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Cloutier M, Fortin JS, Thibodeau J. The transmembrane domain and luminal C-terminal region independently support invariant chain trimerization and assembly with MHCII into nonamers. BMC Immunol 2021; 22:56. [PMID: 34384367 PMCID: PMC8362237 DOI: 10.1186/s12865-021-00444-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 07/20/2021] [Indexed: 05/31/2023] Open
Abstract
Background Invariant chain (CD74, Ii) is a multifunctional protein expressed in antigen presenting cells. It assists the ER exit of various cargos and serves as a receptor for the macrophage migration inhibitory factor. The newly translated Ii chains trimerize, a structural feature that is not readily understood in the context of its MHCII chaperoning function. Two segments of Ii, the luminal C-terminal region (TRIM) and the transmembrane domain (TM), have been shown to participate in the trimerization process but their relative importance and impact on the assembly with MHCII molecules remains debated. Here, we addressed the requirement of these domains in the trimerization of human Ii as well as in the oligomerization with MHCII molecules. We used site-directed mutagenesis to generate series of Ii and DR mutants. These were transiently transfected in HEK293T cells to test their cell surface expression and analyse their interactions by co-immunoprecipitations. Results Our results showed that the TRIM domain is not essential for Ii trimerization nor for intracellular trafficking with MHCII molecules. We also gathered evidence that in the absence of TM, TRIM allows the formation of multi-subunit complexes with HLA-DR. Similarly, in the absence of TRIM, Ii can assemble into high-order structures with MHCII molecules. Conclusions Altogether, our data show that trimerization of Ii through either TM or TRIM sustains nonameric complex formation with MHCII molecules. Supplementary Information The online version contains supplementary material available at 10.1186/s12865-021-00444-6.
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Affiliation(s)
- Maryse Cloutier
- Laboratoire d'Immunologie Moléculaire, Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, Succ Centre-Ville, CP 6128, Montréal, QC, H3C 3J7, Canada
| | - Jean-Simon Fortin
- Laboratoire d'Immunologie Moléculaire, Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, Succ Centre-Ville, CP 6128, Montréal, QC, H3C 3J7, Canada
| | - Jacques Thibodeau
- Laboratoire d'Immunologie Moléculaire, Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, Succ Centre-Ville, CP 6128, Montréal, QC, H3C 3J7, Canada.
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Uhlenbrock F, van Andel E, Andresen L, Skov S. A conserved WW domain-like motif regulates invariant chain-dependent cell-surface transport of the NKG2D ligand ULBP2. Mol Immunol 2015; 66:418-27. [PMID: 25983110 DOI: 10.1016/j.molimm.2015.04.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 04/16/2015] [Accepted: 04/22/2015] [Indexed: 11/16/2022]
Abstract
Malignant cells expressing NKG2D ligands on their cell surface can be directly sensed and killed by NKG2D-bearing lymphocytes. To ensure this immune recognition, accumulating evidence suggests that NKG2D ligands are trafficed via alternative pathways to the cell surface. We have previously shown that the NKG2D ligand ULBP2 traffics over an invariant chain (Ii)-dependent pathway to the cell surface. This study set out to elucidate how Ii regulates ULBP2 cell-surface transport: We discovered conserved tryptophan (Trp) residues in the primary protein sequence of ULBP1-6 but not in the related MICA/B. Substitution of Trp to alanine resulted in cell-surface inhibition of ULBP2 in different cancer cell lines. Moreover, the mutated ULBP2 constructs were retained and not degraded inside the cell, indicating a crucial role of this conserved Trp-motif in trafficking. Finally, overexpression of Ii increased surface expression of wt ULBP2 while Trp-mutants could not be expressed, proposing that this Trp-motif is required for an Ii-dependent cell-surface transport of ULBP2. Aberrant soluble ULBP2 is immunosuppressive. Thus, targeting a distinct protein module on the ULBP2 sequence could counteract this abnormal expression of ULBP2.
