1
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Floch A, Galochkina T, Pirenne F, Tournamille C, de Brevern AG. Molecular dynamics of the human RhD and RhAG blood group proteins. Front Chem 2024; 12:1360392. [PMID: 38566898 PMCID: PMC10985258 DOI: 10.3389/fchem.2024.1360392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/07/2024] [Indexed: 04/04/2024] Open
Abstract
Introduction: Blood group antigens of the RH system (formerly known as "Rhesus") play an important role in transfusion medicine because of the severe haemolytic consequences of antibodies to these antigens. No crystal structure is available for RhD proteins with its partner RhAG, and the precise stoichiometry of the trimer complex remains unknown. Methods: To analyse their structural properties, the trimers formed by RhD and/or RhAG subunits were generated by protein modelling and molecular dynamics simulations were performed. Results: No major differences in structural behaviour were found between trimers of different compositions. The conformation of the subunits is relatively constant during molecular dynamics simulations, except for three large disordered loops. Discussion: This work makes it possible to propose a reasonable stoichiometry and demonstrates the potential of studying the structural behaviour of these proteins to investigate the hundreds of genetic variants relevant to transfusion medicine.
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Affiliation(s)
- Aline Floch
- University Paris Est Créteil, INSERM U955 Equipe Transfusion et Maladies du Globule Rouge, IMRB, Créteil, France
- Laboratoire de Biologie Médicale de Référence en Immuno-Hématologie Moléculaire, Etablissement Français du Sang Ile-de-France, Créteil, France
| | - Tatiana Galochkina
- Université Paris Cité and Université des Antilles and Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, DSIMB Bioinformatics team, Paris, France
| | - France Pirenne
- University Paris Est Créteil, INSERM U955 Equipe Transfusion et Maladies du Globule Rouge, IMRB, Créteil, France
- Laboratoire de Biologie Médicale de Référence en Immuno-Hématologie Moléculaire, Etablissement Français du Sang Ile-de-France, Créteil, France
| | - Christophe Tournamille
- University Paris Est Créteil, INSERM U955 Equipe Transfusion et Maladies du Globule Rouge, IMRB, Créteil, France
- Laboratoire de Biologie Médicale de Référence en Immuno-Hématologie Moléculaire, Etablissement Français du Sang Ile-de-France, Créteil, France
| | - Alexandre G. de Brevern
- Université Paris Cité and Université des Antilles and Université de la Réunion, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, DSIMB Bioinformatics team, Paris, France
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2
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Hutchison CJ, Srivastava K, Polin H, Bueno MU, Flegel WA. Rh flow cytometry: An updated methodology for D antigen density applied to weak D types 164 and 165. Transfusion 2023; 63:2141-2151. [PMID: 37792462 PMCID: PMC10680490 DOI: 10.1111/trf.17543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 10/05/2023]
Abstract
BACKGROUND An original methodology for determining the D antigen density on red cells was published in 2000 and has been applied in many publications since. This flow cytometry-based assay remained largely unrevised utilizing monoclonal anti-Ds that are not readily available anymore. We updated the methodology to quantify erythrocyte D antigen sites using microspheres and monoclonal anti-Ds that are commercially available today. METHODS The absolute D antigen density of a frozen standard CcDEe cell, drawn in 2003, a fresh blood donation from the same individual, drawn in 2022, and an internal control CcDEe cell, was quantified by flow cytometry using fluorescence-labeled microspheres. The internal control CcDEe cell was used in conjunction with 9 commercial anti-Ds to determine D antigen densities of 7 normal D, 4 partial D, and 11 weak D type samples, including 2 novel alleles. RESULTS The reproducibility of the updated assay was evaluated with red cells of published D antigen densities. The current results matched the known ones closely. The new weak D types 164 and 165 carried 4500 and 1505 D antigens/red cell, respectively. The absolute D antigen density decreased from 27,231 to 26,037 in an individual over 19 years. DISCUSSION The updated assay gave highly reproducible results for the D antigen densities of Rh phenotypes. Readily available anti-Ds allowed for the determination of the D antigen densities of 7 weak D types. The assay is suitable to evaluate the effects of distinct amino acid substitutions on the RhD phenotype.
