Figure 4.

Molecular mechanisms of apoptotic cell death.

Notes: There are two major pathways, extrinsic and intrinsic, that are responsible for apoptotic cell death. The extrinsic pathway is initiated by binding between death ligand and death receptor, while the intrinsic pathway is initiated by efflux of cytochrome c from mitochondria. The activation of these two apoptotic pathways leads to activation of downstream effectors of apoptosis caspases 3, 6, and 7.

Abbreviation: Smac, second mitochondria-derived activator of caspases.