FIG. 5.

LS mutants promote EGF-induced GSK-3β phosphorylation through a PI3K- and GAB1-dependent pathway. (A) Immortalized skin fibroblasts from a healthy subject (WT) or LS patients carrying the indicated PTPN11 mutations were treated or not with the indicated inhibitors for 30 min before stimulation with EGF, as shown. The cells were then lysed and processed for anti-P-GSK-3β and anti-tubulin immunoblotting. (B) WT and LS fibroblasts were transfected with control or GAB1 siRNA, as indicated, before stimulation with EGF. The cells were then processed for Western blot analysis and probed with the indicated antibodies. (C) WT and LS cells were infected with adenoviruses encoding GAB1-YF3 or GFP as a control, as shown. Following stimulation with EGF, the cells were processed for Western blot analysis and probed with the indicated antibodies.