Bad: Proteins and Enzymes

The Bcl-2 family of proteins consists of both inhibitors and promoters of apoptosis. The relative ratios of pro- and anti-apoptotic Bcl-2 family proteins determine the sensitivity or resistance of cells to a variety of apoptotic signals. The pro-apoptoptic Bad (Bcl-2-antagonist of cell death) heterodimerizes strongly with Bcl-x, less strongly with Bcl-2, and not at all with Bax, Bcl-xS, Mcl-1, A1, or itself. When Bad dimerizes with Bcl-xL, Bax is displaced and its apoptosis-inducing ability is restored.