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Affiliation(s)
- Chloe Jayne Hutchison
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Kshitij Srivastava
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Helene Polin
- Department of Immunogenetics, Red Cross Transfusion Service for Upper Austria, Linz, Austria
| | - Marina Ursula Bueno
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Willy Albert Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
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3
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Trueba-Gómez R, Rosenfeld-Mann F, Baptista-González HA, Domínguez-López ML, Estrada-Juárez H. Use of computational biology to compare the theoretical tertiary structures of the most common forms of RhCE and RhD. Vox Sang 2023; 118:881-890. [PMID: 37559188 DOI: 10.1111/vox.13509] [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: 01/18/2023] [Revised: 07/11/2023] [Accepted: 07/21/2023] [Indexed: 08/11/2023]
Abstract
BACKGROUND AND OBJECTIVES Computational biology analyses the theoretical tertiary structure of proteins and identifies the 'topological' differences between RhD and RhCE. Our aim was to identify the theoretical structural differences between the four isoforms of RhCE and RhD using computational biological tools. MATERIALS AND METHODS Physicochemical profile was determined by hydrophobicity and electrostatic potential analysis. Secondary and tertiary structures were generated using computational biology tools. The structures were evaluated and validated using Ramachandran algorithm, which calculates the single score, p-value and root mean square deviation (RMSD). Structures were overlaid on local refinement of 'RhAG-RhCE-ANK' (PBDID 7uzq) and RhAG to compare their spatial distribution within the membrane. RESULTS All proteins differed in surface area and electrostatic distance due to variations in hydrophobicity and electrostatic potential. The RMSD between RhD and RhCE was 0.46 ± 0.04 Å, and the comparison within RhCE was 0.57 ± 0.08 Å. The percentage of amino acids in the hydrophobic thickness was 50.24% for RhD while for RhCE it ranged between 73.08% and 76.68%. The RHAG hydrophobic thickness was 34.2 Å, and RhCE's hydrophobic thickness was 33.83 Å. We suggest that the C/c antigens differ exofacially at loops L1 and L2. For the E/e antigens, the difference lies in L6. By contrast, L4 is the same for all proteins except Rhce. CONCLUSION The physicochemical properties of Rh proteins made them different, although their genes are homologous. Using computational biology, we model structures with sufficient precision, similar to those obtained experimentally. An amino acid variation alters the folding of the tertiary structure and the interactions with other proteins, modifying the electrostatic environment, the spatial conformations and therefore the antigenic recognition.
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Affiliation(s)
- Rocio Trueba-Gómez
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Coordinación de Hematología Perinatal, Mexico City, Mexico
- Posgrado en Ciencias Químico Biológicas, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Fany Rosenfeld-Mann
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Coordinación de Hematología Perinatal, Mexico City, Mexico
| | - Hector A Baptista-González
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Coordinación de Hematología Perinatal, Mexico City, Mexico
| | - María L Domínguez-López
- Posgrado en Ciencias Químico Biológicas, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Higinio Estrada-Juárez
- Instituto Nacional de Perinatología "Isidro Espinosa de los Reyes", Coordinación de Hematología Perinatal, Mexico City, Mexico
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4
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Loskutov SI, Proshin SN, Ryabukhin DS. Evolutionary aspects of gastrointestinal tract microbiome-host interaction underlying gastrointestinal barrier integrity. RUSSIAN JOURNAL OF INFECTION AND IMMUNITY 2022. [DOI: 10.15789/2220-7619-eao-1633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the host sustenance and homeostasis, the microbiome is a key component in the functional system. Throughout ontogenetic development, microbiome including that of the gastrointestinal tract (GIT) is the vital factor that ensures not only host functioning, but also its interaction with environment. To uncover the mechanisms underlying GIT microbiome showing a decisive influence on host organism, a systematic approach is needed, because diverse microorganisms are predominantly localized in different parts of the GIT. Recently, a new interdisciplinary direction of science, nanobioinformatics that has been extensively developed considers gene networks as the major object of study representing a coordinated group of genes that functionally account for formation and phenotypic disclosure of various host traits. Here, an important place should be provided to the genetically determined level of the gastrointestinal tract microbiome, its interaction at the level of the host food systems. There have been increasing evidence indicating that the microbiome is directly involved in the pathogenesis of host diseases showing a multi-layered interaction with host metabolic and immune systems. At the same time, the microbial community is unevenly distributed throughout the gastrointestinal tract, and its different portions are variously active while interacting with the host immune system. The architecture of interaction between the microbiome and host cells is extremely complex, and the interaction of individual cells, at the same time, varies greatly. Bacteria colonizing the crypts of the small intestine regulate enterocyte proliferation by affecting DNA replication and gene expression, while bacteria at the tip of the intestinal villi mediate gene expression responsible for metabolism and immune response. Enterocytes and Paneth cells, in turn, regulate the vital activity of the community of microorganisms through the production of polysaccharides (carbohydrates) and antibacterial factors on their surface. Thus, the integrity of the gastrointestinal barrier (GIB) is maintained, which protects the body from infections and inflammation, while violation of its integrity leads to a number of diseases. It has been shown that depending on the dominance of certain types of bacteria the microbiome can maintain or disrupt GIB integrity. The structural and functional GIB integrity is important for body homeostasis. To date, at least 50 proteins have been characterized as being involved in the structural and functional integrability of tight junctions between gastrointestinal tract epithelial cells. The current review comprehensively discusses such issues and presents original research carried out at various facilities of translational biomedicine.
