Modifications and intracellular trafficking of FADD/MORT1 and caspase-8 after stimulation of T lymphocytes.
The adaptor protein FADD/MORT1 is essential for apoptosis induced by 'death receptors', such as Fas (APO-1/CD95), mediating aggregation and autocatalytic activation of caspase-8. Perhaps surprisingly, FADD and caspase-8 are also critical for mitogen-induced proliferation of T lymphocytes. We generated novel monoclonal antibodies specific for mouse FADD and caspase-8 to investigate whether cellular responses, apoptosis or proliferation, might be explained by differences in post-translational modification and subcellular localisation of these proteins. During both apoptosis signalling and mitogenic activation, FADD and caspase-8 aggregated in multiprotein complexes and formed caps at the plasma membrane but they did not colocalise with lipid rafts. Interestingly, mitogenic stimulation, but not Fas ligation, induced a unique post-translational modification of FADD. These different modifications may determine whether FADD and caspase-8 induce cell death or proliferation.
O'Reilly
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The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
Divisekera
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Newton
K
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Scalzo
K
K
Kataoka
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T
Puthalakath
H
H
Ito
M
M
Huang
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Strasser
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A
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D017209:Apoptosis; D015153:Blotting, Western; D053181:Caspase 8; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D002460:Cell Line; D002478:Cells, Cultured; D000939:Epitopes; D053200:Fas-Associated Death Domain Protein; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D006825:Hybridomas / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008856:Microscopy, Fluorescence; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology; D013601:T-Lymphocytes / Q000378:metabolism*; D019014:fas Receptor / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; D000939:Epitopes; C505533:FADD protein, human; C505534:Fadd protein, mouse; C505535:Fadd protein, rat; D053200:Fas-Associated Death Domain Protein; D011993:Recombinant Fusion Proteins; D019014:fas Receptor; D005982:Glutathione Transferase; C505530:CASP8 protein, human; C505526:Casp8 protein, mouse; C505528:Casp8 protein, rat; D053181:Caspase 8; D020169:Caspases