Figure 2. Mitochondrial ROS and apoptosis.
ETC generated ROS induces oxidative stress which leads to upregulation of p53 and FAS gene expression. FAS activation will initiate death receptor pathway of apoptosis. However, p53 gene activation will trigger mitochondrial pathway of apoptosis by induction of cytochrome c release. Both death receptor and mitochondrial pathways are integrated into caspase cascade for apoptosis. Depending on the availability of intracellular ATP, the cell death pathway may switch from apoptosis to necrosis. While apoptosis is the predominant cell death pathway in the presence of adequate ATP 76.