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Holder A, Kolakowski J, Rosentreter C, Knuepfer E, Jégouzo SAF, Rosenwasser O, Harris H, Baumgaertel L, Gibson A, Werling D. Characterisation of the bovine C-type lectin receptor Mincle and potential evidence for an endogenous ligand. Front Immunol 2023; 14:1189587. [PMID: 37275870 PMCID: PMC10235688 DOI: 10.3389/fimmu.2023.1189587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023] Open
Abstract
Innate immune receptors that form complexes with secondary receptors, activating multiple signalling pathways, modulate cellular activation and play essential roles in regulating homeostasis and immunity. We have previously identified a variety of bovine C-type lectin-like receptors that possess similar functionality than their human orthologues. Mincle (CLEC4E), a heavily glycosylated monomer, is involved in the recognition of the mycobacterial component Cord factor (trehalose 6,6'-dimycolate). Here we characterise the bovine homologue of Mincle (boMincle), and demonstrate that the receptor is structurally and functionally similar to the human orthologue (huMincle), although there are some notable differences. In the absence of cross-reacting antibodies, boMincle-specific antibodies were created and used to demonstrate that, like the human receptor, boMincle is predominantly expressed by myeloid cells. BoMincle surface expression increases during the maturation of monocytes to macrophages. However, boMincle mRNA transcripts were also detected in granulocytes, B cells, and T cells. Finally, we show that boMincle binds to isolated bovine CD4+ T cells in a specific manner, indicating the potential to recognise endogenous ligands. This suggests that the receptor might also play a role in homeostasis in cattle.
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Affiliation(s)
- Angela Holder
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Jeannine Kolakowski
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Chloe Rosentreter
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Ellen Knuepfer
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | | | | | - Heather Harris
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Lotta Baumgaertel
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Amanda Gibson
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
- Department of Life Sciences, Aberystwyth University, Aberystwyth, Ceredigion, United Kingdom
| | - Dirk Werling
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
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2
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Feinberg H, Jégouzo SAF, Lasanajak Y, Smith DF, Drickamer K, Weis WI, Taylor ME. Structural analysis of carbohydrate binding by the macrophage mannose receptor CD206. J Biol Chem 2021; 296:100368. [PMID: 33545173 PMCID: PMC7949135 DOI: 10.1016/j.jbc.2021.100368] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 01/27/2021] [Accepted: 02/01/2021] [Indexed: 02/06/2023] Open
Abstract
The human mannose receptor expressed on macrophages and hepatic endothelial cells scavenges released lysosomal enzymes, glycopeptide fragments of collagen, and pathogenic microorganisms and thus reduces damage following tissue injury. The receptor binds mannose, fucose, or N-acetylglucosamine (GlcNAc) residues on these targets. C-type carbohydrate-recognition domain 4 (CRD4) of the receptor contains the site for Ca2+-dependent interaction with sugars. To investigate the details of CRD4 binding, glycan array screening was used to identify oligosaccharide ligands. The strongest signals were for glycans that contain either Manα1-2Man constituents or fucose in various linkages. The mechanisms of binding to monosaccharides and oligosaccharide substructures present in many of these ligands were examined in multiple crystal structures of CRD4. Binding of mannose residues to CRD4 results primarily from interaction of the equatorial 3- and 4-OH groups with a conserved principal Ca2+ common to almost all sugar-binding C-type CRDs. In the Manα1-2Man complex, supplementary interactions with the reducing mannose residue explain the enhanced affinity for this disaccharide. Bound GlcNAc also interacts with the principal Ca2+ through equatorial 3- and 4-OH groups, whereas fucose residues can bind in several orientations, through either the 2- and 3-OH groups or the 3- and 4-OH groups. Secondary contacts with additional sugars in fucose-containing oligosaccharides, such as the Lewis-a trisaccharide, provide enhanced affinity for these glycans. These results explain many of the biologically important interactions of the mannose receptor with both mammalian glycoproteins and microbes such as yeast and suggest additional classes of ligands that have not been previously identified.
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Affiliation(s)
- Hadar Feinberg
- Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, USA
| | - Sabine A F Jégouzo
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Yi Lasanajak
- Emory Comprehensive Glycomics Core, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David F Smith
- Emory Comprehensive Glycomics Core, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Kurt Drickamer
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - William I Weis
- Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, USA.
| | - Maureen E Taylor
- Department of Life Sciences, Imperial College London, London, United Kingdom.