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Affiliation(s)
- Franziska Uhlenbrock
- Laboratory of Immunology, Section for Experimental Animal Models, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 7, DK-1870 Frederiksberg, Denmark.
| | - Esther van Andel
- Laboratory of Immunology, Section for Experimental Animal Models, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 7, DK-1870 Frederiksberg, Denmark
| | - Lars Andresen
- Laboratory of Immunology, Section for Experimental Animal Models, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 7, DK-1870 Frederiksberg, Denmark
| | - Søren Skov
- Laboratory of Immunology, Section for Experimental Animal Models, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 7, DK-1870 Frederiksberg, Denmark.
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Uhlenbrock F, Hagemann-Jensen M, Kehlet S, Andresen L, Pastorekova S, Skov S. The NKG2D ligand ULBP2 is specifically regulated through an invariant chain-dependent endosomal pathway. THE JOURNAL OF IMMUNOLOGY 2014; 193:1654-65. [PMID: 25024379 DOI: 10.4049/jimmunol.1303275] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Soluble ULBP2 is a marker for poor prognosis in several types of cancer. In this study we demonstrate that both soluble and cell surface-bound ULBP2 is transported via a so far unrecognized endosomal pathway. ULBP2 surface expression, but not MICA/B, could specifically be targeted and retained by affecting endosomal/lysosomal integrity and protein kinase C activity. The invariant chain was further essential for endosomal transport of ULBP2. This novel pathway was identified through screening experiments by which methylselenic acid was found to possess notable NKG2D ligand regulatory properties. The protein kinase C inhibitor methylselenic acid induced MICA/B surface expression but dominantly blocked ULBP2 surface transport. Remarkably, by targeting this novel pathway we could specifically block the production of soluble ULBP2 from different, primary melanomas. Our findings strongly suggest that the endosomal transport pathway constitutes a novel therapeutic target for ULBP2-producing tumors.
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Affiliation(s)
- Franziska Uhlenbrock
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
| | - Michael Hagemann-Jensen
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
| | - Stephanie Kehlet
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
| | - Lars Andresen
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
| | - Silvia Pastorekova
- Department of Molecular Medicine, Institute of Virology, Slovak Academy of Sciences, 845 05 Bratislava, Slovak Republic
| | - Søren Skov
- Section for Experimental Animal Models, Laboratory of Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg, Denmark; and
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Temme S, Zacharias M, Neumann J, Wohlfromm S, König A, Temme N, Springer S, Trowsdale J, Koch N. A novel family of human leukocyte antigen class II receptors may have its origin in archaic human species. J Biol Chem 2014; 289:639-53. [PMID: 24214983 PMCID: PMC3887193 DOI: 10.1074/jbc.m113.515767] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/08/2013] [Indexed: 01/10/2023] Open
Abstract
HLA class II α and β chains form receptors for antigen presentation to CD4(+) T cells. Numerous pairings of class II α and β subunits from the wide range of haplotypes and isotypes may form, but most of these combinations, in particular those produced by isotype mixing, yielded mismatched dimers. It is unclear how selection of functional receptors is achieved. At the atomic level, it is not known which interactions of class II residues regulate selection of matched αβ heterodimers and the evolutionary origin of matched isotype mixed dimer formation. In this study we investigated assembly of isotype-mixed HLA class II α and β heterodimers. Assembly and carbohydrate maturation of various HLA-class II isotype-mixed α and β subunits was dependent on the groove binding section of the invariant chain (Ii). By mutation of polymorphic DPβ sequences, we identified two motifs, Lys-69 and GGPM-(84-87), that are engaged in Ii-dependent assembly of DPβ with DRα. We identified five members of a family of DPβ chains containing Lys-69 and GGPM 84-87, which assemble with DRα. The Lys/GGPM motif is present in the DPβ sequence of the Neanderthal genome, and this ancient sequence is related to the human allele DPB1*0401. By site-directed mutagenesis, we inspected Neanderthal amino acid residues that differ from the DPB1*0401 allele and aimed to determine whether matched heterodimers are formed by assembly of DPβ mutants with DRα. Because the *0401 allele is rare in the sub-Saharan population but frequent in the European population, it may have arisen in modern humans by admixture with Neanderthals in Europe.
