In budding yeast, the timing of mitotic exit is tightly controlled by a canonical signaling cascade called the Mitotic Exit Network (MEN). MEN is activated by the GTPase Tem1, which is inhibited by a Bfa1-Bub2 GAP complex. It is known that the Polo-like kinase Cdc5 phosphorylates and inactivates Bfa1 to promote mitotic exit and cytokinesis, however, the mechanism that allows Bfa1 phosphorylation by Cdc5 specifically during late mitosis is not well understood. I made a specific hypothesis that mitotic Cdk is preventing Bfa1 phosphorylation by Cdc5 in metaphase to prevent precocious mitotic exit. We have identified six potential Cdk-dependent phosphorylation sites in Bfa1 and made an unphosphorylatable bfa1 mutant (bfa1-6A). In my experiments, the bfa1-6A mutant was not defective in mitotic arrest or exhibited dominant effects in mitotic exit in the conditions tested. I will discuss physiological relevance of possible roles of Cdk in Bfa1 regulations and future experiments.
- Regulation of Spindle Checkpoint Protein Bfa1 by Mitotic Phosphorylation
- Eric Paulissen
- Satoshi Yoshida (Advisor)
- Brandeis University, Graduate School of Arts and Sciences; Master of Science (MS)
- Master of Science (MS), Brandeis University, Graduate School of Arts and Sciences
- Brandeis University
- Brandeis University, Graduate School of Arts and Sciences
- 10192/27072; 9923879980901921
- Copyright by Eric Paulissen 2014
- Department of Biology
- English
- Thesis