Cell death via apoptosis is a basic cellular function occurring through the cell death receptor family and their ligands which signal through downstream adaptor molecules and the caspase protease family. Caspases have a precursor form composed of a prodomain, and large and small catalytic subunit, and are activated through a cleavage adjacent to an aspartate to liberate units and allow formation of an a2b2 tetramer. Caspase 3 is a cytoplasmic caspase with two isoforms (one acts as a dominant negative inhibitor), and is involved in the activation cascade for apoptosis execution.
