51
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Grotenbreg GM, Nicholson MJ, Fowler KD, Wilbuer K, Octavio L, Yang M, Chakraborty AK, Ploegh HL, Wucherpfennig KW. Empty class II major histocompatibility complex created by peptide photolysis establishes the role of DM in peptide association. J Biol Chem 2007; 282:21425-36. [PMID: 17525157 PMCID: PMC3427782 DOI: 10.1074/jbc.m702844200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DM catalyzes the exchange of peptides bound to Class II major histocompatibility complex (MHC) molecules. Because the dissociation and association components of the overall reaction are difficult to separate, a detailed mechanism of DM catalysis has long resisted elucidation. UV irradiation of DR molecules loaded with a photocleavable peptide (caged Class II MHC molecules) enabled synchronous and verifiable evacuation of the peptide-binding groove and tracking of early binding events in real time by fluorescence polarization. Empty DR molecules generated by photocleavage rapidly bound peptide but quickly resolved into species with substantially slower binding kinetics. DM formed a complex with empty DR molecules that bound peptide with even faster kinetics than empty DR molecules just having lost their peptide cargo. Mathematical models demonstrate that the peptide association rate of DR molecules is substantially higher in the presence of DM. We therefore unequivocally establish that DM contributes directly to peptide association through formation of a peptide-loading complex between DM and empty Class II MHC. This complex rapidly acquires a peptide analogous to the MHC class I peptide-loading complex.
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Affiliation(s)
| | - Melissa J. Nicholson
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Boston Massachusetts 02115
| | - Kevin D. Fowler
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Kathrin Wilbuer
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Boston Massachusetts 02115
| | - Leah Octavio
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Maxine Yang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Arup K. Chakraborty
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Hidde L. Ploegh
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02139
| | - Kai W. Wucherpfennig
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Boston Massachusetts 02115
- To whom correspondence should be addressed: Dr. Kai Wucherpfennig, 44 Binney St., Boston MA 02115. Tel.: 617-632-3086; Fax: 617-632-2662;
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52
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Silva DSP, Reis MIR, Nascimento DS, do Vale A, Pereira PJB, dos Santos NMS. Sea bass (Dicentrarchus labrax) invariant chain and class II major histocompatibility complex: sequencing and structural analysis using 3D homology modelling. Mol Immunol 2007; 44:3758-76. [PMID: 17512596 DOI: 10.1016/j.molimm.2007.03.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Revised: 03/27/2007] [Accepted: 03/29/2007] [Indexed: 11/21/2022]
Abstract
The present manuscript reports for the first time the sequencing and characterisation of sea bass (sb) MHCII alpha and beta chains and Ii chain cDNAs as well as their expression analysis under resting state. 3D homology modelling, using crystal structures from mammalian orthologues, has been used to illustrate and support putative structural homologies of the sea bass counterparts. The sbIi cDNA consists of 96 bp of 5'-UTR, a 843 bp open reading frame (ORF) and 899 bp of 3'-UTR including a canonical polyadenylation signal 16 nucleotides before the polyadenylation tail. The ORF was translated into a 280 amino acid sequence, in which all characteristic domains found in the Ii p41 human form could be identified, including the cytoplasmic N-terminus domain, the transmembrane (TM) region, the CLIP domain, the trimerization domain and the thyroglobulin (Tg) type I domain. The trimerization and Tg domains of sbIi were successfully modelled using the human counterparts as templates. Four different sequences of each class II alpha and beta MHCII were obtained from a single fish, apparently not derived from a single locus. All the characteristic features of the MHCII chain structure could be identified in the predicted ORF of sea bass alpha and beta sequences, consisting of leader peptide (LP), alpha1/beta1 and alpha2/beta2 domains, connecting peptide and TM and cytoplasmic regions. Furthermore, independently of the HLA-DR crystal structure used as template in homology modelling, a similar predicted 3D structure and trimeric quaternary architecture was obtained for sbMHC, with major deviations occurring only within the sea bass MHCII alpha1 domain.
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MESH Headings
- 5' Untranslated Regions/genetics
- Amino Acid Sequence
- Animals
- Antigens, Differentiation, B-Lymphocyte/chemistry
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/metabolism
- Base Sequence
- Bass/genetics
- Bass/immunology
- DNA, Complementary/genetics
- Gene Expression Regulation
- Histocompatibility Antigens Class II/chemistry
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/metabolism
- Hydrophobic and Hydrophilic Interactions
- Models, Molecular
- Molecular Sequence Data
- Phylogeny
- Sequence Alignment
- Sequence Analysis, DNA
- Structural Homology, Protein
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Affiliation(s)
- Daniela S P Silva
- Fish Immunology and Vaccinology, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
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53
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Bondinas GP, Moustakas AK, Papadopoulos GK. The spectrum of HLA-DQ and HLA-DR alleles, 2006: a listing correlating sequence and structure with function. Immunogenetics 2007; 59:539-53. [PMID: 17497145 DOI: 10.1007/s00251-007-0224-8] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 04/03/2007] [Indexed: 10/23/2022]
Abstract
The list of alleles in the HLA-DRB, HLA-DQA, and HLA-DQB gene loci has grown enormously since the last listing in this journal 8 years ago. Crystal structure determination of several human and mouse HLA class II alleles, representative of two gene loci in each species, enables a direct comparison of ortholog and paralog loci. A new numbering system is suggested, extending earlier suggestions by [Fremont et al. in Immunity 8:305-317, (1998)], which will bring in line all the structural features of various gene loci, regardless of animal species. This system allows for structural equivalence of residues from different gene loci. The listing also highlights all amino acid residues participating in the various functions of these molecules, from antigenic peptide binding to homodimer formation, CD4 binding, membrane anchoring, and cytoplasmic signal transduction, indicative of the variety of functions of these molecules. It is remarkable that despite the enormous number of unique alleles listed thus far (DQA = 22, DQB = 54, DRA = 2, and DRB = 409), there is invariance at many specific positions in man, but slightly less so in mouse or rat, despite their much lower number of alleles at each gene locus in the latter two species. Certain key polymorphisms (from substitutions to an eight-residue insertion in the cytoplasmic tail of certain DQB alleles) that have thus far gone unnoticed are highly suggestive of differences or diversities in function and thus call for further investigation into the properties of these specific alleles. This listing is amenable to supplementation by future additions of new alleles and the highlighting of new functions to be discovered, providing thus a unifying platform of reference in all animal species for the MHC class II allelic counterparts, aiding research in the field and furthering our understanding of the functions of these molecules.
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Affiliation(s)
- George P Bondinas
- Laboratory of Biochemistry and Biophysics, Faculty of Agricultural Technology, Epirus Institute of Technology, GR47100 Arta, Greece
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54
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van Lith M, Benham AM. The DMalpha and DMbeta chain cooperate in the oxidation and folding of HLA-DM. THE JOURNAL OF IMMUNOLOGY 2007; 177:5430-9. [PMID: 17015729 DOI: 10.4049/jimmunol.177.8.5430] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HLA-DM (DM) is a heterodimeric MHC molecule that catalyzes the peptide loading of classical MHC class II molecules in the endosomal/lysosomal compartments of APCs. Although the function of DM is well-established, little is known about how DMalpha and beta-chains fold, oxidize, and form a complex in the endoplasmic reticulum (ER). In this study, we show that glycosylation promotes, but is not essential for, DMalphabeta ER exit. However, glycosylation of DMalpha N15 is required for oxidation of the alpha-chain. The DMalpha and beta-chains direct each others fate: single DMalpha chains cannot fully oxidize without DMbeta, while DMbeta forms disulfide-linked homodimers without DMalpha. Correct oxidation and subsequent ER egress depend on the unique DMbeta C25 and C35 residues. This suggests that the C25-C35 disulfide bond in the peptide-binding domain overcomes the need for stabilizing peptides required by other MHC molecules.
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Affiliation(s)
- Marcel van Lith
- Department of Biological Sciences, University of Durham, Durham, United Kingdom
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55
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Lazarski CA, Chaves FA, Sant AJ. The impact of DM on MHC class II-restricted antigen presentation can be altered by manipulation of MHC-peptide kinetic stability. ACTA ACUST UNITED AC 2006; 203:1319-28. [PMID: 16682499 PMCID: PMC2121212 DOI: 10.1084/jem.20060058] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DM edits the peptide repertoire presented by major histocompatibility complex class II molecules by professional antigen-presenting cells (APCs), favoring presentation of some peptides over others. Despite considerable research by many laboratories, there is still significant uncertainty regarding the biochemical attributes of class II–peptide complexes that govern their susceptibility to DM editing. Here, using APCs that either do or do not express DM and a set of unrelated antigens, we found that the intrinsic kinetic stability of class II–peptide complexes is tightly correlated with the effects of DM editing within APCs. Furthermore, through the use of kinetic stability variants of three independent peptides, we demonstrate that increasing or decreasing the kinetic stability of class II–peptide complexes causes a corresponding alteration in DM editing. Finally, we show that the spontaneous kinetic stability of class II complexes correlates directly with the efficiency of presentation by DM+ APCs and the immunodominance of that class II–peptide complex during an immune response. Collectively, these results suggest that the pattern of DM editing in APCs can be intentionally changed by modifying class II–peptide interactions, leading to the desired hierarchy of presentation on APCs, thereby promoting recruitment of CD4 T cells specific for the preferred peptides during an immune response.
