AP BIOLOGY

Detailed explanation-1: -The apoptosome is a complex composed of cyt c, apoptotic protease activating factor-1 (Apaf-1), and deoxy adenosine triphosphate (dATP).

Detailed explanation-2: -Apoptosis in metazoans is executed by a group of intracellular proteases named caspases. One of the caspase-activating pathways in mammals is initiated by the release of cytochrome c from mitochondria to cytosol, where it binds to Apaf-1 to form a procaspase-9-activating heptameric protein complex named apoptosome.

Detailed explanation-3: -During cell apoptosis cytochrome c is released into the cytoplasm where it binds and activates the apoptotic protease activating factor-1 (Apaf-1) allowing its binding to ATP and the formation of the ring-like apoptosome.

Detailed explanation-4: -Once cytoplasmic, cytochrome c initiates the intrinsic pathway of apoptosis by binding to the adaptor protein APAF-1 as it triggers its oligomerization (Li et al., 1997). APAF-1 heptomer, together with cytochrome c and the cofactor dATP, forms the caspase-activating apoptosome platform (Figure 2).