caspase
Summary
Caspases are cysteine-aspartic proteases that serve as the central executioners of programmed cell death (apoptosis). They exist as inactive precursors and are activated through proteolytic cleavage in response to apoptotic signals, leading to systematic cellular dismantling.
Detail
Caspases are a family of proteases that cleave proteins after aspartic acid residues and are essential for apoptosis execution. They are classified into initiator caspases (caspases-8, -9, -10) and executioner caspases (caspases-3, -6, -7). Initiator caspases are activated through death receptor pathways (extrinsic pathway via caspase-8) or mitochondrial pathways (intrinsic pathway via caspase-9). Once activated, they cleave and activate executioner caspases, which systematically dismantle cellular components including nuclear lamins, cytoskeletal proteins, and DNA repair enzymes. This leads to characteristic apoptotic features: cell shrinkage, chromatin condensation, DNA fragmentation, and formation of apoptotic bodies. Dysregulation of caspases contributes to various pathologies - excessive activation leads to neurodegenerative diseases and ischemic injury, while insufficient activation contributes to cancer development and autoimmune disorders. Caspase-3 is often used as a biomarker for apoptosis in research and clinical settings.
Sources
- Robbins and Cotran Pathologic Basis of Disease
- Alberts' Molecular Biology of the Cell
- First Aid for the USMLE Step 1
- Kumar & Clark's Clinical Medicine
Reviewed by AnkiBoss editorial — medical student review. Information here is for study reference only and is not medical advice. Spotted an error? Let us know.