Format

Send to

Choose Destination
Nat Struct Mol Biol. 2009 Sep;16(9):930-7. doi: 10.1038/nsmb.1649. Epub 2009 Aug 9.

The molecular basis for the regulation of the cap-binding complex by the importins.

Author information

1
Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.

Abstract

The binding of capped RNAs to the cap-binding complex (CBC) in the nucleus, and their dissociation from the CBC in the cytosol, represent essential steps in RNA processing. Here we show how the nucleocytoplasmic transport proteins importin-alpha and importin-beta have key roles in regulating these events. As a first step toward understanding the molecular basis for this regulation, we determined a 2.2-A resolution X-ray structure for a CBC-importin-alpha complex that provides a detailed picture for how importin-alpha binds to the CBP80 subunit of the CBC. Through a combination of biochemical studies, X-ray crystallographic information and small-angle scattering experiments, we then determined how importin-beta binds to the CBC through its CBP20 subunit. Together, these studies enable us to propose a model describing how importin-beta stimulates the dissociation of capped RNA from the CBC in the cytosol following its nuclear export.

PMID:
19668212
PMCID:
PMC2782468
DOI:
10.1038/nsmb.1649
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Nature Publishing Group Icon for PubMed Central
Loading ...
Support Center