Mitochondria and apoptosis regulation

Apoptosis is a highly regulated form of programmed cell death,which plays a key role in the development and homeostasis of multicellular organisms.Mitochondria play a central role in the regulation of apoptotic cell death.Upon death stimuli,different apoptogenic factors such as cytochrome c and Smac/Diablo are released during the early stages of apoptosis.A small amount cytochrome c may be sufficient for activating caspases.Once activated,caspases can positively feedback to attack mitochondria leading to a more profound loss of cytochrome c and consequently mitochondrial dysfunction.This caspase-mediated late stage of cyto- chrome c release causes the complete disruption of mitochondrial electron transport chain,leading to the increase in cellular ROS and complete loss of ATP generation,late stage of apoptotic events or secondary necrosis.Bcl-2 and its family proteins are important for regulating cytochrome c release and apoptotic processes.