Fig. 5. Dyn3baa directly binds with a greater affinity than Dyn3aaa to the actin-associated protein cortactin. (A) Comparing the known cortactin binding site of Dyn2 with the correlative site in the Dyn3-PRD reveal that these sequences are almost identical. (B) Cortactin directly binds to both Dyn3aaa and Dyn3baa. GST alone failed to pull down the cortactin protein. (C) Dyn3aaa and Dyn3baa directly bind to cortactin in a blot overlay experiment using a range of recombinant Dyn3 protein amounts. (D) Binding curves representing densitometry measurements demonstrating the greater affinity for cortactin of Dyn3baa compared with Dyn3aaa. Results are normalized to the average maximum in each independent experiment and plotted on a scale of 0 to 1. Error bars represent the s.d. (E) Fold differences in binding of cortactin to Dyn3baa compared with Dyn3aaa. Results were from the average of three experiments and error bars represent the s.e.m.