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3
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Jégouzo SAF, Nelson C, Hardwick T, Wong STA, Lau NKK, Neoh GKE, Castellanos-Rueda R, Huang Z, Mignot B, Hirdaramani A, Howitt A, Frewin K, Shen Z, Fox RJ, Wong R, Ando M, Emony L, Zhu H, Holder A, Werling D, Krishnan N, Robertson BD, Clements A, Taylor ME, Drickamer K. Mammalian lectin arrays for screening host-microbe interactions. J Biol Chem 2020; 295:4541-4555. [PMID: 32094229 PMCID: PMC7135977 DOI: 10.1074/jbc.ra120.012783] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/14/2020] [Indexed: 12/22/2022] Open
Abstract
Many members of the C-type lectin family of glycan-binding receptors have been ascribed roles in the recognition of microorganisms and serve as key receptors in the innate immune response to pathogens. Other mammalian receptors have become targets through which pathogens enter target cells. These receptor roles have often been documented with binding studies involving individual pairs of receptors and microorganisms. To provide a systematic overview of interactions between microbes and the large complement of C-type lectins, here we developed a lectin array and suitable protocols for labeling of microbes that could be used to probe this array. The array contains C-type lectins from cow, chosen as a model organism of agricultural interest for which the relevant pathogen–receptor interactions have not been previously investigated in detail. Screening with yeast cells and various strains of both Gram-positive and -negative bacteria revealed distinct binding patterns, which in some cases could be explained by binding to lipopolysaccharides or capsular polysaccharides, but in other cases they suggested the presence of novel glycan targets on many of the microorganisms. These results are consistent with interactions previously ascribed to the receptors, but they also highlight binding to additional sugar targets that have not previously been recognized. Our findings indicate that mammalian lectin arrays represent unique discovery tools for identifying both novel ligands and new receptor functions.
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Affiliation(s)
- Sabine A F Jégouzo
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Conor Nelson
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Thomas Hardwick
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - S T Angel Wong
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Noel Kuan Kiat Lau
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Gaik Kin Emily Neoh
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | | | - Zhiyao Huang
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Benjamin Mignot
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Aanya Hirdaramani
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Annie Howitt
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Kathryn Frewin
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Zheng Shen
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Rhys J Fox
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Rachel Wong
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Momoko Ando
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Lauren Emony
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Henderson Zhu
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Angela Holder
- Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, Hatfield, Hertfordshire AL9 7TA, United Kingdom
| | - Dirk Werling
- Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, Hatfield, Hertfordshire AL9 7TA, United Kingdom
| | - Nitya Krishnan
- Department of Infectious Disease and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Brian D Robertson
- Department of Infectious Disease and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Abigail Clements
- Department of Life Sciences and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Maureen E Taylor
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Kurt Drickamer
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
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4
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Jégouzo SAF, Feinberg H, Morrison AG, Holder A, May A, Huang Z, Jiang L, Lasanajak Y, Smith DF, Werling D, Drickamer K, Weis WI, Taylor ME. CD23 is a glycan-binding receptor in some mammalian species. J Biol Chem 2019; 294:14845-14859. [PMID: 31488546 PMCID: PMC6791321 DOI: 10.1074/jbc.ra119.010572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 08/30/2019] [Indexed: 01/25/2023] Open
Abstract
CD23, the low-affinity IgE receptor found on B lymphocytes and other cells, contains a C-terminal lectin-like domain that resembles C-type carbohydrate-recognition domains (CRDs) found in many glycan-binding receptors. In most mammalian species, the CD23 residues required to form a sugar-binding site are present, although binding of CD23 to IgE does not involve sugars. Solid-phase binding competition assays, glycoprotein blotting experiments, and glycan array analysis employing the lectin-like domains of cow and mouse CD23 demonstrate that they bind to mannose, GlcNAc, glucose, and fucose and to glycoproteins that bear these sugars in nonreducing terminal positions. Crystal structures of the cow CRD in the presence of α-methyl mannoside and GlcNAcβ1-2Man reveal that a range of oligosaccharide ligands can be accommodated in an open binding site in which most interactions are with a single terminal sugar residue. Although mouse CD23 shows a pattern of monosaccharide and glycoprotein binding similar to cow CD23, the binding is weaker. In contrast, no sugar binding was observed in similar experiments with human CD23. The absence of sugar-binding activity correlates with accumulation of mutations in the gene for CD23 in the primate lineage leading to humans, resulting in loss of key sugar-binding residues. These results are consistent with a role for CD23 in many species as a receptor for potentially pathogenic microorganisms as well as IgE. However, the ability of CD23 to bind several different ligands varies between species, suggesting that it has distinct functions in different organisms.
