Figure 1. Molecular and signal mechanism underpinning oocyte arrest and cell resumption.
Oocyte arrest and resumption are balanced by two determinants: MPF and cAMP. The inactivation of MPF and regimentation of cAMP in arrested oocyte assist cell resumption. The phosphorylation status of Cdk1/cdc2 is activated by Ca2+-CaMKII-Wee1B pathway and inactivated by PKA-Cdc25A pathway. The degradation of cyclin B is promoted by Ca2+-CaMKII-Wee1B- APC/C pathway. What’s more, LH surge facilitates oocyte resumption via AC-cAMP-PKA pathway.