The apoptosome is composed of
Mitochondrial outer-membrane permeabilization (MOMP) releases cytochrome c into the cytosol. Cytochrome c binds Apaf-1, inducing formation of the heptameric apoptosome that recruits and activates caspase-9. Active caspase-9 then propagates the cascade by cleaving executioner caspases. MOMP is therefore the point of no return for the intrinsic apoptotic pathway. Careful
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)