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Affiliation(s)
- Christopher A Lazarski
- David H. Smith Center for Vaccine Biology and Immunology, Aab Institute and Department of Microbiology and Immunology, University of Rochester, Rochester, NY 14642, USA
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56
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Nicholson MJ, Moradi B, Seth NP, Xing X, Cuny GD, Stein RL, Wucherpfennig KW. Small molecules that enhance the catalytic efficiency of HLA-DM. THE JOURNAL OF IMMUNOLOGY 2006; 176:4208-20. [PMID: 16547258 PMCID: PMC3412064 DOI: 10.4049/jimmunol.176.7.4208] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HLA-DM (DM) plays a critical role in Ag presentation to CD4 T cells by catalyzing the exchange of peptides bound to MHC class II molecules. Large lateral surfaces involved in the DM:HLA-DR (DR) interaction have been defined, but the mechanism of catalysis is not understood. In this study, we describe four small molecules that accelerate DM-catalyzed peptide exchange. Mechanistic studies demonstrate that these small molecules substantially enhance the catalytic efficiency of DM, indicating that they make the transition state of the DM:DR/peptide complex energetically more favorable. These compounds fall into two functional classes: two compounds are active only in the presence of DM, and binding data for one show a direct interaction with DM. The remaining two compounds have partial activity in the absence of DM, suggesting that they may act at the interface between DM and DR/peptide. A hydrophobic ridge in the DMbeta1 domain was implicated in the catalysis of peptide exchange because the activity of three of these enhancers was substantially reduced by point mutations in this area.
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Affiliation(s)
- Melissa J. Nicholson
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Babak Moradi
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Nilufer P. Seth
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Xuechao Xing
- Laboratory for Drug Discovery in Neurodegeneration, Harvard Center for Neurodegeneration and Repair (HCNR)
| | - Gregory D. Cuny
- Laboratory for Drug Discovery in Neurodegeneration, Harvard Center for Neurodegeneration and Repair (HCNR)
| | - Ross L. Stein
- Laboratory for Drug Discovery in Neurodegeneration, Harvard Center for Neurodegeneration and Repair (HCNR)
| | - Kai W. Wucherpfennig
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115
- Program in Immunology, Harvard Medical School, Boston, MA 02115
- Department of Neurology, Harvard Medical School, Boston, MA 02115
- Address correspondence and reprint requests to Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115.
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57
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Abstract
The relative plasticity of peptide binding to class II major histocompatibility complex (MHC) molecules permits formation of multiple conformational isomers by the same peptide and MHC molecule; such conformers are specifically recognized by distinct subsets of T cells. Here, we review current knowledge and recent advances in our understanding of peptide-class II MHC conformational isomerism and the mechanisms that generate distinct MHC-peptide conformers. We focus on our studies of two T-cell subsets, type A and B, which recognize distinct conformers of the dominant epitope of hen egg white lysozyme presented by I-A(k). These conformers form via different pathways and in distinct intracellular vesicles: the type A conformer forms in late endosomes upon processing of native protein, while the more flexible type B conformer forms in early endosomes and at the cell surface. In this process, H2-DM acts as a conformational editor, eliminating the type B conformer in late endosomes. Type B T cells constitute a significant component of the naïve T-cell repertoire; furthermore, self-reactive type B T cells escape negative selection and are present in abundance in the periphery. Ongoing studies should elucidate the role of type B T cells in immunity to pathogens and in autoimmune pathology.
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Affiliation(s)
- Scott B Lovitch
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
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58
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Busch R, Rinderknecht CH, Roh S, Lee AW, Harding JJ, Burster T, Hornell TMC, Mellins ED. Achieving stability through editing and chaperoning: regulation of MHC class II peptide binding and expression. Immunol Rev 2005; 207:242-60. [PMID: 16181341 DOI: 10.1111/j.0105-2896.2005.00306.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In antigen-presenting cells (APCs), loading of major histocompatibility complex class II (MHC II) molecules with peptides is regulated by invariant chain (Ii), which blocks MHC II antigen-binding sites in pre-endosomal compartments. Several molecules then act upon MHC II molecules in endosomes to facilitate peptide loading: Ii-degrading proteases, the peptide exchange factor, human leukocyte antigen-DM (HLA-DM), and its modulator, HLA-DO (DO). Here, we review our findings arguing that DM stabilizes a globally altered conformation of the antigen-binding groove by binding to a lateral surface of the MHC II molecule. Our data imply changes in the interactions between specificity pockets and peptide side chains, complementing data from others that suggest DM affects hydrogen bonds. Selective weakening of peptide/MHC interactions allows DM to alter the peptide repertoire. We also review our studies in cells that highlight the ability of several factors to modulate surface expression of MHC II molecules via post-Golgi mechanisms; these factors include MHC class II-associated Ii peptides (CLIP), DM, and microbial products that modulate MHC II traffic from endosomes to the plasma membrane. In this context, we discuss possible mechanisms by which the association of some MHC II alleles with autoimmune diseases may be linked to their low CLIP affinity.
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Affiliation(s)
- Robert Busch
- Division of Pediatric Immunology and Transplantation Biology, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94705, USA
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59
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Deshaies F, Thibodeau J. [HLA-DO: regulator of the immune response]. Med Sci (Paris) 2005; 21:911-2. [PMID: 16274638 DOI: 10.1051/medsci/20052111911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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60
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Abstract
Peptide loading of major histocompatibility class II molecules is catalyzed in late endosomal and lysosomal compartments of cells by the catalytic action of human leukocyte antigen (HLA)-DM (H-2M in mice). In B cells, dendritic cells and thymic epithelial cells, the peptide loading of class II molecules is modified by the expression of the non-classical class II molecule, HLA-DO (H-2O in mice). Collectively, studies to date support that DO/H-2O expression inhibits the presentation of antigens acquired by cells via fluid phase endocytosis. However, in B cells, the expression of H-2O promotes the presentation of antigens internalized by the B-cell receptor. In this review, we summarize the literature pertaining to DO assembly, transport, and function, with an emphasis on the function of DO/H-2O.
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Affiliation(s)
- Lisa K Denzin
- Sloan-Kettering Institute, Immunology Program, Memorial Sloan-Kettering Cancer Center, NY 10021, USA.
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61
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Marsman M, Jordens I, Griekspoor A, Neefjes J. Chaperoning antigen presentation by MHC class II molecules and their role in oncogenesis. Adv Cancer Res 2005; 93:129-58. [PMID: 15797446 DOI: 10.1016/s0065-230x(05)93004-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Tumor vaccine development aimed at stimulating the cellular immune response focuses mainly on MHC class I molecules. This is not surprising since most tumors do not express MHC class II or CD1 molecules. Nevertheless, the most successful targets for cancer immunotherapy, leukemia and melanoma, often do express MHC class II molecules, which leaves no obvious reason to ignore MHC class II molecules as a mediator in anticancer immune therapy. We review the current state of knowledge on the process of MHC class II-restricted antigen presentation and subsequently discuss the consequences of MHC class II expression on tumor surveillance and the induction of an efficient MHC class II mediated antitumor response in vivo and after vaccination.
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Affiliation(s)
- Marije Marsman
- Division of Tumor Biology, The Netherlands Cancer Institute, Amsterdam
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62
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Kim HJ, Guo D, Sant'Angelo DB. Coevolution of TCR-MHC interactions: conserved MHC tertiary structure is not sufficient for interactions with the TCR. Proc Natl Acad Sci U S A 2005; 102:7263-7. [PMID: 15883386 PMCID: PMC1091755 DOI: 10.1073/pnas.0502751102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The specificity for self-MHC that is necessary for T cell function is a consequence of intrathymic selection during which T cell antigen receptors (TCRs) expressed by immature thymocytes are tested for their affinity for self-peptide:self-MHC. The germ-line-encoded segments of the TCR, however, are believed to have an innate specificity for structural features of MHC molecules. We directly tested this hypothesis by generating a transgenic mouse system in which the protein HLA-DM is expressed at the surface of thymic cortical epithelial cells in the absence of classical MHC molecules. The specialized intracellular function of HLA-DM has removed this MHC class II-like protein from the evolutionary forces that have been hypothesized to shape TCR-MHC interactions. Our study shows that a structural mimic of MHC class II is not sufficient to appropriately interact with the TCRs expressed by developing thymocytes. This result emphasizes the unique complementarity of TCR-MHC interactions that are maintained by the evolutionary pressures dictated by positive selection.
