A G2-Phase Microtubule-Damage Response in Fission Yeast

Microtubules assume a variety of structures through out the different stages of the cell cycle. Ensuring the correct assembly Of such structures is essential to guarantee cell division. During mitosis, it is well established that the spindle assembly checkpoint monitors the correct attachment of sister chromatids to the mitotic spindle. However, the role that microtubule cytoskeleton integrity plays for cell-cycle progression during interphase is uncertain. Here we describe the existence of a mechanism, independent of the mitotic checkpoint, that delays entry into mitosis in response to G(2)-phase microtubule damage. Disassembly of the G2-phase microtubule array leads to the stabilization of the universal mitotic inhibitor Wee1, thus actively delaying entry into mitosis via inhibitory Cdc2 Tyr15 phosphorylation.