baculoviral IAP repeat-containing protein 1; neuronal apoptosis inhibitory protein (NAIP, BIRC1)

Function

• anti-apoptotic protein
• acts as a mediator of neuronal survival in pathological conditions
• prevents motor-neuron apoptosis induced by a variety of signals
• possible role in prevention of spinal muscular atrophy that seems to be caused by inappropriate persistence of motor-neuron apoptosis
• inhibits activities of CASP3, CASP7 & CASP9
• can inhibit the autocleavage of pro-CASP9 & cleavage of pro-CASP3 by CASP9
• capable of inhibiting CASP9 autoproteolysis at 'Asp-315' & decreasing the rate of auto proteolysis at 'Asp-330'
• acts as a sensor component of the NLRC4 inflammasome that recognizes & binds bacterial proteins
• the NLRC4 inflammasome is activated as part of the innate immune response to a range of intracellular bacteria

Structure

• contains 3 BIR repeats
• contains 1 NACHT domain
• both the BIR & NACHT domains are essential for effective inhibition of pro-CASP9 cleavage
• BIR3 domain binds to procaspase-9 & the NACHT domain interacts with the NACHT domain of APAF1 forming a bridge between pro-CASP9 & APAF1

Alternative splicing

named isoforms=2

Expression

• expressed in motor neurons
• not expressed in sensory neurons
• found in liver & placenta, & to a lesser extent in spinal cord

Pathology

• defects in NAIP are associated with childhood spinal muscular atrophy

Genetics

• NAIP gene shows lineage-specific gene duplication in the human genome relative to chimpanzee & other great apes

More general terms

• inhibitor of apoptosis protein
• evolutionary divergent human protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=4671
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:4671
• OMIM: https://mirror.omim.org/entry/600355
• UniProt: http://www.uniprot.org/uniprot/Q13075.html