Activation of apoptosis through the TNF family of death receptors.

Activated Fas and TNFR-1 launch the receptor-mediated pathway of apoptosis by recruiting the adapter protein Fadd/Mort-1. In turn, caspase-8 is activated, which cleaves procaspase-3. These receptors also induce apoptosis through an alternate pathway. Through adapter proteins TRADD and TRAF, a phosphorylation cascade is initiated, leading to the activation of JNK. Activated JNK phosphorylates substrates such as p53 and c-Jun, which leads to apoptosis through multiple mechanisms including regulating the Bcl-2 family of proteins.