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Affiliation(s)
- Hye-Jung Kim
- Laboratory of T Cell Immunobiology, Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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63
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Zwart W, Griekspoor A, Kuijl C, Marsman M, van Rheenen J, Janssen H, Calafat J, van Ham M, Janssen L, van Lith M, Jalink K, Neefjes J. Spatial separation of HLA-DM/HLA-DR interactions within MIIC and phagosome-induced immune escape. Immunity 2005; 22:221-33. [PMID: 15723810 DOI: 10.1016/j.immuni.2005.01.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 01/05/2005] [Accepted: 01/12/2005] [Indexed: 12/30/2022]
Abstract
Major Histocompatibility Complex (MHC) class II molecules, including Human Leukocyte Antigen (HLA)-DR, present peptide fragments from proteins degraded in the endocytic pathway. HLA-DR is targeted to late-endocytic structures named MHC class II-containing Compartments (MIIC), where it interacts with HLA-DM. This chaperone stabilizes HLA-DR during peptide exchange and is critical for successful peptide loading. To follow this process in living cells, we have generated cells containing HLA-DR3/Cyan Fluorescent Protein (CFP), HLA-DM/Yellow Fluorescent Protein (YFP), and invariant chain. HLA-DR/DM interactions were observed by Fluorescence Resonance Energy Transfer (FRET). These interactions were pH insensitive, yet occurred only in internal structures and not at the limiting membrane of MIIC. In a cellular model of infection, phagosomes formed a limiting membrane surrounding internalized Salmonella. HLA-DR and HLA-DM did not interact in Salmonella-induced vacuoles, and HLA-DR was not loaded with antigens. The absence of HLA-DR/DM interactions at the limiting membrane prevents local loading of MHC class II molecules in phagosomes. This may allow these bacteria to successfully evade the immune system.
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Affiliation(s)
- Wilbert Zwart
- Division of Tumor Biology , Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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64
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Marin-Esteban V, Falk K, Rötzschke O. “Chemical Analogues” of HLA-DM Can Induce a Peptide-receptive State in HLA-DR Molecules. J Biol Chem 2004; 279:50684-90. [PMID: 15381703 DOI: 10.1074/jbc.m407598200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We had recently identified small molecular compounds that are able to accelerate the ligand exchange reactions of HLA-DR molecules. Here we show that this acceleration is due to the induction of a "peptide-receptive" state. Dissociation experiments of soluble HLA-DR2.CLIP (class II-associated invariant chain peptide) complex and peptide-binding studies with "nonreceptive" empty HLA-DR1 and -DR2 molecules revealed that the presence of a small phenolic compound carrying an H-bond donor group (-OH) results in the drastic increase of both off- and on-rates. The rate-limiting step for ligand exchange, the transition of the major histocompatibility complex molecule from a nonreceptive into the receptive state, is normally mediated by interaction with the chaperone HLA-DM. In this respect, the effect of small molecules resembles that of the natural catalyst, except that they are still active at neutral pH. These "chemical analogues" of HLA-DM can therefore modulate the response of CD4+ T cells by editing the antigen composition of surface-bound class II major histocompatibility complex on living antigen-presenting cells.
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Affiliation(s)
- Viviana Marin-Esteban
- Max Delbrück Center for Molecular Medicine, Robert Rösslestrasse 10, 13125 Berlin, Germany
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65
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Koonce CH, Bikoff EK. Dissecting MHC class II export, B cell maturation, and DM stability defects in invariant chain mutant mice. THE JOURNAL OF IMMUNOLOGY 2004; 173:3271-80. [PMID: 15322189 DOI: 10.4049/jimmunol.173.5.3271] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Invariant (Ii) chain loss causes defective class II export, B cell maturation, and reduced DM stability. In this study, we compare Ii chain and class II mutant mouse phenotypes to dissect these disturbances. The present results demonstrate that ER retention of alphabeta complexes, and not beta-chain aggregates, disrupts B cell development. In contrast, we fail to detect class II aggregates in Ii chain mutant thymi. Ii chain loss in NOD mice leads to defective class II export and formation of alphabeta aggregates, but in this background, downstream signals are misregulated and mature B cells develop normally. Finally, Ii chain mutant strains all display reduced levels of DM, but mice expressing either p31 or p41 alone, and class II single chain mutants, are indistinguishable from wild type. We conclude that Ii chain contributions as a DM chaperone are independent of its role during class II export. This Ii chain/DM partnership favors class II peptide loading via conventional pathway(s).
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Affiliation(s)
- Chad H Koonce
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
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66
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Cobb BA, Wang Q, Tzianabos AO, Kasper DL. Polysaccharide Processing and Presentation by the MHCII Pathway. Cell 2004; 117:677-87. [PMID: 15163414 PMCID: PMC2917993 DOI: 10.1016/j.cell.2004.05.001] [Citation(s) in RCA: 229] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Revised: 04/13/2004] [Accepted: 04/22/2004] [Indexed: 10/26/2022]
Abstract
The adaptive immune system functions through the combined action of antigen-presenting cells (APCs) and T cells. Specifically, class I major histocompatibility complex antigen presentation to CD8(+) T cells is limited to proteosome-generated peptides from intracellular pathogens while the class II (MHCII) endocytic pathway presents only proteolytic peptides from extracellular pathogens to CD4(+) T cells. Carbohydrates have been thought to stimulate immune responses independently of T cells; however, zwitterionic polysaccharides (ZPSs) from the capsules of some bacteria can activate CD4(+) T cells. Here we show that ZPSs are processed to low molecular weight carbohydrates by a nitric oxide-mediated mechanism and presented to T cells through the MHCII endocytic pathway. Furthermore, these carbohydrates bind to MHCII inside APCs for presentation to T cells. Our observations begin to elucidate the mechanisms by which some carbohydrates induce important immunologic responses through T cell activation, suggesting a fundamental shift in the MHCII presentation paradigm.
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Affiliation(s)
- Brian A. Cobb
- Channing Laboratory, Department of Medicine, Brigham & Women’s Hospital, Boston, Massachusetts 02115
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Qun Wang
- Channing Laboratory, Department of Medicine, Brigham & Women’s Hospital, Boston, Massachusetts 02115
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Arthur O. Tzianabos
- Channing Laboratory, Department of Medicine, Brigham & Women’s Hospital, Boston, Massachusetts 02115
| | - Dennis L. Kasper
- Channing Laboratory, Department of Medicine, Brigham & Women’s Hospital, Boston, Massachusetts 02115
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115
- Correspondence:
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67
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Stratikos E, Wiley DC, Stern LJ. Enhanced Catalytic Action of HLA-DM on the Exchange of Peptides Lacking Backbone Hydrogen Bonds between their N-Terminal Region and the MHC Class II α-Chain. THE JOURNAL OF IMMUNOLOGY 2004; 172:1109-17. [PMID: 14707085 DOI: 10.4049/jimmunol.172.2.1109] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The class II MHC homolog HLA-DM catalyzes exchange of peptides bound to class II MHC proteins, and is an important component of the Ag presentation machinery. The mechanism of HLA-DM-mediated catalysis is largely obscure. HLA-DM catalyzes exchange of peptides of varying sequence, suggesting that a peptide sequence-independent component of the MHC-peptide interaction could be involved in the catalytic process. Twelve conserved hydrogen bonds between the peptide backbone and the MHC are a prominent sequence-independent feature of the MHC-peptide interaction. To evaluate the relative importance of these hydrogen bonds toward HLA-DM action, we prepared peptide variants that lacked the ability to form one or more of the hydrogen bonds as a result of backbone amide N-methylation or truncation, and tested their ability to be exchanged by HLA-DM. We found that disruption of hydrogen bonds involving HLA-DR1 residues alpha51-53, a short extended segment at the N terminus of the alpha subunit helical region, led to heightened HLA-DM catalytic efficacy. We propose that those bonds are disrupted in the MHC conformation recognized by HLA-DM to allow structural transitions in that area during DM-assisted peptide release. These results suggest that peptides or compounds that bind MHC but cannot form these interactions would be preferentially edited out by HLA-DM.
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Affiliation(s)
- Efstratios Stratikos
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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68
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Neumann J, Eis-Hübinger AM, Koch N. Herpes simplex virus type 1 targets the MHC class II processing pathway for immune evasion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:3075-83. [PMID: 12960333 DOI: 10.4049/jimmunol.171.6.3075] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HSV type 1 (HSV-1) has evolved numerous strategies for modifying immune responses that protect against infection. Important targets of HSV-1 infection are the MHC-encoded peptide receptors. Previous studies have shown that a helper T cell response and Ab production play important roles in controlling HSV-1 infection. The reduced capacity of infected B cells to stimulate CD4(+) T cells is beneficial for HSV-1 to evade immune defenses. We investigated the impact of HSV-1 infection on the MHCII processing pathway, which is critical to generate CD4(+) T cell help. HSV-1 infection targets the molecular coplayers of MHC class II processing, HLA-DR (DR), HLA-DM (DM), and invariant chain (Ii). HSV-1 infection strongly reduces expression of Ii, which impairs formation of SDS-resistant DR-peptide complexes. Residual activity of the MHC class II processing pathway is diminished by viral envelope glycoprotein B (gB). Binding of gB to DR competes with binding to Ii. In addition, we found gB associated with DM molecules. Both, gB-associated DR and DM heterodimers are exported from the endoplasmic reticulum, as indicated by carbohydrate maturation. Evaluation of DR, DM, and gB subcellular localization revealed abundant changes in intracellular distribution. DR-gB complexes are localized in subcellular vesicles and restrained from cell surface expression.
