Fig. 7.

FGF21 Activates the FGF Signaling Molecules FRS2α and MAPK in 3T3-L1 Fibroblasts Expressing βKlotho

3T3-L1 fibroblasts stably expressing βKlotho (βKlotho/3T3-L1 fibroblasts) were serum starved in OptiMEM-I medium for 18 h, incubated with or without 10 μm SU5402 for 3 h, and then stimulated with 1.1 or 4.5 μg/ml FGF21 for 15 min. The cells were then harvested, and activation of the signaling molecules was analyzed using phosphospecific antibodies against FRS2α and MAPK. FGF1 (18 ng/ml) and PBS served as positive and negative controls, respectively. Essentially the same results were obtained in two separate experiments.