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Affiliation(s)
- Sabine A F Jégouzo
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Hadar Feinberg
- Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305
| | - Andrew G Morrison
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Angela Holder
- Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, Hatfield, Hertfordshire AL9 7TA, United Kingdom
| | - Alisha May
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Zhiyao Huang
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Linghua Jiang
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Yi Lasanajak
- Emory Comprehensive Glycomics Core, Emory University School of Medicine, Atlanta, Georgia 30322
| | - David F Smith
- Emory Comprehensive Glycomics Core, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Dirk Werling
- Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, Hatfield, Hertfordshire AL9 7TA, United Kingdom
| | - Kurt Drickamer
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - William I Weis
- Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305
| | - Maureen E Taylor
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
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5
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Kim JW, Budzak J, Liu Y, Jégouzo SAF, Drickamer K, Taylor ME. Identification of serum glycoprotein ligands for the immunomodulatory receptor blood dendritic cell antigen 2. Glycobiology 2018; 28:592-600. [PMID: 29796630 PMCID: PMC6054153 DOI: 10.1093/glycob/cwy050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/04/2018] [Accepted: 05/19/2018] [Indexed: 12/26/2022] Open
Abstract
Blood dendritic cell antigen 2 (BDCA-2) is a C-type lectin found on the surface of plasmacytoid dendritic cells. It functions as a glycan-binding receptor that downregulates the production of type I interferons and thus plays a role in oligosaccharide-mediated immunomodulation. The carbohydrate recognition domain in BDCA-2 binds selectively to galactose-terminated bi-antennary glycans. Because the plasmacytoid dendritic cells function in a plasma environment rich in glycoproteins, experiments have been undertaken to identify endogenous ligands for blood dendritic cell antigen 2. A combination of blotting, affinity chromatography and proteomic analysis reveals that serum glycoprotein ligands for BDCA-2 include IgG, IgA and IgM. Compared to binding of IgG, which was previously described, IgA and IgM bind with higher affinity. The association constants for the different subclasses of immunoglobulins are below and roughly proportional to the serum concentrations of these glycoprotein ligands. Binding to the other main serum glycoprotein ligand, α2-macroglobulin, is independent of whether this protease inhibitor is activated. Binding to all of these glycoprotein ligands is mediated predominantly by bi-antennary glycans in which each branch bears a terminal galactose residue. The different affinities of the glycoprotein ligands reflect the different numbers of these galactose-terminated glycans and their degree of exposure on the native glycoproteins. The results suggest that normal serum levels of immunoglobulins could downmodulate interferon stimulation of further antibody production.
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Affiliation(s)
- Jong-Won Kim
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College, London, UK
| | - James Budzak
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College, London, UK
| | - Yu Liu
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College, London, UK
| | - Sabine A F Jégouzo
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College, London, UK
| | - Kurt Drickamer
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College, London, UK
| | - Maureen E Taylor
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College, London, UK
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6
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Zheng RB, Jégouzo SAF, Joe M, Bai Y, Tran HA, Shen K, Saupe J, Xia L, Ahmed MF, Liu YH, Patil PS, Tripathi A, Hung SC, Taylor ME, Lowary TL, Drickamer K. Insights into Interactions of Mycobacteria with the Host Innate Immune System from a Novel Array of Synthetic Mycobacterial Glycans. ACS Chem Biol 2017; 12:2990-3002. [PMID: 29048873 PMCID: PMC5735379 DOI: 10.1021/acschembio.7b00797] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
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An
array of homogeneous glycans representing all the major carbohydrate
structures present in the cell wall of the human pathogen Mycobacterium tuberculosis and other mycobacteria has been
probed with a panel of glycan-binding receptors expressed on cells
of the mammalian innate immune system. The results provide an overview
of interactions between mycobacterial glycans and receptors that mediate
uptake and survival in macrophages, dendritic cells, and sinusoidal
endothelial cells. A subset of the wide variety of glycan structures
present on mycobacterial surfaces interact with cells of the innate
immune system through the receptors tested. Endocytic receptors, including
the mannose receptor, DC-SIGN, langerin, and DC-SIGNR (L-SIGN), interact
predominantly with mannose-containing caps found on the mycobacterial
polysaccharide lipoarabinomannan. Some of these receptors also interact
with phosphatidyl-myo-inositol mannosides and mannose-containing
phenolic glycolipids. Many glycans are ligands for overlapping sets
of receptors, suggesting multiple, redundant routes by which mycobacteria
can enter cells. Receptors with signaling capability interact with
two distinct sets of mycobacterial glycans: targets for dectin-2 overlap
with ligands for the mannose-binding endocytic receptors, while mincle
binds exclusively to trehalose-containing structures such as trehalose
dimycolate. None of the receptors surveyed bind furanose residues,
which often form part of the epitopes recognized by antibodies to
mycobacteria. Thus, the innate and adaptive immune systems can target
different sets of mycobacterial glycans. This array, the first of
its kind, represents an important new tool for probing, at a molecular
level, biological roles of a broad range of mycobacterial glycans,
a task that has not previously been possible.
