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Background
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Apoptosis, or programmed cell death, occurs during normal cellular differentiation and development of multicellular organism. It is induced by certain cytokines including TNF and Fas ligand in the TNF family through their death domain containing receptors. TRAIL/Apo2L is a new member of the TNF family which is expressed in a variety of human tissues. Similar to TNF and Fas ligand, TRAIL induces apoptosis and NF-?oB activation in many tissues and cells. Its receptors include the death domain containing proteins DR4 and DR5, both of which mediate TRAIL induced cell death. Two decoy receptors, DcR1 and DcR2, have also been identified. Both of these proteins contain an extracellular TRAIL binding domain but lack intracellular signaling domains. Overexpression of either DcR1 or DcR2 attenuates TRAIL-induced apoptosis.
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