Tome-1, wee1, and the onset of mitosis: coupled destruction for timely entry.

In a recent issue of Cell, Ayad et al. (2003) report the identification of a novel F box protein Tome-1, which mediates the destruction of mitosis-inhibitory kinase wee1 via E3 ligase SCF. Tome-1 itself is targeted for degradation by APC in G1. This synergy of destructive action by APC and SCF has important implications for timely entry into mitosis.