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Mutation Of Hof1 Pest Motif Phosphorylation Sites Leads To Retention Of Hof1 At The Bud Neck And A Decrease In The Rate Of Myosin Contraction, Katherine E. Stockstill, Jungeun Park, Rachel Wille, Grace Bay, Avery Joseph, Katie Shannon

Katie Shannon

Regulation of actomyosin ring contraction is important for the coordination of cytokinesis with mitosis. Hof1, a member of the Pombe Cdc15 homology (PCH) family of proteins, is required for efficient cytokinesis in budding yeast. Phosphorylation of Hof1 depends on the mitotic exit network (MEN), and its degradation at the end of mitosis depends on its PEST motif and interaction with the E3 ligase Grr1. To test the hypothesis that targeted destruction of Hof1 temporally couples mitotic exit with contraction of the actomyosin ring, we mutated the Hof1 PESTmotif to prevent phosphorylation and subsequent degradation. These mutations increased the amount of …