Fission yeast Pak1 phosphorylates anillin-like Mid1 for spatial control of cytokinesis

Joseph O. Magliozzi, Jack Sears, Lauren Cressey, Marielle Brady, Hannah E. Opalko, Arminja N. Kettenbach, James B. Moseley
2020 Journal of Cell Biology  
Protein kinases direct polarized growth by regulating the cytoskeleton in time and space and could play similar roles in cell division. We found that the Cdc42-activated polarity kinase Pak1 colocalizes with the assembling contractile actomyosin ring (CAR) and remains at the division site during septation. Mutations in pak1 led to defects in CAR assembly and genetic interactions with cytokinesis mutants. Through a phosphoproteomic screen, we identified novel Pak1 substrates that function in
more » ... hat function in polarized growth and cytokinesis. For cytokinesis, we found that Pak1 regulates the localization of its substrates Mid1 and Cdc15 to the CAR. Mechanistically, Pak1 phosphorylates the Mid1 N-terminus to promote its association with cortical nodes that act as CAR precursors. Defects in Pak1-Mid1 signaling lead to misplaced and defective division planes, but these phenotypes can be rescued by synthetic tethering of Mid1 to cortical nodes. Our work defines a new signaling mechanism driven by a cell polarity kinase that promotes CAR assembly in the correct time and place.
doi:10.1083/jcb.201908017 pmid:32421151 fatcat:bp32hljfw5fdllvg2dnhexej34