Cysteine-dependent aspartate-specific proteases, shortened to caspases, are proteases that break down specific cellular proteins and induce apoptosis. The cysteine residue located in the caspase active site cleaves the peptide bond of the target protein after aspartic acid present at the primary specificity site, or P1 position, in the specific amino acid sequence. There are two types of apoptotic caspases—initiator caspases and executioner or effector caspases. Both types of caspases are synthesized as procaspases, the inactive precursors. Each initiator monomer contains a catalytic domain with large and small subunits and an adaptor-binding domain. Death signals bring the initiator procaspases close to each other, causing dimerization. The dimerization induces interchain cleavage resulting in the activation of the initiator caspase. The initiator caspases activate the dimeric effector procaspases by splitting them at the linker region. The effector caspases then target different cellular proteins, such as cytoskeletal proteins, which eventually results in apoptosis.