The molecular basis for the regulation of the cap-binding complex by the importins
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-{angstrom} 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.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1005870
- Journal Information:
- Nat. Struct. Mol. Biol., Journal Name: Nat. Struct. Mol. Biol. Journal Issue: (9) ; 09, 2009 Vol. 16; ISSN 1545-9993
- Country of Publication:
- United States
- Language:
- ENGLISH
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