Figure 2.

Apoptotic cell death mediated by the Fas receptor pathway. Effector cells (for example, activated T lymphocytes) present the Fas ligand (FasL) in a conformation that permits crosslinking and aggregation of the Fas receptor on the target cell. The clustering of Fas is the first step in activating the intracellular apoptotic cascade. Formation of a complex, the Fas associated death domain (FADD), then results in binding and activation of procaspase 8 and the caspase cascade.