Mitochondrial redox biology: reactive species production and antioxidant defenses

This chapter describes the main processes by which mitochondria produce and manage reactive species by eliminating them or allowing their use as signaling molecules. It starts by describing mitochondria as the sites of oxidative phosphorylation, which allows the ATP synthesis. It then depicts how mitochondria cause the formation of oxidant species (radicals and other reactive oxygen species, ROS) involved in diseases and aging. It also describes the mitochondrial antioxidant system and the main factors involved in its regulation. Besides, it illustrates how the antioxidant system allows mitochondria not only to protect themselves from oxidative damage but also to detoxify the ROS produced in other cellular sites, which renders mitochondria a sink of ROS. The information reported in this chapter highlights the importance of the mitochondrial antioxidant system that can affect the processes regulated by ROS such as cell signaling and metabolic and neurodegenerative disease progression.