Fig. 2.

Nck is the most effective SH3 adapter in promoting N-WASP–dependent actin assembly. (A) Integrated fluorescence intensity and representative images of bead-localized Alexa568 N-WASP (200 nM) incubated with NTAD-doped lipid-coated beads and the indicated His-SH3 adapters (250 nM). To compensate for differences in N-WASP recruitment efficiency, the NTAD density was increased to 5% for Crk-II, cortactin, CIP4, and Tks4, whereas 1% NTAD was used for Nck1 and Grb2. (B) Representative phase contrast and fluorescence images of actin assembly reactions under conditions reported in A. (Scale bars: 5 μm.) (C) Integrated fluorescence intensity of Alexa488 actin tails and tail lengths (mean ± SD; n > 20). Asterisks indicate significant differences between Nck and Grb2: ***P < 0.001.