Baculoviral IAP repeat-containing protein

Function

• Baculoviral IAP repeat-containing protein 1 (BIRC1 or NAIP) inhibits the activities of caspase-3,7,9. BIRC1 acts as mediator of neuronal survival in pathological conditions and prevents motor-neuron apoptosis.
  
• Baculoviral IAP repeat-containing protein 2 (cIAP1) and Baculoviral IAP repeat-containing protein 3 (cIAP2) inhibit apoptosis by interfering with the activation of caspase and by binding to TNFR-associated factors TRAF1 and TRAF2. cIAP1 is a multi-functional protein which acts as an E3 ubiquitin-protein ligase and plays a role in the modulation of the cell cycle. cIAP1 is involved in controlling b-cell survival under ER stress caused by lipotoxicity. Both cIAP1 and cIAP2 regulate NF-kB activation. cIAP2 inhibits apoptosis caused by serum deprivation but not by inducers of free radicals.
  
• For Baculoviral IAP repeat-containing protein 4 see XIAP in Ubiquitin protein ligase.
  
• Baculoviral IAP repeat-containing protein 6 (BIRC6) inhibits caspase-3,7,9. Has a role in the final stages of cytokinesis, vescilcle targeting to the site of abscission and ubiquitin conjugation.
  
• Baculoviral IAP repeat-containing protein 7 or melanoma inhibitor of apoptosis (ML-IAP) contains one BIR and one RING domain. ML-IAP has 2 isoforms. Isoform-a protects cells from staurosporine-induced apoptosis and isoform-b protects cells from etoposide-induced apoptpsis.
  
• Baculoviral IAP repeat-containing protein 8 (BIRC8).
  

Disease

cIAP1 is a target for intervention against type 2 diabetes. Mutated or deleted BIRC1 were found in individuals with severe muscular atrophy.

Relevance

IAP proteins suppress cell death by inhibiting the activity of caspases.

Structural highlights

cIAPs domains include 3 BIR (zinc-finger found in apoptosis inhibitors) domains in the N-terminal, a UBA (Ubiquitin-Associated), CARD (Caspase Recruitment) and RING finger (zinc finger which contains Cys3-His-Cys4 motif) domain in the C-terminal.