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Affiliation(s)
- Jürgen Neumann
- Section of Immunobiology, Institute for Molecular Physiology, University of Bonn, Bonn, Germany
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69
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Pashine A, Busch R, Belmares MP, Munning JN, Doebele RC, Buckingham M, Nolan GP, Mellins ED. Interaction of HLA-DR with an acidic face of HLA-DM disrupts sequence-dependent interactions with peptides. Immunity 2003; 19:183-92. [PMID: 12932352 DOI: 10.1016/s1074-7613(03)00200-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
HLA-DM (DM) edits major histocompatibility complex class II (MHCII)-bound peptides in endocytic compartments and stabilizes empty MHCII molecules. Crystal structures of DM have revealed similarity to MHCII but not how DM and MHCII interact. We used mutagenesis to map a MHCII-interacting surface on DM. Mutations on this surface impair DM action on HLA-DR and -DP in cells and DM-dependent peptide loading in vitro. The orientation of DM and MHCII predicted by these studies guided design of soluble DM and DR molecules fused to leucine zippers via their beta chains, resulting in stable DM/DR complexes. Peptide release from the complexes was fast and only weakly sequence dependent, arguing that DM diminishes the selectivity of the MHCII groove. Analysis of soluble DM action on soluble DR/peptide complexes corroborates this conclusion.
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Affiliation(s)
- Achal Pashine
- Department of Pediatrics, Stanford University, Stanford, California 94305, USA
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70
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Lich JD, Jayne JA, Zhou D, Elliott JF, Blum JS. Editing of an immunodominant epitope of glutamate decarboxylase by HLA-DM. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:853-9. [PMID: 12847254 DOI: 10.4049/jimmunol.171.2.853] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HLA-DM stabilizes peptide-receptive class II alphabeta dimers and facilitates the capture of high affinity peptides, thus influencing the peptide repertoire presented by class II molecules. Variations in DM levels may therefore have a profound effect on the antigenic focus of T cell-mediated immune responses. Specifically, DM expression may influence susceptibility and resistance to autoimmune diseases. In this study the role of DM in HLA-DR4-restricted presentation of an insulin-dependent diabetes mellitus autoantigen, glutamate decarboxylase (GAD), was tested. Presentation of immunodominant GAD epitope 273-285 was regulated by endogenous DM levels in human B lymphoblasts. T cell responses to exogenous GAD as well as an endogenous cytoplasmic form of this Ag were significantly diminished with increasing cellular expression of DM. Epitope editing by DM was observed only using Ag and not small synthetic peptides, suggesting that this process occurred within endosomes. Results with cytoplasmic GAD also indicated that peptides from this compartment intersect class II proteins in endocytic vesicles where DM editing was facilitated. Changes in DM levels within APC may therefore influence the presentation of autoantigens and the development of autoimmune disorders such as type I diabetes.
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Affiliation(s)
- John D Lich
- Department of Microbiology and Immunology and Walther Oncology Center, Indiana University School of Medicine, and Walther Cancer Institute, Indianapolis, IN 46202, USA
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71
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Rötzschke O, Lau JM, Hofstätter M, Falk K, Strominger JL. A pH-sensitive histidine residue as control element for ligand release from HLA-DR molecules. Proc Natl Acad Sci U S A 2002; 99:16946-50. [PMID: 12471156 PMCID: PMC139249 DOI: 10.1073/pnas.212643999] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2002] [Indexed: 11/18/2022] Open
Abstract
Class II MHC molecules undergo conformational changes on shifts of the pH. As a consequence, low-affinity peptides tightly bound at pH 7.0 can be released at pH 5.0. The imidazole group of histidine is the only amino acid side chain affected within this range. At pH 5.0 the group is positively charged, polar, and hydrophilic, whereas at pH 7.4 it is neutral, apolar, and hydrophobic. In this study, we used soluble forms of HLA-DR and substituted conserved histidine residues with tyrosine, an isosteric analogue to the uncharged form of histidine. The goal of this substitution was to identify crucial His residues by an increase in pH stability of the ligand complex. HLA-DM-mediated release experiments revealed that substitution of His-33 in the alpha(1) domain of the HLA-DR molecule almost doubled the half-life of HLA-DR1class II-associated invariant-chain peptide complexes. The divergence in the off-rate of WT and H33Y mutated complex was strictly pH-dependent and correlated with the theoretical titration curve of the imidazole group. For both HLA-DR1 and HLA-DR4 molecules the mutation resulted in a shift of class II-associated invariant-chain peptide release curves by up to 0.5 pH units. His-33alpha1 is present in all HLA-DR and H-2E molecules. It connects the alpha(1) and alpha(2) domains in its noncharged form by hydrophobic interactions with residue Val-136alpha2. It is located in close proximity to the putative interface with HLA-DM and may function as a pH-sensitive "button," which is closed at pH 7.0 but opens below pH 6.0 to allow conformational transitions necessary for ligand exchange.
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Affiliation(s)
- Olaf Rötzschke
- Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA
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72
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Belmares MP, Busch R, Wucherpfennig KW, McConnell HM, Mellins ED. Structural factors contributing to DM susceptibility of MHC class II/peptide complexes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:5109-17. [PMID: 12391227 DOI: 10.4049/jimmunol.169.9.5109] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Peptide loading of MHC class II (MHCII) molecules is assisted by HLA-DM, which releases invariant chain peptides from newly synthesized MHCII and edits the peptide repertoire. Determinants of susceptibility of peptide/MHCII complexes to DM remain controversial, however. Here we have measured peptide dissociation in the presence and the absence of DM for 36 different complexes of varying intrinsic stability. We found large variations in DM susceptibility for different complexes using either soluble or full-length HLA-DM. The DM effect was significantly less for unstable complexes than for stable ones, although this correlation was modest. Peptide sequence- and allele-dependent interactions along the entire length of the Ag binding groove influenced DM susceptibility. We also observed differences in DM susceptibility during peptide association. Thus, the peptide repertoire displayed to CD4(+) T cells is the result of a mechanistically complicated editing process and cannot be simply predicted from the intrinsic stability of the complexes in the absence of DM.
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73
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Stratikos E, Mosyak L, Zaller DM, Wiley DC. Identification of the lateral interaction surfaces of human histocompatibility leukocyte antigen (HLA)-DM with HLA-DR1 by formation of tethered complexes that present enhanced HLA-DM catalysis. J Exp Med 2002; 196:173-83. [PMID: 12119342 PMCID: PMC2193930 DOI: 10.1084/jem.20020117] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Human histocompatibility leukocyte antigen (HLA)-DM is a major histocompatibility complex (MHC)-like protein that catalyzes exchange of antigenic peptides from MHC class II molecules. To investigate the molecular details of this catalysis we created four covalent complexes between HLA-DM and the MHC class II allele DR1. We introduced a disulfide bond between the naturally occurring cysteine beta46 on HLA-DM and an engineered cysteine on the end of a linker attached to either the NH(2)- or the COOH terminus of an antigenic peptide that is tightly bound on DR1. We find that when DM is attached to the NH(2) terminus of the peptide, it can, for all linker lengths tested, catalyze exchange of the peptide with a half-life a few minutes (compared with uncatalyzed t(1/2) > 100 h). This rate, which is several orders of magnitude greater than the one we obtain in solution assays using micromolar concentrations of HLA-DM, is dominated by a concentration independent factor, indicating an intramolecular catalytic interaction within the complex. A similar complex formed at the COOH terminus of the peptide shows no sign of DM-specific intramolecular catalysis. Restrictions on the possible interaction sites imposed by the length of the linkers indicate that the face of DR1 that accommodates the NH(2) terminus of the antigenic peptide interacts with the lateral face of HLA-DM that contains cysteine beta46.
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Affiliation(s)
- Efstratios Stratikos
- Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA.
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74
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Figueredo Dos Santos C, Tilkin-Mariame AF, De Préval C, Lakhdar-Ghazal F. Influence of histidine beta81 of HLA-DR101 on peptide binding and presentation to T-cell receptor. Hum Immunol 2002; 63:459-66. [PMID: 12039521 DOI: 10.1016/s0198-8859(02)00394-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HA(306-318) is an immunodominant peptide of the hemagglutinin of influenza virus that binds to most human leukocyte antigen (HLA-DR) alleles, while p18(73-85) is a HIV peptide characterized as a DR101 binding peptide. Our results demonstrate that crystal relaxation leads to the loss of a hydrogen bond between the beta81 histidine and the HA(306-318) peptide. This histidine is also involved in the binding of superantigens like SEA via a coordination of a zinc atom. To monitor the interaction of these peptides with this histidine of HLA-DR molecules, chemical modification, peptide binding on HLA-DR101 wild type and mutated molecules, and proliferation experiments were conducted, together with molecular simulation of HLA-DR/peptide molecular complexes. Our data suggest a different binding peptide pattern, depending of whether the peptide is HLA-DR101 allele specific or a shared one. Furthermore, tyrosine substitution at position beta81 does not affect either peptide binding or HA(306-318) clone-specific T-cell proliferation. On the contrary, the alanine substitution at position HLA-DR101 beta81 abrogated both peptide binding and T-cell proliferation. These results suggest that the histidine 81 on the DRbeta chain plays an important role in the HLA-DR peptide binding, more likely by polar interactions of the amino acid side chain ring with the peptide.
