Phosphorylation of the tumor necrosis factor receptor CD120a (p55) recruits Bcl-2 and protects against apoptosis.
Ligation of the tumor necrosis factor alpha receptor CD120a initiates responses as diverse as apoptosis and the expression of NF-kappaB-dependent pro-survival genes. How these opposing responses are controlled remains poorly understood. Here we demonstrate that phosphorylation by p42(mapk/erk2) inhibits the apoptotic activity of CD120a while preserving its ability to activate NF-kappaB. Phosphorylated CD120a is re-localized from the Golgi complex to tubular structures of the endoplasmic reticulum wherein it recruits Bcl-2. Antisense-mediated down-regulation of Bcl-2 antagonized the localization of CD120a to tubular structures and reversed the protection from apoptosis conferred by receptor phosphorylation. We propose that phosphorylation of CD120a represents a novel, Bcl-2-dependent mechanism by which the apoptotic activity of the receptor may be regulated. Thus, oncogenic activation of p42(mapk/erk2) may serve to inhibit the apoptotic activity of this death receptor while preserving NF-kappaB-dependent responses and may thus indirectly contribute to a failure to eliminate cells bearing oncogenes of the Ras-Raf-MEK-p42(mapk/erk2) pathway.
Cottin
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Program in Cell Biology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, Colorado 80206, USA.
Van Linden
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Riches
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DW
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002352:Carrier Proteins / Q000378:metabolism; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival; D053200:Fas-Associated Death Domain Protein; D017930:Genes, Reporter; D019254:Genes, bcl-2; D006056:Golgi Apparatus / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D020287:In Situ Nick-End Labeling; D047908:Intracellular Signaling Peptides and Proteins; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D021381:Protein Transport; D011506:Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D011994:Recombinant Proteins / Q000378:metabolism; D047990:TNF Receptor-Associated Factor 1; D047992:TNF Receptor-Associated Factor 2; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D002352:Carrier Proteins; C505533:FADD protein, human; D053200:Fas-Associated Death Domain Protein; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D011994:Recombinant Proteins; D047990:TNF Receptor-Associated Factor 1; D047992:TNF Receptor-Associated Factor 2; D014409:Tumor Necrosis Factor-alpha; D019950:Mitogen-Activated Protein Kinase 1; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases