Research Project: Fosfotidilinositol-3,5-Bifosfatın Hücre Bölünmesindeki Fonksiyonunun Aydınlatılması
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Contributors
Funders
ID
TB.00337
Authors
Çaydaşı, Ayşe Koca
Faculty Member
Publications
The signalling lipid PI3,5P 2 is essential for timely mitotic exit
(Royal Society Publishing, 2023) Bektaş, Şeyma Nur; Çaydaşı, Ayşe Koca; Huda, Mariam; Bekdaş, Barış; Department of Molecular Biology and Genetics; Graduate School of Sciences and Engineering; Yes; College of Sciences; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING
Coordination of mitotic exit with chromosome segregation is key for successful mitosis. Mitotic exit in budding yeast is executed by the mitotic exit network (MEN), which is negatively regulated by the spindle position checkpoint (SPOC). SPOC kinase Kin4 is crucial for SPOC activation in response to spindle positioning defects. Here, we report that the lysosomal signalling lipid phosphatidylinositol-3,5-bisphosphate (PI3,5P 2) has an unanticipated role in the timely execution of mitotic exit. We show that the lack of PI3,5P 2 causes a delay in mitotic exit, whereas elevated levels of PI3,5P 2 accelerates mitotic exit in mitotic exit defective cells. Our data indicate that PI3,5P 2 promotes mitotic exit in part through impairment of Kin4. This process is largely dependent on the known PI3,5P 2 effector protein Atg18. Our work thus uncovers a novel link between PI3,5P 2 and mitotic exit. © 2023 Royal Society Publishing. All rights reserved.
Protein phosphatase 1 in association with Bud14 inhibits mitotic exit in Saccharomyces cerevisiae
(eLife Sciences Publications, 2021) Bektaş, Şeyma Nur; Çaydaşı, Ayşe Koca; Dilege, Cansu; Karabürk, Hüseyin; Kırdök, İdil; Kocakaplan, Dilara; Department of Molecular Biology and Genetics; Graduate School of Sciences and Engineering; Yes; College of Engineering; College of Sciences; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING
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.