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Affiliation(s)
- Ruixiang Blake Zheng
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | | | - Maju Joe
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Yu Bai
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Huu-Anh Tran
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Ke Shen
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Jörn Saupe
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Li Xia
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Md. Faiaz Ahmed
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Yu-Hsuan Liu
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | | | - Ashish Tripathi
- Genomics
Research Centre, Academia Sinica, Nangang, Taipei 11529, Taiwan
| | - Shang-Cheng Hung
- Genomics
Research Centre, Academia Sinica, Nangang, Taipei 11529, Taiwan
| | - Maureen E. Taylor
- Department
of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
| | - Todd L. Lowary
- Department
of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Kurt Drickamer
- Department
of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
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7
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Feinberg H, Jégouzo SAF, Rex MJ, Drickamer K, Weis WI, Taylor ME. Mechanism of pathogen recognition by human dectin-2. J Biol Chem 2017; 292:13402-13414. [PMID: 28652405 PMCID: PMC5555199 DOI: 10.1074/jbc.m117.799080] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 06/23/2017] [Indexed: 11/17/2022] Open
Abstract
Dectin-2, a C-type lectin on macrophages and other cells of the innate immune system, functions in response to pathogens, particularly fungi. The carbohydrate-recognition domain (CRD) in dectin-2 is linked to a transmembrane sequence that interacts with the common Fc receptor γ subunit to initiate immune signaling. The molecular mechanism by which dectin-2 selectively binds to pathogens has been investigated by characterizing the CRD expressed in a bacterial system. Competition binding studies indicated that the CRD binds to monosaccharides with modest affinity and that affinity was greatly enhanced for mannose-linked α1–2 or α1–4 to a second mannose residue. Glycan array analysis confirmed selective binding of the CRD to glycans that contain Manα1–2Man epitopes. Crystals of the CRD in complex with a mammalian-type high-mannose Man9GlcNAc2 oligosaccharide exhibited interaction with Manα1–2Man on two different termini of the glycan, with the reducing-end mannose residue ligated to Ca2+ in a primary binding site and the nonreducing terminal mannose residue occupying an adjacent secondary site. Comparison of the binding sites in DC-SIGN and langerin, two other pathogen-binding receptors of the innate immune system, revealed why these two binding sites accommodate only terminal Manα1–2Man structures, whereas dectin-2 can bind Manα1–2Man in internal positions in mannans and other polysaccharides. The specificity and geometry of the dectin-2-binding site provide the molecular mechanism for binding of dectin-2 to fungal mannans and also to bacterial lipopolysaccharides, capsular polysaccharides, and lipoarabinomannans that contain the Manα1–2Man disaccharide unit.
