Figure 5

MKP3 is dependent on ERK1/2 but not Akt activation. (A) Beads soaked with specific inhibitors were placed in the caudal hindbrain or in the presumptive MHB of HH7⁺-8 explanted embryos. Pharmacological treatments were as follows: DMSO (a), FGFR inhibitor SU5402 (b), ERK1/2 inhibitor PD184352 (c), PI3K inhibitor LY294002 (d). Explants were incubated during 6 h at 38°C. (B) Jurkat cells (left side lanes) and HH7-8 explanted embryos (right side lanes) were treated with DMSO, SU5402, PD184352 or LY294002 and analyzed by western blot for total and phosphorylated forms of Akt and ERK1/2. PD184352 treatment impeded ERK1/2 phosphorylation without affecting the PI3K-Akt pathway and, conversely, LY294002 treatment abolished Akt phosphorylation without affecting the Ras-ERK1/2 pathway. Embryos are shown in whole-mount with anterior to the top.