Phospho-regulation of the anillin-related scaffolding protein, Mid1
Cell and Molecular Biology
College of Liberal Arts and Sciences
In fission yeast, the anillin-related protein Mid1 plays a critical role in organizing the early steps of contractile ring formation and functions as a scaffold to bridge the cell cortex with the contractile ring. Cells lacking mid1 form off-centered, highly disorganized ring structures and exhibit severe cytokinesis defects. Coincident with its cortical accumulation, Mid1 becomes hyper-phosphorylated. Our previous research demonstrates that cyclin-dependent kinase, Cdc2, and the polo-like kinase, Plo1, directly phosphorylate Mid1. In addition to consensus phosphorylation motifs for Plo1 and Cdc2, Mid1 contains several RXXS motifs, which fit the phosphorylation consensus sequence for Sid2 kinase. Sid2 is the most downstream kinase in the Septation Initiation Network signaling cascade, which signals from the spindle pole body to trigger constriction of the contractile ring. Our current efforts are directed at identifying specific Sid2 phosphorylation sites and elucidating the physiological relevance of Mid1 phosphorylation. Given that Mid1 departure from the contractile ring coincides with Sid2 relocalization to the division site, Sid2 may temporally regulate the interaction of Mid1 with the membrane or other contractile ring components; our initial experiments favor Sid2 regulating Mid1 dissociation from the cell cortex.
International Fission Yeast Conference
Hart, Dawn C. and DeWitt, Ashley, "Phospho-regulation of the anillin-related scaffolding protein, Mid1" (2013). Faculty Scholarly Dissemination Grants. 1190.
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