In vertebrates, caspase ware the initiator and effector molecules (enzymes) of apoptosis; and

A、death signal the Fas ligands bind to their Fas receptors, leading to dimerization and activation of the death receptor, which initiate the “cell Murder” apoptosis;

B、the effector “destruction” caspases are activated by dimerization with each of the subunit to stabilizing the active sit of the other;

C、“destruction” caspases can cleave one and another including the initiator caspases;

D、caspase8 and caspase9 are the initiator “killer” protein respectively in the immune system and in the others