What is the role of the caspases in apoptosis?

Apoptosis is a highly complex process form of programmed cell death that involves a number of different proteins. Caspases are the key enzymes that initiate and facilitate this process.  

Caspases are a family of protease enzymes. The two main caspases that serve as primary mediators of apoptosis are the initiator caspases and the executioner caspases. The initiator caspases provide the cues that initiate the process. On receiving the signal, the executioner caspases carry out the mass proteolysis that results in the cellular death. 

Caspases remain inactive in normal, healthy cells. They only get activated when an abnormal cell is detected or during the development phase in which cells are programmed to commit suicide. When activated, caspases initiate cell death by cutting up specific proteins within the cytoplasm and nucleus. This is done in a controlled manner with minimal impact to the surrounding tissues.