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Aisihaer X, Guo H, Liu C. Interchain Disulfide Engineering Enables Efficient Production of Functional HLA-DQ-Fc Fusion Proteins. J Biol Chem 2024:107652. [PMID: 39121997 DOI: 10.1016/j.jbc.2024.107652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 07/13/2024] [Accepted: 07/30/2024] [Indexed: 08/12/2024] Open
Abstract
HLA-DQ molecules drive unwanted alloimmune responses after solid-organ transplants and several autoimmune diseases, including Type1 Diabetes and celiac disease. Biologics with HLA molecules as part of the design are emerging therapeutic options for these allo- and autoimmune conditions. However, the soluble α and β chains of class II HLA molecules do not dimerize efficiently without their transmembrane domains, which hinders their production. In this study, we examined the feasibility of inter-chain disulfide engineering by introducing paired cysteines to juxtaposed positions in the α and β chains of HLA-DQ7, encoded by HLA-DQA1*05:01 and HLA-DQB1*03:01 respectively. We identified three variant peptide-HLA-DQ7-Fc fusion proteins (DQ7Fc) with increased expression and production yield, namely Y19C-D6C (YCDC), A83C-E5C (ACEC), and A84C-N33C (ACNC). The mutated residues were conserved across all HLA-DQ proteins and had limited solvent exposure. Further characterizations of the YCDC variant showed that the expression of the fusion protein is peptide-dependent; inclusion of a higher-affinity peptide correlated with increased protein expression. However, high-affinity peptide alone was insufficient for stabilizing the DQ7 complex without the engineered disulfide bond. Multiple DQ7Fc variants demonstrated expected binding characteristics with commercial anti-DQ antibodies in two immunoassays and by a cell-based assay. Lastly, DQ7Fc variants demonstrated dose-dependent killing of DQ7-specific B cell hybridomas in a flow cytometric, complement-dependent cytotoxicity assay. These data support inter-chain disulfide engineering as a novel approach to efficiently producing functional HLA-DQ molecules and potentially other class II HLA molecules as candidate therapeutic agents.
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Affiliation(s)
| | - Hongjie Guo
- Antiger Therapeutics Inc., 4340 Duncan Ave STE 284, St. Louis, MO 63110.
| | - Chang Liu
- Antiger Therapeutics Inc., 4340 Duncan Ave STE 284, St. Louis, MO 63110.
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Qian K, Fu S, Wang J, Li Y, Xian J, Ye J. Major histocompatibility complex class IIα and IIβ of pufferfish (Takifugu obscurus): Identification and functional characterization in response to bacterial challenge. JOURNAL OF FISH DISEASES 2023; 46:1049-1064. [PMID: 37357462 DOI: 10.1111/jfd.13824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/31/2023] [Accepted: 06/05/2023] [Indexed: 06/27/2023]
Abstract
Classical major histocompatibility complex (MHC) class II molecules play an essential role in immune system. In this study, MHC IIα (Pf-MHC IIα) and MHC IIβ (Pf-MHC IIβ) homology genes from pufferfish (Takifugu obscurus) were cloned and their functional characterization in response to bacterial challenge was identified. The nucleotide sequences of the open reading frames (ORFs) of pufferfish Pf-MHC IIα and Pf-MHC IIβ were 708 bp and 750 bp, encoding 235 aa and 249 aa, respectively. The structure of Pf-MHC IIα or Pf-MHC IIβ contained a signal peptide, an α1/β1 domain, an α2/β2 domain, a transmembrane region and a cytoplasmic region. Multiple sequence alignment and phylogenetic analysis showed that Pf-MHC IIα and Pf-MHC IIβ molecules had the highest similarity with Fugu rubripes (Takifugu rubripes). Cellular localization analysis indicated that the distribution of Pf-MHC IIα and Pf-MHC IIβ was in the lymphocyte membrane and cytoplasm. qRT-PCR results showed that Pf-MHC IIα and Pf-MHC IIβ expressed relatively high in skin, gills and gut. In addition, after stimulation challenge in vitro (lipopolysaccharide, or polyinosinic: polycytidylic acid) and in vivo (A. hydrophila), the mRNA expressions of Pf-MHC IIα and Pf-MHC IIβ were significantly up-regulated in lymphocytes and in tissues of skin, gills, gut and head kidney. Moreover, Pf-MHC IIα or Pf-MHC IIβ neutralization reduced the ability of A. hydrophila to induce the expressions of lymphocyte cytokines (TNF-α, IL-1β and IL-10). Overall, it is speculated that Pf-MHC IIα and Pf-MHC IIβ may play an important role in the host response against A. hydrophila in pufferfish.
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Affiliation(s)
- Kun Qian
- Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Shengli Fu
- Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Junru Wang
- Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yuan Li
- Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jianan Xian
- Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Institute of Tropical Biosciences and Biotechnology, CATAS, Haikou, China
| | - Jianmin Ye
- Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, School of Life Sciences, South China Normal University, Guangzhou, China
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Wang B, Zhu F, Shi Z, Huang Z, Sun R, Wang Q, Ouyang G, Ji W. Molecular characteristics, polymorphism and expression analysis of mhc Ⅱ in yellow catfish(pelteobagrus fulvidraco)responding to Flavobacterium columnare infection. FISH & SHELLFISH IMMUNOLOGY 2022; 125:90-100. [PMID: 35483597 DOI: 10.1016/j.fsi.2022.04.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 04/04/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
The major histocompatibility complex (MHC) is an important component of the immune system of vertebrates, which plays a vital role in presenting extrinsic antigens. In this study, we cloned and characterized the mhc ⅡA and mhc ⅡB genes of yellow catfish Pelteobagrus fulvidraco. The open reading frames (ORFs) of mhc ⅡA and mhc ⅡB genes were 708 bp and 747bp in length, encoding 235 and 248 amino acids, respectively. The structure of mhc ⅡA and mhc ⅡB includes a signal peptide, an α1/β1 domain, an α2/β2 domain, a transmembrane region and a cytoplasmic region. Homologous identity analysis revealed that both mhc ⅡA and mhc ⅡB shared high protein sequence similarity with that of Chinese longsnout catfish Leiocassis longirostris. mhc ⅡA and mhc ⅡB showed similar expression patterns in different tissues, with the higher expression level in spleen, head kidney and gill and lower expression in liver, stomach, gall bladder and heart. The mRNA expression level of mhc ⅡA and mhc ⅡB in different embryonic development stages also showed the similar trends. The higher expression was detected from fertilized egg to 32 cell stage, low expression from multicellular period to 3 days post hatching (dph), and then the expression increased to a higher level from 4 dph to 14 dph. The mRNA expression levels of mhc ⅡA and mhc ⅡB were significantly up-regulated not only in the body kidney and spleen, but also in the midgut, hindgut, liver and gill after challenge of Flavobacterium columnare. The results suggest that Mhc Ⅱ plays an important role in the anti-infection process of yellow catfish P. fulvidraco.
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Affiliation(s)
- Bingchao Wang
- Department of Aquatic Animal Medicines, College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture and Rural Affair/Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Fangzheng Zhu
- Department of Aquatic Animal Medicines, College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture and Rural Affair/Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zechao Shi
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China
| | - Zhenyu Huang
- Department of Aquatic Animal Medicines, College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture and Rural Affair/Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ruhan Sun
- Department of Aquatic Animal Medicines, College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture and Rural Affair/Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qingchao Wang
- Department of Aquatic Animal Medicines, College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture and Rural Affair/Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Gang Ouyang
- Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
| | - Wei Ji
- Department of Aquatic Animal Medicines, College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture and Rural Affair/Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China.
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Discovery of an ancient MHC category with both class I and class II features. Proc Natl Acad Sci U S A 2021; 118:2108104118. [PMID: 34903649 PMCID: PMC8713811 DOI: 10.1073/pnas.2108104118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2021] [Indexed: 11/28/2022] Open
Abstract
Two classes of major histocompatibility complex (MHC) molecules, MHC class I and MHC class II, constitute the basis of our elaborate, adaptive immune system as antigen-presenting molecules. They perform distinct, critical functions: especially, MHC class I in case of antivirus and antitumor defenses, and MHC class II, in case of effective antibody responses. This important class diversification has long been enigmatic, as vestiges of the evolutionary molecular changes have not been found. The revealed ancient MHC category represents a plausible intermediate group between the two classes, and the data suggest that class II preceded class I in molecular evolution. Fundamental understanding of the molecular evolution of MHC molecules should contribute to understanding the basis of our complex biological defense system. Two classes of major histocompatibility complex (MHC) molecules, MHC class I and class II, play important roles in our immune system, presenting antigens to functionally distinct T lymphocyte populations. However, the origin of this essential MHC class divergence is poorly understood. Here, we discovered a category of MHC molecules (W-category) in the most primitive jawed vertebrates, cartilaginous fish, and also in bony fish and tetrapods. W-category, surprisingly, possesses class II–type α- and β-chain organization together with class I–specific sequence motifs for interdomain binding, and the W-category α2 domain shows unprecedented, phylogenetic similarity with β2-microglobulin of class I. Based on the results, we propose a model in which the ancestral MHC class I molecule evolved from class II–type W-category. The discovery of the ancient MHC group, W-category, sheds a light on the long-standing critical question of the MHC class divergence and suggests that class II type came first.
