Caspase 8 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Caspase-8 (CASP8) is an initiator caspase that plays a central role in extrinsic apoptosis by activating the caspase cascade in response to death receptor signaling. Caspase-8 contains two death effector domains (DEDs) at its N-terminus that facilitate recruitment to death receptors (Fas/CD95, TRAIL-R1/DR4, TRAIL-R2/DR5, TNFR1) via adaptor proteins like FADD. Upon receptor engagement, Caspase-8 forms the death-inducing signaling complex (DISC), where it undergoes autocatalytic cleavage into the active p18/p10 heterotetramer. Active Caspase-8 can directly cleave and activate executioner caspases (caspase-3, -6, -7) or cleave Bid to tBid, linking extrinsic apoptosis to the mitochondrial intrinsic pathway. Beyond apoptosis, Caspase-8 has important roles in cell proliferation, necroptosis regulation, and immune cell activation. Dysregulated Caspase-8 activity contributes to cancer (where decreased activity allows tumor cell survival) and neurodegenerative diseases (where excessive activation causes neuronal death).
Caspase-8 is synthesized as a zymogen (procaspase-8) of 479 amino acids:
Activation involves dimerization and cleavage at Asp374 to separate large and small subunits, forming the active heterotetramer (p10/p10/p20/p20).
Caspase-8 is the initiator caspase of the extrinsic apoptosis pathway, activated at death receptors:
Death Receptor Signaling:
Substrate Cleavage:
In neurons, caspase-8 is expressed at low levels but is rapidly activated following death receptor engagement.
Alzheimer's Disease: Caspase-8 is activated in AD brain and:
Parkinson's Disease:
Stroke:
ALPS: Dominant-negative mutations in CASP8 DED cause defective death receptor signaling.
Caspase-8 as therapeutic target:
Balancing apoptosis inhibition with tumor surveillance remains challenging.
CASP8 Gene, Apoptosis Pathway, FADD Protein, Extrinsic Apoptosis
The study of Caspase 8 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.