(eLife Sciences Publications, 2021) Department of Molecular Biology and Genetics; Çaydaşı, Ayşe Koca; Kocakaplan, Dilara; Karabürk, Hüseyin; Dilege, Cansu; Kırdök, İdil; Bektaş, Şeyma Nur; Faculty Member; Department of Molecular Biology and Genetics; Graduate School of Sciences and Engineering; College of Engineering; 252978; N/A; N/A; N/A; N/A; N/A
Mitotic exit in budding yeast is dependent on correct orientation of the mitotic spindle along the cell polarity axis. When accurate positioning of the spindle fails, a surveillance mechanism named the Spindle Position Checkpoint (SPOC) prevents cells from exiting mitosis. Mutants with a defective SPOC become multinucleated and lose their genomic integrity. Yet, a comprehensive understanding of the SPOC mechanism is missing. In this study, we identified the type 1 protein phosphatase, Glc7, in association with its regulatory protein Bud14 as a novel checkpoint component. We further showed that Glc7-Bud14 promotes dephosphorylation of the SPOC effector protein Bfa1. Our results suggest a model in which two mechanisms act in parallel for a robust checkpoint response: first, the SPOC kinase Kin4 isolates Bfa1 away from the inhibitory kinase Cdc5 and second, Glc7-Bud14 dephosphorylates Bfa1 to fully activate the checkpoint effector.
