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Li M, Yu Y. Innate immune receptor clustering and its role in immune regulation. J Cell Sci 2021; 134:134/4/jcs249318. [PMID: 33597156 DOI: 10.1242/jcs.249318] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The discovery of receptor clustering in the activation of adaptive immune cells has revolutionized our understanding of the physical basis of immune signal transduction. In contrast to the extensive studies of adaptive immune cells, particularly T cells, there is a lesser, but emerging, recognition that the formation of receptor clusters is also a key regulatory mechanism in host-pathogen interactions. Many kinds of innate immune receptors have been found to assemble into nano- or micro-sized domains on the surfaces of cells. The clusters formed between diverse categories of innate immune receptors function as a multi-component apparatus for pathogen detection and immune response regulation. Here, we highlight these pioneering efforts and the outstanding questions that remain to be answered regarding this largely under-explored research topic. We provide a critical analysis of the current literature on the clustering of innate immune receptors. Our emphasis is on studies that draw connections between the phenomenon of receptor clustering and its functional role in innate immune regulation.
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Affiliation(s)
- Miao Li
- Department of Chemistry, Indiana University, Bloomington, IN 47401, USA
| | - Yan Yu
- Department of Chemistry, Indiana University, Bloomington, IN 47401, USA
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Portman MA, Navarro SL, Bruce ME, Lampe JW. Soy isoflavone intake is associated with risk of Kawasaki disease. Nutr Res 2016; 36:827-34. [PMID: 27440537 PMCID: PMC4987172 DOI: 10.1016/j.nutres.2016.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/30/2016] [Accepted: 04/07/2016] [Indexed: 01/31/2023]
Abstract
Kawasaki disease (KD) is an acute vasculitis affecting children. Incidence of KD varies according to ethnicity and is highest in Asian populations. Although genetic differences may explain this variation, dietary or environmental factors could also be responsible. The objectives of this study were to determine dietary soy and isoflavone consumption in a cohort of KD children just before disease onset and their mothers' intake during pregnancy and nursing. We tested the hypothesis that soy isoflavone consumption is associated with risk of KD in US children, potentially explaining some of the ethnic-cultural variation in incidence. We evaluated soy food intake and isoflavone consumption in nearly 200 US KD cases and 200 age-matched controls using a food frequency questionnaire for children and in their mothers. We used a logistic regression model to test the association of isoflavones and KD. Maternal surveys on soy intake during pregnancy and nursing showed no significant differences in isoflavone consumption between groups. However, we identified significantly increased KD risk in children for total isoflavone (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.37-3.96) and genistein (OR, 2.46; 95% CI, 1.46-4.16) intakes, when comparing high soy consumers vs nonconsumers. In addition, significantly increased KD risk occurred in Asian-American children with the highest consumption (total isoflavones: OR, 7.29; 95% CI, 1.73-30.75; genistein: OR, 8.33; 95% CI, 1.92-36.24) compared to whites. These findings indicate that childhood dietary isoflavone consumption, but not maternal isoflavone intake during pregnancy and nursing, relates to KD risk in an ethnically diverse US population.
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Affiliation(s)
- Michael A Portman
- Division of Cardiology, Department of Pediatrics, University of Washington, Seattle, WA, USA; Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA, USA.
| | - Sandi L Navarro
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Margaret E Bruce
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA, USA
| | - Johanna W Lampe
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA; Department of Epidemiology, University of Washington, Seattle, WA, USA
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Renshaw PS, Lightbody KL, Veverka V, Muskett FW, Kelly G, Frenkiel TA, Gordon SV, Hewinson RG, Burke B, Norman J, Williamson RA, Carr MD. Structure and function of the complex formed by the tuberculosis virulence factors CFP-10 and ESAT-6. EMBO J 2005; 24:2491-8. [PMID: 15973432 PMCID: PMC1176459 DOI: 10.1038/sj.emboj.7600732] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Accepted: 06/07/2005] [Indexed: 11/09/2022] Open
Abstract
The secreted Mycobacterium tuberculosis complex proteins CFP-10 and ESAT-6 have recently been shown to play an essential role in tuberculosis pathogenesis. We have determined the solution structure of the tight, 1:1 complex formed by CFP-10 and ESAT-6, and employed fluorescence microscopy to demonstrate specific binding of the complex to the surface of macrophage and monocyte cells. A striking feature of the complex is the long flexible arm formed by the C-terminus of CFP-10, which was found to be essential for binding to the surface of cells. The surface features of the CFP-10.ESAT-6 complex, together with observed binding to specific host cells, strongly suggest a key signalling role for the complex, in which binding to cell surface receptors leads to modulation of host cell behaviour to the advantage of the pathogen.
