Figure 1.

Schematic representation of the Fas–FasL pathway. Binding of the Fas leads to recruitment and activation by the protein adaptor FADD of procaspase-8 and formation of the death-inducing signalling complex (DISC). Active caspase-8 directly cleaves caspase-3 and initiates the caspase cascade, which ultimately leads to cell death. Soluble Fas and soluble FasL bind to the respective ligands inhibiting activation of the pathway. FLIP inhibits activation of caspase-8 and is thus a major anti-apoptotic protein.