The function of BID (BH3 interacting domain death agonist, Ensembl gene identifier ENSG00000015475) is as follows. Induces caspases and apoptosis (PubMed:14583606). Counters the protective effect of BCL2 (By similarity). . [BH3-interacting domain death agonist p15]: Induces caspase activation and apoptosis (PubMed:15661737, PubMed:32029622). Translocates to mitochondria following cleavage and disrupts the outer mitochondrial membrane leading to the release of cytochrome c (PubMed:10480954, PubMed:32029622, PubMed:9727491). {ECO:0000269|PubMed:10480954, ECO:0000269|PubMed:15661737, ECO:0000269|PubMed:32029622, ECO:0000269|PubMed:9727491}. [Isoform 1]: Induces ICE-like proteases and apoptosis. . [Isoform 2]: Induces ICE-like proteases and apoptosis. . [Isoform 3]: Does not induce apoptosis. . [Isoform 4]: Induces ICE-like proteases and apoptosis. .