Fig. 4. NCAM prevents the binding of FGF to FGFR. (A,B) L cells stably transfected with an empty vector (L-mock) or with NCAM were subjected to the ¹²⁵I-FGF2 binding assay. Specific binding to low-affinity HSPGs (A) and to high-affinity FGFR (B) was determined as described in the Materials and Methods. (C) Non-transfected L cells were subjected to binding assay with 20 ng/ml ¹²⁵I-FGF2 in the presence of either FGL or FGL_mut at the indicated concentrations. Specific binding to high-affinity FGFR was determined as described in the Materials and Methods, and is represented as the percentage of ¹²⁵I-FGF2 binding in the absence of peptides. ^*P<0.005, relative to cells incubated with FGL_mut.