Fig. 7: WSC-dependent polymerization of branched actin in cell-free extracts.

Beads coated with GST or GST-RAC1 Q61L were incubated with extracts of MCF10A cells. Rhodamine-labeled actin structures polymerized on the beads were examined by fluorescent microscopy and quantified by average fluorescence intensity and total structure length. All drug treatments were for 1 h and were controlled with DMSO. Three biological repeats with similar results for all experiments. n corresponds to the total number of beads used for quantification from all three experiments. Data are shown as mean ± SEM. a Cells were treated with 200 µM CK666 or depleted from NCKAP1 before preparation of extracts. n = 41 for fluorescence intensity, n = 19 for structure length. b Extracts were prepared from MCF10A cells depleted of PPP2R1A, NHSL1 or both with siRNAs. n = 58 for fluorescence intensity, n = 29 for structure length. c Extracts were prepared from MCF10A cells treated with the NSC23766 inhibitor of RAC1 activation or with the phosphatase inhibitors reported to inactivate PP2A phosphatase activity, okadaic acid (OA, 30 nM), calyculin A (CalA, 10 nM), or cantharidin (CAN, 10 µM). n = 62 for fluorescence intensity, n = 40 for structure length. d Extracts were prepared from MCF10A cells depleted of RAC1 with siRNAs. n = 52 for fluorescence intensity, n = 40 for structure length. Statistical significance was calculated with Kruskal-Wallis test with post hoc Dunn’s multiple comparison test (a–c) or two-tailed unpaired t-test (d) and P values are indicated. *P < 0.05; ****P < 0.0001. Source data are provided as a Source Data file.