FIGURE 7.

TOCA1 stimulates N-WASP/WIP-mediated actin assembly in vitro. A, actin (2 μm) was polymerized using 10 nm Arp2/3 complex, 20 nm N-WASP, and the indicated concentrations of TOCA1 wild type. Pyrene-actin fluorescence was measured in arbitrary units (AU) over time. B, actin (2 μm) was polymerized using 20 nm Arp2/3 complex, 20 nm N-WASP/WIP complex, and the indicated concentrations of TOCA1 wild type or the W518K mutant as in part A. C, actin (2 μm) was polymerized using 20 nm Arp2/3 complex, 20 nm N-WASP/WIP complex, and the indicated concentrations of GST-SH3 fusion proteins. Barbed end concentrations were calculated when F-actin reached its half-maximal value.