Apoptosis Inhibitor

Apoptosis inhibitors are a family of proteins that prevent programmed cell death, primarily by interfering with the intrinsic pathway of apoptosis. They mainly function by blocking the activity of caspases. Dysregulation or mutation can lead to diseases such as cancer, where cells evade normal death signals and continue to survive abnormally. The Inhibitor of Apoptosis Proteins (IAPs) are a prominent family, including NAIP, cIAP1, cIAP2, XIAP, Survivin, Bruce/Apollon, ML-IAP/Livin and ILP-2. These proteins contain BIR domains and often RING finger domains, conferring E3 ubiquitin ligase activity. IAPs directly bind and inhibit caspases, especially caspase-9, caspase-3, and caspase-7, blocking the execution phase of apoptosis. They also act as E3 ubiquitin ligases, regulating protein degradation and non-degradative signaling pathways, such as NF-kB and MAPK. Overexpression or dysregulation contributes to cancer by enabling tumor cells to evade immune destruction or resist chemotherapy-induced cell death. Small molecule antagonists called Smac-mimetics are being developed to restore apoptotic sensitivity in tumor cells.

Other names

Inhibitor of Apoptosis ProteinsIAP familyCell Death Inhibitor

Caspase inhibition; E3 ubiquitin ligase activity modulation of cellular signaling pathways.