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5
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Vallese F, Kim K, Yen LY, Johnston JD, Noble AJ, Calì T, Clarke OB. Architecture of the human erythrocyte ankyrin-1 complex. Nat Struct Mol Biol 2022; 29:706-718. [PMID: 35835865 PMCID: PMC10373098 DOI: 10.1038/s41594-022-00792-w] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 05/24/2022] [Indexed: 12/28/2022]
Abstract
The stability and shape of the erythrocyte membrane is provided by the ankyrin-1 complex, but how it tethers the spectrin-actin cytoskeleton to the lipid bilayer and the nature of its association with the band 3 anion exchanger and the Rhesus glycoproteins remains unknown. Here we present structures of ankyrin-1 complexes purified from human erythrocytes. We reveal the architecture of a core complex of ankyrin-1, the Rhesus proteins RhAG and RhCE, the band 3 anion exchanger, protein 4.2, glycophorin A and glycophorin B. The distinct T-shaped conformation of membrane-bound ankyrin-1 facilitates recognition of RhCE and, unexpectedly, the water channel aquaporin-1. Together, our results uncover the molecular details of ankyrin-1 association with the erythrocyte membrane, and illustrate the mechanism of ankyrin-mediated membrane protein clustering.
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Affiliation(s)
- Francesca Vallese
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA.,Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA.,Irving Institute for Clinical and Translational Research, Columbia University, New York, NY, USA
| | - Kookjoo Kim
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA.,Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA.,Irving Institute for Clinical and Translational Research, Columbia University, New York, NY, USA
| | - Laura Y Yen
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Jake D Johnston
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA.,Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Alex J Noble
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA
| | - Tito Calì
- Department of Biomedical Sciences, University of Padua, Padua, Italy.,Padua Neuroscience Center (PNC), University of Padua, Padua, Italy.,Study Center for Neurodegeneration (CESNE), University of Padua, Padua, Italy
| | - Oliver Biggs Clarke
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA. .,Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA. .,Irving Institute for Clinical and Translational Research, Columbia University, New York, NY, USA.
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6
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Flegel WA. Proceed with care: the "uncommon" serologic weak D phenotypes. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2021; 19:272-276. [PMID: 34704554 PMCID: PMC8297679 DOI: 10.2450/2021.0147-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Willy Albert Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, United States of America
- Huazhong University of Science and Technology, Wuhan, Hubei, China
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7
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Raud L, Le Tertre M, Vigneron L, Ka C, Richard G, Callebaut I, Chen JM, Férec C, Le Gac G, Fichou Y. Missense RHD single nucleotide variants induce weakened D antigen expression by altering splicing and/or protein expression. Transfusion 2021; 61:2468-2476. [PMID: 34110623 DOI: 10.1111/trf.16538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 04/09/2021] [Accepted: 04/28/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Although D variant phenotype is known to be due to genetic defects, including rare missense single nucleotide variants (SNVs), within the RHD gene, few studies have addressed the molecular and cellular mechanisms driving this altered expression. We and others showed previously that splicing is commonly disrupted by SNVs in constitutive splice sites and their vicinity. We thus sought to investigate whether rare missense SNVs located in "deep" exonic regions could also impair this mechanism. STUDY DESIGN AND METHODS Forty-six missense SNVs reported within exons 6 and 7 were first selected from the Human RhesusBase. Their respective effect on splicing was assessed by using an in vitro assay. An RhD-negative cell model was further generated by using the CRISPR-Cas9 approach. RhD-mutated proteins were overexpressed in the newly created model, and cell membrane expression of the D antigen was measured by flow cytometry. RESULTS Minigene splicing assay showed that 14 of 46 (30.4%) missense SNVs alter splicing. Very interestingly, further investigation of two missense SNVs, which both affect codon 338 and confer a weak D phenotype, showed various mechanisms: c.1012C>G (p.Leu338Val) disrupts splicing only, while c.1013T>C (p.Leu338Pro) alters only the protein structure, in agreement with in silico prediction tools and 3D protein structure visualization. CONCLUSION Our functional data set suggests that missense SNVs damage quantitatively D antigen expression by, at least, two different mechanisms (splicing alteration and protein destabilization) that may act independently. These data thereby contribute to extend the current knowledge of the molecular mechanisms governing weakened D expression.
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Affiliation(s)
- Loann Raud
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Marlène Le Tertre
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | | | - Chandran Ka
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | - Gaëlle Richard
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Paris, France
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | - Gérald Le Gac
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | - Yann Fichou
- Univ Brest, Inserm, EFS, UMR1078, GGB, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
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8
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Ekman S, Flower R, Barnard RT, Gould A, Bui XT. Computational modeling - an approach to the development of blood grouping reagents. Expert Rev Hematol 2021; 14:329-334. [PMID: 33759674 DOI: 10.1080/17474086.2021.1908119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Blood group antigens are defined by an immune response that generates antibodies against a red blood cell molecule. Antibodies against these antigens can be associated with hemolytic transfusion reactions. However, difficulties can arise when developing antibodies against antigens through the use of peptide sequences alone. Three-dimensional representations (models) of the molecular structure of antigen-bearing proteins can provide valuable insights into tertiary structures and their consequent antigenicity. This can be achieved through predictive computational modeling to produce both structural and molecular dynamics models of blood group proteins.Areas covered: Authors discuss the use of molecular dynamic simulations on existing structures, as well as the use of computational modeling techniques in the development of protein models lacking preexisting data. Finally, the authors discuss specific examples of the use of computationally derived models of the MNS blood group system and its use in attempts to produce antibodies against MNS proteins.Expert opinion: Although in silico techniques have limitations, computer-based predictive models can inform the direction of research into blood group proteins. It is to be expected that as computer-based techniques grow more powerful these contributions will be even more significant.
