BIRC7 is a part of the inhibitor of apoptosis protein （IAP） family and contains a single copy of a baculovirus IAP repeat （BIR） as well as a RING-type zinc finger domain. The BIR domain is necessary for inhibitory activity & cooperates with caspases， while the RING finger domain sometimes increases anti-apoptotic activity but doesn’t inhibit apoptosis by itself. 2 transcript variants encoding diverse isoforms have been found for this gene. The 2 isoforms have dissimilar antiapoptotic characteristics， with isoform a protecting cells from apoptosis induced by staurosporine and isoform b defending cells from apoptosis induced by etoposide.
BIRC7 has direct contact with several caspases together with caspase-3， caspase-7， & caspase –9. BIRC7 inhibits the activation of caspase-9 induced by Apaf-1， cytochrome c， and dATP.
