title: The requirements for Fas-associated death domain signaling in mature T cell activation and survival.
abstract: Fas-associated death domain (FADD) is a death domain containing cytoplasmic adapter molecule required for the induction of apoptosis by death receptors. Paradoxically, FADD also plays a crucial role in the development and proliferation of T cells. Using T cells from mice expressing a dominant negative form of FADD (FADDdd), activation with anti-TCR Ab and costimulation or exogenous cytokines is profoundly diminished. This is also seen in wild-type primary T cells transduced with the same transgene, demonstrating that FADD signaling is required in normally differentiated T cells. The defective proliferation does not appear to be related to the early events associated with TCR stimulation. Rather, with a block in FADD signaling, stimulated T cells exhibit a high rate of cell death corresponding to the initiation of cell division. Although CD4 T cells exhibit a moderate deficiency, this effect is most profound in CD8 T cells. In vivo, the extent of this defective accumulation is most apparent; lymphocytic choriomenigitis virus-infected FADDdd-expressing mice completely fail to mount an Ag-specific response. These results show that, in a highly regulated fashion, FADD, and most likely caspases, can transduce either a signal for survival or one that leads directly to apoptosis and that the balance between these opposing outcomes is crucial to adaptive immunity.
authors.affiliation: Molecular Biology Section, Division of Biological Sciences, University of California, San Diego, CA 92093, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Beisner
authors.forename: Isaac H
authors.initials: IH
authors.lastname: Chu
authors.forename: Adrian F
authors.initials: AF
authors.lastname: Arechiga
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Hedrick
authors.forename: Craig M
authors.initials: CM
authors.lastname: Walsh
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology*; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000821:virology; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D016923:Cell Death / Q000235:genetics / Q000276:immunology; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D002470:Cell Survival / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000276:immunology; D053200:Fas-Associated Death Domain Protein; D006801:Humans; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology*; D008216:Lymphocytic Choriomeningitis / Q000235:genetics / Q000276:immunology / Q000473:pathology / Q000821:virology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D012190:Retroviridae / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D014161:Transduction, Genetic; D019076:Transgenes / Q000276:immunology; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology; D019014:fas Receptor / Q000235:genetics / Q000502:physiology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018984:Epitopes, T-Lymphocyte; C505533:FADD protein, human; C505534:Fadd protein, mouse; D053200:Fas-Associated Death Domain Protein; D019014:fas Receptor