I have been trying to develop a ROS profile of HEK/DDR2 cell line. Within the 4hr incubation span, after 3hr I exposed cells to UV-B for 20 min and then again incubate for 1hr. But my Western-Blotting showed less activation of DDR2 comparing to that of non-UV group. But the phosphorylation (ptyr) signals showed that it happened. So, my guess is UV-B damaged the collagen but phosphorylate DDR2 irrespective of collagen. Requesting your valuable suggestion whether I am right or wrong.