Figure 4.

SIPS is associated with up-regulation of caveolin-1. (A) NIH 3T3 cells were left untreated or treated for 2 h with the indicated concentration of H₂O₂ and were allowed to recover for 11 d. Cells were then subjected to immunoblot analysis with monospecific antibody probes that recognize only caveolin-1 (mAb 2297) or caveolin-2 (mAb 65). Note that the treatment with H₂O₂ (15–150 μM) induces up-regulation of endogenous caveolin-1, but not caveolin-2. Immunoblotting with anti-β-actin IgG served as a control for equal loading. (B) NIH 3T3 cells were left untreated or treated with 150 μM H₂O₂ for 2 h and were allowed to recover for the indicated period of time. Cells were then subjected to immunoblot analysis with monospecific antibody probes that recognize only caveolin-1 (mAb 2297) or caveolin-2 (mAb 65). Note that caveolin-1 protein expression is induced 3 d after the treatment with 150 μM H₂O₂ and remains elevated for up to 11 d. In contrast, caveolin-2 expression was not affected. Immunoblotting with anti-β-actin IgG served as a control for equal loading.