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Affiliation(s)
- Serena Ekman
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia.,Clinical Services and Research, Australian Red Cross Lifeblood (Formerly Australian Red Cross Blood Service), Research and Development, Kelvin Grove, Australia
| | - Robert Flower
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia.,Clinical Services and Research, Australian Red Cross Lifeblood (Formerly Australian Red Cross Blood Service), Research and Development, Kelvin Grove, Australia
| | - Ross T Barnard
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Alison Gould
- Australian Red Cross Lifeblood (Formerly Australian Red Cross Blood Service), Research and Development, Alexandria, Australia
| | - Xuan T Bui
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia.,Clinical Services and Research, Australian Red Cross Lifeblood (Formerly Australian Red Cross Blood Service), Research and Development, Kelvin Grove, Australia
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9
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Floch A, Pirenne F, Barrault A, Chami B, Toly-Ndour C, Tournamille C, de Brevern AG. Insights into anti-D formation in carriers of RhD variants through studies of 3D intraprotein interactions. Transfusion 2021; 61:1286-1301. [PMID: 33586199 DOI: 10.1111/trf.16301] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 11/04/2020] [Accepted: 01/13/2021] [Indexed: 01/11/2023]
Abstract
BACKGROUND Many RhD variants associated with anti-D formation (partial D) in carriers exposed to the conventional D antigen carry mutations affecting extracellular loop residues. Surprisingly, some carry mutations affecting transmembrane or intracellular domains, positions not thought likely to have a major impact on D epitopes. STUDY DESIGN AND METHODS A wild-type Rh trimer (RhD1 RhAG2 ) was modeled by comparative modeling with the human RhCG structure. Taking trimer conformation, residue accessibility, and position relative to the lipid bilayer into account, we redefine the domains of the RhD protein. We generated models for RhD variants carrying one or two amino acid substitutions associated with anti-D formation in published articles (25 variants) or abstracts (12 variants) and for RHD*weak D type 38. We determined the extracellular substitutions and compared the interactions of the variants with those of the standard RhD. RESULTS The findings of the three-dimensional (3D) analysis were correlated with anti-D formation for 76% of RhD variants: 15 substitutions associated with anti-D formation concerned extracellular residues, and structural differences in intraprotein interactions relative to standard RhD were observed in the others. We discuss the mechanisms by which D epitopes may be modified in variants in which the extracellular residues are identical to those of standard RhD and provide arguments for the benignity of p.T379M (RHD*DAU0) and p.G278D (RHD*weak D type 38) in transfusion medicine. CONCLUSION The study of RhD intraprotein interactions and the precise redefinition of residue accessibility provide insight into the mechanisms through which RhD point mutations may lead to anti-D formation in carriers.
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Affiliation(s)
- Aline Floch
- Univ Paris Est Creteil, INSERM U955, Transfusion et Maladies du Globule Rouge, IMRB, Creteil, France.,Etablissement francais du sang Ile-de-France, Creteil, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - France Pirenne
- Univ Paris Est Creteil, INSERM U955, Transfusion et Maladies du Globule Rouge, IMRB, Creteil, France.,Etablissement francais du sang Ile-de-France, Creteil, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Aurélie Barrault
- Univ Paris Est Creteil, INSERM U955, Transfusion et Maladies du Globule Rouge, IMRB, Creteil, France.,Etablissement francais du sang Ile-de-France, Creteil, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Btissam Chami
- Etablissement francais du sang Ile-de-France, Creteil, France
| | - Cécile Toly-Ndour
- Unité Fonctionnelle d'expertise en Immuno-Hémobiologie Périnatale, Centre National de Référence en Hémobiologie Périnatale (CNRHP), Service de Médecine Fœtale, Pôle Périnatalité, Hôpital Trousseau, GH HUEP, APHP, Paris, France
| | - Christophe Tournamille
- Univ Paris Est Creteil, INSERM U955, Transfusion et Maladies du Globule Rouge, IMRB, Creteil, France.,Etablissement francais du sang Ile-de-France, Creteil, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Alexandre G de Brevern
- Laboratoire d'Excellence GR-Ex, Paris, France.,Université de Paris, Biologie Intégrée du Globule Rouge UMR_S1134, Inserm, Université de la Réunion, Université des Antilles, Paris, France.,Institut National de la Transfusion Sanguine (INTS), Paris, France
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10
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Wen J, Verhagen OJ, Jia S, Liang Q, Wang Z, Wei L, Luo H, Luo G, Vidarsson G, Akker E, Ji Y, Schoot CE. A variant RhAG protein encoded by theRHAG*572Aallele causes serological weak D expression while maintaining normal RhCE phenotypes. Transfusion 2018; 59:405-411. [DOI: 10.1111/trf.14969] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 08/01/2018] [Accepted: 08/17/2018] [Indexed: 01/30/2023]
Affiliation(s)
- Jizhi Wen
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center Guangzhou People's Republic of China
