Fig. 4.

Regulation of apoptosis under activation of TNF-α. The signaling pathway triggered by TNF-α can be either pro-apoptotic or anti-apoptotic. The caspase family plays a vital role during the process of apoptosis. Activation of caspase proteins and subsequent proteins could induce a cascade amplification of apoptosis. The apoptotic pathway can be triggered by the activation of Caspase-8, which then activates Caspases 3, 6, and 7, leading to apoptosis. The anti-apoptotic pathway is triggered through recognition of TNF-α and its receptor. Activation of TRAF2, TRADD or CYLD can cause subsequent activation of nuclear factor kappa-B (NF-κB), which is responsible for the activation of the transcription of anti-apoptotic proteins, such as BCL-2, Fas, and Bim under the extracellular stimuli of cytokines.