p38 and ERK are not activated by cGMP-dependent protein kinase (PKG). Washed human platelets were incubated with thrombin (0.01 U/mL), 8-pCPT-cGMP (200 μM), 8-Br-cGMP (200 μM), or SNAP (100 μM) for 0.5, 2, or 5 minutes, and analyzed for VASP (VASP-P Ser239), p38 (p38-P), and ERK (ERK-P) phosphorylation by Western blotting. p38 and ERK proteins served as loading control. The blots shown are representative of 3 individual experiments.