The mitochondrial protein BCL-2 family are critical in apoptosis. They are structurally related and can be classified as a functional and structural. Can be subdivided into multidomain proapoptotic proteins (such as BAX and BAK), multidomain antiapoptotic proteins (such as BCL-2), and BH3-only proteins (such as BID or BIM). All these lead to the regulated permeability of the mitochondrial outer membrane with release of cytochrome c and activation of effector caspases. They may also have other functions in other subcellular compartments. (more...)