Cytochrome c is a crucial component of the intrinsic pathway. When released into the cytosol, it binds to the protein Apaf-1 and, in the presence of ATP, forms the apoptosome. This complex subsequently recruits and activates caspase-9, which then activates downstream effector caspases, such as caspase-3 and caspase-7, leading to the execution phase of apoptosis.