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75
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Busch R, Pashine A, Garcia KC, Mellins ED. Stabilization of soluble, low-affinity HLA-DM/HLA-DR1 complexes by leucine zippers. J Immunol Methods 2002; 263:111-21. [PMID: 12009208 DOI: 10.1016/s0022-1759(02)00034-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The ectodomains of interacting membrane-bound proteins, when expressed as recombinant soluble molecules, often have low affinities for each other, hampering studies of their interaction. We reasoned that stabilization of unstable protein-protein complexes should aid our understanding of the structural and functional consequences of complex formation. Here, we have used fusion with leucine zipper (LZ) domains to stabilize a complex formed between the class II major histocompatibility complex (MHC-II) protein, HLA-DR1 (which binds peptides for presentation to CD4+ T cells) and HLA-DM (which catalyzes peptide exchange of MHC-II molecules). To this end, the DM beta chain ectodomains were fused to acidic LZ domains (AcidP1 or Fos); similarly, the DR1 beta chain ectodomains were fused to basic LZ domains (BaseP1 or Jun). We expressed LZ-modified soluble DM or DR1 alphabeta dimers, or both, in insect cells and purified the secreted sDM-AcidP1 and sDR1-BaseP1 molecules as well as the complex. LZ modification greatly enhanced DM-catalyzed peptide binding to DR1 compared to unmodified soluble DM and DR1. We readily detected LZ-modified DM/DR complexes on native PAGE gels and by coimmunoprecipitation. Thus, fusion with artificial LZ domains can stabilize unstable protein-protein complexes for biochemical and structural studies of interactions within the complex.
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Affiliation(s)
- Robert Busch
- Department of Pediatrics, Stanford University Medical Center, Room 2120 CCSR Bldg., 269 Campus Drive, CA 94305-5164, USA.
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76
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Abstract
The presentation of peptides to T cells by MHC class II molecules is of critical importance in specific recognition by the immune system. Expression of class II molecules is exquisitely controlled at the transcriptional level. A large set of proteins interact with the promoters of class II genes. The most important of these is CIITA, a master controller that orchestrates expression but does not bind directly to the promoter. The transcriptosome complex formed at class II promoters is a model for induction of gene expression.
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Affiliation(s)
- Jenny Pan-Yun Ting
- Department of Microbiology and Immunology and The Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA.
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77
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Hennecke J, Wiley DC. Structure of a complex of the human alpha/beta T cell receptor (TCR) HA1.7, influenza hemagglutinin peptide, and major histocompatibility complex class II molecule, HLA-DR4 (DRA*0101 and DRB1*0401): insight into TCR cross-restriction and alloreactivity. J Exp Med 2002; 195:571-81. [PMID: 11877480 PMCID: PMC2193773 DOI: 10.1084/jem.20011194] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The alpha/beta T cell receptor (TCR) HA1.7 specific for the hemagglutinin (HA) antigen peptide from influenza A virus is HLA-DR1 restricted but cross-reactive for the HA peptide presented by the allo-major histocompatibility complex (MHC) class II molecule HLA-DR4. We report here the structure of the HA1.7/DR4/HA complex, determined by X-ray crystallography at a resolution of 2.4 A. The overall structure of this complex is very similar to the previously reported structure of the HA1.7/DR1/HA complex. Amino acid sequence differences between DR1 and DR4, which are located deep in the peptide binding groove and out of reach for direct contact by the TCR, are able to indirectly influence the antigenicity of the pMHC surface by changing the conformation of HA peptide residues at position P5 and P6. Although TCR HA1.7 is cross-reactive for HA presented by DR1 and DR4 and tolerates these conformational differences, other HA-specific TCRs are sensitive to these changes. We also find a dependence of the width of the MHC class II peptide-binding groove on the sequence of the bound peptide by comparing the HA1.7/DR4/HA complex with the structure of DR4 presenting a collagen peptide. This structural study of TCR cross-reactivity emphasizes how MHC sequence differences can affect TCR binding indirectly by moving peptide atoms.
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Affiliation(s)
- Jens Hennecke
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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78
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McFarland BJ, Beeson C. Binding interactions between peptides and proteins of the class II major histocompatibility complex. Med Res Rev 2002; 22:168-203. [PMID: 11857638 DOI: 10.1002/med.10006] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The activation of helper T cells by peptides bound to proteins of the class II Major Histocompatibility Complex (MHC II) is pivotal to the initiation of an immune response. The primary functional requirement imposed on MHC II proteins is the ability to efficiently bind thousands of different peptides. Structurally, this is reflected in a unique architecture of binding interactions. The peptide is bound in an extended conformation within a groove on the membrane distal surface of the protein that is lined with several pockets that can accommodate peptide side-chains. Conserved MHC II protein residues also form hydrogen bonds along the length of the peptide main-chain. Here we review recent advances in the study of peptide-MHC II protein reactions that have led to an enhanced understanding of binding energetics. These results demonstrate that peptide-MHC II protein complexes achieve high affinity binding from the array of hydrogen bonds that are energetically segregated from the pocket interactions, which can then add to an intrinsic hydrogen bond-mediated affinity. Thus, MHC II proteins are unlike antibodies, which utilize cooperativity among binding interactions to achieve high affinity and specificity. The significance of these observations is discussed within the context of possible mechanisms for the HLA-DM protein that regulates peptide presentation in vivo and the design of non-peptide molecules that can bind MHC II proteins and act as vaccines or immune modulators.
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Affiliation(s)
- Benjamin J McFarland
- Program in Biomolecular Structure and Design, Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700
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79
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Brocke P, Garbi N, Momburg F, Hämmerling GJ. HLA-DM, HLA-DO and tapasin: functional similarities and differences. Curr Opin Immunol 2002; 14:22-9. [PMID: 11790529 DOI: 10.1016/s0952-7915(01)00294-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In both the MHC class II and class I pathways of antigen presentation, accessory molecules influence formation of MHC-peptide complexes. In the MHC class II pathway, DM functions in the loading and editing of peptides; recent work demonstrated that it is acting not only in late endosomal compartments but also in recycling compartments and on the surface of B cells and immature dendritic cells. DM activity is modulated by another accessory molecule, DO, but this modulation is mainly operative in B cells, where it may lead to preferential activation of B cells producing high-affinity antibodies. In the MHC class I pathway of antigen presentation, recent in vivo experiments with knockout mice confirmed the role of tapasin in antigen presentation and indicate that it acts as a peptide editor and as a chaperone for TAP and the MHC class I heavy chain. In the class I loading complex, calreticulin and the thiol-dependent oxidoreductase ER60/ERp57 appear to support the function of tapasin in an as-yet-unknown fashion. The picture emerges that DM and tapasin have analogous functions in shaping the peptide repertoire presented by the respective MHC class II and class I molecules.
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Affiliation(s)
- Pascale Brocke
- DKFZ Deutsches Krebsforschungszentrum, German Cancer Research Center, Molecular Immunology, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany
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80
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Falk K, Lau JM, Santambrogio L, Esteban VM, Puentes F, Rotzschke O, Strominger JL. Ligand exchange of major histocompatibility complex class II proteins is triggered by H-bond donor groups of small molecules. J Biol Chem 2002; 277:2709-15. [PMID: 11602608 DOI: 10.1074/jbc.m109098200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hydrogen bonds (H-bonds) are crucial for the stability of the peptide-major histocompatibility complex (MHC) complex. In particular, the H-bonds formed between the peptide ligand and the MHC class II binding site appear to have a great influence on the half-life of the complex. Here we show that functional groups with the capacity to disrupt hydrogen bonds (e.g. -OH) can efficiently catalyze ligand exchange reactions on HLA-DR molecules. In conjunction with simple carrier molecules (such as propyl or benzyl residues), they trigger the release of low affinity ligands, which permits the rapid binding of peptides with higher affinity. Similar to HLA-DM, these compounds are able to influence the MHC class II ligand repertoire. In contrast to HLA-DM, however, these simple small molecules are still active at neutral pH. Under physiological conditions, they increase the number of "peptide-receptive" MHC class II molecules and facilitate exogenous peptide loading of dendritic cells. The drastic acceleration of the ligand exchange on these antigen presenting cells suggests that, in general, availability of H-bond donors in the extracellular milieu controls the rate of MHC class II ligand exchange reactions on the cell surface. These molecules may therefore be extremely useful for the loading of antigens onto dendritic cells for therapeutic purposes.
