The intrinsic pathway is primarily centered around the mitochondria. Stress signals lead to the activation of pro-apoptotic proteins such as Bax and Bak. These proteins permeabilize the mitochondrial outer membrane, resulting in the release of cytochrome c into the cytosol. Cytochrome c then binds to Apaf-1 and procaspase-9 to form the apoptosome, which subsequently activates caspases that execute apoptosis.
