Activity of the modified compounds. The in planta modification products of compound 10 were isolated and assayed for their potency to inhibit BIN2 activity in vitro. Compound 15 was used as a control. Each substance was used at a concentration of 10 μM. The same conditions as in Figure 3 were applied except that [γ-33P]-ATP was used as co-substrate. A stain with coomassie R250 is included as a loding control.