Oxidation of Prx2 and phosphorylation of GRP58 by angiotensin II in human coronary smooth muscle cells identified by 2D-DIGE analysis

To study early changes in angiotensin II (Ang II)-induced signaling with post-translational modifications, we analyzed proteins from cultured human coronary smooth muscle cells stimulated with Ang II, using two-dimensional difference gel electrophoresis (2D-DIGE) combined with ProQ Diamond and SYPRO Ruby staining, followed by mass spectrometry or Western blotting. Among 40 proteins identified, peroxiredoxin 2 (Prx2) was oxidized and 58 kDa glucose-regulated protein (GRP58) was phosphorylated after 5 min of Ang II (1 μM) stimulation. Valsartan, a selective Ang II type 1 (AT1) receptor blocker, and N-acetylcysteine, an antioxidant, inhibited both of these modifications, indicating the contribution of AT1 receptor and reactive oxygen species to oxidation of Prx2 and phosphorylation of GRP58 by Ang II.