Binding to the Tda2–Aim21 complex depends on conserved residues on the surface of actin-capping protein. GST-Aim21 pulldown assays were performed as in Fig. 7 A. GST-Aim21 was incubated with His-Tda2 and His-Cap1/Cap2 WT or a mutant in which the R15A and Y80A point mutations were introduced in the Cap2 subunit. Bound proteins were analyzed by anti-His immunoblotting (IB). Binding of His-Cap1/Cap2 mutant was significantly decreased compared with His-Cap1/Cap2 WT.