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Leddon SA, Fettis MM, Abramo K, Kelly R, Oleksyn D, Miller J. The CD28 Transmembrane Domain Contains an Essential Dimerization Motif. Front Immunol 2020; 11:1519. [PMID: 32765524 PMCID: PMC7378745 DOI: 10.3389/fimmu.2020.01519] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 06/09/2020] [Indexed: 12/13/2022] Open
Abstract
CD28 plays a critical role in regulating immune responses both by enhancing effector T cell activation and differentiation and controlling the development and function of regulatory T cells. CD28 is expressed at the cell surface as a disulfide linked homodimer that is thought to bind ligand monovalently. How ligand binding triggers CD28 to induce intracellular signaling as well as the proximal signaling pathways that are induced are not well-understood. In addition, recent data suggest inside-out signaling initiated by the T cell antigen receptor can enhance CD28 ligand binding, possibly by inducing a rearrangement of the CD28 dimer interface to allow for bivalent binding. To understand how possible conformational changes during ligand-induced receptor triggering and inside-out signaling are mediated, we examined the CD28 transmembrane domain. We identified an evolutionarily conserved YxxxxT motif that is shared with CTLA-4 and resembles the transmembrane dimerization motif within CD3ζ. We show that the CD28 transmembrane domain can drive protein dimerization in a bacterial expression system at levels equivalent to the well-known glycophorin A transmembrane dimerization motif. In addition, ectopic expression of the CD28 transmembrane domain into monomeric human CD25 can drive dimerization in murine T cells as detected by an increase in FRET by flow cytometry. Mutation of the polar YxxxxT motif to hydrophobic leucine residues (Y145L/T150L) attenuated CD28 transmembrane mediated dimerization in both the bacterial and mammalian assays. Introduction of the Y145L/T150L mutation of the CD28 transmembrane dimerization motif into the endogenous CD28 locus by CRISPR resulted in a dramatic loss in CD28 cell surface expression. These data suggest that under physiological conditions the YxxxxT dimerization motif within the CD28 transmembrane domain plays a critical role in the assembly and/or expression of stable CD28 dimers at the cell surface.
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Affiliation(s)
- Scott A Leddon
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Margaret M Fettis
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Kristin Abramo
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Ryan Kelly
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - David Oleksyn
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Jim Miller
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
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Chen Y, Liu Y, Song M, Lai J, Sun J, Gong Q. Molecular polymorphism and expression of MHC I α, II α, II β and II invariant chain in the critically endangered Dabry's sturgeon (Acipenser dabryanus). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 103:103494. [PMID: 31513821 DOI: 10.1016/j.dci.2019.103494] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 09/07/2019] [Accepted: 09/07/2019] [Indexed: 06/10/2023]
Abstract
The major histocompatibility complex (MHC) is a key player in the regulation of immune responses through presenting foreign antigens to T lymphocytes. In this study, three MHC genes, namely, MHC I α, II α, II β and the II invariant chain (Ii), were identified and characterized in the critically endangered Dabry's sturgeon (Acipenser dabryanus). A tissue distribution study showed that the MHC and Ii transcripts were widely expressed in various tissues. The highest expression levels of MHC I α, II α and Ii were found in the gill, while MHC II β was primarily expressed in the spleen. Challenge of A. dabryanus with a pathogenic bacterium in vivo resulted in significant upregulation of both MHC and Ii expression, indicating potential roles of these genes in immune response. Phylogenetic analysis showed that A. dabryanus MHC grouped with other teleost MHC genes and sequences from Polyodon spathula and A. dabryanus had an intermingling of alleles. According to the split time between paddlefishes and sturgeons, this result indicated that trans-species MHC lineages in Chondrostei were much older than those in tetrapods. The molecular polymorphisms of the complete open reading frame regions of the MHC genes were analysed in several A. dabryanus individuals. MHC II α and II β were highly polymorphic in different individuals, while MHC I α was more conserved. The ratio of non-synonymous substitution occurred at a significantly higher frequency than synonymous substitution in peptide-binding regions (PBR) of MHC II α and II β, demonstrating the existence of positive selection at peptide-binding sites. Our study suggested potential roles of the MHC chains in immune response to pathogen microbial infection, and the numerous alleles identified in this study will help further genetic management and molecular marker-assisted selective breeding programmes in A. dabryanus.
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Affiliation(s)
- Yeyu Chen
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Ya Liu
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Mingjiang Song
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Jiansheng Lai
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Jiahua Sun
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China
| | - Quan Gong
- The Fishery Institute of the Sichuan Academy of Agricultural Sciences, Chengdu, 611730, China.
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7
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Serra P, Garabatos N, Singha S, Fandos C, Garnica J, Solé P, Parras D, Yamanouchi J, Blanco J, Tort M, Ortega M, Yang Y, Ellestad KK, Santamaria P. Increased yields and biological potency of knob-into-hole-based soluble MHC class II molecules. Nat Commun 2019; 10:4917. [PMID: 31664029 PMCID: PMC6820532 DOI: 10.1038/s41467-019-12902-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/04/2019] [Indexed: 12/19/2022] Open
Abstract
Assembly of soluble peptide-major histocompatibility complex class II (pMHCII) monomers into multimeric structures enables the detection of antigen-specific CD4+ T cells in biological samples and, in some configurations, their reprogramming in vivo. Unfortunately, current MHCII-αβ chain heterodimerization strategies are typically associated with low production yields and require the use of foreign affinity tags for purification, precluding therapeutic applications in humans. Here, we show that fusion of peptide-tethered or empty MHCII-αβ chains to the IgG1-Fc mutated to form knob-into-hole structures results in the assembly of highly stable pMHCII monomers. This design enables the expression and rapid purification of challenging pMHCII types at high yields without the need for leucine zippers and purification affinity tags. Importantly, this design increases the antigen-receptor signaling potency of multimerized derivatives useful for therapeutic applications and facilitates the detection and amplification of low-avidity T cell specificities in biological samples using flow cytometry.
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Affiliation(s)
- Pau Serra
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain.
| | - Nahir Garabatos
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain
| | - Santiswarup Singha
- Julia McFarlane Diabetes Research Centre (JMDRC) and Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Alberta, T2N 4N1, Canada
| | - César Fandos
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain
| | - Josep Garnica
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain
| | - Patricia Solé
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain
| | - Daniel Parras
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain
| | - Jun Yamanouchi
- Julia McFarlane Diabetes Research Centre (JMDRC) and Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Alberta, T2N 4N1, Canada
| | - Jesús Blanco
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain
- Division of Endocrinology, Hospital Clinic i Provincial de Barcelona, Barcelona, Spain
| | - Meritxell Tort
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain
| | - Mireia Ortega
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain
| | - Yang Yang
- Julia McFarlane Diabetes Research Centre (JMDRC) and Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Alberta, T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Alberta, T2N 4N1, Canada
| | - Kristofor K Ellestad
- Julia McFarlane Diabetes Research Centre (JMDRC) and Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Alberta, T2N 4N1, Canada
| | - Pere Santamaria
- Institut D'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, 08036, Spain.
- Julia McFarlane Diabetes Research Centre (JMDRC) and Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Alberta, T2N 4N1, Canada.
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Molecular and Structural Characterization of MHC Class II β Genes Reveals High Diversity in the Cold-Adapted Icefish Chionodraco hamatus. Sci Rep 2019; 9:5523. [PMID: 30940855 PMCID: PMC6445107 DOI: 10.1038/s41598-019-42003-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 03/21/2019] [Indexed: 01/04/2023] Open
Abstract
This study reports the presence of two distinct MHC class II β genes in the Antarctic icefish Chionodraco hamatus, belonging to the classical (ChhaDAB) and nonclassical (ChhaDBB) evolutionary lineages. By the application of targeted sequencing approach, a remarkable molecular diversity in the exon 2 sequence of the highly expressed gene ChhaDAB has been observed, resulting in an estimate of 92 different variants translated in 87 different peptides from 54 analysed icefish individuals. A highly conservative estimate, based on a 95% sequence identity threshold clustering, translate this variability in 41 different peptide clusters belonging to four different clades and showing the signature of different kinds of selection. In stark contrast, the poorly expressed ChhaDBB gene displayed a very low level of molecular diversity within exon 2, in agreement with expectations for a nonclassical MHC class II β gene.
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Dixon AM, Roy S. Role of membrane environment and membrane-spanning protein regions in assembly and function of the Class II Major Histocompatibility complex. Hum Immunol 2019; 80:5-14. [PMID: 30102939 DOI: 10.1016/j.humimm.2018.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/19/2018] [Accepted: 07/09/2018] [Indexed: 10/28/2022]
Abstract
Class II Major Histocompatibility complex (MHC-II) is a polymorphic heterodimer that binds antigen-derived peptides and presents them on the surface of antigen presenting cells. This mechanism of antigen presentation leads to recognition by CD4 T-cells and T-cell activation, making it a critical element of adaptive immune response. For this reason, the structural determinants of MHC-II function have been of great interest for the past 30 years, resulting in a robust structural understanding of the extracellular regions of the complex. However, the membrane-localized regions have also been strongly implicated in protein-protein and protein-lipid interactions that facilitate Class II assembly, transport and function, and it is these regions that are the focus of this review. Here we describe studies that reveal the strong and selective interactions between the transmembrane domains of the MHC α, and invariant chains which, when altered, have broad reaching impacts on antigen presentation and Class II function. We also summarize work that clearly demonstrates the link between membrane lipid composition (particularly the presence of cholesterol) and MHC-II conformation, subsequent peptide binding, and downstream T-cell activation. We have integrated these studies into a comprehensive view of Class II transmembrane domain biology.
