CYCS and Reoviridae infectious disease: In addition, following reovirus infection, the mitochondrial pro-apoptotic proteins cytochrome c and second mitochondrion-derived activator of caspase (Smac/DIABLO) are released, without disturbance of the mitochondrial membrane potential or release of apoptosis-inducing factor (AIF), and eventually activate downstream effector caspases with or without caspase-9 (caspase-9 is activated by cytochrome c but has been shown to be dispensable in the mitochondrial-associated pathway) (48, 51).