Fig. 1

C1q binds to DDR2. A, B Microtiter plates were immobilized with 2 μg/mL collagen-I (A) and 8 μg/mL C1q (B). Respective concentrations of BSA were also coated as a negative control protein. Various concentrations of sDDR2 were added to the wells and ELISA was conducted to observe the binding. Blank well values were subtracted for analysis. C Microtiter plates were immobilized with 2 μg/mL each of sDDR2 and BSA, and various concentrations of C1q (0.1, 0.5, 2, and 8 μg/mL) were added to evaluate the binding of DDR2 with C1q. The graph shows the mean ± SEM of three independent experiments. *** p < 0.001 (one-way ANOVA). D Pull-down assay of 100 ng sDDR2 and 100 ng C1q were tested with Sepharose-based complete His-tag purification resin. Antibodies for western blot analyses are as indicated. E Surface plasmon analysis of C1q binding to DDR2. Various concentrations of C1q protein (0, 2.5, 5, 10, 20, and 40 μg/mL) were applied on an sDDR2-immobilized sensor chip CM5