Figure 4

Activation of FGFR1 and FGFR3 by FGF-2. (A) Human articular chondrocytes in monolayer were stimulated with FGF-2 (100 ng/mL) for five minutes before whole cell lysates were prepared. The lysates were incubated with antibody against FGFR1 or FGFR3 in separate tubes. Equal amounts of total protein after immunoprecipitation (IP) were resolved on SDS-PAGE gel, followed by immunoblotting of phospho-tyrosine. Antibody against total FGFR1 or FGFR3 was used to evaluate loading precision. (B) Human articular chondrocytes in monolayer were stimulated with FGF18 (100 ng/mL) for five minutes before whole cell lysates were prepared. The following steps were performed as described above. FGF, fibroblast growth factor; FGFR, FGF receptor.