Mitosis is a fundamental process required for the generation of multicellular organisms, for tissue renewal and homeostasis. During development, both the orientation of the division plane and the timing of mitotic entry, have fundamental influence on the positioning of daughter cells and their organization into tissues. However, the mechanisms that control the timing of mitotic entry remain poorly understood. Entry into mitosis is triggered by the activation of a mitotic kinase cascade and the simultaneous inactivation of counteracting phosphatases. Since the mitotic kinases themselves are activated by phosphorylation, a central question arises: how are mitotic kinases activated while phosphatases activity predominates? During development, how does the regulation and cross-talk between mitotic kinases and opposing phosphatases ensure timely mitotic entry? The objective of this proposal is to decipher how the parallel regulation of kinases and phosphatases control asynchronous mitotic entry during development.