Apoptosis is induced by certain cytokines including TNF and Fas ligand in the TNF family through their death domain containing receptors. TRAIL/Apo2L, a member of the TNF family, induces apoptosis of a variety of tumor cell lines. DR4 and DR5 are functional receptors for TRAIL, and DcR1/TRID is a decoy receptor. Another member of the TRAIL receptor family was identified and designated DcR2. The DcR2 receptor is 386 amino acids in length and has an extracellular TRAIL binding domain, but la