In humans, the BH3-only subgroup consists of seven well-characterized proteins (for BID see Nomenclature). Contrary to cellular BCL-2 homologous proteins, these classical BH3-only proteins are evolutionarily unrelated to each other (i.e., they have not arisen from a common ancestor by gene duplication). In invertebrate species, there is only one well-characterized BH3-only protein: EGL-1 (encoded by the C. elegans genome).

Gene nameProtein nameSynonymsPrimary functionBCL2DB acc.Reference
BCL2L11BimBcl2l11, BodpromoterO43521O'Connor et al., 1998
BBC3PumaBbc3promoterQ9BXH1Han et al., 2001
BADBadBcl2l8, Bbc2promoterQ92934Yang et al., 1995
BIKBikNbk, BlkpromoterQ13323Boyd et al., 1995
BMFBmf-promoterQ96LC9Puthalakath et al., 2001
egl-1Egl-1-promoterO61667Conradt et al., 1998
HRKHrkDp5promoterO00198Inohara et al., 1997
PMAIP1NoxaApr, Pmaip1promoterQ13794Oda et al., 2000