Exposure of PC12 cells to 100 μM peroxynitrite promotes phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) sensitive to PD98059 or U0126. At higher concentrations, however, ERK1/2 phosphorylation was prevented by U0126 and increased by PD98059 via a U0126-sensitive mechanism. PD98059, unlike U0126, enhanced the peroxynitrite-dependent formation of reactive oxygen species (ROS). These results, along with others obtained using respiratory chain inhibitors and respiration-deficient cells, lead to the conclusion that PD98059, while effectively inhibiting the peroxynitrite-induced Raf/MEK signaling leading to ERK1/2 phosphorylation, promotes an enforced mitochondrial formation of ROS inducing ERK1/2 phosphorylation via a Raf-1-independent/MEK-dependent mechanism. © 2003 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.
Cerioni, L., Palomba, L., & Cantoni, O. (2003). The Raf/MEK inhibitor PD98059 enhances ERK1/2 phosphorylation mediated by peroxynitrite via enforced mitochondrial formation of reactive oxygen species. FEBS Letters, 547(1–3), 92–96. https://doi.org/10.1016/S0014-5793(03)00675-6