Dissecting protein interactions during cytokinesis.

Appropriate assembly and constriction of the acto-myosin based contractile ring is essential for the final separation of the two daughter cells in mitosis. This is orchestrated by the small GTPase Rho as well as convergent signals from the prior events of mitosis. Contractile ring assembly requires the physical interaction of structural proteins like the microtubules of the central spindle, motor proteins and Rho activators. These and the interaction of newly localised proteins downstream of active Rho are essential for stability of the contractile ring and its proper constriction. Here, we discuss our recent findings that reveal a complex network of protein interactions during the early stages of cytokinesis. This includes evidence for a direct interaction between Polo Kinase and RacGAP50C as well as unpublished data suggesting other interactions of interest within the contractile ring.