Two converging apoptotic pathways, which are initiated either through the activation of death domain (DD) receptors by an extrinsic pathway or by an intrinsic pathway in the mitochondria, mediate the activation and progression of apoptosis within the cell. Both these pathways lead to the activation of the Serine proteinase cascade (caspases) and to cleavage of these pro-caspases. A novel protein, BAR, for bifunctional apoptosis regulator, contains domains that enable it to interact with components of both major apoptosis pathways, where it negatively regulates apoptotic signaling. Like the other anti-apoptosis proteins Bap31 and FLIP, BAR contains a DED-like domain that is capable of suppressing apoptosis mediated at the receptor level. In addition, BAR contains a domain that also enables it to interact with the mitochondrial Bcl-2 family of proteins. The presence of these various RING, SAM, DED and TM domains suggests that BAR may serve as a scaffold protein that integrates signaling components of the cells apoptosis-regulatory machinery.