Editors' ChoiceDevelopment

Cell Cycle Fertilization Trigger

Science Signaling  26 Apr 2011:
Vol. 4, Issue 170, pp. ec121
DOI: 10.1126/scisignal.4170ec121

A critical point of cell cycle control, with implications for reproduction, is the exit of oocytes from meiosis II, the stage at which oocytes arrest until they are fertilized. One mechanism that contributes to this process is proteolytic degradation of cyclin B and consequent inactivation of the cyclin-dependent kinase Cdc2. Another mechanism for inhibiting activity of Cdc2 is phosphorylation by the protein kinase Wee1B. Oh et al. present evidence that this mechanism is also critical in mouse oocytes. Fertilization causes an increase in the intracellular concentration of free Ca2+, thus activating calcium-calmodulin–dependent protein kinase II, which in turn activates Wee1B.

J. S. Oh, A. Susor, M. Conti, Protein tyrosine kinase Wee1B is essential for metaphase II exit in mouse oocytes. Science 332, 462–465 (2011). [Abstract] [Full Text]