| | - Onno J.H.M. Verhagen
- Sanquin Research and Landsteiner Laboratory, Academic Medical CentreUniversity of Amsterdam Amsterdam The Netherlands
| | - Shuangshuang Jia
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center Guangzhou People's Republic of China
| | - Qianni Liang
- Department of Blood TransfusionGuangdong No. 2 Provincial People's Hospital Guangzhou People's Republic of China
| | - Zhen Wang
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center Guangzhou People's Republic of China
| | - Ling Wei
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center Guangzhou People's Republic of China
| | - Hong Luo
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center Guangzhou People's Republic of China
| | - Guangping Luo
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center Guangzhou People's Republic of China
| | - Gestur Vidarsson
- Sanquin Research and Landsteiner Laboratory, Academic Medical CentreUniversity of Amsterdam Amsterdam The Netherlands
| | - Emile Akker
- Sanquin Research and Landsteiner Laboratory, Academic Medical CentreUniversity of Amsterdam Amsterdam The Netherlands
| | - Yanli Ji
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center Guangzhou People's Republic of China
| | - C. Ellen Schoot
- Sanquin Research and Landsteiner Laboratory, Academic Medical CentreUniversity of Amsterdam Amsterdam The Netherlands
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11
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de Brevern AG, Floch A, Barrault A, Martret J, Bodivit G, Djoudi R, Pirenne F, Tournamille C. Alloimmunization risk associated with amino acid 223 substitution in the RhD protein: analysis in the light of molecular modeling. Transfusion 2018; 58:2683-2692. [DOI: 10.1111/trf.14809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 04/09/2018] [Accepted: 04/21/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Alexandre G. de Brevern
- INSERM UMR_S 1134; Univ. Paris Diderot, Sorbonne Paris Cité, Univ. de la Réunion, Univ. Antilles; Paris
- Laboratory of Excellence GR-Ex; Paris
- Institut National de la Transfusion Sanguine (INTS); Paris
| | - Aline Floch
- Laboratory of Excellence GR-Ex; Paris
- Etablissement Français du Sang Ile de France; Créteil France
- IMRB-INSERM U955 Team 2 “Transfusion et Maladies du Globule Rouge”; Créteil France
- UPEC; Université Paris Est-Créteil; Créteil France
| | | | | | - Gwellaouen Bodivit
- Laboratory of Excellence GR-Ex; Paris
- Etablissement Français du Sang Ile de France; Créteil France
- IMRB-INSERM U955 Team 2 “Transfusion et Maladies du Globule Rouge”; Créteil France
| | - Rachid Djoudi
- Etablissement Français du Sang Ile de France; Créteil France
| | - France Pirenne
- Laboratory of Excellence GR-Ex; Paris
- Etablissement Français du Sang Ile de France; Créteil France
- IMRB-INSERM U955 Team 2 “Transfusion et Maladies du Globule Rouge”; Créteil France
- UPEC; Université Paris Est-Créteil; Créteil France
| | - Christophe Tournamille
- Laboratory of Excellence GR-Ex; Paris
- Etablissement Français du Sang Ile de France; Créteil France
- IMRB-INSERM U955 Team 2 “Transfusion et Maladies du Globule Rouge”; Créteil France
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12
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Howe JG, Stack G. Relationship of epitope glycosylation and other properties of blood group proteins to the immunogenicity of blood group antigens. Transfusion 2018; 58:1739-1751. [PMID: 29770450 DOI: 10.1111/trf.14609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND The intrinsic properties of polypeptide blood group antigens that determine their relative immunogenicities are unknown. Because size, composition, charge, dose, and epitope glycosylation affect the immunogenicity of other polypeptides, we examined whether similar properties were related to the immunogenicity of blood group antigens. STUDY DESIGN AND METHODS Amino acid (AA) sequences of antithetical blood group antigens were searched for N- and O-glycosylation sites. Regression analysis was carried out to determine whether blood group protein properties, including total and ectodomain size, red blood cell (RBC) antigen site density, number of mismatched AAs between an antigen and its closest homolog, and differences in mass, charge, and hydrophobicity of the mismatched AAs, were related to immunogenicity. RESULTS The immunogenicities of non-RhD polypeptide antigens were directly related to the total and ectodomain sizes of their carrier proteins. A negative power relationship existed between RBC antigen site density and immunogenicity, such that the most immunogenic antigens had the lowest site density. The strong immunogenicity of RhD was related to the number of AA mismatches between RhD and RhCE, to their cumulative hydrophobicity and electrostatic mismatch scores, and the cumulative AA mass difference. No N- or O-glycosylation differences were predicted for antithetical or homologous antigens, other than a previously known N-glycosylation difference between K and k. CONCLUSION Epitope glycosylation appeared not to be a determinant of immunogenicity for blood group antigens, except possibly for K. The immunogenicity of blood group antigens was positively related to total and ectodomain sizes of blood group proteins and negatively related to antigen site density. Such findings should be considered hypothesis generating for future, more definitive studies.
