FIG. 6.

V12-RacB increases the amount of F-actin in cells. (A and B) The forward scatter (FSC) data from flow cytometry of parental (A) and V12-RacB (B) cells shows that the average size was increased about twofold in V12-RacB-expressing cells. F-actin was quantified by measuring the TRITC-phalloidin fluorescence of cells of similar size. Two areas, marked R3 and R5, indicate two different size ranges of cells. (C and D) The fluorescence intensity of cells in each size range was plotted (R3 and R5, respectively). The solid gray line represents the fluorescence intensity of the parental Ax4 cells, and the black line represents the V12RacB cells. (E) The amount of actin was also quantified by SDS-polyacrylamide gel electrophoresis by loading whole-cell extracts and cytoskeletal fractions on a gel. The total amount of actin was not changed significantly; however, the amount of cytoskeleton-associated F-actin increased about twofold in V12-RacB-expressing cells (see Table 1).