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Affiliation(s)
- Hadar Feinberg
- From the Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305 and
| | - Sabine A F Jégouzo
- the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Maximus J Rex
- the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Kurt Drickamer
- the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - William I Weis
- From the Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305 and
| | - Maureen E Taylor
- the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
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8
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Feinberg H, Rambaruth NDS, Jégouzo SAF, Jacobsen KM, Djurhuus R, Poulsen TB, Weis WI, Taylor ME, Drickamer K. Binding Sites for Acylated Trehalose Analogs of Glycolipid Ligands on an Extended Carbohydrate Recognition Domain of the Macrophage Receptor Mincle. J Biol Chem 2016; 291:21222-21233. [PMID: 27542410 PMCID: PMC5076529 DOI: 10.1074/jbc.m116.749515] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Indexed: 11/29/2022] Open
Abstract
The macrophage receptor mincle binds to trehalose dimycolate on the surface of Mycobacterium tuberculosis. Signaling initiated by this interaction leads to cytokine production, which underlies the ability of mycobacteria to evade the immune system and also to function as adjuvants. In previous work the mechanism for binding of the sugar headgroup of trehalose dimycolate to mincle has been elucidated, but the basis for enhanced binding to glycolipid ligands, in which hydrophobic substituents are attached to the 6-hydroxyl groups, has been the subject of speculation. In the work reported here, the interaction of trehalose derivatives with bovine mincle has been probed with a series of synthetic mimics of trehalose dimycolate in binding assays, in structural studies by x-ray crystallography, and by site-directed mutagenesis. Binding studies reveal that, rather than reflecting specific structural preference, the apparent affinity of mincle for ligands with hydrophobic substituents correlates with their overall size. Structural and mutagenesis analysis provides evidence for interaction of the hydrophobic substituents with multiple different portions of the surface of mincle and confirms the presence of three Ca2+-binding sites. The structure of an extended portion of the extracellular domain of mincle, beyond the minimal C-type carbohydrate recognition domain, also constrains the way the binding domains may interact on the surface of macrophages.
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Affiliation(s)
- Hadar Feinberg
- From the Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305
| | - Neela D S Rambaruth
- the Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom, and
| | - Sabine A F Jégouzo
- the Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom, and
| | - Kristian M Jacobsen
- Chemical Biology Laboratory, Department of Chemistry, Aarhus University, DK-8000 Aarhus, Denmark
| | - Rasmus Djurhuus
- Chemical Biology Laboratory, Department of Chemistry, Aarhus University, DK-8000 Aarhus, Denmark
| | - Thomas B Poulsen
- Chemical Biology Laboratory, Department of Chemistry, Aarhus University, DK-8000 Aarhus, Denmark
| | - William I Weis
- From the Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305
| | - Maureen E Taylor
- the Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom, and
| | - Kurt Drickamer
- the Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom, and
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9
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Jégouzo SAF, Feinberg H, Dungarwalla T, Drickamer K, Weis WI, Taylor ME. A Novel Mechanism for Binding of Galactose-terminated Glycans by the C-type Carbohydrate Recognition Domain in Blood Dendritic Cell Antigen 2. J Biol Chem 2015; 290:16759-71. [PMID: 25995448 PMCID: PMC4505424 DOI: 10.1074/jbc.m115.660613] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Indexed: 11/06/2022] Open
Abstract
Blood dendritic cell antigen 2 (BDCA-2; also designated CLEC4C or CD303) is uniquely expressed on plasmacytoid dendritic cells. Stimulation of BDCA-2 with antibodies leads to an anti-inflammatory response in these cells, but the natural ligands for the receptor are not known. The C-type carbohydrate recognition domain in the extracellular portion of BDCA-2 contains a signature motif typical of C-type animal lectins that bind mannose, glucose, or GlcNAc, yet it has been reported that BDCA-2 binds selectively to galactose-terminated, biantennary N-linked glycans. A combination of glycan array analysis and binding competition studies with monosaccharides and natural and synthetic oligosaccharides have been used to define the binding epitope for BDCA-2 as the trisaccharide Galβ1-3/4GlcNAcβ1-2Man. X-ray crystallography and mutagenesis studies show that mannose is ligated to the conserved Ca(2+) in the primary binding site that is characteristic of C-type carbohydrate recognition domains, and the GlcNAc and galactose residues make additional interactions in a wide, shallow groove adjacent to the primary binding site. As predicted from these studies, BDCA-2 binds to IgG, which bears galactose-terminated glycans that are not commonly found attached to other serum glycoproteins. Thus, BDCA-2 has the potential to serve as a previously unrecognized immunoglobulin Fc receptor.
