Apaf-1 functions by binding to cytochrome c, which is released from the mitochondria into the cytosol in response to apoptotic signals. Upon binding to cytochrome c, Apaf-1 undergoes a conformational change that allows it to oligomerize and form the apoptosome. The apoptosome then recruits and activates pro-caspase-9 to its active form, caspase-9. Activated caspase-9 subsequently activates downstream effector caspases, such as caspase-3, which execute the apoptosis process by degrading cellular components.
