caspases
Summary
Caspases are cysteine proteases that execute programmed cell death (apoptosis) by cleaving specific cellular proteins. They exist as inactive zymogens and are activated in a cascade manner during apoptosis, with initiator caspases (8, 9, 10) activating executioner caspases (3, 6, 7).
Detail
Caspases (cysteine-aspartic proteases) are the central executioners of apoptosis, cleaving proteins after aspartate residues. The apoptotic pathway involves two main routes: the extrinsic pathway (death receptor-mediated, activating caspase-8) and intrinsic pathway (mitochondrial-mediated, activating caspase-9 via cytochrome c release and apoptosome formation). Both converge on executioner caspases (primarily caspase-3) that cleave key cellular proteins including PARP, lamins, and cytoskeletal proteins, leading to characteristic apoptotic morphology (cell shrinkage, chromatin condensation, DNA fragmentation). Dysregulation of caspase activity is implicated in cancer (insufficient apoptosis) and neurodegenerative diseases (excessive apoptosis). Caspase-1 is unique as an inflammatory caspase involved in pyroptosis and IL-1β/IL-18 processing rather than apoptosis.
Sources
- Robbins Basic Pathology
- Alberts Molecular Biology of the Cell
- First Aid for USMLE Step 1
- Janeway's Immunobiology
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.