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Affiliation(s)
- Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK.
| | - Syamal Roy
- National Institute of Pharmaceutical Education and Research-Kolkata, 4 Raja SC, Mullick Road, Kolkata 700032, India
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Thibodeau J, Moulefera MA, Balthazard R. On the structure–function of MHC class II molecules and how single amino acid polymorphisms could alter intracellular trafficking. Hum Immunol 2019; 80:15-31. [DOI: 10.1016/j.humimm.2018.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/25/2018] [Accepted: 10/01/2018] [Indexed: 12/01/2022]
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11
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Ancient features of the MHC class II presentation pathway, and a model for the possible origin of MHC molecules. Immunogenetics 2018; 71:233-249. [DOI: 10.1007/s00251-018-1090-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/06/2018] [Indexed: 10/28/2022]
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12
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Cao Z, Wang L, Xiang Y, Liu X, Tu Z, Sun Y, Zhou Y. MHC class IIα polymorphism and its association with resistance/susceptibility to Vibrio harveyi in golden pompano (Trachinotus ovatus). FISH & SHELLFISH IMMUNOLOGY 2018; 80:302-310. [PMID: 29902561 DOI: 10.1016/j.fsi.2018.06.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/13/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
The major histocompatibility complex (MHC) plays an important role in the vertebrate immune response to antigenic peptides, and it is essential for recognizing foreign pathogens in organisms. In this study, MHC class IIα (Trov-MHC IIα) from the golden pompano (Trachinotus ovatus) was first cloned and identified. The gene structure of Trov-MHC IIα was contained four exons and three introns. High levels of polymorphism were found in the exon 2 of Trov-MHC IIα. A total of 29 different MHC class IIα alleles with high polymorphism were identified from 80 individuals. The ratio of non-synonymous substitutions (dN) to synonymous substitutions (dS) was 3.157 (>1) in the peptide binding regions (PBRs) of Trov-MHC IIα, suggesting positive balancing selection. Six alleles were selected to analyze the association between alleles and resistance/susceptibility to Vibrio harveyi in golden pompano. The results showed that Trov-DAA*6401 and Trov-DAA*6702 alleles were associated with the resistance to V. harveyi in golden pompano, while alleles Trov-DAA*6304 and Trov-DAA*7301 were associated with the susceptibility to V. harveyi in golden pompano. This study confirmed the association between alleles of MHC class IIα and disease resistance, and also detected some alleles which might be correlated with high V. harveyi-resistance. These disease resistance-related MHC alleles could be used as potential genetic markers for molecular marker-assisted selective breeding in the golden pompano.
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Affiliation(s)
- Zhenjie Cao
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China; Institute of Tropical Agriculture and Forestry, Hainan University, PR China
| | - Lu Wang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, PR China
| | - Yajing Xiang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, PR China
| | - Xiaocen Liu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, PR China
| | - Zhigang Tu
- Hainan Academy of Ocean and Fisheries Sciences, Haikou, Hainan, China
| | - Yun Sun
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China.
| | - Yongcan Zhou
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China.
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13
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Zhang Y, Li LF, Munir M, Qiu HJ. RING-Domain E3 Ligase-Mediated Host-Virus Interactions: Orchestrating Immune Responses by the Host and Antagonizing Immune Defense by Viruses. Front Immunol 2018; 9:1083. [PMID: 29872431 PMCID: PMC5972323 DOI: 10.3389/fimmu.2018.01083] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 05/01/2018] [Indexed: 01/07/2023] Open
Abstract
The RING-domain E3 ligases (RING E3s), a group of E3 ligases containing one or two RING finger domains, are involved in various cellular processes such as cell proliferation, immune regulation, apoptosis, among others. In the host, a substantial number of the RING E3s have been implicated to inhibit viral replication through regulating immune responses, including activation and inhibition of retinoic acid-inducible gene I-like receptors, toll-like receptors, and DNA receptor signaling pathways, modulation of cell-surface expression of major histocompatibility complex, and co-stimulatory molecules. During the course of evolution and adaptation, viruses encode RING E3s to antagonize host immune defense, such as the infected cell protein 0 of herpes simplex virus type 1, the non-structural protein 1 of rotavirus, and the K3 and K5 of Kaposi’s sarcoma-associated herpesvirus. In addition, recent studies suggest that viruses can hijack the host RING E3s to facilitate viral replication. Based on emerging and interesting discoveries, the RING E3s present novel links among the host and viruses. Herein, we focus on the latest research progresses in the RING E3s-mediated host–virus interactions and discuss the outlooks of the RING E3s for future research.
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Affiliation(s)
- Yuexiu Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lian-Feng Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Muhammad Munir
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, City of Lancaster, United Kingdom
| | - Hua-Ji Qiu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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14
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Bauer J, Bakke O, Morth JP. Overview of the membrane-associated RING-CH (MARCH) E3 ligase family. N Biotechnol 2017; 38:7-15. [DOI: 10.1016/j.nbt.2016.12.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/05/2016] [Accepted: 12/13/2016] [Indexed: 12/17/2022]
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15
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Roy K, Mandloi S, Chakrabarti S, Roy S. Cholesterol Corrects Altered Conformation of MHC-II Protein in Leishmania donovani Infected Macrophages: Implication in Therapy. PLoS Negl Trop Dis 2016; 10:e0004710. [PMID: 27214205 PMCID: PMC4877013 DOI: 10.1371/journal.pntd.0004710] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/23/2016] [Indexed: 12/20/2022] Open
Abstract
Background Previously we reported that Kala-azar patients show progressive decrease in serum cholesterol as a function of splenic parasite burden. Splenic macrophages (MΦ) of Leishmania donovani (LD) infected mice show decrease in membrane cholesterol, while LD infected macrophages (I-MΦ) show defective T cell stimulating ability that could be corrected by liposomal delivery of cholesterol. T helper cells recognize peptide antigen in the context of class II MHC molecule. It is known that the conformation of a large number of membrane proteins is dependent on membrane cholesterol. In this investigation we tried to understand the influence of decreased membrane cholesterol in I-MΦ on the conformation of MHC-II protein and peptide-MHC-II stability, and its bearing on the antigen specific T-cell activation. Methodology/Principal Findings MΦ of CBA/j mice were infected with Leishmania donovani (I-MΦ). Two different anti-Aκ mAbs were used to monitor the status of MHC-II protein under parasitized condition. One of them (11.5–2) was conformation specific, whereas the other one (10.2.16) was not. Under parasitized condition, the binding of 11.5–2 decreased significantly with respect to the normal counterpart, whereas that of 10.2.16 remained unaltered. The binding of 11.5–2 was restored to normal upon liposomal delivery of cholesterol in I-MΦ. By molecular dynamics (MD) simulation studies we found that there was considerable conformational fluctuation in the transmembrane domain of the MHC-II protein in the presence of membrane cholesterol than in its absence, which possibly influenced the distal peptide binding groove. This was evident from the faster dissociation of the cognate peptide from peptide-MHC complex under parasitized condition, which could be corrected by liposomal delivery of cholesterol in I-MΦ. Conclusion The decrease in membrane cholesterol in I-MΦ may lead to altered conformation of MHC II, and this may contribute to a faster dissociation of the peptide. Furthermore, liposomal delivery of cholesterol in I-MΦ restored its normal antigen presenting function. This observation brings strength to our previous observation on host directed therapeutic application of liposomal cholesterol in experimental visceral leishmaniasis. The disease visceral leishmaniasis is caused by the protozoan parasite Leishmania donovani (LD). One of the hallmarks of the disease is immune suppression. The parasites replicate within the macrophages and dendritic cells, and such cells are known as antigen presenting cells (APCs). APCs present peptide to T-helper cells in association with the transplantation antigen-II (MHC-II). The infected macrophages show decrease in membrane cholesterol leading to increase in membrane fluidity. The membrane cholesterol is important for maintaining conformation of membrane proteins. Here we show that conformation of MHC-II protein is altered in parasitized macrophages, which results faster dissociation of peptide from peptide-MHC-II complex as compared to normal counterpart. The conformational change in MHC-II protein is also supported by molecular dynamic simulation studies, as there is considerable structural fluctuation of MHC-II peptide binding domain in presence and absence of cholesterol. This observation indicated that cholesterol is important for maintaining conformation of MHC-II protein and stability of the peptide-MHC complex. Thus, Leishmania parasites by modulating membrane cholesterol influence above processes leading to defective T-cell stimulation in leishmaniasis. The above defects displayed by infected macrophages could be corrected by liposomal delivery of cholesterol indicating a possible therapeutic role of liposomal cholesterol in infection.
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Affiliation(s)
- Koushik Roy
- Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Sapan Mandloi
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Saikat Chakrabarti
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
- * E-mail: (SC); (SR)
| | - Syamal Roy
- Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
- * E-mail: (SC); (SR)
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Drake LA, Drake JR. A triad of molecular regions contribute to the formation of two distinct MHC class II conformers. Mol Immunol 2016; 74:59-70. [PMID: 27148821 DOI: 10.1016/j.molimm.2016.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 04/18/2016] [Accepted: 04/18/2016] [Indexed: 02/07/2023]
Abstract
MHC class II molecules present antigen-derived peptides to CD4T cells to drive the adaptive immune response. Previous work has established that class II αβ dimers can adopt two distinct conformations, driven by the differential pairing of transmembrane domain GxxxG dimerization motifs. These class II conformers differ in their ability to be loaded with antigen-derived peptide and to effectively engage CD4T cells. Motif 1 (M1) paired I-A(k) class II molecules are efficiently loaded with peptides derived from the processing of B cell receptor-bound antigen, have unique B cell signaling properties and high T cell stimulation activity. The 11-5.2mAb selectively binds M1 paired I-A(k) class II molecules. However, the molecular determinants of 11-5.2 binding are currently unclear. Here, we report the ability of a human class II transmembrane domain to drive both M1 and M2 class II conformer formation. Protease sensitivity analysis further strengthens the idea that there are conformational differences between the extracellular domains of M1 and M2 paired class II. Finally, MHC class II chain alignments and site directed mutagenesis reveals a triad of molecular regions that contributes to 11-5.2mAb binding. In addition to transmembrane GxxxG motif domain pairing, 11-5.2 binding is influenced directly by α chain residue Glu-71 and indirectly by the region around the inter-chain salt bridge formed by α chain Arg-52 and β chain Glu-86. These findings provide insight into the complexity of 11-5.2mAb recognition of the M1 paired I-A(k) class II conformer and further highlight the molecular heterogeneity of peptide-MHC class II complexes that drive T cell antigen recognition.
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Affiliation(s)
- Lisa A Drake
- Center for Immunology and Microbial Disease, Albany Medical College, 47 New Scotland Ave, MC-151, Albany, NY 12208, United States
| | - James R Drake
- Center for Immunology and Microbial Disease, Albany Medical College, 47 New Scotland Ave, MC-151, Albany, NY 12208, United States.