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Affiliation(s)
- Kirsten Falk
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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81
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Faubert A, Samaan A, Thibodeau J. Functional analysis of tryptophans alpha 62 and beta 120 on HLA-DM. J Biol Chem 2002; 277:2750-5. [PMID: 11713260 DOI: 10.1074/jbc.m110300200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the endocytic pathway of antigen-presenting cells, HLA-DM catalyzes the exchange between class II-associated invariant chain peptide (CLIP) and antigenic peptides onto major histocompatibility complex class II molecules. At low pH of lysosomal compartments, both HLA-DM and HLA-DR undergo conformational changes, and it was recently postulated that two partially exposed tryptophans on HLA-DM might be involved in the interaction between the two molecules. To define contact regions on HLA-DM, we have conducted site-directed mutagenesis on those two hydrophobic residues. The HLA-DM alphaW62A,betaW120A (DM(W62A/W120A)) double mutant was expressed in HLA-DR(+) HeLa cells expressing invariant chain, and the activity of this DM molecule was assessed. Flow cytometry analysis of cell surface DR-CLIP complexes revealed that DM(W62A/W120A) removes CLIP as efficiently as its wild-type counterpart. DM(W62A/W120A) was found in the endocytic pathway by immunofluorescence, and DM-DR complexes were immunoprecipitated from these cells at pH 5. Finally, mutations alphaW62A and betaW120A on HLA-DM did not affect the association with HLA-DO. The complex egresses the endoplasmic reticulum and accumulates in endocytic vesicles. Moreover, DO and DM(W62A/)W120A were co-immunoprecipitated at pH 7. We conclude that the alpha62 and beta120 tryptophan residues are not required for the activity of DM, nor are they directly implicated in the interaction with DR or DO.
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Affiliation(s)
- Amélie Faubert
- Laboratoire d'Immunologie Moléculaire, Département de Microbiologie et d'Immunologie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
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82
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Abstract
The stable assembly of Major Histocompatibility Complex (MHC) molecules with peptides is controlled by a number of cofactors, including proteins with general housekeeping functions and proteins with dedicated functions in MHC assembly. Recent work in my laboratory has focused on two chaperones, tapasin (tpn) and DM, that play critical roles in the loading of peptides onto MHC class I and MHC class II molecules, respectively. Tapasin is a transmembrane protein that tethers empty class I molecules in the endoplasmic reticulum to the transporter associated with antigen processing. DM is a peptide exchange factor that binds with empty and peptide-loaded class II molecules in endosomal and lysosomal compartments. Although a number of different functions for tapasin and DM have been proposed, emerging evidence suggests that both of these chaperones retain unstable MHC molecules in peptide-loading compartments until they bind with high-affinity peptides. These cofactors therefore promote the surface expression of long-lived MHC-peptide complexes.
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Affiliation(s)
- L Van Kaer
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-0295, USA.
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83
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Bryant PW, Lennon-Duménil AM, Fiebiger E, Lagaudrière-Gesbert C, Ploegh HL. Proteolysis and antigen presentation by MHC class II molecules. Adv Immunol 2002; 80:71-114. [PMID: 12078484 PMCID: PMC7130937 DOI: 10.1016/s0065-2776(02)80013-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Proteolysis is the primary mechanism used by all cells not only to dispose of unwanted proteins but also to regulate protein function and maintain cellular homeostasis. Proteases that reside in the endocytic pathway are the principal actors of terminal protein degradation. The proteases contained in the endocytic pathway are classified into four major groups based on the active-site amino acid used by the enzyme to hydrolyze amide bonds of proteins: cysteine, aspartyl, serine, and metalloproteases. The presentation of peptide antigens by major histocompatibility complex (MHC) class II molecules is strictly dependent on the action of proteases. Class II molecules scour the endocytic pathway for antigenic peptides to bind and present at the cell surface for recognition by CD4+ T cells. The specialized cell types that support antigen presentation by class II molecules are commonly referred to as professional antigen presenting cells (APCs), which include bone marrow-derived B lymphocytes, dendritic cells (DCs), and macrophages. In addition, the expression of certain endocytic proteases is regulated either at the level of gene transcription or enzyme maturation and their activity is controlled by the presence of endogenous protease inhibitors.
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Affiliation(s)
- Paula Wolf Bryant
- Department of Microbiology, Ohio State University, Columbus, Ohio 43210, USA
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84
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Mayer WE, Klein J. Is tapasin a modified Mhc class I molecule? Immunogenetics 2001; 53:719-23. [PMID: 11862402 DOI: 10.1007/s00251-001-0403-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2001] [Accepted: 11/16/2001] [Indexed: 11/28/2022]
Affiliation(s)
- W E Mayer
- Max-Planck-Institut für Biologie, Abteilung Immungenetik, Corrensstrasse 42, 72076 Tübingen, Germany.
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85
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Weber DA, Dao CT, Jun J, Wigal JL, Jensen PE. Transmembrane domain-mediated colocalization of HLA-DM and HLA-DR is required for optimal HLA-DM catalytic activity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:5167-74. [PMID: 11673529 DOI: 10.4049/jimmunol.167.9.5167] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HLA-DM catalyzes peptide loading and exchange reactions by MHC class II molecules. Soluble recombinant DM, lacking transmembrane and cytoplasmic domains, was observed to have 200- to 400-fold less activity compared with the full-length protein in assays measuring DM-catalyzed peptide dissociation from purified HLA-DR1 in detergent solutions. Additional studies with truncated soluble DR1 demonstrated that transmembrane domains in DR1 molecules are also required for optimal activity. The potential requirement for specific interaction between the transmembrane domains of DM and DR was ruled out in experiments with chimeric DR1 molecules containing transmembrane domains from either DM or the unrelated protein CD80. These results suggested that the major role of the transmembrane domains is to facilitate colocalization of DM and DR in detergent micelles. The latter conclusion was further supported by the observation that HLA-DM-catalyzed peptide binding to certain murine class II proteins is increased by reducing the volume of detergent micelles. The importance of membrane colocalization was directly demonstrated in experiments in which DM and DR were reconstituted separately or together into membrane bilayers in unilamellar liposomes. Our findings demonstrate the importance of membrane anchoring in DM activity and underscore the potential importance of membrane localization in regulating peptide exchange by class II molecules.
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Affiliation(s)
- D A Weber
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
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86
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Zarutskie JA, Busch R, Zavala-Ruiz Z, Rushe M, Mellins ED, Stern LJ. The kinetic basis of peptide exchange catalysis by HLA-DM. Proc Natl Acad Sci U S A 2001; 98:12450-5. [PMID: 11606721 PMCID: PMC60074 DOI: 10.1073/pnas.211439398] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2001] [Accepted: 08/20/2001] [Indexed: 11/18/2022] Open
Abstract
The mechanism by which the peptide exchange factor HLA-DM catalyzes peptide loading onto structurally homologous class II MHC proteins is an outstanding problem in antigen presentation. The peptide-loading reaction of class II MHC proteins is complex and includes conformational changes in both empty and peptide-bound forms in addition to a bimolecular binding step. By using a fluorescence energy transfer assay to follow the kinetics of peptide binding to the human class II MHC protein HLA-DR1, we find that HLA-DM catalyzes peptide exchange by facilitating a conformational change in the peptide-bound complex, and not by promoting the bimolecular MHC-peptide reaction or the conversion between peptide-receptive and -averse forms of the empty protein. Thus, HLA-DM serves essentially as a protein-folding or conformational catalyst.
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Affiliation(s)
- J A Zarutskie
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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87
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Gewurz BE, Gaudet R, Tortorella D, Wang EW, Ploegh HL. Virus subversion of immunity: a structural perspective. Curr Opin Immunol 2001; 13:442-50. [PMID: 11498300 DOI: 10.1016/s0952-7915(00)00239-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Over the past year, we have witnessed the discovery of further virus immuno-evasins--proteins that alter the host immune response. Although many of these factors have been described over the past decade, the structural basis underlying their biology has lagged behind. Structural data have now been obtained for several such proteins. Major advances of the past year include the structures of a viral chemokine-binding protein, of an intact viral regulator of complement activation and of an immuno-evasin with its cellular target.
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Affiliation(s)
- B E Gewurz
- Department of Pathology, Harvard Medical School, Building D2, Room 137, 200 Longwood Avenue, Boston, MA 02115, USA.
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88
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McFarland BJ, Katz JF, Beeson C, Sant AJ. Energetic asymmetry among hydrogen bonds in MHC class II*peptide complexes. Proc Natl Acad Sci U S A 2001; 98:9231-6. [PMID: 11470892 PMCID: PMC55403 DOI: 10.1073/pnas.151131498] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Comparison of crystallized MHC class II*peptide complexes has revealed that, in addition to pocket interactions involving the peptide side chains, peptide binding to MHC class II molecules is characterized by a series of hydrogen bonds between genetically conserved amino acid residues in the class II molecule and the main chain of the peptide. Many class II*peptide structures have two sets of symmetrical hydrogen bonds at the opposite ends of the class II antigen-binding groove (beta-His-81, beta-Asn-82 vs. alpha-His-68, alpha-Asn-69). In this study, we alter these peripheral hydrogen bonds and measure the apparent contribution of each to the kinetic stability of peptide* II complexes. Single conservative amino substitutions were made in the I-A(d) protein to eliminate participation as a hydrogen bonding residue, and the kinetic stability of a diverse set of peptides bound to the substituted I-A(d) proteins was measured. Although each hydrogen bond does contribute to peptide binding, our results point to the striking conclusion that those hydrogen bonds localized to the amino terminus of the peptide contribute profoundly and disproportionately to the stability of peptide interactions with I-A(d). We suggest that the peripheral hydrogen bonds at the amino terminus of the bound peptide that are conserved in all class II*peptide crystal structures solved thus far form a cooperative network that critically regulates peptide dissociation from the class II molecule.