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Affiliation(s)
- Sebastian Temme
- From the Section of Immunobiology, Institute of Genetics, University of Bonn, 53115 Bonn, Germany
- Department of Molecular Cardiology, University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Martin Zacharias
- Physics Department, Technical University Munich, 85747 Garching, Germany
| | - Jürgen Neumann
- From the Section of Immunobiology, Institute of Genetics, University of Bonn, 53115 Bonn, Germany
| | - Sebastian Wohlfromm
- Biologisch-Medizinisches Forschungszentrum, University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Angelika König
- From the Section of Immunobiology, Institute of Genetics, University of Bonn, 53115 Bonn, Germany
| | - Nadine Temme
- From the Section of Immunobiology, Institute of Genetics, University of Bonn, 53115 Bonn, Germany
- Forschungszentrum Caesar, 53175 Bonn, Germany
| | | | - John Trowsdale
- Division of Immunology, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kindgom
| | - Norbert Koch
- From the Section of Immunobiology, Institute of Genetics, University of Bonn, 53115 Bonn, Germany
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Xu FZ, Wu SG, Yu WY. Intracellular localization and association of MHC class I with porcine invariant chain. GENETICS AND MOLECULAR RESEARCH 2013; 12:693-701. [PMID: 23546951 DOI: 10.4238/2013.march.11.17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The objective was to investigate the intracellular localization and association of pig major histocompatibility complex (MHC) class I subunits with invariant chain (Ii). Pig MHC class I subunit cDNAs were cloned by RT-PCR and eukaryotic expression plasmids of α and β2m were constructed with fusions to red or enhanced green fluorescent protein (pDsRed2-N1-α, pEGFP-N1-α, pDsRed2-N1-β2m, and pEGFP-N1-β2m). A pig Ii mutant with a deleted CLIP region (DCLIP-Ii) was constructed by overlap extension PCR. Wild-type Ii and mutant Ii were cloned into pEGFP-C1 (pEGFP-C1-Ii, pEGFP-C1-DCLIP-Ii). The recombinant plasmids of MHC I subunits and pEGFP-C1-Ii (pEGFP-C1-ΔCLIP-Ii) were transiently cotransfected into COS-7 cells with Lipofectamine 2000. Immunofluorescence microscopy was performed to detect expression and intracellular localization of Ii and MHC I subunits, and immunoprecipitation was used to analyze their association. Our results indicated that pig Ii associates with integrated MHC I subunits to form oligomers, but cannot associate with single MHC I subunits. Furthermore, deletion of the Ii CLIP sequence blocks association with integrated MHC I subunits. Thus, pig Ii cannot associate with a single MHC I molecule, the α or β2m chain, but Ii and the integrated MHC I molecule can form complexes that colocalize in the endomembranes of COS-7 cells. The Ii of CLIP plays a key role in assembly of Ii and MHC I.
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Affiliation(s)
- F Z Xu
- Anhui Agricultural University, Hefei, China.
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Ryan SO, Cobb BA. Host glycans and antigen presentation. Microbes Infect 2012; 14:894-903. [PMID: 22580092 DOI: 10.1016/j.micinf.2012.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/06/2012] [Accepted: 04/11/2012] [Indexed: 12/21/2022]
Abstract
The cell-mediated adaptive immune response depends upon the activation of T cells via recognition of antigen in the context of a major histocompatibility complex (MHC) molecule. Although studies have shown that alterations in T cell receptor glycosylation reduces the activation threshold, the data on MHC is far less definitive. Here, we discuss the data on MHC glycosylation and the role the glycans might play during the adaptive host response.
