FIGURE 3.

FSH-stimulated phosphorylation of ERK1/2(Thr²⁰²/Tyr²⁰⁴) is not regulated by Ser/Thr and Tyr phosphatases. A, GCs were pretreated without (EtOH) or with 0.2 μm okadaic acid, a PP2 inhibitor, for 1 h, followed by treatment without (veh) and with FSH for 15 min. Samples were collected as described in Fig. 1A. The results are representative of three independent experiments. The results for pGSK3β and its S6 loading control were published previously (58). B, GCs were pretreated without (EtOH) or with 1 μm tautomycin, a PP1 inhibitor, for 5.5 h, followed by treatment without (veh) and with FSH for 15 min. Samples were collected as described in Fig. 1A. The results are representative of six independent experiments. C, GCs were pretreated without (H₂O) or with 50 μm Na₂VO₃, a pan tyrosine phosphatase inhibitor, for 12 h, followed by treatment without (veh) and with FSH for 30 min. Samples were collected as described in Fig. 1A. The results are representative of three independent experiments. The results for the SHP2 loading control were published previously (58).