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Affiliation(s)
- B J McFarland
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
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89
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Lee KH, Wucherpfennig KW, Wiley DC. Structure of a human insulin peptide-HLA-DQ8 complex and susceptibility to type 1 diabetes. Nat Immunol 2001; 2:501-7. [PMID: 11376336 DOI: 10.1038/88694] [Citation(s) in RCA: 281] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The class II major histocompatibility complex (MHC) glycoproteins HLA-DQ8 and HLA-DQ2 in humans and I-A(g7) in nonobese diabetic (NOD) mice are the major risk factors for increased susceptibility to type 1 diabetes. Using X-ray crystallography, we have determined the three-dimensional structure of DQ8 complexed with an immunodominant peptide from insulin. The similarity of the DQ8, DQ2 and I-A(g7) peptide-binding pockets suggests that diabetes is caused by the same antigen-presentation event(s) in humans and NOD mice. Correlating type 1 diabetes epidemiology and MHC sequences with the DQ8 structure suggests that other structural features of the P9 pocket in addition to position 57 contribute to susceptibility to type 1 diabetes.
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Affiliation(s)
- K H Lee
- Laboratory of Molecular Medicine, The Department of Medicine, The Children's Hospital, 320 Longwood Avenue, Boston, MA 02115, USA
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90
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Bikoff EK, Wutz G, Kenty GA, Koonce CH, Robertson EJ. Relaxed DM requirements during class II peptide loading and CD4+ T cell maturation in BALB/c mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:5087-98. [PMID: 11290790 DOI: 10.4049/jimmunol.166.8.5087] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Current ideas about DM actions have been strongly influenced by studies of mutant strains expressing the H-2(b) haplotype. To evaluate DM contributions to class II activities in BALB/c mice, we generated a novel mutation at the DMa locus via embryonic stem cell technology. Unlike long-lived A(b)/class II-associated invariant chain-derived peptide (CLIP) complexes, mature A(d) and E(d) molecules are loosely occupied by class II-associated invariant chain-derived peptide and are SDS unstable. BALB/c DM mutants weakly express BP107 conformational epitopes and toxic shock syndrome toxin-1 superantigen-binding capabilities, consistent with partial occupancy by wild-type ligands. Near normal numbers of mature CD4(+) T cells fail to undergo superantigen-mediated negative selection, as judged by TCR Vbeta usage. Ag presentation assays reveal consistent differences for A(d)- and E(d)-restricted T cells. Indeed, the mutation leads to decreased peptide capture by A(d) molecules, and in striking contrast causes enhanced peptide loading by E(d) molecules. Thus, DM requirements differ for class II structural variants coexpressed under physiological conditions in the intact animal.
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MESH Headings
- Alleles
- Animals
- Antigen Presentation/genetics
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/metabolism
- CD4-Positive T-Lymphocytes/cytology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Line
- Clone Cells
- Crosses, Genetic
- Dimerization
- Female
- Gene Targeting
- Haplotypes
- Histocompatibility Antigens Class II/chemistry
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/immunology
- Histocompatibility Antigens Class II/metabolism
- Lymphocyte Activation/genetics
- Male
- Mice
- Mice, Inbred BALB C/genetics
- Mice, Inbred BALB C/immunology
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Knockout
- Peptides/genetics
- Peptides/immunology
- Peptides/metabolism
- Protein Conformation
- Sequence Deletion
- Sodium Dodecyl Sulfate
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Affiliation(s)
- E K Bikoff
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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91
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Patil NS, Hall FC, Drover S, Spurrell DR, Bos E, Cope AP, Sonderstrup G, Mellins ED. Autoantigenic HCgp39 epitopes are presented by the HLA-DM-dependent presentation pathway in human B cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:33-41. [PMID: 11123274 DOI: 10.4049/jimmunol.166.1.33] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
It is hypothesized that autoimmune diseases manifest when tolerance to self-Ags fails. One possible mechanism to break tolerance is presentation of self-Ag in an altered form. Most Ags are presented by APCs via the traditional presentation pathway that includes "epitope editing" by intracellular HLA-DM, a molecule that selects for stable MHC-peptide complexes. We were interested in testing the hypothesis that autoreactive MHC-peptide complexes may reach the cell surface by an alternate pathway without being edited by HLA-DM. We selected a cartilage autoantigen human cartilage glycoprotein 39 to which T cell responses are observed in rheumatoid arthritis (RA) patients and some DR(*)04 healthy subjects. RA is genetically associated with certain DRB1 alleles, including DRB1(*)0401 but closely related allele DRB1(*)0402 is either neutral or mildly protective with respect to RA. We generated human B lymphoblastoid cell line cells expressing DR(*)0401 or DR(*)0402 in the presence or absence of intracellular HLA-DM and assessed their ability to present a candidate autoantigen, human cartilage glycoprotein 39. Our results show that the presence of intracellular HLA-DM is critical for presentation of this autoantigen to CD4(+) T cell hybridomas generated from DR(*)04-transgenic mice. Presentation of an autoantigen by the traditional HLA-DM-dependent pathway has implications for Ag presentation events in RA.
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Affiliation(s)
- N S Patil
- Department of Pediatric Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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92
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Chou CL, Sadegh-Nasseri S. HLA-DM recognizes the flexible conformation of major histocompatibility complex class II. J Exp Med 2000; 192:1697-706. [PMID: 11120767 PMCID: PMC2213500 DOI: 10.1084/jem.192.12.1697] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
DM facilitates formation of high affinity complexes of peptide-major histocompatibility complex (MHC) by release of class II MHC-associated invariant chain peptide (CLIP). This has been proposed to occur through discrimination of complex stability. By probing kinetic and conformational intermediates of the wild-type and mutant human histocompatibility leukocyte antigen (HLA)-DR1-peptide complexes, and examining their reactivities with DM, we propose that DM interacts with the flexible hydrophobic pocket 1 of DR1 and converts the molecule into a conformation that is highly peptide receptive. A more rigid conformation, generated upon filling of pocket 1, is less susceptible to DM effects. Thus, DM edits peptide-MHC by recognition of the flexibility rather than stability of the complex.
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Affiliation(s)
- Chih-Ling Chou
- Graduate Program in Molecular Biophysics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Scheherazade Sadegh-Nasseri
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Graduate Program in Molecular Biophysics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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93
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Hennecke J, Carfi A, Wiley DC. Structure of a covalently stabilized complex of a human alphabeta T-cell receptor, influenza HA peptide and MHC class II molecule, HLA-DR1. EMBO J 2000; 19:5611-24. [PMID: 11060013 PMCID: PMC305780 DOI: 10.1093/emboj/19.21.5611] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An alphabeta T-cell receptor (alphabetaTCR)/hemagglutinin (HA) peptide/human leukocyte antigen (HLA)-DR1 complex was stabilized by flexibly linking the HA peptide with the human HA1.7 alphabetaTCR, to increase the local concentration of the interacting proteins once the peptide has been loaded onto the major histocompatibility complex (MHC) molecule. The structure of the complex, determined by X-ray crystallography, has a binding mode similar to that of the human B7 alphabetaTCR on a pMHCI molecule. Twelve of the 15 MHC residues contacted are at the same positions observed earlier in class I MHC/peptide/TCR complexes. One contact, to an MHC loop outside the peptide-binding site, is conserved and specific to pMHCII complexes. TCR gene usage in the response to HA/HLA-DR appears to conserve charged interactions between three lysines of the peptide and acidic residues on the TCR.
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MESH Headings
- Amino Acid Sequence
- Binding Sites/genetics
- Crystallography, X-Ray
- Drug Stability
- HLA-DR1 Antigen/chemistry
- HLA-DR1 Antigen/genetics
- Hemagglutinin Glycoproteins, Influenza Virus/chemistry
- Hemagglutinin Glycoproteins, Influenza Virus/genetics
- Humans
- In Vitro Techniques
- Macromolecular Substances
- Models, Molecular
- Molecular Sequence Data
- Protein Conformation
- Protein Engineering
- Protein Folding
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Sequence Homology, Amino Acid
- Static Electricity
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Affiliation(s)
- J Hennecke
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, 7 Divinity Avenue, Cambridge, MA 02138, USA
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94
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Doebele RC, Busch R, Scott HM, Pashine A, Mellins ED. Determination of the HLA-DM interaction site on HLA-DR molecules. Immunity 2000; 13:517-27. [PMID: 11070170 DOI: 10.1016/s1074-7613(00)00051-0] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
HLA-DM removes CLIP and other loosely bound peptides from MHC class II molecules. The crystal structures of class II molecules and of HLA-DM have not permitted identification of their interaction sites. Here, we describe mutations in class II that impair interactions with DM. Libraries of randomly mutagenized DR3 alpha and beta chains were screened for their ability to cause cell surface accumulation of CLIP/DR3 complexes in EBV-B cells. Seven mutations were associated with impaired peptide loading in vivo, as detected by SDS stability assays. In vitro, these mutant DR3 molecules were resistant to DM-catalyzed CLIP release and showed reduced binding to DM. All mutations localize to a single lateral face of HLA-DR, which we propose interacts with DM during peptide exchange.