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17
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Harton J, Jin L, Hahn A, Drake J. Immunological Functions of the Membrane Proximal Region of MHC Class II Molecules. F1000Res 2016; 5. [PMID: 27006762 PMCID: PMC4798158 DOI: 10.12688/f1000research.7610.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/10/2016] [Indexed: 12/30/2022] Open
Abstract
Major histocompatibility complex (MHC) class II molecules present exogenously derived antigen peptides to CD4 T cells, driving activation of naïve T cells and supporting CD4-driven immune functions. However, MHC class II molecules are not inert protein pedestals that simply bind and present peptides. These molecules also serve as multi-functional signaling molecules delivering activation, differentiation, or death signals (or a combination of these) to B cells, macrophages, as well as MHC class II-expressing T cells and tumor cells. Although multiple proteins are known to associate with MHC class II, interaction with STING (stimulator of interferon genes) and CD79 is essential for signaling. In addition, alternative transmembrane domain pairing between class II α and β chains influences association with membrane lipid sub-domains, impacting both signaling and antigen presentation. In contrast to the membrane-distal region of the class II molecule responsible for peptide binding and T-cell receptor engagement, the membrane-proximal region (composed of the connecting peptide, transmembrane domain, and cytoplasmic tail) mediates these "non-traditional" class II functions. Here, we review the literature on the function of the membrane-proximal region of the MHC class II molecule and discuss the impact of this aspect of class II immunobiology on immune regulation and human disease.
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Affiliation(s)
- Jonathan Harton
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, 12208-3479, USA
| | - Lei Jin
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, 12208-3479, USA
| | - Amy Hahn
- Transplantation Immunology Laboratory, Albany Medical College, Albany, New York, 12208-3479, USA
| | - Jim Drake
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, 12208-3479, USA
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18
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Characterization and expression of MHC class II alpha and II beta genes in mangrove red snapper ( Lutjanus argentimaculatus ). Mol Immunol 2015; 68:373-81. [DOI: 10.1016/j.molimm.2015.09.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 09/13/2015] [Accepted: 09/22/2015] [Indexed: 01/25/2023]
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Abstract
Transmembrane (TM) helices of integral membrane proteins can facilitate strong and specific noncovalent protein-protein interactions. Mutagenesis and structural analyses have revealed numerous examples in which the interaction between TM helices of single-pass membrane proteins is dependent on a GxxxG or (small)xxx(small) motif. It is therefore tempting to use the presence of these simple motifs as an indicator of TM helix interactions. In this Current Topic review, we point out that these motifs are quite common, with more than 50% of single-pass TM domains containing a (small)xxx(small) motif. However, the actual interaction strength of motif-containing helices depends strongly on sequence context and membrane properties. In addition, recent studies have revealed several GxxxG-containing TM domains that interact via alternative interfaces involving hydrophobic, polar, aromatic, or even ionizable residues that do not form recognizable motifs. In multipass membrane proteins, GxxxG motifs can be important for protein folding, and not just oligomerization. Our current knowledge thus suggests that the presence of a GxxxG motif alone is a weak predictor of protein dimerization in the membrane.
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Affiliation(s)
- Mark G Teese
- Lehrstuhl für Chemie der Biopolymere, Technische Universität München , 85354 Freising, Germany.,Center for Integrated Protein Science Munich (CIPSM) , 81377 Munich, Germany
| | - Dieter Langosch
- Lehrstuhl für Chemie der Biopolymere, Technische Universität München , 85354 Freising, Germany.,Center for Integrated Protein Science Munich (CIPSM) , 81377 Munich, Germany
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20
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Perrin J, Le Coadic M, Vernay A, Dias M, Gopaldass N, Ouertatani-Sakouhi H, Cosson P. TM9 family proteins control surface targeting of glycine-rich transmembrane domains. J Cell Sci 2015; 128:2269-77. [PMID: 25999474 PMCID: PMC4510845 DOI: 10.1242/jcs.164848] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 04/30/2015] [Indexed: 11/20/2022] Open
Abstract
TM9 family proteins (also named Phg1 proteins) have been previously shown to control cell adhesion by determining the cell surface localization of adhesion proteins such as the Dictyostelium SibA protein. Here, we show that the glycine-rich transmembrane domain (TMD) of SibA is sufficient to confer Phg1A-dependent surface targeting to a reporter protein. Accordingly, in Dictyostelium phg1A-knockout (KO) cells, proteins with glycine-rich TMDs were less efficiently transported out of the endoplasmic reticulum (ER) and to the cell surface. Phg1A, as well as its human ortholog TM9SF4 specifically associated with glycine-rich TMDs. In human cells, genetic inactivation of TM9SF4 resulted in an increased retention of glycine-rich TMDs in the endoplasmic reticulum, whereas TM9SF4 overexpression enhanced their surface localization. The bulk of the TM9SF4 protein was localized in the Golgi complex and a proximity-ligation assay suggested that it might interact with glycine-rich TMDs. Taken together, these results suggest that one of the main roles of TM9 proteins is to serve as intramembrane cargo receptors controlling exocytosis and surface localization of a subset of membrane proteins. Summary: TM9 proteins facilitate transport to the cell surface of proteins with gylcine-rich transmembrane domains. They might represent a new class of cargo receptors controlling transport in the secretory pathway.
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Affiliation(s)
- Jackie Perrin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, Geneva 4 CH-1211, Switzerland
| | - Marion Le Coadic
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, Geneva 4 CH-1211, Switzerland
| | - Alexandre Vernay
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, Geneva 4 CH-1211, Switzerland
| | - Marco Dias
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, Geneva 4 CH-1211, Switzerland
| | - Navin Gopaldass
- Department of Biochemistry, Sciences II, University of Geneva, 30 quai Ernest-Ansermet, Geneva 4 CH-1211, Switzerland
| | - Hajer Ouertatani-Sakouhi
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, Geneva 4 CH-1211, Switzerland
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, Geneva 4 CH-1211, Switzerland
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21
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Nash A, Notman R, Dixon AM. De novo design of transmembrane helix–helix interactions and measurement of stability in a biological membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1248-57. [DOI: 10.1016/j.bbamem.2015.02.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 01/29/2015] [Accepted: 02/18/2015] [Indexed: 01/03/2023]
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22
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Shen T, He X, Lei M, Wang J, Li X, Li J. Cloning and structure of a histocompatibility class IIA gene (Lelo-DAA) in Chinese longsnout catfish (Leiocassis longirostris). Genes Genomics 2014. [DOI: 10.1007/s13258-014-0208-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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23
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Sharonov GV, Bocharov EV, Kolosov PM, Astapova MV, Arseniev AS, Feofanov AV. Point mutations in dimerization motifs of the transmembrane domain stabilize active or inactive state of the EphA2 receptor tyrosine kinase. J Biol Chem 2014; 289:14955-64. [PMID: 24733396 DOI: 10.1074/jbc.m114.558783] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The EphA2 receptor tyrosine kinase plays a central role in the regulation of cell adhesion and guidance in many human tissues. The activation of EphA2 occurs after proper dimerization/oligomerization in the plasma membrane, which occurs with the participation of extracellular and cytoplasmic domains. Our study revealed that the isolated transmembrane domain (TMD) of EphA2 embedded into the lipid bicelle dimerized via the heptad repeat motif L(535)X3G(539)X2A(542)X3V(546)X2L(549) rather than through the alternative glycine zipper motif A(536)X3G(540)X3G(544) (typical for TMD dimerization in many proteins). To evaluate the significance of TMD interactions for full-length EphA2, we substituted key residues in the heptad repeat motif (HR variant: G539I, A542I, G553I) or in the glycine zipper motif (GZ variant: G540I, G544I) and expressed YFP-tagged EphA2 (WT, HR, and GZ variants) in HEK293T cells. Confocal microscopy revealed a similar distribution of all EphA2-YFP variants in cells. The expression of EphA2-YFP variants and their kinase activity (phosphorylation of Tyr(588) and/or Tyr(594)) and ephrin-A3 binding were analyzed with flow cytometry on a single cell basis. Activation of any EphA2 variant is found to occur even without ephrin stimulation when the EphA2 content in cells is sufficiently high. Ephrin-A3 binding is not affected in mutant variants. Mutations in the TMD have a significant effect on EphA2 activity. Both ligand-dependent and ligand-independent activities are enhanced for the HR variant and reduced for the GZ variant compared with the WT. These findings allow us to suggest TMD dimerization switching between the heptad repeat and glycine zipper motifs, corresponding to inactive and active receptor states, respectively, as a mechanism underlying EphA2 signal transduction.
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Affiliation(s)
- George V Sharonov
- From the Department of Structural Biology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of RAS, 117997 Moscow, Russia, the Faculty of Medicine, Moscow State University, 119992 Moscow, Russia
| | - Eduard V Bocharov
- From the Department of Structural Biology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of RAS, 117997 Moscow, Russia
| | - Peter M Kolosov
- the Department of Molecular Neurobiology, Institute of Higher Nervous Activity and Neurophysiology of RAS, 117485 Moscow, Russia, and
| | - Maria V Astapova
- From the Department of Structural Biology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of RAS, 117997 Moscow, Russia
| | - Alexander S Arseniev
- From the Department of Structural Biology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of RAS, 117997 Moscow, Russia
| | - Alexey V Feofanov
- From the Department of Structural Biology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of RAS, 117997 Moscow, Russia, the Biological Faculty, Moscow State University, 119992 Moscow, Russia
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24
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Dixon AM, Drake L, Hughes KT, Sargent E, Hunt D, Harton JA, Drake JR. Differential transmembrane domain GXXXG motif pairing impacts major histocompatibility complex (MHC) class II structure. J Biol Chem 2014; 289:11695-11703. [PMID: 24619409 DOI: 10.1074/jbc.m113.516997] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Major histocompatibility complex (MHC) class II molecules exhibit conformational heterogeneity, which influences their ability to stimulate CD4 T cells and drive immune responses. Previous studies suggest a role for the transmembrane domain of the class II αβ heterodimer in determining molecular structure and function. Our previous studies identified an MHC class II conformer that is marked by the Ia.2 epitope. These Ia.2(+) class II conformers are lipid raft-associated and able to drive both tyrosine kinase signaling and efficient antigen presentation to CD4 T cells. Here, we establish that the Ia.2(+) I-A(k) conformer is formed early in the class II biosynthetic pathway and that differential pairing of highly conserved transmembrane domain GXXXG dimerization motifs is responsible for formation of Ia.2(+) versus Ia.2(-) I-A(k) class II conformers and controlling lipid raft partitioning. These findings provide a molecular explanation for the formation of two distinct MHC class II conformers that differ in their inherent ability to signal and drive robust T cell activation, providing new insight into the role of MHC class II in regulating antigen-presenting cell-T cell interactions critical to the initiation and control of multiple aspects of the immune response.
