title: Intracellular antibody-bound pathogens stimulate immune signaling via the Fc receptor TRIM21.
abstract: During pathogen infection, antibodies can be carried into the infected cell, where they are detected by the ubiquitously expressed cytosolic antibody receptor TRIM21. Here we found that recognition of intracellular antibodies by TRIM21 activated immune signaling. TRIM21 catalyzed the formation of Lys63 (K63)-linked ubiquitin chains and stimulated the transcription factor pathways of NF-κB, AP-1, IRF3, IRF5 and IRF7. Activation resulted in the production of proinflammatory cytokines, modulation of natural killer stress ligands and induction of an antiviral state. Intracellular antibody signaling was abrogated by genetic deletion of TRIM21 and was restored by ectopic expression of TRIM21. The sensing of antibodies by TRIM21 was stimulated after infection by DNA or RNA nonenveloped viruses or intracellular bacteria. Thus, the antibody-TRIM21 detection system provides potent, comprehensive activation of the innate immune system independently of known pattern-recognition receptors.
authors: Division of Protein and Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK. wmcewan@mrc-lmb.cam.ac.uk
authors: William A
authors: WA
authors: McEwan
authors: Jerry C H
authors: JC
authors: Tam
authors: Ruth E
authors: RE
authors: Watkinson
authors: Susanna R
authors: SR
authors: Bidgood
authors: Donna L
authors: DL
authors: Mallery
authors: Leo C
authors: LC
authors: James
mesh_terms: D000256:Adenoviridae / Q000276:immunology; D000818:Animals; D000914:Antibodies, Viral / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D000936:Antigen-Antibody Complex / Q000276:immunology / Q000378:metabolism; D001419:Bacteria / Q000276:immunology; D002460:Cell Line; D003429:Cross Reactions; D016207:Cytokines / Q000096:biosynthesis; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D050835:Interferon Regulatory Factors / Q000378:metabolism; D042541:Intracellular Space / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D062105:Molecular Docking Simulation; D016328:NF-kappa B / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D011961:Receptors, Fc / Q000378:metabolism*; D051192:Receptors, Pattern Recognition / Q000378:metabolism; D012261:Ribonucleoproteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014780:Viruses / Q000276:immunology*; D000099207:SS-A Antigen
chemical_list: D000914:Antibodies, Viral; D000936:Antigen-Antibody Complex; D016207:Cytokines; D018836:Inflammation Mediators; D050835:Interferon Regulatory Factors; D016328:NF-kappa B; D011961:Receptors, Fc; D051192:Receptors, Pattern Recognition; D012261:Ribonucleoproteins; D018808:Transcription Factor AP-1; D000099207:SS-A Antigen