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Affiliation(s)
- Philip S Renshaw
- Department of Biochemistry, University of Leicester, Leicester, UK
| | | | - Vaclav Veverka
- Department of Biochemistry, University of Leicester, Leicester, UK
| | - Fred W Muskett
- Department of Biochemistry, University of Leicester, Leicester, UK
| | - Geoff Kelly
- MRC Biomedical NMR Centre, National Institute for Medical Research, Mill Hill, London, UK
| | - Thomas A Frenkiel
- MRC Biomedical NMR Centre, National Institute for Medical Research, Mill Hill, London, UK
| | - Stephen V Gordon
- TB Research Group, Veterinary Laboratories Agency, Addlestone, Surrey, UK
| | - R Glyn Hewinson
- TB Research Group, Veterinary Laboratories Agency, Addlestone, Surrey, UK
| | - Bernard Burke
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Jim Norman
- Department of Biochemistry, University of Leicester, Leicester, UK
| | | | - Mark D Carr
- Department of Biochemistry, University of Leicester, Leicester, UK
- Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 7HN, UK. Tel.: +44 116 229 7075; Fax: +44 116 229 7018; E-mail:
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Abdel Shakor AB, Kwiatkowska K, Sobota A. Cell Surface Ceramide Generation Precedes and Controls FcγRII Clustering and Phosphorylation in Rafts. J Biol Chem 2004; 279:36778-87. [PMID: 15194692 DOI: 10.1074/jbc.m402170200] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite the role of sphingolipid/cholesterol rafts as signaling platforms for Fcgamma receptor II (FcgammaRII), the mechanism governing translocation of an activated receptor toward the rafts is unknown. We show that at the onset of FcgammaRII cross-linking acid sphingomyelinase is rapidly activated. This enzyme is extruded from intracellular compartments to the cell surface, and concomitantly, exofacially oriented ceramide is produced. Both non-raft and, to a lesser extent, raft sphingomyelin pools were hydrolyzed at the onset of FcgammaRII cross-linking. The time course of ceramide production preceded the recruitment of FcgammaRII to rafts and the receptor phosphorylation. Exogenous C(16)-ceramide facilitated clustering of FcgammaRII and its association with rafts. In contrast, inhibition of acid sphingomyelinase diminished both the ceramide generation and clustering of cross-linked FcgammaRII. Under these conditions, tyrosine phosphorylation of FcgammaRII and receptor-accompanying proteins was also reduced. All the inhibitory effects were bypassed by treatment of cells with exogenous ceramide. These data provide evidence that the generation of cell surface ceramide is a prerequisite for fusion of cross-linked FcgammaRII and rafts, which triggers the receptor tyrosine phosphorylation and signaling.
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Affiliation(s)
- Abo Bakr Abdel Shakor
- Nencki Institute of Experimental Biology, the Department of Cell Biology, 3 Pasteur St., 02-093 Warsaw, Poland
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Kwiatkowska K, Frey J, Sobota A. Phosphorylation of FcgammaRIIA is required for the receptor-induced actin rearrangement and capping: the role of membrane rafts. J Cell Sci 2003; 116:537-50. [PMID: 12508114 DOI: 10.1242/jcs.00254] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Activation of Fcgamma receptor II (FcgammaRII) induces rearrangement of the actin-based cytoskeleton that serves as a driving force for FcgammaRII-mediated phagocytosis and FcgammaRII capping. To get insight into the signaling events that lead to the actin reorganization we investigated the role of raft-associated Src family tyrosine kinases in capping of FcgammaRII in U937 cells. After crosslinking, FcgammaRII was found to be recruited to detergent-resistant membrane domains (DRMs), rafts, where it coexisted with Lyn kinase and underwent tyrosine phosphorylation. Lyn was displaced from DRMs under the influence of DL-alpha-hydroxymyristic acid and 2-bromopalmitic acid, agents blocking N-terminal myristoylation and palmitoylation of proteins, respectively, and after disruption of DRM integrity by depletion of plasma membrane cholesterol with beta-cyclodextrin. Under these conditions, phosphorylation of the crosslinked FcgammaRII was diminished and assembly of FcgammaRII caps was blocked. The similar reduction of FcgammaRII cap formation correlated with inhibition of receptor phosphorylation was achieved with the use of PP1 and herbimycin A, specific inhibitors of Src family tyrosine kinases. Phosphorylation of FcgammaRIIA expressed in BHK cells, lacking endogenous FcgammaRs, was abolished by substitution of tyrosine 298 by phenylalanine in the ITAM of the receptor. The mutant receptor did not undergo translocation towards cap-like structures and failed to promote the receptor-mediated spreading of the cells, as compared to BHK cells transfected with the wild-type FcgammaRIIA. On the basis of these data, we suggest that tyrosine phosphorylation of activated FcgammaRIIA by raft-residing tyrosine kinases of the Src family triggers signaling pathways that control the rearrangement of the actin cytoskeleton required for FcgammaRII-mediated motility.
