University of Massachusetts Medical School Faculty Publications

UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology

Publication Date

11-2-2017

Document Type

Article Preprint

Disciplines

Amino Acids, Peptides, and Proteins | Cell Biology | Cells | Enzymes and Coenzymes

Abstract

Commitment to mitosis is regulated by cyclin-dependent kinase (CDK) activity. In the fission yeast Schizosaccharomyces pombe, the major B-type cyclin, Cdc13, is necessary and sufficient to drive mitotic entry. Furthermore, Cdc13 is also sufficient to drive S phase, demonstrating that a single cyclin can regulate alternating rounds of replication and mitosis and providing the foundation of the quantitative model of CDK function. It has been assumed that Cig2, a B-type cyclin expressed only during S-phase and incapable of driving mitosis in wild-type cells, was specialized for S-phase regulation. Here, we show that Cig2 is capable of driving mitosis. Cig2/CDK activity drives mitotic catastrophe -- lethal mitosis in inviably small cells -- in cells that lack CDK inhibition by tyrosine-phosphorylation. Moreover, Cig2/CDK can drive mitosis in the absence of Cdc13/CDK activity. These results demonstrate that in fission yeast, not only can the presumptive M-phase cyclin drive S phase, but the presumptive S-phase cyclin can drive M phase, further supporting the quantitative model of CDK function. Furthermore, these results provide an explanation, previously proposed on the basis of computation analyses, for the surprising observation that cells expressing a single-chain Cdc13-Cdc2 CDK do not require Y15 phosphorylation for viability. Their viability is due to the fact that in such cells, which lack Cig2/CDK complexes, Cdc13/CDK activity is unable to drive mitotic catastrophe.

Keywords

fission yeast, Schizosaccharomyces pombe, Cdc13, cyclin, cyclin-dependent kinase, Cig2, cell biology

Rights and Permissions

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It is made available under a CC-BY-NC 4.0 International license.

DOI of Published Version

10.1101/213330

Source

bioRxiv 213330; doi: https://doi.org/10.1101/213330. Link to preprint on bioRxiv service.

Journal/Book/Conference Title

bioRxiv

Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

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