Caspase family of cysteine proteases has been shown to play a key role in apoptosis. Caspase-8 is a 55 kDa cytosolic protein that is synthesized as an inactive pro-enzyme. Activation of caspase-8 involves a two-step proteolysis: the cleavage of caspase-8 to generate a 43 and a 12 kDa fragment which is further processed to 10 kDa. The p43 is then cleaved to yield p26 and the release of the active site containing p18.