WAVE2 directly binds to PKA. A, purified GST-WAVE2 protein was confirmed by Coomassie Brilliant Blue staining. B and C, purified PKA subunits (B) or the PKA holoenzyme (C) was subjected to in vitro binding assay with purified GST or GST-WAVE2 as described under “Experimental Procedures.” Precipitates were separated by SDS-PAGE and visualized by Coomassie Brilliant Blue staining. Vinculin (V) was used as a negative control. C, I, and II, PKA Cα, RI, and RII subunits, respectively.