affinity for CRM1 among natural NESs are demonstrated, suggesting that the steady-state nucleocytoplasmic distribution of shuttling proteins could be determined by the relative strengths of their NESs. We also show that a trimeric CRM1-NES-RanGTP complex is disassembled by RanBP1 in the presence of RanGAP, even though RanBP1 itself contains a leucine-rich NES. Selection of CRM1-binding proteins from Xenopus egg extract leads to the identification of an NES-containing DEAD-box helicase, An3, that continuously shuttles between the nucleus and the cytoplasm. In addition, we identify the Xenopus homologue of the nucleoporin CAN/Nup214 as a RanGTP- and NES cargo-specific binding site for CRM1, suggesting that this nucleoporin plays a role in export complex disassembly and/or CRM1 recycling.
CITATION STYLE
Askjaer, P., Bachi, A., Wilm, M., Bischoff, F. R., Weeks, D. L., Ogniewski, V., … Fornerod, M. (1999). RanGTP-Regulated Interactions of CRM1 with Nucleoporins and a Shuttling DEAD-Box Helicase. Molecular and Cellular Biology, 19(9), 6276–6285. https://doi.org/10.1128/mcb.19.9.6276
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