1. A Snu114-GTP-Prp8 module forms a relay station for efficient splicing in yeast.
- Author
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Jia J, Ganichkin OM, Preußner M, Absmeier E, Alings C, Loll B, Heyd F, and Wahl MC
- Subjects
- GTP Phosphohydrolases chemistry, GTP Phosphohydrolases metabolism, Models, Molecular, Protein Conformation, Ribonucleoprotein, U4-U6 Small Nuclear metabolism, Ribonucleoprotein, U5 Small Nuclear metabolism, Saccharomyces cerevisiae Proteins metabolism, Guanosine Triphosphate chemistry, RNA Splicing, Ribonucleoprotein, U4-U6 Small Nuclear chemistry, Ribonucleoprotein, U5 Small Nuclear chemistry, Saccharomyces cerevisiae Proteins chemistry
- Abstract
The single G protein of the spliceosome, Snu114, has been proposed to facilitate splicing as a molecular motor or as a regulatory G protein. However, available structures of spliceosomal complexes show Snu114 in the same GTP-bound state, and presently no Snu114 GTPase-regulatory protein is known. We determined a crystal structure of Snu114 with a Snu114-binding region of the Prp8 protein, in which Snu114 again adopts the same GTP-bound conformation seen in spliceosomes. Snu114 and the Snu114-Prp8 complex co-purified with endogenous GTP. Snu114 exhibited weak, intrinsic GTPase activity that was abolished by the Prp8 Snu114-binding region. Exchange of GTP-contacting residues in Snu114, or of Prp8 residues lining the Snu114 GTP-binding pocket, led to temperature-sensitive yeast growth and affected the same set of splicing events in vivo. Consistent with dynamic Snu114-mediated protein interactions during splicing, our results suggest that the Snu114-GTP-Prp8 module serves as a relay station during spliceosome activation and disassembly, but that GTPase activity may be dispensable for splicing., (© The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2020
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