Apoptosis is induced by certain cytokines including TNF and Fas ligand in the TNF family through their death domain containing receptors. Several novel members in the TNFR family including DR3, DR4, DR5, and DR6 were recently discovered and function as cell death receptors. Two decoy receptors, DcR1 and DcR2, were recently identified to compete with DR4 and DR5 for their ligand TRAIL binding. A novel decoy receptor was more recently discovered and designated DcR3 and TR6, respectively,. Unlike DcR1 and DcR2, DcR3 is a soluble rather than a membrane associated molecule. DcR3 binds to FasL and LIGHT and inhibits FasL and LIGHT induced apoptosis. DcR3 transcript is expressed in a number of lung and colon carcinomas and in some normal tissues.
