Fig. 8

(A) Embryos were injected with a hyperactive variant of MEK, MEK^F53L, in combination with MAP4K4 variants. Embryos were imaged at 11 hpf, and the aspect ratio was calculated. MEK^F53L increases aspect ratio, and this elongation is rescued by MAP4K4^WT but not MAP4K4^L889X. (B) Embryos were injected with MAP4K4^D153N and then treated with an inhibitor of MAPK kinase (MEK), PD0325901, or the fibroblast growth factor receptor (FGFR), SU5402. Embryos were imaged at 11 hpf, and the aspect ratio was calculated. Inhibiting ligand binding or MEK activity rescues the elongation caused by MAP4K4^D153N. DMSO, dimethyl sulfoxide. (C) Western blotting with quantification and normalization of the level of dually phosphorylated extracellular signal–regulated kinase (dpERK) to the amount of total ERK. Scale bars, 250 μm (A and B). Graph (A): pale gray, vehicle (Veh); orange, drug treated. Graph (B): pale gray, vehicle; purple, MAP4K4^D153N. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001 by pairwise Student’s t test compared to vehicle. ANOVA gives P < 0.0001 for (A) and (B). n numbers are inset to graphs in gray text. Error bars represent the SEM.