Fig 1: Functional Changes Regulated by Disulfides, Not S-Nitrosation(A) The oxidation state of PTEN was measured in SMCs treated with CysNO.(B) After exposure of CysNO, there was a decrease in reduced PTEN. Reduced PTEN was observed after reduction by DTT but not ascorbate.(C) PTEN’s enzymatic activity was inhibited after exposure to CysNO, as measured by in vitro phosphatase activity assay. Enzyme activity was restored after addition of DTT but not ascorbate.(D) Calpain-1’s enzymatic activity was inhibited in vitro after exposure to the nitrosating agent CysNO, the disulfide-inducing reagents GSSG, H2O2, or diamide, or the irreversible calpain inhibitor Z-LLY-FMK.Data are represented as mean ± SEM; ∗p < 0.05.