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Affiliation(s)
- Sabine A F Jégouzo
- the Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
| | - Hadar Feinberg
- From the Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305 and
| | - Tabassum Dungarwalla
- the Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
| | - Kurt Drickamer
- the Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
| | - William I Weis
- From the Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305 and
| | - Maureen E Taylor
- the Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
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Rambaruth NDS, Jégouzo SAF, Marlor H, Taylor ME, Drickamer K. Mouse mincle: characterization as a model for human mincle and evolutionary implications. Molecules 2015; 20:6670-82. [PMID: 25884549 PMCID: PMC4533885 DOI: 10.3390/molecules20046670] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/07/2015] [Accepted: 04/13/2015] [Indexed: 12/03/2022] Open
Abstract
Mincle, the macrophage-inducible C-type lectin also known as CLEC-4E, binds to the mycobacterial glycolipid trehalose dimycolate and initiates a signaling cascade by serving as a receptor for Mycobacterium tuberculosis and other pathogenic mycobacterial species. Studies of the biological functions of human mincle often rely on mouse models, based on the assumption that the biological properties of the mouse receptor mimic those of the human protein. Experimental support for this assumption has been obtained by expression of the carbohydrate-recognition domain of mouse mincle and characterization of its interaction with small molecule analogs of trehalose dimycolate. The results confirm that the ligand-binding properties of mouse mincle closely parallel those of the human receptor. These findings are consistent with the conservation of key amino acid residues that have been shown to form the ligand-binding site in human and cow mincle. Sequence alignment reveals that these residues are conserved in a wide range of mammalian species, suggesting that mincle has a conserved function in binding ligands that may include endogenous mammalian glycans or pathogen glycans in addition to trehalose dimycolate.
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Affiliation(s)
| | | | - Hayley Marlor
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK.
| | - Maureen E Taylor
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK.
| | - Kurt Drickamer
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK.
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Jégouzo SAF, Harding EC, Acton O, Rex MJ, Fadden AJ, Taylor ME, Drickamer K. Defining the conformation of human mincle that interacts with mycobacterial trehalose dimycolate. Glycobiology 2014; 24:1291-300. [PMID: 25028392 PMCID: PMC4211601 DOI: 10.1093/glycob/cwu072] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Trehalose dimycolate, an unusual glycolipid in the outer membrane of Mycobacterium tuberculosis, stimulates macrophages by binding to the macrophage receptor mincle. This stimulation plays an important role both in infection by mycobacteria and in the use of derivatives of mycobacteria as adjuvants to enhance the immune response. The mechanism of trehalose dimycolate binding to the C-type carbohydrate-recognition domain in human mincle has been investigated using a series of synthetic analogs of trehalose dimycolate and site-directed mutagenesis of the human protein. The results support a mechanism of binding acylated trehalose derivatives to human mincle that is very similar to the mechanism of binding to bovine mincle, in which one glucose residue in the trehalose headgroup of the glycolipid is ligated to the principle Ca2+-binding site in the carbohydrate-recognition domain, with specificity for the disaccharide resulting from interactions with the second glucose residue. Acyl chains attached to the 6-OH groups of trehalose enhance affinity, with the affinity dependent on the length of the acyl chains and the presence of a hydrophobic groove adjacent to the sugar-binding sites. The results indicate that the available crystal structure of the carbohydrate-recognition domain of human mincle is unlikely to be in a fully active conformation. Instead, the ligand-binding conformation probably resembles closely the structure observed for bovine mincle in complex with trehalose. These studies provide a basis for targeting human mincle as a means of inhibiting interactions with mycobacteria and as an approach to harnessing the ability of mincle to stimulate the immune response.
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Affiliation(s)
- Sabine A F Jégouzo
- Department of Life Sciences, Imperial College, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Edward C Harding
- Department of Life Sciences, Imperial College, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Oliver Acton
- Department of Life Sciences, Imperial College, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Maximus J Rex
- Department of Life Sciences, Imperial College, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Andrew J Fadden
- Department of Life Sciences, Imperial College, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Maureen E Taylor
- Department of Life Sciences, Imperial College, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Kurt Drickamer
- Department of Life Sciences, Imperial College, Sir Ernst Chain Building, London SW7 2AZ, UK
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Feinberg H, Jégouzo SAF, Rowntree TJW, Guan Y, Brash MA, Taylor ME, Weis WI, Drickamer K. Mechanism for recognition of an unusual mycobacterial glycolipid by the macrophage receptor mincle. J Biol Chem 2013; 288:28457-65. [PMID: 23960080 PMCID: PMC3789947 DOI: 10.1074/jbc.m113.497149] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Binding of the macrophage lectin mincle to trehalose dimycolate, a key glycolipid virulence factor on the surface of Mycobacterium tuberculosis and Mycobacterium bovis, initiates responses that can lead both to toxicity and to protection of these pathogens from destruction. Crystallographic structural analysis, site-directed mutagenesis, and binding studies with glycolipid mimics have been used to define an extended binding site in the C-type carbohydrate recognition domain (CRD) of bovine mincle that encompasses both the headgroup and a portion of the attached acyl chains. One glucose residue of the trehalose Glcα1–1Glcα headgroup is liganded to a Ca2+ in a manner common to many C-type CRDs, whereas the second glucose residue is accommodated in a novel secondary binding site. The additional contacts in the secondary site lead to a 36-fold higher affinity for trehalose compared with glucose. An adjacent hydrophobic groove, not seen in other C-type CRDs, provides a docking site for one of the acyl chains attached to the trehalose, which can be targeted with small molecule analogs of trehalose dimycolate that bind with 52-fold higher affinity than trehalose. The data demonstrate how mincle bridges between the surfaces of the macrophage and the mycobacterium and suggest the possibility of disrupting this interaction. In addition, the results may provide a basis for design of adjuvants that mimic the ability of mycobacteria to stimulate a response to immunization that can be employed in vaccine development.
