Caspase-9 and effector caspases have sequential and distinct effects on mitochondria.

Proapoptotic Bcl-2 family members alter mitochondrial permeability resulting in the release of apoptogenic factors that initiate a caspase cascade. These changes are well described; however, the effects of caspases on mitochondrial function are less well characterized. Here we describe the consequence of caspase-9 and effector caspase inhibition on mitochondrial physiology during intrinsic cell death.