Fig. 2.

Death receptor-mediated apoptosis. Upon binding of a ligand to the extracellular portion of the death receptor, the receptor intracellular domain recruits adaptor proteins, such as Fas-associated protein with death domain (FADD) and pro-caspase 8, to form a signaling platform termed the death-inducing signaling complex. Caspase 8 then undergoes proteolytic autoactivation, resulting in direct or indirect (via mitochondria) activation of caspases 3, 6, and 7 that execute the final steps of cellular demolition.