Abstract
The molecular regulation of the recruitment of initial signaling complexes at the TNF-R1 is poorly defined. We demonstrate here that within minutes internalized TNF-R1 (TNF receptosomes) recruits TRADD, FADD, and caspase-8 to establish the "death-inducing signaling complex" (DISC). In addition, we identified the TNF-R1 internalization domain (TRID) required for receptor endocytosis and provide evidence that TNF-R1 internalization, DISC formation, and apoptosis are inseparable events. Analyzing cell lines expressing an internalization-deficient receptor (TNF-R1 DeltaTRID) revealed that recruitment of RIP-1 and TRAF-2 to TNF-R1 occurred at the level of the plasma membrane. In contrast, aggregation of TRADD, FADD, and caspase-8 to establish the TNF-R1-associated DISC is critically dependent on receptor endocytosis. Furthermore, fusion of TNF receptosomes with trans-Golgi vesicles results in activation of acid sphingomyelinase and cathepsin D. Thus, TNF receptosomes establish the different TNF signaling pathways by compartmentalization of plasma membrane-derived endocytic vesicles harboring the TNF-R1-associated DISC.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Animals
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Antigens, CD / metabolism*
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Apoptosis / physiology*
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Carrier Proteins / metabolism
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Caspase 8
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Caspases / metabolism
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Cell Membrane / physiology
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Cell Membrane / ultrastructure
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Death Domain Receptor Signaling Adaptor Proteins
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Endocytosis / physiology
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Endosomes / physiology*
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Endosomes / ultrastructure
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Fas-Associated Death Domain Protein
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Fluorescent Antibody Technique
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GPI-Linked Proteins
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Golgi Apparatus / physiology
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Golgi Apparatus / ultrastructure
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HeLa Cells
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Humans
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Mice
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Microscopy, Electron
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NIH 3T3 Cells
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Precipitin Tests
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Proteins / metabolism
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Receptors, Tumor Necrosis Factor / metabolism*
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Receptors, Tumor Necrosis Factor / ultrastructure
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Receptors, Tumor Necrosis Factor, Member 10c
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Receptors, Tumor Necrosis Factor, Type I
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Signal Transduction / physiology*
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TNF Receptor-Associated Death Domain Protein
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TNF Receptor-Associated Factor 1
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Tumor Necrosis Factor Decoy Receptors
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Tumor Necrosis Factor Receptor-Associated Peptides and Proteins*
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U937 Cells
Substances
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Adaptor Proteins, Signal Transducing
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Antigens, CD
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Carrier Proteins
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Death Domain Receptor Signaling Adaptor Proteins
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FADD protein, human
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Fadd protein, mouse
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Fas-Associated Death Domain Protein
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GPI-Linked Proteins
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Proteins
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Receptors, Tumor Necrosis Factor
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Receptors, Tumor Necrosis Factor, Member 10c
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Receptors, Tumor Necrosis Factor, Type I
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TNF Receptor-Associated Death Domain Protein
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TNF Receptor-Associated Factor 1
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TNFRSF10C protein, human
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Tradd protein, mouse
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Tumor Necrosis Factor Decoy Receptors
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Tumor Necrosis Factor Receptor-Associated Peptides and Proteins
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CASP8 protein, human
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Casp8 protein, mouse
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Caspase 8
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Caspases