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Affiliation(s)
- John G Howe
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Gary Stack
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut.,Pathology and Laboratory Medicine Service, VA Connecticut Healthcare System, West Haven, Connecticut
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13
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Zimmer AM, Wright PA, Wood CM. Ammonia and urea handling by early life stages of fishes. ACTA ACUST UNITED AC 2018; 220:3843-3855. [PMID: 29093184 DOI: 10.1242/jeb.140210] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nitrogen metabolism in fishes has been a focus of comparative physiologists for nearly a century. In this Review, we focus specifically on early life stages of fishes, which have received considerable attention in more recent work. Nitrogen metabolism and excretion in early life differs fundamentally from that of juvenile and adult fishes because of (1) the presence of a chorion capsule in embryos that imposes a limitation on effective ammonia excretion, (2) an amino acid-based metabolism that generates a substantial ammonia load, and (3) the lack of a functional gill, which is the primary site of nitrogen excretion in juvenile and adult fishes. Recent findings have shed considerable light on the mechanisms by which these constraints are overcome in early life. Perhaps most importantly, the discovery of Rhesus (Rh) glycoproteins as ammonia transporters and their expression in ion-transporting cells on the skin of larval fishes has transformed our understanding of ammonia excretion by fishes in general. The emergence of larval zebrafish as a model species, together with genetic knockdown techniques, has similarly advanced our understanding of ammonia and urea metabolism and excretion by larval fishes. It has also now been demonstrated that ammonia excretion is one of the primary functions of the developing gill in rainbow trout larvae, leading to new hypotheses regarding the physiological demands driving gill development in larval fishes. Here, we highlight and discuss the dramatic changes in nitrogen handling that occur over early life development in fishes.
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Affiliation(s)
- Alex M Zimmer
- Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N57
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.,Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
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14
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Mu S, Cui Y, Wang W, Wang L, Xu H, Zhu O, Zhu D. A RHAG point mutation selectively disrupts Rh antigen expression. Transfus Med 2018; 29:121-127. [PMID: 29508504 DOI: 10.1111/tme.12519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 12/29/2017] [Accepted: 02/11/2018] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The aim of this study was to characterise a novel mutation in the gene encoding RhAG in order to elucidate a molecular mechanism for Rh antigen expression and spherocytosis. BACKGROUND Rhesus-associated glycoprotein (RhAG) is critical for maintaining the structure and stability of erythrocytes. Single missense mutations in the gene encoding RhAG are sufficient to induce spherocytosis and deficiencies in Rh complex formation. We report a novel missense mutation that incompletely disrupts Rh antigen expression and selectively knocks out RhD antigen expression. METHODS Blood samples were taken from a 38-year-old male, his brother, his wife and his daughter in Xi'an, China. To detect the proband's RhAG and D antigen expression, the RBC were stained with anti-D and anti-RhAG and analysed by flow cytometry. Red blood cell morphology was detected with atomic force microscopy (AFM). Genomic DNA was isolated from whole blood samples, and the RHD, RHCE and RHAG alleles were sequenced and analysed. The mutation was mapped onto a predicted crystal structure of RhAG by the I-TASSER server and visualised using PyMOL. RESULTS Morphological testing by AFM found clear evidence of spherocytosis in the proband's erythrocytes. RHAG gene sequencing identified the mutation at sequence 236G > A, resulting in a serine to asparagine substitution at residue 79 (S79N). Family survey indicated that inheriting this allele is necessary and sufficient to cause the condition. Mapping the mutation onto a predicted crystal structure of RhAG revealed the proximity of the mutation to the critical structural elements of the protein. CONCLUSIONS A novel RHAG mutation significantly lowers RhAG antigen expression and antigen-mediated agglutination intensity.
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Affiliation(s)
- S Mu
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - Y Cui
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - W Wang
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - L Wang
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - H Xu
- Shanxi Blood Center, Xi'an, China
| | - O Zhu
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA
| | - D Zhu
- Department of Transfusion Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
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15
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Denomme GA, Anani WQ, Avent ND, Bein G, Briggs LB, Lapadat RC, Montemayor C, Rios M, St-Louis M, Uhl L, Wendel S, Flegel WA. Red cell genotyping precision medicine: a conference summary. Ther Adv Hematol 2017; 8:277-291. [PMID: 29051799 DOI: 10.1177/2040620717729128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This review summarizes the salient points of the symposium 'Red Cell Genotyping 2015: Precision Medicine' held on 10 September 2015 in the Masur Auditorium of the National Institutes of Health. The specific aims of this 6th annual symposium were to: (1) discuss how advances in molecular immunohematology are changing patient care; (2) exemplify patient care strategies by case reports (clinical vignettes); (3) review the basic molecular studies and their current implications in clinical practice; (4) identify red cell genotyping strategies to prevent alloimmunization; and (5) compare and contrast future options of red cell genotyping in precision transfusion medicine. This symposium summary captured the state of the art of red cell genotyping and its contribution to the practice of precision medicine.