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Affiliation(s)
- Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Lisa Drake
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Kelly T Hughes
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Elizabeth Sargent
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Danielle Hunt
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Jonathan A Harton
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - James R Drake
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208.
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Reuven EM, Fink A, Shai Y. Regulation of innate immune responses by transmembrane interactions: lessons from the TLR family. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1586-93. [PMID: 24480409 DOI: 10.1016/j.bbamem.2014.01.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/15/2014] [Accepted: 01/18/2014] [Indexed: 02/06/2023]
Abstract
The mammalian innate immune response is responsible for the early stages of defense against invading pathogens. One of the major receptor families facilitating innate immune activation is the Toll-like receptor (TLR) family. These receptors are type 1 membrane proteins spanning the membrane with a single transmembrane domain (TMD). All TLRs form homo- and hetero-dimers within membranes and new data suggest that the single transmembrane domain of some of these receptors is involved in their dimerization and function. Newly identified TLR dimers are continuously reported but only little is known about the importance of the TMDs for their dimer assembly and signaling regulation. Uncontrolled or untimely activation of TLRs is related to a large number of pathologies ranging from cystic fibrosis to sepsis and cancer. In this review we will focus on the contribution of the TMDs of innate immune receptors - specifically TLR2-to their regulation and function. In addition, we will address the current issues remaining to be solved regarding the mechanistic insights of this regulation. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.
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Affiliation(s)
- Eliran Moshe Reuven
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Avner Fink
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yechiel Shai
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
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26
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Molecular cloning, genomic structure, polymorphism and expression analysis of major histocompatibility complex class IIA gene of swamp eel Monopterus albus. Biologia (Bratisl) 2014; 69:236-246. [PMID: 32214413 PMCID: PMC7089440 DOI: 10.2478/s11756-013-0307-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 10/26/2013] [Indexed: 11/20/2022]
Abstract
Major histocompatibility complex (MHC) class II molecules play an important role in the immune response of vertebrates. In this paper, full-length MHC IIA cDNA was isolated from swamp eel (Monopterus albus) by rapid amplification of cDNA ends PCR. The genomic structure, molecular polymorphism, tissue distribution, and immune response of the MHC IIA gene to bacterial challenge were investigated. The full-length cDNA (GenBank accession No.: KC616308) is 1,509 bp in length including an 83 bp-long 5' untranslated region (UTR) and a 709 bp-long 3' UTR, which encoded a 238 amino acids protein. In the 2,339 bp-long MHC IIA genomic DNA, four exons and three introns were identified. Sequence comparison exhibited that the deduced amino acid sequence shared 27.1-66.3% identity with those of other species. Seven alleles were identified from five healthy individuals. Number of alleles per individual diversified from two to five. Five different 5' UTR sequences and two different 3' UTR sequences from one individual may infer the existence of five loci at least. Real-time quantitative PCR demonstrated that swamp eel MHC IIA transcripts were ubiquitously expressed in ten tissues, but the expression level was distinctly different. Significant changes were observed in liver, spleen, kidney and intestine after challenged with pathogenic bacteria Aeromonas hydrophilia.
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27
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Bannai HP, Nonaka M. Comprehensive analysis of medaka major histocompatibility complex (MHC) class II genes: implications for evolution in teleosts. Immunogenetics 2013; 65:883-95. [PMID: 23989892 DOI: 10.1007/s00251-013-0731-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/19/2013] [Indexed: 12/29/2022]
Abstract
The major histocompatibility complex (MHC) class II molecules play central roles in adaptive immunity by regulating immune response via the activation of CD4 T cells. The full complement of the MHC class II genes has been elucidated only in mammalian species to date. To understand the evolution of these genes, we performed their first comprehensive analysis in nonmammalian species using a teleost, medaka (Oryzias latipes). Based on a database search, cDNA cloning, and genomic PCR, medaka was shown to possess five pairs of expressed class II genes, comprising one IIA and one IIB gene. Each pair was located on a different chromosome and was not linked to the class I genes. Only one pair showed a high degree of polymorphism and was considered to be classical class II genes, whereas the other four pairs were nonclassical. Phylogenetic analysis of all medaka class II genes and most reported teleost class II genes revealed that the IIA and IIB genes formed separate clades, each containing three well-corresponding lineages. One lineage contained three medaka genes and all known classical class II genes of Ostariophysi and Euteleostei and was presumed to be an original lineage of the teleost MHC class II genes. The other two lineages contained one nonclassical medaka gene each and some Euteleostei genes. These results indicate that multiple lineages of the teleost MHC class II genes have been conserved for hundreds of millions of years and that the tightly linked IIA and IIB genes have undergone concerted evolution.
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Affiliation(s)
- Hidemi P Bannai
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
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Ma Q, Su YQ, Wang J, Zhuang ZM, Tang QS. Molecular cloning and expression analysis of major histocompatibility complex class IIB gene of the Whitespotted bambooshark (Chiloscyllium plagiosum). FISH PHYSIOLOGY AND BIOCHEMISTRY 2013; 39:131-142. [PMID: 22752338 DOI: 10.1007/s10695-012-9685-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 06/20/2012] [Indexed: 06/01/2023]
Abstract
Major histocompatibility complex (MHC) plays an important role in the immune response to antigenic peptides in vertebrates. In this study, the full length of MHC IIB cDNA was isolated from the Whitespotted bambooshark (Chiloscyllium plagiosum) by homology cloning, and the rapid amplification of cDNA ends polymerase chain reaction. As a result, the MHC IIB cDNA is 1,407 bp, which contains an open reading frame (ORF) of 831 bp encoding a protein of 276 amino acids. Furthermore, seven alleles of the complete MHC IIB ORF were detected and the variable sites were mainly located in the immunoglobulin-like (β2) region. Tissue distribution analysis showed that MHC IIB can be detected in all the ten tissues examined, with the highest expression in the spleen and gill. Challenge of C. plagiosum with the pathogenic bacteria, Vibrio harveyi, resulted in significant changes in the expression of MHC IIB mRNA in the three immune-related tissues (gill, liver and spleen). These results show that the MHC IIB plays an important role in response to bacterial infection in elasmobranches.
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Affiliation(s)
- Qian Ma
- Key Laboratory for Fishery Resources and Eco-environment, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
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Pang JC, Gao FY, Lu MX, Ye X, Zhu HP, Ke XL. Major histocompatibility complex class IIA and IIB genes of Nile tilapia Oreochromis niloticus: genomic structure, molecular polymorphism and expression patterns. FISH & SHELLFISH IMMUNOLOGY 2013; 34:486-496. [PMID: 23261509 DOI: 10.1016/j.fsi.2012.11.048] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 11/15/2012] [Accepted: 11/27/2012] [Indexed: 06/01/2023]
Abstract
Major histocompatibility complex (MHC) is a large genomic region characterized by extremely high polymorphism, and it plays an important role in the immune response of vertebrates. In the present study, we isolated MHC class II genes from Nile tilapia in order to investigate the immune mechanism in tilapia and develop better strategies for disease prevention. Moreover, we cloned the full-length cDNA sequences of MHC IIA and IIB from Nile tilapia by the RACE approach. In addition, the genomic structure, molecular polymorphism and expression patterns of MHC II genes in Nile tilapia were also examined. Compared with that of other teleosts, Nile tilapia MHC class IIA contained four exons and three introns. The deduced amino acid sequence of the MHC IIA molecule shared 25.4-64.5% similarity with those of other teleosts and mammals. Six exons and five introns were identified from Nile tilapia MHC IIB, and the deduced amino acid sequence shared 26.9-74.7% similarity with those of other teleosts and mammals. All the characteristic features of MHC class II chain structure could be identified in the deduced sequences of MHC IIA and IIB molecules, including the leader peptide, α1/β1 and α2/β2 domains, connecting peptide and transmembrane and cytoplasmic regions, as well as conserved cysteines and N-glycosylation site. A total of 12 MHC IIA alleles were identified from six individuals. Four alleles originating from a single individual suggested that at least four MHC IIA loci existed. Moreover, 10 MHC IIB alleles were identified, among which four were detected in a single individual, suggesting that at least four MHC IIB loci existed. The expression of MHC IIA and IIB at the mRNA level in 10 types of normal tissues was determined using quantitative real-time PCR analysis. The highest expression level was detected in stomach and gill, whereas the lowest expression was detected in muscle and brain. Furthermore, MHC IIA and IIB were probably two candidate immune molecules involved in the resistance against streptococcosis, because their expression was significantly up-regulated in gill, kidney, intestine and spleen after the intraperitoneal injection of Streptococcus agalactiae.
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Affiliation(s)
- Ji-cai Pang
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou, Guangdong 510380, PR China
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Jahnke M, Trowsdale J, Kelly AP. Structural requirements for recognition of major histocompatibility complex class II by membrane-associated RING-CH (MARCH) protein E3 ligases. J Biol Chem 2012; 287:28779-89. [PMID: 22761441 PMCID: PMC3436574 DOI: 10.1074/jbc.m112.381541] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/26/2012] [Indexed: 01/12/2023] Open
Abstract
MARCH E3 ligases play a key role in controlling MHC class II surface expression by regulated ubiquitination of a lysine residue in the β-chain. Little is known concerning how these enzymes target their specific substrates. Here we show that recognition of HLA-DR by MARCH proteins is complex. Several features associated with the transmembrane domain and bordering regions influence the overall efficiency of receptor internalization. A cluster of residues at the interface of the lipid bilayer and the cytosol plays the most important role in MARCH8 recognition of HLA-DRβ. Variation in this sequence also determines specificity of MARCH9 for HLA-DQ. Residues located in helical face four of HLA-DRβ together with a charged residue at the boundary with the stalk region also contribute significantly to recognition. Truncation analysis suggested that a dileucine-like motif in the DRβ cytoplasmic tail influences the efficiency of co-localization of HLA-DR with MARCH8. The DRβ-encoded acceptor lysine functioned optimally when placed in its natural location relative to the bilayer. In the DRα/DRβ dimer most other amino acids in the cytoplasmic tail could be substituted for alanine with minimal influence on function. Our data support a model whereby multiple features of HLA-DR are involved in substrate recognition by MARCH8. The single most important region is located at the interface between the transmembrane domain and the cytosol. Variation in sequence in this location between different class II isotypes controls efficiency of recognition by different MARCH E3 ligases.
