Fig. 4.

Actin polymerization stimulated by PI(3)P and PI(4,5)P₂ uses Cdc42 and is enhanced by GTPγS. (A) Schematic diagram of signaling from membranes through Cdc42, N-WASP, toca-1, and Arp2/3 complex and highlighting the steps that were inhibited. (B) Dose–response of actin polymerization in a pyrene actin assay in the presence of increasing concentrations of dominant negative Cdc42 with PI(4,5)P₂ and PI(3)P/PI(4,5)P₂ stimuli (composition used in Fig. 3). (C) Dose–response of actin polymerization in response to Cdc42.GTPγS, PI(4,5)P₂, PI(3)P/PI(4,5)P₂ stimuli with increasing concentrations of Arp2/3 complex-activation inhibitor, GST-CA domain. PI(3)P/PI(4,5)P₂ and Cdc42.GTPγS are more resistant to the inhibitor.