Fig. 1. Actin filament disassembling activity of the recombinant UNC-78 protein. (A) Purified bacterially expressed recombinant UNC-78 protein (3.2 µg). (B) UNC-60B-dependent filament disassembly by UNC-78. Rabbit muscle F-actin (10 µM) was incubated for 30 minutes with buffer (lanes 1 and 2), UNC-60B (10 µM) (lanes 3 and 4), UNC-78 (2 µM) (lanes 5 and 6), or both UNC-60B and UNC-78 (lanes 7 and 8) and separated into supernatants (s) and pellets (p) after ultracentrifugation. UNC-78 was treated in the absence of F-actin as a control (lanes 9 and 10). (C) Dose-dependence of filament disassembly by UNC-78 in the presence of UNC-60B. F-actin (10 µM) and UNC-60B (20 µM) were incubated for 30 minutes with the indicated concentrations of UNC-78 and analyzed by pelleting assays. Molecular mass markers in kDa are indicated on the left of A-C. (D,E) Quantitative analysis of UNC-78-induced filament disassembly. Rabbit muscle actin (D) or C. elegans actin (E) was incubated with various concentrations of UNC-60B and UNC-78 and subjected to pelleting assays. Percentages of actin in the pellets were quantified and plotted as a function of the UNC-78 concentration at different UNC-60B concentrations (0-30 µM). Data shown are mean±s.d. of three experiments.