Apoptosis, or programmed cell death, occurs during normal cellular differentiation and development of multicellular organisms. Apoptosis is induced by certain cytokines including TNF and Fas ligand in the TNF family through their death domain containing receptors, TNFR1 and Fas. A novel death domain containing receptor was recently identified and designated DR6 (for death receptor 6) (1). The extracellular domain of DR6 contains four TNFR-like cysteine rich motifs that are related to those of osteoprotegerin (OPG) (2) and TNFR2 (3) with 36% and 42% amino acid identities, respectively. The death domain of DR6 (amino acids 428-494) located adjacent to the transmembrane domain is most related to TNFR1 (27.2%) and least to DR5 (19.7%) (1).
1. Pan, G., Bauer, J.H., Haridas, V., Wang, S., Liu, D., Yu, G., Vincenz, C., Aggarwal, B., Ni, J. and Dixit, V.M. FEBS Lett. 431: 351-356 (1998).
2. Simonet WS, Lacey DL, Dunstan CR, Kelley M. et al. Cell 89: 309-310 (1997).
3. Baker, S.J. and Reddy, E.P. Oncogene 12: 1-9 (1996).