Multimeric protein complexes formed in the cytosol that play a role in the activation of apoptosis. They can occur when mitochondria become damaged due to cell stress and release CYTOCHROME C. Cytosolic cytochrome C associates with apoptotic protease-activating factor 1 to form the apoptosomal protein complex. The apoptosome signals apoptosis by binding to and activating specific INITIATOR caspases such as caspase 9.