Crashing waves of destruction: the cell cycle and APC(Cdh1) regulation of SCF(Skp2).

Coordination of events required for cell cycle progression is orchestrated in large part by the ubiquitin (Ub)-mediated destruction of key regulatory proteins such as cyclins and their inhibitors. Until now, the G1/S and mitotic phases of the cell cycle were thought to be controlled by discrete families of multisubunit Ub-ligases: SCF ligases controlled the G1 to S transition, whereas APC ligases controlled the onset and exit from mitosis. New work, published in the March 11 issue of Nature, challenges this concept by revealing that an essential function of APC is to limit SCF activity during the G1 phase of the cell cycle.