Cytochrome c, once released into the cytoplasm, binds to Apaf-1 (apoptotic protease activating factor-1) and ATP, forming the apoptosome complex. This complex then recruits and activates procaspase-9, which in turn activates downstream effector caspases such as caspase-3. These caspases execute the apoptotic program by cleaving various cellular substrates, ultimately leading to cell death.