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Affiliation(s)
- R C Doebele
- School of Medicine, University of Pennsylvania, Philadelphia 19104, USA.
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95
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Abstract
Major histocompatibility complex (MHC) class II molecules are cell surface proteins that present peptides to CD4(+) T cells. In addition to these wellcharacterized molecules, two other class II-like proteins are produced from the class II region of the MHC, HLA-DM (DM) and HLA-DO (DO) (called H2-M, or H2-DM and H2-O in the mouse). The function of DM is well established; it promotes peptide loading of class II molecules in the endosomal/lysosomal system by catalyzing the release of CLIP peptides (derived from the class II-associated invariant chain) in exchange for more stably binding peptides. While DM is present in all class II- expressing antigen presenting cells, DO is expressed mainly in B cells. In this cell type the majority of DM molecules are not present as free heterodimers but are instead associated with DO in tight heterotetrameric complexes. The association with DM is essential for the intracellular transport of DO, and the two molecules remain associated in the endosomal system. DO can clearly modify the peptide exchange activity of DM both in vitro and in vivo, but the physiological relevance of this interaction is still only partly understood.
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Affiliation(s)
- C Alfonso
- The R.W. Johnson Pharmaceutical Research Institute, San Diego, California 92121, USA
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96
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van Ham M, van Lith M, Lillemeier B, Tjin E, Grüneberg U, Rahman D, Pastoors L, van Meijgaarden K, Roucard C, Trowsdale J, Ottenhoff T, Pappin D, Neefjes J. Modulation of the major histocompatibility complex class II-associated peptide repertoire by human histocompatibility leukocyte antigen (HLA)-DO. J Exp Med 2000; 191:1127-36. [PMID: 10748231 PMCID: PMC2193174 DOI: 10.1084/jem.191.7.1127] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/1999] [Accepted: 01/21/2000] [Indexed: 11/24/2022] Open
Abstract
Antigen presentation by major histocompatibility complex class II molecules is essential for antibody production and T cell activation. For most class II alleles, peptide binding depends on the catalytic action of human histocompatibility leukocyte antigens (HLA)-DM. HLA-DO is selectively expressed in B cells and impedes the activity of DM, yet its physiological role remains unclear. Cell surface iodination assays and mass spectrometry of major histocompatibility complex class II-eluted peptides show that DO affects the antigenic peptide repertoire of class II. DO generates both quantitative and qualitative differences, and inhibits presentation of large-sized peptides. DO function was investigated under various pH conditions in in vitro peptide exchange assays and in antigen presentation assays using DO(-) and DO(+) transfectant cell lines as antigen-presenting cells, in which effective acidification of the endocytic pathway was prevented with bafilomycin A(1), an inhibitor of vacuolar ATPases. DO effectively inhibits antigen presentation of peptides that are loaded onto class II in endosomal compartments that are not very acidic. Thus, DO appears to be a unique, cell type-specific modulator mastering the class II-mediated immune response induced by B cells. DO may serve to increase the threshold for nonspecific B cell activation, restricting class II-peptide binding to late endosomal compartments, thereby affecting the peptide repertoire.
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Affiliation(s)
- M van Ham
- Division of Tumor Biology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands.
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97
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Arndt SO, Vogt AB, Markovic-Plese S, Martin R, Moldenhauer G, Wölpl A, Sun Y, Schadendorf D, Hämmerling GJ, Kropshofer H. Functional HLA-DM on the surface of B cells and immature dendritic cells. EMBO J 2000; 19:1241-51. [PMID: 10716924 PMCID: PMC305665 DOI: 10.1093/emboj/19.6.1241] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
HLA-DM (DM) plays a critical role in antigen presentation through major histocompatibility complex (MHC) class II molecules. DM functions as a molecular chaperone by keeping class II molecules competent for antigenic peptide loading and serves as an editor by favoring presentation of high-stability peptides. Until now, DM has been thought to exert these activities only in late endosomal/lysosomal compartments of antigen-presenting cells. Here we show that a subset of DM resides at the cell surface of B cells and immature dendritic cells. Surface DM engages in complexes with putatively empty class II molecules and controls presentation of those antigens that rely on loading on the cell surface or in early endosomal recycling compartments. For example, epitopes derived from myelin basic protein that are implicated in the autoimmune disease multiple sclerosis are down-modulated by DM, but are presented in the absence of DM. Thus, this novel concept of functional DM on the surface may be relevant to both protective immune responses and autoimmunity.
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Affiliation(s)
- S O Arndt
- Department of Molecular Immunology, German Cancer Research Center, D-69120 Heidelberg, Germany
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98
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Busch R, Doebele RC, Patil NS, Pashine A, Mellins ED. Accessory molecules for MHC class II peptide loading. Curr Opin Immunol 2000; 12:99-106. [PMID: 10679402 DOI: 10.1016/s0952-7915(99)00057-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Accessory molecules, such as HLA-DM and invariant chain, modulate the ligands bound to MHC class II molecules in antigen-presenting cells. Recent investigations, including gene targeting experiments, have shed light on the functions of these molecules, their mechanisms of action, interactions with class II molecules, and the relationships with associated molecules such as tetraspanins and HLA-DO.
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Affiliation(s)
- R Busch
- Department of Pediatrics, Stanford University Medical Center, Stanford, CA 94305-5208, USA.
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99
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Sato AK, Zarutskie JA, Rushe MM, Lomakin A, Natarajan SK, Sadegh-Nasseri S, Benedek GB, Stern LJ. Determinants of the peptide-induced conformational change in the human class II major histocompatibility complex protein HLA-DR1. J Biol Chem 2000; 275:2165-73. [PMID: 10636922 DOI: 10.1074/jbc.275.3.2165] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human class II major histocompatibility complex protein HLA-DR1 has been shown previously to undergo a distinct conformational change from an open to a compact form upon binding peptide. To investigate the role of peptide in triggering the conformational change, the minimal requirements for inducing the compact conformation were determined. Peptides as short as two and four residues, which occupy only a small fraction of the peptide-binding cleft, were able to induce the conformational change. A mutant HLA-DR1 protein with a substitution in the beta subunit designed to fill the P1 pocket from within the protein (Gly(86) to Tyr) adopted to a large extent the compact, peptide-bound conformation. Interactions important in stabilizing the compact conformation are shown to be distinct from those responsible for high affinity binding or for stabilization of the complex against thermal denaturation. The results suggest that occupancy of the P1 pocket is responsible for partial conversion to the compact form but that both side chain and main chain interactions contribute to the full conformational change. The implications of the conformational change to intracellular antigen loading and presentation are discussed.
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Affiliation(s)
- A K Sato
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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100
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Reinherz EL, Tan K, Tang L, Kern P, Liu J, Xiong Y, Hussey RE, Smolyar A, Hare B, Zhang R, Joachimiak A, Chang HC, Wagner G, Wang J. The crystal structure of a T cell receptor in complex with peptide and MHC class II. Science 1999; 286:1913-21. [PMID: 10583947 DOI: 10.1126/science.286.5446.1913] [Citation(s) in RCA: 329] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The crystal structure of a complex involving the D10 T cell receptor (TCR), 16-residue foreign peptide antigen, and the I-Ak self major histocompatibility complex (MHC) class II molecule is reported at 3.2 angstrom resolution. The D10 TCR is oriented in an orthogonal mode relative to its peptide-MHC (pMHC) ligand, necessitated by the amino-terminal extension of peptide residues projecting from the MHC class II antigen-binding groove as part of a mini beta sheet. Consequently, the disposition of D10 complementarity-determining region loops is altered relative to that of most pMHCI-specific TCRs; the latter TCRs assume a diagonal orientation, although with substantial variability. Peptide recognition, which involves P-1 to P8 residues, is dominated by the Valpha domain, which also binds to the class II MHC beta1 helix. That docking is limited to one segment of MHC-bound peptide offers an explanation for epitope recognition and altered peptide ligand effects, suggests a structural basis for alloreactivity, and illustrates how bacterial superantigens can span the TCR-pMHCII surface.
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MESH Headings
- Animals
- Antigens/chemistry
- Antigens/immunology
- Antigens/metabolism
- Binding Sites
- CD4-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/immunology
- Conalbumin/chemistry
- Conalbumin/immunology
- Crystallization
- Crystallography, X-Ray
- Histocompatibility Antigens Class I/immunology
- Histocompatibility Antigens Class II/chemistry
- Histocompatibility Antigens Class II/immunology
- Histocompatibility Antigens Class II/metabolism
- Hydrogen Bonding
- Ligands
- Mice
- Mice, Inbred AKR
- Models, Molecular
- Oligopeptides/chemistry
- Oligopeptides/immunology
- Oligopeptides/metabolism
- Protein Conformation
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Superantigens/immunology
- Superantigens/metabolism
- Thymus Gland/cytology
- Thymus Gland/immunology
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Affiliation(s)
- E L Reinherz
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
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