Oncogenic Ras decreases the amount of F-actin in a p53-dependent manner. (A) NIH3T3 cells were treated with 0.5 µM cytochalasin D, 0.2 µM latrunculin A, or 50 µM blebbistatin for 30 min. The levels of phosphorylated p130Cas (p-p130Cas) and phosphorylated FAK (p-FAK) were evaluated by immunoblotting. (B–D) NIH3T3 cells, iMEFs, and p53^−/− MEFs were infected with a control or Ha-RasV12–expressing retrovirus. (E–G) NIH3T3 cells were infected with a Ha-RasV12–expressing retrovirus together with a control or p53R175H-expressing retrovirus. (B and E) Cells were stained for F-actin (middle) and G-actin (bottom). Ratio images of F/G-actin (top). Bars, 20 µm. (C, D, F, and G) Intensity ratios of F/G-actin (C and F) or F-actin (D and G) were quantified from images in B and E. Values were normalized with the mean value of the control cells. Data represent the mean ± SD of >28 cells. *, P < 0.01. (H) Ras-transformed NIH3T3 cells were treated with 50 nM jasplakinolide for 2 h. The level of phosphorylated p130Cas was evaluated by immunoblotting.