Sharpin promotes lamellipodium formation through interaction with the Arp2/3 complex. (A) Sharpin-silenced NCI-H460 cells or (B) Sharpin KO2 NCI-H460 cells overexpressing the indicated proteins were stained for cortactin. Graphs depict the number of GFP-positive cells with cortactin-positive lamellipodia, relative to GFP–Sharpin WT, for (A) Sharpin-silenced (n=4 experiments, >30 cells per condition per experiment) and (B) Sharpin-knockout cells (n=3 or 4 experiments, 19–56 cells per condition per experiment). All numerical data are mean±s.e.m. *P<0.05, **P<0.01. Scale bars: 10 μm.