title: Modulation of the CD95-induced apoptosis: the role of CD95 N-glycosylation.
abstract: Protein modifications of death receptor pathways play a central role in the regulation of apoptosis. It has been demonstrated that O-glycosylation of TRAIL-receptor (R) is essential for sensitivity and resistance towards TRAIL-mediated apoptosis. In this study we ask whether and how glycosylation of CD95 (Fas/APO-1), another death receptor, influences DISC formation and procaspase-8 activation at the CD95 DISC and thereby the onset of apoptosis. We concentrated on N-glycostructure since O-glycosylation of CD95 was not found. We applied different approaches to analyze the role of CD95 N-glycosylation on the signal transduction: in silico modeling of CD95 DISC, generation of CD95 glycosylation mutants (at N136 and N118), modulation of N-glycosylation by deoxymannojirimycin (DMM) and sialidase from Vibrio cholerae (VCN). We demonstrate that N-deglycosylation of CD95 does not block DISC formation and results only in the reduction of the procaspase-8 activation at the DISC. These findings are important for the better understanding of CD95 apoptosis regulation and reveal differences between apoptotic signaling pathways of the TRAIL and CD95 systems.
authors.affiliation: Division of Immunogenetics, German Cancer Research Center, Heidelberg, Germany.
authors.forename: Olga M
authors.initials: OM
authors.lastname: Shatnyeva
authors.forename: Andriy V
authors.initials: AV
authors.lastname: Kubarenko
authors.forename: Claudia E M
authors.initials: CE
authors.lastname: Weber
authors.forename: Alexander
authors.initials: A
authors.lastname: Pappa
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schwartz-Albiez
authors.forename: Alexander N R
authors.initials: AN
authors.lastname: Weber
authors.forename: Peter H
authors.initials: PH
authors.lastname: Krammer
authors.forename: Inna N
authors.initials: IN
authors.lastname: Lavrik
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D053181:Caspase 8 / Q000378:metabolism*; D002478:Cells, Cultured; D019295:Computational Biology; D053418:Death Domain Receptor Signaling Adaptor Proteins; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006031:Glycosylation; D006801:Humans; D047468:Immunoprecipitation; D008214:Lymphocytes / Q000166:cytology / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D011487:Protein Conformation; D015398:Signal Transduction; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism; D019014:fas Receptor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D053418:Death Domain Receptor Signaling Adaptor Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D019014:fas Receptor; D053181:Caspase 8