Extrinsic apoptosis pathway:Extrinsic apoptosis pathway: The Fas receptor (FasR) is stimulated by Fas ligand (FasL), recruiting FADD to the FasR via an interaction between the death domains (DD) of both molecules. Procaspase 8 is recruited to FADD and interacts via the Death effector domains (DED) of both molecules. This results in the cleavage and activation of procaspase 8, forming caspase 8, which goes on to cleave and activate other caspases such as procaspase 3 to initiate the caspase cascade which leads to cell death.