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Affiliation(s)
- Martin Jahnke
- From the Division of Immunology, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - John Trowsdale
- From the Division of Immunology, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Adrian P. Kelly
- From the Division of Immunology, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
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Abstract
LacY mutant Cys154 → Gly exhibits a periplasmic-closed crystal structure identical to the WT, but is periplasmic-open in the membrane. The mutant hardly catalyzes transport, but binds galactosides from either side of the membrane with the same affinity and is resistant to site-directed proteolysis relative to the pseudo-WT. Site-directed alkylation was also applied to 11 single-Cys mutants in Cys154 → Gly LacY in right-side-out membrane vesicles or after solubilization and purification in dodecyl-β-D-maltopyranoside (DDM). Unlike the pseudo-WT, Cys replacements on the periplasmic side of the Cys154 → Gly mutant label rapidly in the membrane without sugar, but labeling decreases markedly after the mutant proteins are purified. Thus, Cys154 → Gly LacY likely favors a higher-energy intermediate periplasmic-open conformation in situ, but collapses to a lower-energy periplasmic-closed conformation in DDM after purification. Notably, branched-chain or neopentyl glycol maltoside detergents stabilize Cys154 → Gly LacY in the membrane-embedded form.
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Li H, Jiang L, Han J, Su H, Yang Q, He C. Major histocompatibility complex class IIA and IIB genes of the spotted halibut Verasper variegatus: genomic structure, molecular polymorphism, and expression analysis. FISH PHYSIOLOGY AND BIOCHEMISTRY 2011; 37:767-780. [PMID: 21424758 DOI: 10.1007/s10695-011-9476-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 03/03/2011] [Indexed: 05/30/2023]
Abstract
The major histocompatibility complex (MHC) is a large genomic region characterized by extremely high polymorphism and its association with resistance/susceptibility to disease in vertebrates. In this study, the full lengths of MHC IIA and IIB cDNA were obtained from spotted halibut (Verasper variegates) by expressed sequence tag (EST) and rapid amplification of cDNA ends (RACE) approaches. The genomic structure, molecular polymorphism, and expression patterns were examined to study MHC II gene functions in fish. As in other teleosts, the genomic structure of the spotted halibut MHC IIA contained 4 exons and 3 introns. The deduced amino acid sequence of the class IIA molecule shared 28-79% similarity with those of teleosts and mammals. Nine class IIA alleles were identified from five individuals. Three alleles originating from a single individual suggested the existence of at least two class IIA loci in the genome. Six exons and 5 introns were identified from spotted halibut MHC IIB, and the deduced amino acid sequence shared 33-79% similarity with those of teleosts and mammals. Twelve alleles were identified, among which five were observed in a single individual, which suggested at least three class IIB loci. Quantitative real-time PCR analysis revealed the presence of class IIA and IIB transcripts in nine normal tissues with high expression level in kidney and gill. Furthermore, MHC IIA and IIB are probably two candidates of immune molecules involved in the acute-phase response in spotted halibut, because their transcriptional levels were significantly up-regulated in blood and liver after bacterial challenge.
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Affiliation(s)
- Hongjun Li
- Liaoning Key Laboratory of Marine Fishery Molecular Biology, Liaoning Ocean and Fishery Science Institute, Dalian, China
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33
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Abstract
The transmembrane domains (TMDs) of integral membrane proteins do not merely function as membrane anchors but play active roles in many important biological processes. The downregulation of the CD4 coreceptor by the Vpu protein of HIV-1 is a prime example of a process that is dependent on specific properties of TMDs. Here we report the identification of Trp22 in the Vpu TMD and Gly415 in the CD4 TMD as critical determinants of Vpu-induced targeting of CD4 to endoplasmic reticulum (ER)-associated degradation (ERAD). The two residues participate in different aspects of ERAD targeting. Vpu Trp22 is required to prevent assembly of Vpu into an inactive, oligomeric form and to promote CD4 polyubiquitination and subsequent recruitment of the VCP-UFD1L-NPL4 dislocase complex. In the presence of a Vpu Trp22 mutant, CD4 remains integrally associated with the ER membrane, suggesting that dislocation from the ER into the cytosol is impaired. CD4 Gly415, on the other hand, contributes to CD4-Vpu interactions. We also identify two residues, Val20 and Ser23, in the Vpu TMD that mediate retention of Vpu and, by extension, CD4 in the ER. These findings highlight the exploitation of several TMD-mediated mechanisms by HIV-1 Vpu in order to downregulate CD4 and thus promote viral pathogenesis.
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34
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Smirnova I, Kasho V, Kaback HR. Lactose permease and the alternating access mechanism. Biochemistry 2011; 50:9684-93. [PMID: 21995338 DOI: 10.1021/bi2014294] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Crystal structures of the lactose permease of Escherichia coli (LacY) reveal 12, mostly irregular transmembrane α-helices surrounding a large cavity open to the cytoplasm and a tightly sealed periplasmic side (inward-facing conformation) with the sugar-binding site at the apex of the cavity and inaccessible from the periplasm. However, LacY is highly dynamic, and binding of a galactopyranoside causes closing of the inward-facing cavity with opening of a complementary outward-facing cavity. Therefore, the coupled, electrogenic translocation of a sugar and a proton across the cytoplasmic membrane via LacY very likely involves a global conformational change that allows alternating access of sugar- and H(+)-binding sites to either side of the membrane. Here the various biochemical and biophysical approaches that provide strong support for the alternating access mechanism are reviewed. Evidence is also presented indicating that opening of the periplasmic cavity is probably the limiting step for binding and perhaps transport.
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Affiliation(s)
- Irina Smirnova
- Department of Physiology and Department of Microbiology, University of California, Los Angeles, California 90095, United States
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35
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Watt B, Tenza D, Lemmon MA, Kerje S, Raposo G, Andersson L, Marks MS. Mutations in or near the transmembrane domain alter PMEL amyloid formation from functional to pathogenic. PLoS Genet 2011; 7:e1002286. [PMID: 21949659 PMCID: PMC3174235 DOI: 10.1371/journal.pgen.1002286] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 07/28/2011] [Indexed: 11/18/2022] Open
Abstract
PMEL is a pigment cell-specific protein that forms physiological amyloid fibrils upon which melanins ultimately deposit in the lumen of the pigment organelle, the melanosome. Whereas hypomorphic PMEL mutations in several species result in a mild pigment dilution that is inherited in a recessive manner, PMEL alleles found in the Dominant white (DW) chicken and Silver horse (HoSi)--which bear mutations that alter the PMEL transmembrane domain (TMD) and that are thus outside the amyloid core--are associated with a striking loss of pigmentation that is inherited in a dominant fashion. Here we show that the DW and HoSi mutations alter PMEL TMD oligomerization and/or association with membranes, with consequent formation of aberrantly packed fibrils. The aberrant fibrils are associated with a loss of pigmentation in cultured melanocytes, suggesting that they inhibit melanin production and/or melanosome integrity. A secondary mutation in the Smoky chicken, which reverts the dominant DW phenotype, prevents the accumulation of PMEL in fibrillogenic compartments and thus averts DW-associated pigment loss; a secondary mutation found in the Dun chicken likely dampens a HoSi-like dominant mutation in a similar manner. We propose that the DW and HoSi mutations alter the normally benign amyloid to a pathogenic form that antagonizes melanosome function, and that the secondary mutations found in the Smoky and Dun chickens revert or dampen pathogenicity by functioning as null alleles, thus preventing the formation of aberrant fibrils. We speculate that PMEL mutations can model the conversion between physiological and pathological amyloid.
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Affiliation(s)
- Brenda Watt
- Department of Pathology and Laboratory Medicine and Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Danièle Tenza
- Institut Curie, Centre de Recherche, Paris, France
- CNRS, UMR-144, Paris, France
| | - Mark A. Lemmon
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Susanne Kerje
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Graça Raposo
- Institut Curie, Centre de Recherche, Paris, France
- CNRS, UMR-144, Paris, France
| | - Leif Andersson
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Michael S. Marks
- Department of Pathology and Laboratory Medicine and Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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36
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Xu T, Sun Y, Shi G, Cheng Y, Wang R. Characterization of the major histocompatibility complex class II genes in miiuy croaker. PLoS One 2011; 6:e23823. [PMID: 21901139 PMCID: PMC3162010 DOI: 10.1371/journal.pone.0023823] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 07/27/2011] [Indexed: 11/18/2022] Open
Abstract
Major histocompatibility complex (MHC) has a central role in the adaptive immune system by presenting foreign peptide to the T-cell receptor. In order to study the molecular function and genomic characteristic of class II genes in teleost, the full lengths of MHC class IIA and IIB cDNA and genomic sequence were cloned from miiuy croaker (Miichthys miiuy). As in other teleost, four exons and three introns were identified in miiuy croaker class IIA gene; but the difference is that six exons and five introns were identified in the miiuy croaker class IIB gene. The deduced amino acid sequence of class IIA and class IIB had 26.3–85.7% and 11.0–88.8% identity with those of mammal and teleost, respectively. Real-time quantitative RT-PCR demonstrated that the MHC class IIA and IIB were ubiquitously expressed in ten normal tissues; expression levels of MHC genes were found first upregulated and then downregulated, and finally by a recovery to normal level throughout the pathogenic bacteria infection process. In addition, we report on the underlying mechanism that maintains sequences diversity among many fish species. A series of site-model tests implemented in the CODEML program revealed that positive Darwinian selection is likely the cause of the molecular evolution in the fish MHC class II genes.
