靶标信息
Apoptosis is a spontaneous cell suicide process triggered in response to physiological and pathological stress stimuli. It is an initiative, tightly regulated and gene controlled process involved in the participation of a series of enzymes. Caspases are a group of cysteine enzymes which cleave proteins in response to intrinsic and extrinsic pathways that cause apoptotic cell death. The caspases can be grouped into two subgroups based on their roles in apoptosis. Initiator caspases (including 8, 9, 10 and 12) are closely coupled to proapoptotic signals. And effector caspases (including 3, 6 and 7) participate in apoptosis execution, which disintegrate cytoskeletal and nuclear proteins like PARP, α-fodrin, DFF and lamin A, and induce apoptosis. Activated caspase-9 will then cleave and activate downstream caspases such as caspase-3, -6, and -7. Cytochrome c released from mitochondria is coupled to the activation of caspase-9, a key initiator caspase. Proapoptotic stimuli include the FasL, TNF-α, DNA damage and ER stress. Fas and TNFR activate caspases 8 and 10, DNA damage leads to the activation of caspase-9 and ER stress leads to the calcium-mediated activation of caspase-12. The inhibitor of apoptosis protein (IAP) family includes XIAP and survivin and functions by binding and inhibiting several caspases. Smac/Diablo, a mitochondrial protein, is released into the cytosol upon mitochondrial stress and competes with caspases for binding of IAPs. The interaction of Smac/Diablo with IAPs relieves the inhibitory effects of the IAPs on caspases.