Department of Molecular Biology and Genetics2024-11-0920212050-084X10.7554/eLife.728332-s2.0-85118199734https://hdl.handle.net/20.500.14288/2876Mitotic 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.pdfLife sciencesBiomedicineJournal Articlehttps://doi.org/10.7554/eLife.72833716751000001Q1NOIR03286