(A, B) Bulk actin polymerization assays containing G-actin (2 µM, 5% pyrene-labeled) and the indicated concentrations of Arp2/3 complex, VCA, Gmf1, and Crn1. (C) Bulk actin polymerization assays, performed as in A and B, except using full-length Las17 (yeast WASP) instead of VCA. (D) Percentage of Arp2/3 complex particles with Crn1 bound in the presence and absence of Gmf1 (- Gmf1, n = 366; + Gmf1, n = 398).