Fig. 6. Modulation of FRS2 phosphorylation by FGF2 and CNP. (A) Serum-starved cells were treated with FGF2 and CNP for 30 minutes and immunoprecipitated FRS2 was analyzed for tyrosine phosphorylation by WB with the 4G10 antibody. The WB signal was quantified by densitometry and graphed. (B) Serum-starved cells were treated as indicated for 30 minutes and FRS2, phosphorylated Erk1/2, and total Erk1/2 were detected by WB. Note that upon FGF2 treatment, FRS2 underwent an electrophoretic mobility shift that disappeared when Erk activation was prevented by CNP or U0126. (C) Serum-starved cells were treated as indicated for 30 minutes and FRS2 was detected by WB. Note that KT5823 abolishes the FRS2 electrophoretic mobility shift seen in CNP-treated cells.