Induces caspases and apoptosis (PubMed:14583606). Counters the protective effect of BCL2 (By similarity). Induces caspase activation and apoptosis (PubMed:15661737, PubMed:32029622). Allows the release of cytochrome c (PubMed:32029622). Induces ICE-like proteases and apoptosis. Induces ICE-like proteases and apoptosis. Does not induce apoptosis. Induces ICE-like proteases and apoptosis. Forms heterodimers either with the pro-apoptotic protein BAX or the anti-apoptotic protein BCL2 (By similarity). Interacts with PLEKHN1 (PubMed:29531808). Interacts with humanin; forms fibers with humanin which results in BID conformational changes and sequestering of BID into the fibers, preventing BID activation. Interacts with ITCH (PubMed:20392206). Interacts with humanin; the interaction prevents BID-induced apoptosis (PubMed:15661737). Interacts with MTCH2 (By similarity). When uncleaved, it is predominantly cytoplasmic. Translocates to mitochondria as an integral membrane protein. Associated with the mitochondrial membrane. A significant proportion of isoform 2 localizes to mitochondria, it may be cleaved constitutively. Expressed in spleen, pancreas and placenta (at protein level). Expressed in lung, pancreas and spleen (at protein level). Expressed in lung and pancreas (at protein level). Intact BH3 motif is required by BIK, BID, BAK, BAD and BAX for their pro-apoptotic activity and for their interaction with anti-apoptotic members of the Bcl-2 family. TNF-alpha induces caspase-mediated cleavage into a major p15 and minor p13 and p11 products (By similarity). Cleaved by CASP6 into a major p15 and minor p13 products, leading to release of cytochrome c and subsequent nonalcoholic steatohepatitis (PubMed:32029622). Ubiquitinated by ITCH; ubiquitination results in proteasome-dependent degradation.