Fig. 1

Schematic representation of caspase-8 mediated extrinsic apoptosis. Caspase-8 is activated by the death-inducing signaling complex (DISC), subsequently cleaving effector proteins caspase-3 and caspase-7, thereby initiating apoptosis. In the apoptosis pathway activated by tumor necrosis factor receptor 1 (TNFR1), the ubiquitination status of receptor-interacting protein kinase 1 (RIPK1) is a critical determinant of cell fate, dictating survival or death. Moreover, when the activity of caspase-8 is inhibited, the apoptotic pathway is suppressed, potentially triggering necroptotic cell death (by Figdraw)