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Affiliation(s)
- Gregory A Denomme
- Diagnostic Laboratories, BloodCenter of Wisconsin, 638 N 18th Street, PO Box 2178, Milwaukee, WI 53201-2178, USA
| | - Waseem Q Anani
- Medical Sciences Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
| | | | | | - Lynne B Briggs
- Information Services Versiti/BloodCenter of Wisconsin, Milwaukee, WI, USA
| | - Razvan C Lapadat
- Medical Sciences Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
| | - Celina Montemayor
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Maria Rios
- Office of Blood Research and Review, CBER/FDA, Rockville, MD, USA
| | | | - Lynne Uhl
- Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | | | - Willy A Flegel
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, MD, USA
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16
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Schulze AB, Schmidt LH, Baie L, Heitkötter B, Kuemmel A, Mohr M, Buhl R, Hillmann H, Geißler G, Kelsch R, Görlich D, Berdel WE, Hartmann W, Wiewrodt R. Rhesus CE expression on patient red blood cells is an independent prognostic factor for adenocarcinoma of the lung. CLINICAL RESPIRATORY JOURNAL 2017; 12:1106-1117. [PMID: 28398662 DOI: 10.1111/crj.12638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 02/27/2017] [Accepted: 03/20/2017] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The influence of blood group antigens on cancerogenesis is shown for distinct tumor types, yet the impact of Rhesus blood group antigens in lung cancer is not clarified. MATERIALS AND METHODS To investigate the impact of Rhesus blood groups a non-small cell lung cancer (NSCLC) collective (n = 1047) was analyzed retrospectively. Using a second cohort of n = 340 primarily operated stage I-III NSCLC patients, we evaluated immunohistochemistry of CD47-antibody stained tissue samples in correlation to histopathologic subtype and Rhesus blood group. RESULTS AND CONCLUSION In 516 of 1047 patients blood group data were available. Seven different RhCE phenotypes were grouped as "··ee," "ccE·," and "C·E·." Adenocarcinoma patients with Rh "··ee" revealed improved overall survival (29 (21.2-36.8) m; HR 1.00 [index]) compared with Rh "ccE·" (19 (1.9-36.1) m; HR 1.76 [1.15-2.70]) and Rh "C·E·" (10 (7.4-12.6) m; HR 2.65 [1.70-4.12]) univariately (P < .001) and multivariately (P < .001). Rh "··ee" showed reduced incidence of CNS-metastasis (P = .014) and metastasis count (P = .032) in stage IV adenocarcinoma. Immunohistochemistry associated CD47-positivity with adenocarcinomas (n = 340, P = .048). In n = 51 cases blood group data were available. The prognostic effect of Rh "··ee" compared with Rh "ccE·" and Rh "C·E·" was stated (P = .001), foremost in CD47-positive adenocarcinomas (Rh "··ee" vs. Rh "ccE·" and Rh "C·E·," P = .008). Inversely Rh "ccE·" or Rh "C·E·" was found beneficial in CD47-negative non-adenocarcinomas (P = .046). Phenotypic RhCE expression may be an independent prognostic factor for overall survival in adeno-NSCLC. We hypothesize an erythrocytic-immunologic interaction with tumor tissue, possibly altered by RhCE and CD47, resulting in a metastatic prone condition.
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Affiliation(s)
- A B Schulze
- Department of Medicine A, Hematology, Oncology and Pneumology, University Hospital Muenster, Muenster, Germany
| | - L H Schmidt
- Department of Medicine A, Hematology, Oncology and Pneumology, University Hospital Muenster, Muenster, Germany
| | - L Baie
- Department of Medicine A, Hematology, Oncology and Pneumology, University Hospital Muenster, Muenster, Germany
| | - B Heitkötter
- Gerhard Domagk Institute of Pathology, University Hospital Muenster, Muenster, Germany
| | - A Kuemmel
- III. Medical Department, Hematology, Oncology and Pneumology, University Hospital Mainz, Mainz, Germany
| | - M Mohr
- Department of Medicine A, Hematology, Oncology and Pneumology, University Hospital Muenster, Muenster, Germany
| | - R Buhl
- III. Medical Department, Hematology, Oncology and Pneumology, University Hospital Mainz, Mainz, Germany
| | - H Hillmann
- Institute of Transfusion Medicine and Transplantation Immunology, University Hospital Muenster, Muenster, Germany
| | - G Geißler
- Institute of Transfusion Medicine and Transplantation Immunology, University Hospital Muenster, Muenster, Germany
| | - R Kelsch
- Institute of Transfusion Medicine and Transplantation Immunology, University Hospital Muenster, Muenster, Germany
| | - D Görlich
- Institute of Biostatistics and Clinical Research, Westfaelische Wilhelms-Universitaet Muenster, Muenster, Germany
| | - W E Berdel
- Department of Medicine A, Hematology, Oncology and Pneumology, University Hospital Muenster, Muenster, Germany
| | - W Hartmann
- Gerhard Domagk Institute of Pathology, University Hospital Muenster, Muenster, Germany
| | - R Wiewrodt
- Department of Medicine A, Hematology, Oncology and Pneumology, University Hospital Muenster, Muenster, Germany
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17
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Howe JG, Stack G. Structural and functional impacts of amino acid substitutions that create blood group antigens: implications for immunogenicity. Transfusion 2017; 57:541-553. [PMID: 28164302 DOI: 10.1111/trf.13966] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 11/03/2016] [Accepted: 11/04/2016] [Indexed: 01/17/2023]
