Initiator caspases contain a long pro-domain that allows them to interact with adaptor proteins. These interactions are vital for their activation mechanism. Upon receiving apoptotic signals, initiator caspases are recruited to multi-protein complexes like the apoptosome for caspase-9 or the death-inducing signaling complex (DISC) for caspase-8. This recruitment facilitates their dimerization and subsequent auto-activation, which then leads to the activation of downstream effector caspases such as caspase-3, caspase-6, and caspase-7.
