Apoptosis inhibitor 2 (API2) is a member of a family of proteins that inhibits apoptosis by binding to tumor necrosis factor receptor-associated factors TRAF1 and TRAF2, probably by interfering with activation of ICE-like proteases. API2 inhibits apoptosis induced by serum deprivation but does not affect apoptosis resulting from exposure to menadione, a potent inducer of free radicals. The amino acid sequence predicts three baculovirus IAP repeat domains and a ring finger domain. The names of API1 and API2 have been confusing. Suffice it to say that 'apoptosis inhibitor 2' is hiap-1 (inhibitor of apoptosis 1).Synonyms: API2, Apoptosis inhibitor 2, Baculoviral IAP repeat-containing protein 3, C-IAP2, HIAP-1, IAP homolog C, Inhibitor of apoptosis protein 1, MIHC, RING finger protein 49, RNF49, TNFR2-TRAF-signaling complex protein 1, cIAP2