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Affiliation(s)
- Katarzyna Kwiatkowska
- Department of Cell Biology, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland. Universität Bielefeld, Fakultät für Chemie, Biochemie II, 33615 Bielefeld, Germany
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Djaldetti M, Salman H, Bergman M, Djaldetti R, Bessler H. Phagocytosis--the mighty weapon of the silent warriors. Microsc Res Tech 2002; 57:421-31. [PMID: 12112425 DOI: 10.1002/jemt.10096] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Professional phagocytes, comprising polymorphonuclear neutrophils and monocyte/macrophage cells, play an important role in the host defense. Any defect in their function exposes the organism to microbial intruders terminating in fatal diseases. The functional responses of the phagocytes to bacterial and fungal infections include chemotaxis, actin assembly, migration, adhesion, aggregation, phagocytosis, degranulation, and reactive oxygen species production. Superoxide generation by phagocytic NADPH oxidase is an imperative step toward bacterial killing. Phagocytes participate in inflammatory reactions and exert tumoricidal activity. They are supported by serum factors such as immunoglobulins, cytokines, complement, the acute phase reactant C-reactive protein, production of antibacterial proteins, and others. In addition to their principal task to eliminate bacteria, they are engaged in removing damaged, senescent, and apoptotic cells. Engulfed cell debris, large particles such as latex beads, fat, and oil droplets, are examples of phagocytic activity illustrated in the present review with transmission and scanning electron microscope micrographs. Numerous factors, such as diseases and stressful conditions, affect the engulfing activity of the professional phagocytes. Our experience regarding the impaired phagocytic capacity of cells in patients with diabetes and chronic renal failure is discussed. The results obtained in our laboratory from experiments detecting the effect of strenuous physical exercise, hypothermia, fasting, and abdominal photon irradiation on the phagocytic capacity of human polymorphonuclear neutrophils and rat peritoneal macrophages are hereby summarized and the reports on those subjects in the recent literature are reviewed. A variety of assays are applied for quantifying phagocytosis. Flow cytometry based on incubation of phagocytic cells with fluorescent conjugated particles and measuring the amount of fluorescence as an indicator of the engulfing capacity of the cells is a useful method. A direct visualization of the ingested particles using light or electron microscopy is a valuable tool for estimation of phagocytic function. In our hands, the use of semithin sections of embedded phagocytes following their incubation with latex particles provided satisfactory results for measuring the total number of phagocytic cells, as well as the internalizing capacity of each individual cell. Microbiological assays, the nitroblue tetrazolium test, quantitation of antibody- and antigen-mediated phagocytosis, as well as methods reviewed in detail in other reports are additional applications for determination of this intricate process.
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Affiliation(s)
- Meir Djaldetti
- Laboratory for Immunology and Hematology Research, Rabin Medical Center, Golda Campus, Petah Tiqva, Israel.
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Latif R, Graves P, Davies TF. Oligomerization of the human thyrotropin receptor: fluorescent protein-tagged hTSHR reveals post-translational complexes. J Biol Chem 2001; 276:45217-24. [PMID: 11535591 DOI: 10.1074/jbc.m103727200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To examine thyrotropin (TSH) receptor homophilic interactions we fused the human TSH receptor (hTSHR) carboxyl terminus to green fluorescent protein (GFP) and the corresponding chimeric cDNA was expressed in Chinese hamster ovary cells. Fluorescent TSH receptors on the plasma membrane were functional as assessed by TSH-induced cAMP synthesis. The binding of TSH, as well as TSHR autoantibodies, induced time- and dose-dependent receptor capping. Fluorescence resonance energy transfer between receptors differentially tagged with GFP variants (RFP and YFP) provided evidence for the close proximity of individual receptor molecules. This was consistent with previous studies demonstrating the presence of TSHR dimers and oligomers in thyroid tissue. Co-immunoprecipitation of GFP-tagged and Myc-tagged receptor complexes was performed using doubly transfected cells with Myc antibody. Western blotting of the immunoprecipitated complex revealed the absence of noncleaved TSH holoreceptors. This further suggested that cleavage of the holoreceptor into its two-subunit structure, comprising disulfide-linked TSHR-alpha and TSHR-beta subunits, was required for the formation of TSHR dimers and higher order complexes.
