Fig. 1

Schematic depiction of coordination between GPR-Gs-ADCY and cAMP-PDE maintain high level of cAMP in the oocyte. After the trans-membrane receptor GPR2 is activated, its conformation changes. GPR2 couples with Gs protein and initiates Gs-adenylyl cyclise to convert ATP to cAMP. This process is accompanied by the inhibition of cAMP-PDE from unknown signalling preventing the hydrolysis of cAMP, resulting the accumulation of cAMP in the oocyte. The increase of cAMP in the oocyte activates the PKA, causing the phosphorylation of CDC25B and Weel/Myt1, which in return inactivate MPF, ultimately inducing meiotic arrest at the diplotene stage