– Death Domain-Containing Protein CRADD (CRADD) is widely expressed in most tissues, with particularly high expression in the adult heart, testis, liver, skeletal muscle, fetal liver, and kidney. CRADD contains one CARD domain that mediates the interaction with caspase-2, and one death domain involved in the binding of RIP protein. CRADD functions as an apoptotic adaptor molecule specific for caspase-2 and FASL/TNF receptor-interacting protein RIP. CRADD induces cell apoptosis/cell death in numerous tissues. Defects in CRADD will result in mental retardation.