title: FADD is required for DR4- and DR5-mediated apoptosis: lack of trail-induced apoptosis in FADD-deficient mouse embryonic fibroblasts.
abstract: TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is a member of the tumor necrosis factor family that can kill a wide variety of tumor cells but not normal cells. TRAIL-induced apoptosis in humans is mediated by its receptors DR4 (TRAIL-R1) and DR5 (TRAIL-R2). What constitutes the signaling molecules downstream of these receptors, however, remains highly controversial. Using the FADD dominant negative molecule, several groups have reached different conclusions with respect to the role of FADD in TRAIL-induced apoptosis. More recently, using FADD-deficient (-/-) mouse embryonic fibroblasts, Yeh et al. (Yeh, W.-C., Pompa, J. L., McCurrach, M. E., Shu, H.-B., Elia, A. J., Shahinian, A., Ng, M., Wakeham, A., Khoo, W., Mitchell, K., El-Deiry, W. S., Lowe, S. W., Goeddel, D. V., and Mak, T. W. (1998) Science 279, 1954-1958) concluded that DR4 utilizes a FADD-independent apoptotic pathway. The latter experiment, however, involved transient overexpression, which often leads to nonspecific aggregation of death domain-containing receptors. To address this issue in a more physiological setting, we stably transfected mouse DR4/5, human DR4, or human DR5 into FADD(-/-) mouse embryonic fibroblast cells. We showed that FADD(-/-) MEF cells stably transfected with TRAIL receptors are resistant to TRAIL-mediated cell death. In contrast, TRAIL receptors stably transfected into heterozygous FADD(+/-) cells or FADD(-/-) cells reconstituted with a FADD retroviral construct are sensitive to the TRAIL cytotoxic effect. We conclude that FADD is required for DR4- and DR5-mediated apoptosis.
authors.affiliation: Department of Molecular and Cell Biology, Cancer Research Laboratory and Division of Immunology, University of California, Berkeley 94720-3200, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Kuang
authors.forename: G E
authors.initials: GE
authors.lastname: Diehl
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: A
authors.initials: A
authors.lastname: Winoto
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D015153:Blotting, Western; D002352:Carrier Proteins / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D020224:Expressed Sequence Tags; D053200:Fas-Associated Death Domain Protein; D005347:Fibroblasts / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D008562:Membrane Glycoproteins / Q000494:pharmacology; D051379:Mice; D016133:Polymerase Chain Reaction; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction; D053221:TNF-Related Apoptosis-Inducing Ligand; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D017304:Annexin A5; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; C505533:FADD protein, human; C505534:Fadd protein, mouse; D053200:Fas-Associated Death Domain Protein; D008562:Membrane Glycoproteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505639:TNFRSF10B protein, human; C505653:TNFSF10 protein, human; C505640:Tnfrsf10b protein, mouse; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha