Death domain-containing protein CRADD, also known as Caspase and RIP adapter with death domain, RIP-associated protein with a death domain, CRADD and RAIDD, is a protein which is constitutively expressed in most tissues, with particularly high expression in adult heart, testis, liver, skeletal muscle, fetal liver and kidney. CRADD / RAIDD contains oneCARD domain and onedeath domain. CRADD / RAIDD contains a death domain involved in the binding of RIP protein. The CARD domain mediates the interaction with caspase-2. FADD / MORT1 is a death domain (DD)-containing adaptor / signaling molecule that interacts with the intracellular DD of FAS / APO-I ( CD95 ) and tumor necrosis factor receptor 1 and the prodomain of caspase-8 ( Mch5 / MACH / FLICE). CRADD / RAIDD has a dual-domain structure similar to that of FADD. CRADD / RAIDD has an NH2-terminal caspase homology domain that interacts with caspase-2 and a COOH-terminal DD that interacts with RIP. CRADD / RAIDD could play a role in regulating apoptosis in mammalian cells. CRADD / RAIDD is a apoptotic adaptor molecule specific for caspase-2 and FASL / TNF receptor-interacting protein RIP. In the presence of RIP and TRADD, CRADD / RAIDD recruits caspase-2 to the TNFR-1 signalling complex.