FADD (Fas Associated Death Domain) is an apoptosis adapter molecule enabling transduction of the apoptosis signal initiated via the FasL/Fas receptor interaction. The protein contains a C terminal death domain that interacts with the Fas receptor death domain. The N terminus contains a death effectors domain (DED) which recruits caspase to the death inducing signaling complex (DISC) and initiates the apoptotic caspase cascade. Recruitment of Caspase 8 to the Fas receptor results in oligomerization of the Caspase 8 protein, which in turn drives its autoactivation through self-cleavage. Activated Caspase 8 then activates other downstream caspases including Caspase 9, thereby commiting the cell to undergo apoptosis. FADD is implicated in non-apoptotic cellular pathways such as the regulation of cell cycle machinery in T lymphocytes. This is connected to the phosphorylation state of FADD and to the FasL/TRAIL induced transcriptional activation of cfos protooncogene. FADD also interacts with the hepatitis C virus core protein in the HEK 293 cell line.