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Affiliation(s)
- R Latif
- Division of Endocrinology, Diabetes and Bone Diseases, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
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Kwiatkowska K, Sobota A. The clustered Fcgamma receptor II is recruited to Lyn-containing membrane domains and undergoes phosphorylation in a cholesterol-dependent manner. Eur J Immunol 2001; 31:989-98. [PMID: 11298323 DOI: 10.1002/1521-4141(200104)31:4<989::aid-immu989>3.0.co;2-v] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Phosphorylation of clustered Fcgamma receptor II (FcgammaRII) by Src family tyrosine kinases is the earliest event in the receptor signaling cascade. However, the molecular mechanisms for the interaction between FcgammaRII and these kinases are not elucidated. To asses this problem we isolated high molecular weight complexes of cross-linked FcgammaRII from non-ionic detergent lysates of U937 monocytic cells. CD55, a glycosylphosphatidylinositol-anchored protein, a ganglioside GM1 and Lyn, a Src family tyrosine kinase, were also located in these complexes. Gradient centrifugation demonstrated that the complexes containing cross-linked FcgammaRII displayed a low buoyant density. The FcgammaRII present in the complexes underwent tyrosine phosphorylation. Cross-linked FcgammaRII and Lyn occupied common 100-200 nm detergent-resistant membrane fragments, as demonstrated by immunoprecipitation and microscopy studies. Pretreatment of the cells with beta-cyclodextrin, a cholesterol acceptor, depleted membrane cholesterol and released CD55, GM1 and Lyn from the detergent-resistant complexes. In parallel, the association of Lyn with cross-linked FcgammaRII was disrupted and phosphorylation of the receptor inhibited. Reincorporation of cholesterol evoked the relocation of Lyn into the detergent-resistant membrane fraction and restored both Lyn association with cross-linked FcgammaRII and tyrosine phosphorylation of the receptor. Our data demonstrate that cholesterol-enriched membrane rafts can facilitate tyrosine phosphorylation of clustered FcgammaRII by Lyn kinase.
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Affiliation(s)
- K Kwiatkowska
- Nencki Institute of Experimental Biology, Department of Cell Biology, Warsaw, Poland
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Kwiatkowska K, Sobota A. Engagement of spectrin and actin in capping of FcgammaRII revealed by studies on permeabilized U937 cells. Biochem Biophys Res Commun 1999; 259:287-93. [PMID: 10362500 DOI: 10.1006/bbrc.1999.0769] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Plasma membrane receptors can undergo translocation in the plane of plasma membrane after binding of polyvalent ligands. Ligand/receptor clusters, named patches, can collect into a polar cap, presumably due to their association with the submembrane actin-based cytoskeleton. We found that the assembly of Fcgamma receptor II caps in human monocytic U937 cells was accompanied by the accumulation of spectrin and actin in the cap region. Permeabilization of cells with streptolysin O rendered capping sensitive to inhibition by phalloidin, an actin filament stabilizing agent. A rabbit antibody directed against the chicken erythrocyte alpha-subunit of spectrin, an actin- and membrane-binding protein, also blocked the capping in a dose dependent manner. The inhibition reached approximately 50% after 20 minutes of cell treatment with the antibody. Anti-alpha-spectrin targeted specifically its submembrane antigen, in contrast to unspecific antibodies which remained dispersed in the cell interior and had no influence on the cap assembly. Our results indicate an active engagement of spectrin and actin filaments in the capping of Fcgamma receptor II.
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Affiliation(s)
- K Kwiatkowska
- Department of Cell Biology, Nencki Institute of Experimental Biology, 3 Pasteur Street, Warsaw, 02-093, Poland
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Abstract
Phagocytosis is an uptake of large particles governed by the actin-based cytoskeleton. Binding of particles to specific cell surface receptors is the first step of phagocytosis. In higher Eucaryota, the receptors able to mediate phagocytosis are expressed almost exclusively in macrophages, neutrophils, and monocytes, conferring immunodefence properties to these cells. Receptor clustering is thought to occur upon particle binding, that in turn generates a phagocytic signal. Several pathways of phagocytic signal transduction have been identified, including the activation of tyrosine kinases and (or) serine/threonine kinase C in pivotal roles. Kinase activation leads to phosphorylation of the receptors and other proteins, recruited at the sites of phagocytosis. Monomeric GTPases of the Rho and ARF families are likely to be engaged downstream of activated receptors. The GTPases, in cooperation with phosphatidylinositol 4-phosphate 5-kinase and phosphatidylinositol 3-kinase lipid modifying enzymes, can modulate locally the assembly of the submembranous actin filament system leading to particle internalization.
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Affiliation(s)
- K Kwiatkowska
- Nencki Institute of Experimental Biology, Department of Cell Biology, Warsaw, Poland
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