title: Potentiation of Fas-mediated apoptosis by an engineered glycosylphosphatidylinositol-linked Fas.
abstract: FasL and TRAIL are apoptotic ligands of the TNF-like cytokines family, acting via activation of the transmembrane death domain containing receptors Fas for FasL, and DR4 or DR5 for TRAIL. A glycosylphosphatidylinositol-linked TRAIL receptor called DcR1 behaves as a decoy receptor inhibiting TRAIL-mediated cell death in several cellular systems. We engineered and stably expressed a chimeric GPI-linked Fas receptor (Fas-GPI) in T-lymphocyte cell lines constitutively expressing functional transmembrane Fas. Surprisingly, despite lacking the death domain region of functional Fas, Fas-GPI was able to significantly increase Fas-mediated cell death triggered by membrane bound or soluble FasL, whereas engagement of Fas-GPI alone did not trigger apoptosis. This potentiating effect, but not transmembrane Fas activation, was selectively inhibited by protein kinase C activation with phorbol esters, demonstrating that Fas-GPI activated a specific synergistic signal transduction pathway. Fas-GPI and transmembrane Fas were localized in distinct membrane compartments, since Fas-GPI, but not transmembrane Fas, was found in the glycolipid-rich membrane microdomains. These results suggest that apoptosis induced by members of this ligand/receptors family may be differentially modulated through other and parallel signalling pathways.
authors.affiliation: Laboratoire d'Immunologie, CNRS UMR 5540, Université de Bordeaux 2, bâtiment 1b, 146 rue Léo-Saignat, 33076 Bordeaux, France.
authors.forename: P
authors.initials: P
authors.lastname: Legembre
authors.forename: P
authors.initials: P
authors.lastname: Moreau
authors.forename: S
authors.initials: S
authors.lastname: Daburon
authors.forename: J-F
authors.initials: JF
authors.lastname: Moreau
authors.forename: J-L
authors.initials: JL
authors.lastname: Taupin
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects; D053222:Fas Ligand Protein; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D008562:Membrane Glycoproteins / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism; D051379:Mice; D015202:Protein Engineering; D011493:Protein Kinase C / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D019014:fas Receptor / Q000502:physiology*
chemical_list: C505661:FASLG protein, human; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D017261:Glycosylphosphatidylinositols; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D019014:fas Receptor; D011493:Protein Kinase C; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; C505409:Casp3 protein, mouse; C505526:Casp8 protein, mouse; C506434:Casp9 protein, mouse; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D013755:Tetradecanoylphorbol Acetate