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Affiliation(s)
- Sean O Ryan
- Department of Pathology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, WRB Rm. 6532, Cleveland, OH 44106, USA
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Ryan SO, Cobb BA. Roles for major histocompatibility complex glycosylation in immune function. Semin Immunopathol 2012; 34:425-41. [PMID: 22461020 DOI: 10.1007/s00281-012-0309-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 03/05/2012] [Indexed: 12/22/2022]
Abstract
The major histocompatibility complex (MHC) glycoprotein family, also referred to as human leukocyte antigens, present endogenous and exogenous antigens to T lymphocytes for recognition and response. These molecules play a central role in enabling the immune system to distinguish self from non-self, which is the basis for protective immunity against pathogenic infections and disease while at the same time representing a serious obstacle for tissue transplantation. All known MHC family members, like the majority of secreted, cell surface, and other immune-related molecules, carry asparagine (N)-linked glycans. The immune system has evolved increasing complexity in higher-order organisms along with a more complex pattern of protein glycosylation, a relationship that may contribute to immune function beyond the early protein quality control events in the endoplasmic reticulum that are commonly known. The broad MHC family maintains peptide sequence motifs for glycosylation at sites that are highly conserved across evolution, suggesting importance, yet functional roles for these glycans remain largely elusive. In this review, we will summarize what is known about MHC glycosylation and provide new insight for additional functional roles for this glycoprotein modification in mediating immune responses.
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Affiliation(s)
- Sean O Ryan
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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Koch N, Zacharias M, König A, Temme S, Neumann J, Springer S. Stoichiometry of HLA class II-invariant chain oligomers. PLoS One 2011; 6:e17257. [PMID: 21364959 PMCID: PMC3043101 DOI: 10.1371/journal.pone.0017257] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 01/27/2011] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND The HLA gene complex encodes three class II isotypes, DR, DQ, and DP. HLA class II molecules are peptide receptors that present antigens for recognition by T lymphocytes. In antigen presenting cells, the assembly of matched α and β subunits to heterodimers is chaperoned by invariant chain (Ii). Ii forms a homotrimer with three binding sites for class II heterodimers. The current model of class II and Ii structure states that three αβ heterodimers bind to an Ii trimer. METHODOLOGY/PRINCIPAL FINDINGS [corrected] We have now analyzed the composition and size of the complexes of class II and Ii using epitope tagged class II subunits and density gradient experiments. We show here that class II-Ii oligomers consist of one class II heterodimer associated with one Ii trimer, such that the DR, DQ and DP isotypes are contained within separate complexes with Ii. CONCLUSION/SIGNIFICANCE We propose a structural model of the class II-Ii oligomer and speculate that the pentameric class II-Ii complex is bent towards the cell membrane, inhibiting the binding of additional class II heterodimers to Ii.
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Affiliation(s)
- Norbert Koch
- Division of Immunobiology, Institute of Genetics, University of Bonn, Bonn, Germany.
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Landsverk OJB, Bakke O, Gregers TF. MHC II and the endocytic pathway: regulation by invariant chain. Scand J Immunol 2009; 70:184-93. [PMID: 19703008 DOI: 10.1111/j.1365-3083.2009.02301.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The major histocompatibility complex (MHC) class I and II molecules perform vital functions in innate and adaptive immune responses towards invading pathogens. MHC class I molecules load peptides in the endoplasmatic reticulum (ER) and display them to the T cell receptors (TcR) on CD8(+) T lymphocytes. MHC class II molecules (MHC II) acquire their peptides in endosomes and present these to the TcR on CD4+ T lymphocytes. They are vital for the generation of humoral immune responses. MHC II assembly in the ER and trafficking to endosomes is guided by a specialized MHC II chaperone termed the invariant chain (Ii). Ii self-associates into a trimer in the ER, this provides a scaffold for the assembly of three MHC II heterodimers and blocks their peptide binding grooves, thereby avoiding premature peptide binding. Ii then transports the nascent MHC II to more or less specialized compartment where they can load peptides derived from internalized pathogens.
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Affiliation(s)
- O J B Landsverk
- Centre for Immune Regulation, Department of Molecular Biosciences, University of Oslo, 0316 Oslo, Norway
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Ye H, Xu F, Yu W. The intracellular localization and oligomerization of chicken invariant chain with major histocompatibility complex class II subunits. Poult Sci 2009; 88:1594-600. [DOI: 10.3382/ps.2009-00058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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