Are mitochondria the main contributor of reactive oxygen species in cells?

ABSTRACT Physiologists often assume that mitochondria are the main producers of reactive oxygen species (ROS) in cells. Consequently, biomedicine, considered as important targets for therapeutic treatments, and evolutionary biology, they mediators life-history tradeoffs. Surprisingly, data supporting such an assumption lacking, at least partially due to technical difficulties accurately measuring level ROS produced by different subcellular compartments intact In this Commentary, we first review three potential reasons underlying misassumption mitochondrial dominance production cellular ROS. We then introduce some other major sites/enzymes responsible production. With use a recently developed cell-based assay, further discuss contribution total rate release cell lines primary cells species. these cells, varies between types but never source This indicates although one significant sources ROS, not necessarily contributor under normal conditions. Intriguingly, similar findings were also observed variety stressors, strategies pathological stages, which rates significantly enhanced. Finally, make recommendations designing future studies. hope paper will encourage investigators carefully consider non-mitochondrial their study systems or models.