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Affiliation(s)
- Tianjun Xu
- Laboratory for Marine Living Resources and Molecular Engineering, College of Marine Science, Zhejiang Ocean University, Zhoushan, People's Republic of China.
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37
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Zhou Y, Madej MG, Guan L, Nie Y, Kaback HR. An early event in the transport mechanism of LacY protein: interaction between helices V and I. J Biol Chem 2011; 286:30415-30422. [PMID: 21730060 DOI: 10.1074/jbc.m111.268433] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Helix V in LacY, which abuts and crosses helix I in the N-terminal helix bundle of LacY, contains Arg(144) and Trp(151), two residues that play direct roles in sugar recognition and binding, as well as Cys(154), which is important for conformational flexibility. In this study, paired Cys replacement mutants in helices V and I were strategically constructed with tandem factor Xa protease cleavage sites in the loop between the two helices to test cross-linking. None of the mutants form disulfides spontaneously; however, three mutants (Pro(28) → Cys/Cys(154), Pro(28) → Cys/Val(158) → Cys, and Phe(29) → Cys/Val(158) → Cys) exhibit cross-linking after treatment with copper/1,10-phenanthroline (Cu/Ph) or 1,1-methanediyl bismethanethiosulfonate ((MTS)(2)-1), 3-4 Å), and cross-linking is quantitative in the presence of ligand. Remarkably, with one mutant, complete cross-linking with (MTS)(2)-1 has no effect on lactose transport, whereas quantitative disulfide cross-linking catalyzed by Cu/Ph markedly inhibits transport activity. The findings are consistant with a number of previous conclusions suggesting that sugar binding to LacY causes a localized scissors-like movement between helices V and I near the point where the two helices cross in the middle of the membrane. This ligand-induced movement may act to initiate the global conformational change resulting from sugar binding.
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Affiliation(s)
- Yonggang Zhou
- Departments of Physiology, University of California, Los Angeles, California 90095-1662
| | - M Gregor Madej
- Departments of Physiology, University of California, Los Angeles, California 90095-1662
| | - Lan Guan
- Departments of Physiology, University of California, Los Angeles, California 90095-1662
| | - Yiling Nie
- Departments of Physiology, University of California, Los Angeles, California 90095-1662
| | - H Ronald Kaback
- Departments of Physiology, University of California, Los Angeles, California 90095-1662; Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095-1662; Molecular Biology Institute, University of California, Los Angeles, California 90095-1662.
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Busman-Sahay K, Sargent E, Harton JA, Drake JR. The Ia.2 epitope defines a subset of lipid raft-resident MHC class II molecules crucial to effective antigen presentation. THE JOURNAL OF IMMUNOLOGY 2011; 186:6710-7. [PMID: 21543648 DOI: 10.4049/jimmunol.1100336] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Previous work established that binding of the 11-5.2 anti-I-A(k) mAb, which recognizes the Ia.2 epitope on I-A(k) class II molecules, elicits MHC class II signaling, whereas binding of two other anti-I-A(k) mAbs that recognize the Ia.17 epitope fail to elicit signaling. Using a biochemical approach, we establish that the Ia.2 epitope recognized by the widely used 11-5.2 mAb defines a subset of cell surface I-A(k) molecules predominantly found within membrane lipid rafts. Functional studies demonstrate that the Ia.2-bearing subset of I-A(k) class II molecules is critically necessary for effective B cell-T cell interactions, especially at low Ag doses, a finding consistent with published studies on the role of raft-resident class II molecules in CD4 T cell activation. Interestingly, B cells expressing recombinant I-A(k) class II molecules possessing a β-chain-tethered hen egg lysosome peptide lack the Ia.2 epitope and fail to partition into lipid rafts. Moreover, cells expressing Ia.2(-) tethered peptide-class II molecules are severely impaired in their ability to present both tethered peptide or peptide derived from exogenous Ag to CD4 T cells. These results establish the Ia.2 epitope as defining a lipid raft-resident MHC class II conformer vital to the initiation of MHC class II-restricted B cell-T cell interactions.
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Affiliation(s)
- Kathleen Busman-Sahay
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208, USA
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Shen T, Xu S, Yang M, Pang S, Yang G. Molecular cloning, expression pattern, and 3D structural analysis of the MHC class IIB gene in the Chinese longsnout catfish (Leiocassis longirostris). Vet Immunol Immunopathol 2011; 141:33-45. [PMID: 21377740 DOI: 10.1016/j.vetimm.2011.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 01/25/2011] [Accepted: 02/07/2011] [Indexed: 11/19/2022]
Affiliation(s)
- Tong Shen
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, China
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40
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Hubert P, Sawma P, Duneau JP, Khao J, Hénin J, Bagnard D, Sturgis J. Single-spanning transmembrane domains in cell growth and cell-cell interactions: More than meets the eye? Cell Adh Migr 2010; 4:313-24. [PMID: 20543559 PMCID: PMC2900628 DOI: 10.4161/cam.4.2.12430] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 05/20/2010] [Indexed: 01/28/2023] Open
Abstract
As a whole, integral membrane proteins represent about one third of sequenced genomes, and more than 50% of currently available drugs target membrane proteins, often cell surface receptors. Some membrane protein classes, with a defined number of transmembrane (TM) helices, are receiving much attention because of their great functional and pharmacological importance, such as G protein-coupled receptors possessing 7 TM segments. Although they represent roughly half of all membrane proteins, bitopic proteins (with only 1 TM helix) have so far been less well characterized. Though they include many essential families of receptors, such as adhesion molecules and receptor tyrosine kinases, many of which are excellent targets for biopharmaceuticals (peptides, antibodies, et al.). A growing body of evidence suggests a major role for interactions between TM domains of these receptors in signaling, through homo and heteromeric associations, conformational changes, assembly of signaling platforms, etc. Significantly, mutations within single domains are frequent in human disease, such as cancer or developmental disorders. This review attempts to give an overview of current knowledge about these interactions, from structural data to therapeutic perspectives, focusing on bitopic proteins involved in cell signaling.
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Affiliation(s)
- Pierre Hubert
- LISM UPR 9027, CNRS-Aix-Marseille University, Marseille, France.
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41
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Jiang X, Fares MA. Identifying coevolutionary patterns in human leukocyte antigen (HLA) molecules. Evolution 2009; 64:1429-45. [PMID: 19930454 DOI: 10.1111/j.1558-5646.2009.00903.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The antigenic peptide, major histocompatibility complex molecule (MHC; also called human leukocyte antigen, HLA), coreceptor CD8, or CD4 and T-cell receptor (TCR) function as a complex to initiate effectors' mechanisms of the immune system. The tight functional and physical interaction among these molecules may have involved strong coevolution links among domains within and between proteins. Despite the importance of unraveling such dependencies to understand the arms race of host-pathogen interaction, no previous studies have aimed at achieving such an objective. Here, we perform an exhaustive coevolution analysis and show that indeed such dependencies are strongly shaping the evolution and probably the function of these molecules. We identify intramolecular coevolution in HLA class I and II at domains important for their immune activity. Most of the amino acid sites identified to be coevolving in HLAI have been also detected to undergo positive Darwinian selection highlighting therefore their adaptive value. We also identify coevolution among antigen-binding pockets (P1-P9) and among these and TCR-binding sites. Conversely to HLAI, coevolution is weaker in HLAII. Our results support that such coevolutionary patterns are due to selective pressures of host-pathogen coevolution and cooperative binding of TCRs, antigenic peptides, and CD8/CD4 to HLAI and HLAII.
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Affiliation(s)
- Xiaowei Jiang
- Evolutionary Genetics and Bioinformatics Laboratory, Department of Genetics, Smurfit Institute of Genetics, University of Dublin, Trinity College Dublin, Dublin 2, Ireland.
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42
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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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43
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Truncation of the membrane-spanning domain of human immunodeficiency virus type 1 envelope glycoprotein defines elements required for fusion, incorporation, and infectivity. J Virol 2009; 83:11588-98. [PMID: 19726514 DOI: 10.1128/jvi.00914-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The membrane-spanning domain (MSD) of the envelope (Env) glycoprotein from human (HIV) and simian immunodeficiency viruses plays a key role in anchoring the Env complex into the viral membrane but also contributes to its biological function in fusion and virus entry. In HIV type 1 (HIV-1), it has been predicted to span 27 amino acids, from lysine residue 681 to arginine 707, and encompasses an internal arginine at residue 694. By examining a series of C-terminal-truncation mutants of the HIV-1 gp41 glycoprotein that substituted termination codons for amino acids 682 to 708, we show that this entire region is required for efficient viral infection of target cells. Truncation to the arginine at residue 694 resulted in an Env complex that was secreted from the cells. In contrast, a region from residues 681 to 698, which contains highly conserved hydrophobic residues and glycine motifs and extends 4 amino acids beyond 694R, can effectively anchor the protein in the membrane, allow efficient transport to the plasma membrane, and mediate wild-type levels of cell-cell fusion. However, these fusogenic truncated Env mutants are inefficiently incorporated into budding virions. Based on the analysis of these mutants, a "snorkeling" model, in which the flanking charged amino acid residues at 681 and 694 are buried in the lipid while their side chains interact with polar head groups, is proposed for the HIV-1 MSD.
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Glaberman S, Moreno MA, Caccone A. Characterization and evolution of MHC class II B genes in Galápagos marine iguanas (Amblyrhynchus cristatus). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2009; 33:939-947. [PMID: 19454336 DOI: 10.1016/j.dci.2009.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 02/10/2009] [Accepted: 03/14/2009] [Indexed: 05/27/2023]
Abstract
Major histocompatibility complex (MHC) class II molecules play a key role in the adaptive immune system of vertebrates. Class II B genes appear to evolve in a very different manner in mammals and birds. Orthology is commonly observed among mammal loci, while genes tend to cluster phylogenetically within bird species. Here we present class II B data from a representative of another major group of amniotes, the squamates (i.e. lizards, snakes, amphisbaenians), with the ultimate goal of placing mammalian and avian MHC evolution into a broader context. In this study, eight class II B cDNA sequences were obtained from the Galápagos marine iguana (Amblyrhynchus cristatus) which were divided into five locus groups, Amcr-DAB1 through -DAB5, based on similarities along most of the coding and noncoding portions of the transcribed gene. All marine iguana sequences were monophyletic with respect to class II genes from other vertebrates indicating that they originated from a common ancestral locus after squamates split from other reptiles. The beta-1 domain, which is involved in antigen binding, exhibited signatures of positive selection as well as interlocus gene conversion in both long and short tracts-a pattern also observed in birds and fish, but not in mammals. On the other hand, the beta-2 domain was divergent between gene groups, which is characteristic of mammals. Based on these results, we preliminarily show that squamate class II B genes have been shaped by a unique blend of evolutionary forces that have been observed in differing degrees in other vertebrates.
