Figure 5

PKC-activating tumor promoter induces rapid activation of myosin II. (A) Representative Western blots and (B) densitometric quantification show an increase in the amounts of mono-phosphorylated (p) and di-phosphorylated (pp), but not total regulatory myosin light chain (RMLC) in HPAF-II lysates after 1 and 3 h exposure to OI-V (1 μM). Data are presented as mean ± SE (n = 4); *p < 0.05 compared to the vehicle-treated group. (C) Double-fluorescence labeling of p-RMLC (red) and F-actin (green) shows diffuse apical staining of p-RLMC in control HPAF-II cells and a lateral accumulation of p-RLMC (arrows) after 3 h of the OI-V treatment. Bar, 20 μm.