Function: Promotes apoptosis by activating caspases in the cytochrome c/Apaf-1/caspase-9 pathway. Acts by opposing the inhibitory activity of inhibitor of apoptosis proteins (IAP). Inhibits the activity of BIRC6/bruce by inhibiting its binding to caspases. Isoform 3 attenuates the stability and apoptosis-inhibiting activity of XIAP/BIRC4 by promoting XIAP/BIRC4 ubiquitination and degradation through the ubiquitin-proteasome pathway. Isoform 3 also disrupts XIAP/BIRC4 interacting with processed caspase-9 and promotes caspase-3 activation. Isoform 1 is defective in the capacity to down-regulate the XIAP/BIRC4 abundance. Ref.1 Ref.3 Ref.7
Subunit structure: Homodimer. Interacts with NGFRAP1/BEX3
By similarity. Interacts with BIRC2/c-IAP1, BIRC3/c-IAP2, XIAP/BIRC4, BIRC6/bruce and BIRC7/livin. Interacts with the monomeric and dimeric form of BIRC5/survivin. Ref.7 Ref.8 Ref.10
Subcellular location: Mitochondrion. Note: Released into the cytosol when cells undergo apoptosis. Ref.3
Tissue specificity: Ubiquitously expressed with highest expression in testis. Expression is also high in heart, liver, kidney, spleen, prostate and ovary. Low in brain, lung, thymus and peripheral blood leukocytes. Isoform 3 is ubiquitously expressed. Ref.1 Ref.3
Domain: The mature N-terminus mediates interaction with XIAP/BIRC4.
Post-translational modification: Ubiquitinated by BIRC7/livin. Ref.8
Involvement in disease: Deafness, autosomal dominant, 64 (DFNA64) [MIM:614152]: A form of non-syndromic sensorineural hearing loss. Sensorineural deafness results from damage to the neural receptors of the inner ear, the nerve pathways to the brain, or the area of the brain that receives sound information.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.13
Show more