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Affiliation(s)
- Scott Glaberman
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520-8105, United States.
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Xu TJ, Chen SL, Ji XS, Sha ZX. Molecular cloning, genomic structure, polymorphism and expression analysis of major histocompatibility complex class IIA and IIB genes of half-smooth tongue sole (Cynoglossus semilaevis). FISH & SHELLFISH IMMUNOLOGY 2009; 27:192-201. [PMID: 19442741 DOI: 10.1016/j.fsi.2009.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 04/16/2009] [Accepted: 04/21/2009] [Indexed: 05/27/2023]
Abstract
Major histocompatibility complex (MHC) genes play an important role in the immune response of vertebrates. Its function is to present foreign peptide to the T-cell. In order to study the function and molecular polymorphism of class II genes in teleost, the full lengths of MHC class IIA and IIB cDNA were cloned from half-smooth tongue sole by homology cloning and rapid amplification of cDNA ends polymerase chain reaction (RACE-PCR). Genomic organizations, molecular polymorphism, and expression profiles of class IIA and IIB were examined to study the function in fish. As in other teleost, four exons and three introns were identified in half-smooth tongue sole class IIA gene, five exons and four introns were identified in class IIB gene. The deduced amino acid sequence of class IIA had 27.3-69.8% identity with those of mammal and teleost. Nine class IIA alleles were identified from four individuals. Four different alleles observed in a single individual may infer the existence of two loci at least. The deduced amino acid sequence of class IIB had 7.9-71.9% identity with those of other species. Fifteen class IIB alleles were identified. Six different alleles observed in a single individual may suggest that there are at least three loci in class IIB genes. Real-time quantitative RT-PCR demonstrated that the MHC class IIA and IIB were ubiquitously expressed in twelve normal tissues. Challenge of half-smooth tongue sole with the pathogenic bacteria, Vibrio anguillarum, resulted in significant changes in the expression of MHC IIA and IIB mRNA in three tissues.
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Affiliation(s)
- Tian-Jun Xu
- Key Lab for Sustainable Utilization of Marine Fisheries Resources, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 266071 Qingdao, China
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46
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Poulsen BE, Rath A, Deber CM. The assembly motif of a bacterial small multidrug resistance protein. J Biol Chem 2009; 284:9870-5. [PMID: 19224913 DOI: 10.1074/jbc.m900182200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Multidrug transporters such as the small multidrug resistance (SMR) family of bacterial integral membrane proteins are capable of conferring clinically significant resistance to a variety of common therapeutics. As antiporter proteins of approximately 100 amino acids, SMRs must self-assemble into homo-oligomeric structures for efflux of drug molecules. Oligomerization centered at transmembrane helix four (TM4) has been implicated in SMR assembly, but the full complement of residues required to mediate its self-interaction remains to be characterized. Here, we use Hsmr, the 110-residue SMR family member of the archaebacterium Halobacterium salinarum, to determine the TM4 residue motif required to mediate drug resistance and SMR self-association. Twelve single point mutants that scan the central portion of the TM4 helix (residues 85-104) were constructed and were tested for their ability to confer resistance to the cytotoxic compound ethidium bromide. Six residues were found to be individually essential for drug resistance activity (Gly(90), Leu(91), Leu(93), Ile(94), Gly(97), and Val(98)), defining a minimum activity motif of (90)GLXLIXXGV(98) within TM4. When the propensity of these mutants to dimerize on SDS-PAGE was examined, replacements of all but Ile resulted in approximately 2-fold reduction of dimerization versus the wild-type antiporter. Our work defines a minimum activity motif of (90)GLXLIXXGV(98) within TM4 and suggests that this sequence mediates TM4-based SMR dimerization along a single helix surface, stabilized by a small residue heptad repeat sequence. These TM4-TM4 interactions likely constitute the highest affinity locus for disruption of SMR function by directly targeting its self-assembly mechanism.
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Affiliation(s)
- Bradley E Poulsen
- Division of Molecular Structure and Function, Research Institute, Hospital for Sick Children, Toronto, Ontario M5G 1X8
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Kawashita SY, da Silva CV, Mortara RA, Burleigh BA, Briones MRS. Homology, paralogy and function of DGF-1, a highly dispersed Trypanosoma cruzi specific gene family and its implications for information entropy of its encoded proteins. Mol Biochem Parasitol 2009; 165:19-31. [PMID: 19393159 DOI: 10.1016/j.molbiopara.2008.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 12/12/2008] [Accepted: 12/23/2008] [Indexed: 11/30/2022]
Abstract
Surface adhesion proteins are essential for Trypanosoma cruzi invasion of mammalian cells. Here we show that Dispersed Gene Family-1 (DGF-1) members, previously identified as nuclear repeated sequences present in several chromosomes and comprising the third largest T. cruzi specific gene family, have conserved adhesin motifs including four segments with significant similarity to human beta 7 integrin. Flow cytometry and biotinylation assays with anti-DGF-1 antibodies indicated that, as expected, DGF-1 members are expressed on the trypomastigote surface. The DGF-1 genealogy, inferred using T. cruzi Genome Project data and network phylogeny algorithms, suggests that this gene family is separated in at least three groups with differential distribution of functional domains. To identify which members of this gene family are expressed we used a combined approach of RT-PCR and codon usage profiles, showing that expressed members have a very biased codon usage favoring GC, whereas non-expressed members have a homogeneous distribution. Shannon information entropy was used to measure sequence variability and revealed four major high entropy segments in the extracellular domain of DGF-1 overlapping with important putative functional modules of the predicted proteins. Testing for natural selection, however, indicated that these high entropy segments were not under positive selection, which contradicts the notion that positive selection is the cause of high variability in specific domains of a protein relative to other less variable regions in the same molecule. We conjectured that members of the DGF-1 family might be associated with the ability of T. cruzi to bind extracellular matrix proteins, such as fibronectin and laminin, and speculated on mechanisms that would be generating the localized diversity in these molecules in the absence of selection.
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Affiliation(s)
- Silvia Y Kawashita
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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Moore DT, Berger BW, DeGrado WF. Protein-protein interactions in the membrane: sequence, structural, and biological motifs. Structure 2008; 16:991-1001. [PMID: 18611372 PMCID: PMC3771515 DOI: 10.1016/j.str.2008.05.007] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 05/25/2008] [Accepted: 05/30/2008] [Indexed: 01/10/2023]
Abstract
Single-span transmembrane (TM) helices have structural and functional roles well beyond serving as mere anchors to tether water-soluble domains in the vicinity of the membrane. They frequently direct the assembly of protein complexes and mediate signal transduction in ways analogous to small modular domains in water-soluble proteins. This review highlights different sequence and structural motifs that direct TM assembly and discusses their roles in diverse biological processes. We believe that TM interactions are potential therapeutic targets, as evidenced by natural proteins that modulate other TM interactions and recent developments in the design of TM-targeting peptides.
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Affiliation(s)
- David T. Moore
- Department of Biochemistry and Molecular Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA
| | - Bryan W. Berger
- Department of Biochemistry and Molecular Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA
| | - William F. DeGrado
- Department of Biochemistry and Molecular Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA
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Buonocore F, Randelli E, Casani D, Costantini S, Facchiano A, Scapigliati G, Stet RJM. Molecular cloning, differential expression and 3D structural analysis of the MHC class-II beta chain from sea bass (Dicentrarchus labrax L.). FISH & SHELLFISH IMMUNOLOGY 2007; 23:853-66. [PMID: 17493833 DOI: 10.1016/j.fsi.2007.03.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 03/15/2007] [Accepted: 03/15/2007] [Indexed: 05/15/2023]
Abstract
The major histocompatibility complex class I and II molecules (MHC-I and MHC-II) play a pivotal role in vertebrate immune response to antigenic peptides. In this paper we report the cloning and sequencing of the MHC class II beta chain from sea bass (Dicentrarchus labrax L.). The six obtained cDNA sequences (designated as Dila-DAB) code for 250 amino acids, with a predicted 21 amino acid signal peptide and contain a 28bp 5'-UTR and a 478bp 3'-UTR. A multiple alignment of the predicted translation of the Dila-DAB sequences was assembled together with other fish and mammalian sequences and it showed the conservation of most amino acid residues characteristic of the MHC class II beta chain structure. The highest basal Dila-DAB expression was found in gills, followed by gut and thymus, lower mRNA levels were found in spleen, peripheral blood leucocytes (PBL) and liver. Stimulation of head kidney leukocytes with LPS for 4h showed very little difference in the Dila-DAB expression, but after 24h the Dila-DAB level decreased to a large extent and the difference was statistically significant. Stimulation of head kidney leukocytes with different concentrations of rIL-1beta (ranging from 0 to 100ng/ml) resulted in a dose-dependent reduction of the Dila-DAB expression. Moreover, two 3D Dila-DAB*0101 homology models were obtained based on crystallographic mouse MHC-II structures complexed with D10 T-cell antigen receptor or human CD4; features and differences between the models were evaluated and discussed. Taken together these results are of interest as MHC-II structure and function, molecular polymorphism and differential gene expression are in correlation with disease resistance to virus and bacteria in teleost fish.
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Affiliation(s)
- Francesco Buonocore
- Dipartimento di Scienze Ambientali, University of Tuscia, Largo dell'Università snc, I-01100, Viterbo, Italy.
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50
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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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