FIG. 2.

Inverse relationship of mitochondrial ATP synthesis and ROS production. An increased production of mitochondrial ROS under redox signaling is coupled with reduced ATP production. The overproduction of mitochondrial ROS may result in the impairment of mitochondrial respiration, leading to a further decrease in ATP and mitochondrial oxidative stress, which may trigger programmed cell death apoptosis. Apoptosis requires ATP; thus, a further decline in ATP may result in ATP-independent cell death necrosis.