Fig. 5. H₂O₂ induced RhoA activation in A549 cells. (A) Serum-starved A459 cells were treated with 100 µM t-H₂O₂ for 5, 15 and 30 minutes. 1% Triton X-100-soluble membrane fractions were obtained and RhoA translocation was evaluated by western blot. Top: points on the curve represent mean ± s.e.m. (n=3). ^**P<0.01. Bottom: a representative western blot for RhoA translocation and ₁-Na,K-ATPase as loading control. (B) A549 cells were exposed to 100 µM t-H₂O₂ for 15 minutes; stress fiber formation was assessed in cells fixed and stained with rhodamin-palloidin and evaluated by fluorescence microscopy. Representative photomicrographs of control cells (V), and t-H₂O₂ treated cells are shown.