During the execution phase of intrinsic apoptosis, BAX and BAK oligomerize in the mitochondrial outer membrane to form pores. This leads to release of cytochrome c into the cytoplasm where it binds APAF-1 and procaspase-9 to form the:

• A Death-inducing signaling complex (DISC) activating caspase-8
• B Apoptosome, which activates caspase-9 to cleave and activate effector caspases 3 and 7 ✓
• C Necrosome complex activating MLKL-driven necroptosis
• D Inflammasome activating caspase-1 and IL-1β maturation

Explanation

Cytochrome c released from mitochondria binds APAF-1 (apoptosis protease activating factor 1) and ATP to form the heptameric apoptosome; this complex recruits and activates procaspase-9, which in turn cleaves and activates effector caspases 3, 6, and 7 to execute cell death. The DISC is formed by death receptors (extrinsic pathway), activating caspase-8. The necrosome (RIPK1/RIPK3) drives necroptosis, and the inflammasome activates caspase-1.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.