Figure 3.

S109 phosphorylation of ARPP19 prevents the prophase release of the oocyte in response to Pg.
(a) Injection of S109D-GST-ARPP inhibits GVBD induction by Pg. GVBD time-course induced by Pg in prophase-arrrested oocytes injected with 775 ng of WT-, S67A-, S109A- or S109D-GST-ARPP.
(b) S109D-GST-ARPP prevents Cdk1 activation induced by Pg. Oocytes from the experiment described in panel (a) were collected at GVBD and lysates were immunoblotted for Cdc27 phosphorylation, Mos accumulation and phosphorylated MAPK (pMAPK).