Activation of procaspases can occur through intrinsic or extrinsic pathways. The intrinsic pathway is typically triggered by internal stress signals, such as DNA damage or oxidative stress, leading to the release of cytochrome c from mitochondria and the formation of the apoptosome complex. This complex facilitates the activation of initiator caspases, such as caspase-9, which in turn activate executioner caspases like caspase-3 and caspase-7. The extrinsic pathway involves the binding of extracellular death ligands to cell surface death receptors, activating initiator caspases such as caspase-8.
