The mitochondrial dysfunction is characterized by disruption of mitochon-
Both the intrinsic and the extrinsic pathways rely on a group of proteolytic enzymes called caspases
(cysteinyl aspartate-specific proteases) as central executors of the cell death program. Indeed,
activated caspases are responsible for the degradation of several cellular substrates that results in
the morphological and biochemical alterations characteristic of the apoptotic phenotype. Endogenous
inhibitors of caspases (i.e., inhibitors of apoptosis proteins [IAPs]) are present in the cell to
prevent accidental caspase activation. Other proteolytic enzymes, such as calpain and the lysosomal
cathepsins, can be activated during apoptosis, but their role in the apoptotic program has not been
completely defined and seems to be dependent on cell type and nature of the apoptotic stimulus.4