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A Snu114-GTP-Prp8 module forms a relay station for efficient splicing in yeast
Junqiao Jia1, Oleg M Ganichkin1, Marco Preußner2
1Freie Universität Berlin, Laboratory of Structural Biochemistry, Takustraβe 6, D-14195 Berlin, Germany.
Nucleic Acids Research
|March 21, 2020
Summary
The spliceosome's G protein, Snu114, may act as a relay station, not a motor. Its GTPase activity, regulated by Prp8, is crucial for splicing, but might be dispensable.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- The spliceosome's G protein, Snu114, is proposed to function as a molecular motor or regulatory protein in splicing.
- Existing structures show Snu114 in a consistent GTP-bound state, with no known GTPase-regulatory protein identified.
Purpose of the Study:
- To investigate the structural and functional relationship between Snu114 and the Prp8 protein.
- To elucidate the role of Snu114's GTPase activity in spliceosome function.
Main Methods:
- Determined the crystal structure of Snu114 in complex with the Prp8 binding region.
- Co-purified Snu114-Prp8 complex with endogenous GTP.
- Assessed intrinsic GTPase activity and effects of residue mutations on splicing in vivo.
Main Results:
- The crystal structure revealed Snu114 in a GTP-bound conformation, interacting with Prp8.
- The Prp8 binding region abolished Snu114's weak intrinsic GTPase activity.
- Mutations in Snu114 or Prp8 affected splicing and yeast growth, indicating functional importance.
Conclusions:
- The Snu114-GTP-Prp8 module likely acts as a dynamic relay station during spliceosome activation and disassembly.
- While crucial for protein interactions, Snu114's GTPase activity may not be essential for the splicing process itself.
