Knockdown of p130Cas suppresses lamellipodia formation in Ras-transformed cells. (A–E) NIH3T3 cells were infected with Ha-RasV12– and HtrA2/Omi shRNA–expressing retroviruses together with a control or p130Cas shRNA–expressing retrovirus. (F–J) NIH3T3 cells were infected with Ha-RasV12– and p53R175H-expressing retroviruses together with a control or p130Cas shRNA–expressing retrovirus. (A and F) Confocal images of cells stained for F-actin. Arrowheads indicate lamellipodia. Bar, 20 µm. (B and G) Cells were transfected with a Lifeact-GFP expression vector to label F-actin. Single section of protrusions from Videos 2 and 3 (B) or Videos 4 and 5 (G). Bars, 10 µm. (C and H) Cells were stained for F-actin (middle) and G-actin (bottom). Ratio images of F/G-actin (top). Bars, 20 µm. (D, E, I, and J) Intensity ratios of F/G-actin (D and I) or F-actin (E and J) were quantified from images in C and H. Values were normalized with the mean value of the control cells. Data represent the mean ± SD; n = 28 cells.