Supplementary Figure 8
(a) Uncapping efficiency of PI3P is dose-dependent. Uncapping assays were performed with 2 μMα-actin and 10 nM CapZ. The indicated concentrations of PI3P were added to the reactions 20 min after the start point. Uncapping efficiency was measured by the increase in the rate of actin polymerization. (b) Comparison of the effects of PI(4,5)P2 and PI3P on uncapping of actin filaments. Uncapping assays were performed with 2 μMα-actin and 10 nM CapZ. 90 μM PI3P (cyan curve) or PI(4,5)P2 (blue curve) was added to the reactions. Both PI3P and PI(4,5)P2 induced a large increase in the rate of actin polymerization from capped actin filaments.
