Figure 2. K5 specifically bound to retinal Müller cells. A: Rat Müller cells were incubated with increasing concentrations of ¹²⁵I-labeled K5 for 1 h followed with thorough washing with PBS. Then ¹²⁵I-K5 bound to the cells were quantified using a γ-counter (mean±SD, n=3). The binding of ¹²⁵I-K5 to Müller cells appeared concentration-dependent and saturated above 100 nm of K5. B: The cells were incubated with 50 nM of ¹²⁵I- K5 and increasing concentrations of unlabeled K5 at 37 °C for 1 h, washed with PBS, and ¹²⁵I-K5 on the cells was quantified by γ-counting (mean±SD, n=3). C: The cells were incubated with 50 nM of ¹²⁵I- K5 and increasing concentrations of unlabeled angiostatin under the same conditions. After thorough washing, ¹²⁵I-K5 on the cells were quantified (mean±SD, n=3). The binding of ¹²⁵I-K5 to Müller cells was competed off by increasing concentrations of unlabeled K5 but not by angiostatin.