Fig. 4.

Competition of Bud6^core and c-Bud6 polypeptides for binding to Bni1 (FH1-FH2-C). (A) Monomeric actin (2 μM) was assembled in the presence of 10 nM Bni1 (FH1-FH2-C), 100 nM WT c-Bud6, and indicated concentrations of WT Bud6^core. (B) Reactions were performed as in A, except using the indicated mutant Bud6^core polypeptides. Each data point represents a single trial, where the slope of the raw curve was measured at 50% polymerization. Red datasets indicate mutations that impair the NPF activity of c-Bud6 (Fig. 3B); blue datasets indicate mutations in c-Bud6 that were pseudo-WT for stimulating Bni1.