Figure 2. Tks5 is not essential for lamellipodia formation.

A.-D. BEAS-2B cells were transfected with control (scrambled), XB130 or Tks5 siRNA and subjected to a wound-healing assay over an 8 h time course. Unlike XB130 down regulation, Tks5 down regulation does not inhibit wound closure. E. Percentage of original wound width per hour shows that only XB130 siRNA significantly reduces wound healing at 7 h and 8 h, as compared to control, control siRNA-transfected or Tks5 siRNA-transfected cells. F. High magnification phase contrast microscopy at the leading edge of wounds shows that control and Tks5 downregulated cells form dark ruffled edges (arrow), indicative of lamellipodia, whereas XB130 down-regulated cells appear to lack these structures (asterisk). G. Quantification of cells with lamellipodia at the leading edge shows that XB130 downregulation significantly reduced the percentage of cells displaying lamellipodia, as observed by phase contrast microscopy. Data is summarized from three independent experiments and presented as mean ± SD. * represents p < 0.01 compared with controls (non-transfected BEAS-2B cells and non-targeting siRNA-transfected cells). H. Co-immunofluorescence staining of XB130 (green), actin (blue) and Tks5 (red). BEAS2B cells were treated with or without 50 ng/mL EGF or 0.1 uM NNK. No treatment control shows normal stress fibers. EGF stimulation shows formation of lamellipodia as detected by actin bands at the cell periphery and XB130 staining. NNK stimulation shows the formation of lamellipodia and podosomes (white arrows) as detected by actin and Tks5. XB130 only translocates to lamellipodia after stimulation.