Invertebrate and mammalian BCL-2 family proteins. Core conserved, multi-BH motif-containing members of the BCL-2 family often exhibit both anti- and pro-death activities depending on the circumstances (see text). Conserved caspase cleavage sites (vertical white lines), BH (BCL-2 homology) motifs, C-terminal transmembrane domain (tm), color key in consensus map, light gray boxes mark position of helix 1 but lacks amino acid homology to BH4. BID lacks significant overall amino acid sequence similarity, but retains the BCL-2 helical bundle structure.