A primer on meiotic resumption in starfish oocytes: the proposed signaling pathway triggered by maturation-inducing hormone.

This short review updates the maturation-inducing hormonal signaling in starfish oocytes. In this system, the activation of cyclin B-Cdc2 kinase (Cdk1) that leads to meiotic resumption does not require new protein synthesis. The key intracellular mediator after hormonal stimulation by 1-methyladenine is the protein kinase Akt/PKB, which in turn directly downregulates Myt1 and upregulates Cdc25 toward the activation of cyclin B-Cdc2. Mitotic kinases including Aurora, Plk1 and Greatwall are activated downstream of cyclin B-Cdc2. The starfish oocyte thus provides a simple model system for the study of meiotic resumption.