Description
Baculoviral IAP repeat-containing protein 2, also known as Inhibitor of apoptosis protein 2, HIAP2, c-IAP1, RING finger protein 48, and BIRC2, is a member of the IAP family. The inhibitor of apoptosis (IAP) proteins are a family of anti-apoptotic regulators found in viruses and metazoans. The UBA (ubiquitin-associated) domain of IAPs is located between the BIR (baculovirus IAP repeat) domains and the CARD (caspase activation and recruitment domain) or the RING (really interesting new gene) domain of c-IAP1 and c-IAP2 or XIAP (X-linked IAP) respectively. c-IAP1 contains three BIR repeats, one CARD domain and one RING-type zinc finger. c-IAP1 and c-IAP2 are recruited to tumor necrosis factor receptor 1 (TNFR1) associated complexes where they can regulate receptor-mediated signaling. Both c-IAP1 and c-IAP2 have been implicated in TNFalpha-stimulated NF-kappaB activation. Treatment of cells with IAP antagonists leads to proteasomal degradation of c-IAP1 and c-IAP2. Deletion or mutation of the UBA domain decreases this degradation, probably by diminishing the interaction of the c-IAPs with the proteasome. Ubiquitin binding may be an important mechanism for rapid turnover of auto-ubiquitinated c-IAP1 and c-IAP2