FIGURE 2.

SSH1L phosphatase activation is mediated by H₂O₂. A, N-acetylcysteine blocks PDGF-induced SSH1L phosphatase activity. Human smooth muscle cells were serum deprived for 48 h and pretreated with 20 nm NAC for 1 h before PDGF stimulation 30 min. SSH1L phosphatase activity was measured after immunoprecipitation. Bar graph is representative of three independent experiments. B, exogenous H₂O₂ induces cofilin dephosphorylation. VSMCs were serum starved for 48 h, and then stimulated for the indicated times with 100 μm H₂O₂. Cell lysates were harvested and protein phosphorylation measured using Western blots probed with p-cofilin antibody. The blot is representative of three independent experiments. C, exogenous H₂O₂ induces SSH1L activation.VSMCs were treated with 100 μm H₂O₂ for 30 min. SSH1L phosphatase activity was measured after immunoprecipitation. Data represent mean ± S.E. of two independent experiments.