In the intrinsic (mitochondrial) pathway of apoptosis, cytochrome c released into the cytosol binds a cytosolic protein to form a multimeric complex that activates the initiator caspase. Which complex and caspase are involved?

• A DISC complex activating caspase-8
• B Inflammasome activating caspase-1
• C Apoptosome activating caspase-9 ✓
• D PIDDosome activating caspase-2

Explanation

Cytochrome c binds Apaf-1 (apoptotic protease activating factor 1); oligomerization forms the apoptosome, which recruits and activates procaspase-9. Caspase-9 then cleaves and activates executioner caspases-3 and 7. The DISC activating caspase-8 belongs to the extrinsic death receptor pathway, and the inflammasome activating caspase-1 mediates pyroptotic IL-1 processing rather than classical apoptosis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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