Inhibitor of apoptosis
|This article does not cite any references or sources. (March 2007)|
The Inhibitors of Apoptosis (IAP) are a family of functionally and structurally related proteins, which serve as endogenous inhibitors of programmed cell death (apoptosis). A common feature of all IAPs is the presence of a BIR (Baculovirus IAP Repeat, a ~70 amino acid domain) in one to three copies. The human IAP family consists of 8 members, and IAP homologs have been identified in numerous organisms.
The first members of the IAPs identified were from the baculovirus IAPs, Cp-IAP and Op-IAP, which bind to and inhibit caspases as a mechanism that contributes to its efficient infection and replication cycle in the host. Later, five more human IAPs were discovered which included XIAP, c-IAPl, C-IAP2, NAIP, Livin and Survivin.
The best characterized IAP is XIAP, which binds caspase-9, caspase-3 and caspase-7, thereby inhibiting their activation and preventing apoptosis. Also cIAP1 and cIAP2 have been shown to bind caspases, although how the IAPs inhibit apoptosis mechanistically at the molecular level is not completely understood.
- The MEROPS online database for peptidases and their inhibitors: I32.002
- Inhibitor of Apoptosis Proteins at the US National Library of Medicine Medical Subject Headings (MeSH)