RIPK1 and familial cylindromatosis: In cylindromatosis (CYLD), RIP1 recruits CASPASE 8 and Fas-associated protein via a death domain (FADD) and TNFR1-associated death domain (TRADD) to trigger apoptosis when CASPASE 8 is activated (37, 38), whereas when CASPASE 8 is blocked, RIP1 and RIP3 interact with each other without degradation and form necrosome to activate necroptosis (25).