Fig. 4.

Inhibition of the binding of VEGF₁₆₅a-TMR to NLuc-VEGFR2 by unlabeled VEGF isoforms. Fixed concentrations of VEGF₁₆₅a-TMR (0.1–3 nM) were added simultaneously with increasing concentrations of (a) VEGF₁₆₅b, (b) VEGF₁₂₁a, (c) VEGF₁₄₅a and (d) VEGF₁₈₉a, and incubated for 1 h at 37 °C. Data represent mean ± S.E.M of 5 independent experiments, each performed in triplicate. Bars represent the binding of VEGF₁₆₅a-TMR obtained at each fluorescent ligand concentration in the absence of competing ligand. The open bar shows the BRET ratio obtained in the absence of VEGF₁₆₅a-TMR.