Investigating the Role of CDK11 in Animal Cytokinesis

Finely tuned spatio-temporal regulation of cell division is required for genome stability. Cytokinesis constitutes the final stages of cell division, from chromosome segregation to the physical separation of cells, abscission. Abscission is tightly regulated to ensure it occurs after earlier cytokinetic events, like the maturation of the stem body, the regulatory platform for abscission. Active Aurora B kinase enforces the abscission checkpoint, which blocks abscission until chromosomes have been cleared from the cytokinetic machinery. Currently, it is unclear how this checkpoint is overcome. Here, I demonstrate that the cyclin-dependent kinase CDK11 is required for cytokinesis. Both inhibition and depletion of CDK11 block abscission. Furthermore, the mitosis-specific CDK11p58 kinase localizes to the stem body, where its kinase activity rescues the defects of CDK11 depletion and inhibition. These results suggest a model whereby CDK11p58 antagonizes Aurora B kinase to overcome the abscission checkpoint to allow for successful completion of cytokinesis.M.Sc