Inhibitor of apoptosis

Apoptosis, or programmed cell death, is a highly regulated process used by many multicellular organisms. Like any regulated process, apoptosis is subject to either activation or inhibition by a variety of chemical factors. Apoptosis can be triggered through two main pathways; extrinsic and intrinsic. The extrinsic pathway mostly involves extracellular signals triggering intracellular apoptosis mechanisms by binding to receptors in the cell membrane and sending signals from the outside of the cell. Intrinsic pathways involved internal cell signaling primarily through the mitochondria. Inhibitors of apoptosis are a group of proteins that mainly act on the intrinsic pathway that block programmed cell death, which can oftentimes lead to cancer or other effects for the cell if mutated or improperly regulated. Many of these inhibitors act to block caspases, a family of cysteine proteases that play an integral role in apoptosis. Some of these inhibitors include the Bcl-2 family, viral inhibitor crmA, and IAP's.