Dose-dependent differential binding of FGF21, FGF19 and FGF1 to KLB or FGFR4 alone.

<p>(A) Interaction of FGF21, FGF19 and FGF1 with KLB. Graded concentrations as indicated for FGF21 (open square), FGF19 (not shown) and FGF1 (filled circle) were added together with 2 ng/ml ¹²⁵I-FGF19 to the cells expressing KLB alone, and the remaining specific bindings of ¹²⁵I-FGF1 under these conditions were then determined. (B) Competitive binding of FGF21 and FGF1 with FGF19 to FGFR4 alone. Graded concentrations as indicated for FGF21 (open square), FGF19 (not shown) and FGF1 (filled circle) were added together with 2 ng/ml ¹²⁵I-FGF19 to the cells expressing FGFR4 alone, and the remaining specific bindings of ¹²⁵I-FGF1 under these conditions were then determined.