Figure 1.

Multiple sites of ROS and RNS production are present in skeletal muscle cells. The network of different proteins that leads to ROS/RNS production in the extracellular, cytosolic, and mitochondrial compartments of skeletal muscle cell is illustrated. XO: xanthine oxidase; NOX: NADPH oxidase; DG: dystrophin-glycoprotein; nNOS: neuronal nitric oxide synthase; PLA2: phospholipase A2; I–V: complexes of electron transport/oxidative phosphorylation; UCP: uncoupling protein; O₂: oxygen; ^∙O₂ ⁻: superoxide; H₂O₂: hydrogen peroxide; ^∙NO: nitric oxide; ONOO⁻: peroxynitrite.