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Affiliation(s)
- Hadar Feinberg
- From the Departments of Structural Biology and Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305 and
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Jégouzo SAF, Quintero-Martínez A, Ouyang X, dos Santos Á, Taylor ME, Drickamer K. Organization of the extracellular portion of the macrophage galactose receptor: a trimeric cluster of simple binding sites for N-acetylgalactosamine. Glycobiology 2013; 23:853-64. [PMID: 23507965 PMCID: PMC3671775 DOI: 10.1093/glycob/cwt022] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The properties of the human macrophage galactose receptor have been investigated. Specificity for N-acetylgalactosamine (GalNAc) residues with exposed 3- and 4-hydroxyl groups explains virtually all of the results obtained from a recently expanded array of synthetic glycans and is consistent with a model for the structure of the binding site. This simple interaction is sufficient to explain the ability of the receptor to bind to tumor-cell glycans bearing Tn and sialyl-Tn antigens, but not to more elaborate O-linked glycans that predominate on normal cells. This specificity also allows for binding of parasite glycans and screening of an array of bacterial outer membrane oligosaccharides confirms that the receptor binds to a subset of these structures with appropriately exposed GalNAc residues. A key feature of the receptor is the clustering of binding sites in the extracellular portion of the protein, which retains the trimeric structure observed in the cell membrane. Chemical crosslinking, gel filtration, circular dichroism analysis and differential scanning calorimetry demonstrate that this trimeric structure of the receptor is stabilized by an α-helical coiled coil that extends from the surface of the membrane to the globular carbohydrate-recognition domains. The helical neck domains form independent trimerization domains. Taken together, these results indicate that the macrophage galactose receptor shares many of the features of serum mannose-binding protein, in which clusters of monosaccharide-binding sites serve as detectors for a simple epitope that is not common on endogenous cell surface glycans but that is abundant on the surfaces of tumor cells and certain pathogens.
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Affiliation(s)
- Sabine A F Jégouzo
- Department of Life Sciences, Imperial College, Sir Ernst Chain Building, London SW7 2AZ, UK
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Graham SA, Jégouzo SAF, Yan S, Powlesland AS, Brady JP, Taylor ME, Drickamer K. Prolectin, a glycan-binding receptor on dividing B cells in germinal centers. J Biol Chem 2009; 284:18537-44. [PMID: 19419970 PMCID: PMC2709368 DOI: 10.1074/jbc.m109.012807] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prolectin, a previously undescribed glycan-binding receptor, has been identified by re-screening of the human genome for genes encoding proteins containing potential C-type carbohydrate-recognition domains. Glycan array analysis revealed that the carbohydrate-recognition domain in the extracellular domain of the receptor binds glycans with terminal alpha-linked mannose or fucose residues. Prolectin expressed in fibroblasts is found at the cell surface, but unlike many glycan-binding receptors it does not mediate endocytosis of a neoglycoprotein ligand. However, compared with other known glycan-binding receptors, the receptor contains an unusually large intracellular domain that consists of multiple sequence motifs, including phosphorylated tyrosine residues, that allow it to interact with signaling molecules such as Grb2. Immunohistochemistry has been used to demonstrate that prolectin is expressed on a specialized population of proliferating B cells in germinal centers. Thus, this novel receptor has the potential to function in carbohydrate-mediated communication between cells in the germinal center.
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Affiliation(s)
- Sarah A Graham
- Division of Molecular Biosciences, Department of Life Sciences, Imperial College, London SW7 2AZ, United Kingdom
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