Apoptosis — MFDS Part 1 MCQ

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ModeratePhysiologyApoptosisMFDS Part 1

Activation of caspase-8 or caspase-9, followed by activation of caspase-3, caspase-6 and caspase-7, is the characteristic proteolytic cascade of which cellular process?

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Correct answer: D — Apoptosis

The correct answer is D, apoptosis. Caspase-8 and caspase-9 are initiator caspases in the extrinsic and intrinsic apoptotic pathways, respectively. They activate executioner caspases, particularly caspase-3, caspase-6 and caspase-7, which cleave cellular proteins and produce controlled cell dismantling. Pyroptosis is an inflammatory form of regulated cell death primarily associated with inflammatory caspases such as caspase-1, caspase-4 and caspase-5. Necroptosis is mediated mainly by RIPK1, RIPK3 and MLKL and commonly occurs when caspase-8 activity is inhibited. Autophagy is a lysosome-dependent recycling pathway, while cellular senescence is a persistent state of cell-cycle arrest rather than a caspase execution cascade.

Reference: Kumar S, Dorstyn L, Lim Y. The role of caspases as executioners of apoptosis. Biochemical Society Transactions. 2022;50(1):33-45. https://pubmed.ncbi.nlm.nih.gov/34940803/