Kicking off the polo game

Polo-like kinase 1 (Plk1) is essential for checkpoint recovery and the activation of key mitotic enzymes; however, its own activation mechanism has remained elusive. Recent findings show that Bora, a G(2)-M expressed protein, facilitates Plk1 activation by the oncogenic kinase Aurora A in G(2). During mitosis, Plk1-dependent Bora degradation promotes Aurora A localization to the centrosome and/or spindle. Bora-dependent regulation provides important new insights into interactions between key mitotic kinases.