Fas is a member of the tumor necrosis factor (TNF)-receptor superfamily and plays a key role in the physiological regulation of programmed cell death. This receptor contains a death domain which enables the formation of a signaling complex that includes Fas-associated death domain protein (FADD), caspase 8, and caspase 10. The auto-proteolytic processing of these complexed caspases triggers a downstream cascade that leads to membrane-mediated apoptosis.