Abstract
BACKGROUND The immunogenicities of polypeptide blood group antigens vary widely. One possible determinant of immunogenicity is antigenic foreignness. The goal was to employ alternative ways of assessing foreignness and determine whether foreignness was related to immunogenicity. STUDY DESIGN AND METHODS Foreignness was assessed as the extent of protein functional disruption caused by the exofacial amino acid (AA) substitutions that create blood group antigens, using AA substitution prediction algorithms such as Meta-SNP and according to whether those substitutions were radical or conservative. RESULTS AA substitutions that create the most immunogenic antigens had the highest Meta-SNP scores, predictive of greater protein structure and function changes. Four of the 11 exofacial AAs that distinguish the most immunogenic antigen, RhD, from RhCE, and substitutions creating four of the five next most immunogenic antigens had the highest Meta-SNP scores (0.293-0.649). Excluding the outlier Jka , the mean Meta-SNP score of the four most immunogenic non-RhD antigens (K, Lua , E, c) was 3.7-fold higher than the mean of the four least immunogenic (M, Fya , C, S), 0.459 versus 0.123 (p = 0.0026). Regression analysis revealed a relationship between immunogenicity and Meta-SNP score (R2 = 0.953). Actual protein functional disruption was predicted for the AA substitution creating the E antigen. An AA cluster at Positions 350, 353, and 354 of RhD was unique, containing radical substitutions according to two classification schemes and relatively high Meta-SNP scores (0.351-0.432). CONCLUSION The immunogenicity of blood group antigens was related to the functional disruption caused by the AA substitutions that create the antigens, as measured by Meta-SNP score.
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Affiliation(s)
- John G Howe
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Gary Stack
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut.,Pathology and Laboratory Medicine Service, VA Connecticut Healthcare System, West Haven, Connecticut
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18
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Abdulnour-Nakhoul S, Le T, Rabon E, Hamm LL, Nakhoul NL. Structural determinants of NH3 and NH4+ transport by mouse Rhbg, a renal Rh glycoprotein. Am J Physiol Renal Physiol 2016; 311:F1280-F1293. [PMID: 27681563 PMCID: PMC5210199 DOI: 10.1152/ajprenal.00556.2015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 09/21/2016] [Indexed: 11/22/2022] Open
Abstract
Renal Rhbg is localized to the basolateral membrane of intercalated cells and is involved in NH3/NH4+ transport. The structure of Rhbg is not yet resolved; however, a high-resolution crystal structure of AmtB, a bacterial homolog of Rh, has been determined. We aligned the sequence of Rhbg to that of AmtB and identified important sites of Rhbg that may affect transport. Our analysis positioned three conserved amino acids, histidine 183 (H183), histidine 342 (H342), and tryptophan 230 (W230), within the hydrophobic pore where they presumably serve to control NH3 transport. A fourth residue, phenylalanine 128 (F128) was positioned at the upper vestibule, presumably contributing to recruitment of NH4+ We generated three mutations each of H183, H342, W230, and F128 and expressed them in frog oocytes. Immunolabeling showed that W230 and F128 mutants were localized to the cell membrane, whereas H183 and H342 staining was diffuse and mostly intracellular. To determine function, we compared measurements of NH3/NH4+ and methyl amine (MA)/methyl ammonium (MA+)-induced currents, intracellular pH, and surface pH (pHs) among oocytes expressing the mutants, Rhbg, or injected with H2O. In H183 and W230 mutants, NH4+-induced current and intracellular acidification were inhibited compared with that of Rhbg, and MA-induced intracellular alkalinization was completely absent. Expression of H183A or W230A mutants inhibited NH3/NH4+- and MA/MA+-induced decrease in pHs to the level observed in H2O-injected oocytes. Mutations of F128 did not significantly affect transport of NH3 or NH4+ These data demonstrated that mutating H183 or W230 caused loss of function but not F128. H183 and H342 may affect membrane expression of the transporter.
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Affiliation(s)
- Solange Abdulnour-Nakhoul
- Southeast Louisiana Veterans Health Care Network and Department of Medicine, Section of Nephrology, Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Louisiana
| | - Trang Le
- Southeast Louisiana Veterans Health Care Network and Department of Medicine, Section of Nephrology, Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Louisiana
| | - Edd Rabon
- Southeast Louisiana Veterans Health Care Network and Department of Medicine, Section of Nephrology, Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Louisiana
| | - L Lee Hamm
- Southeast Louisiana Veterans Health Care Network and Department of Medicine, Section of Nephrology, Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Louisiana
| | - Nazih L Nakhoul
- Southeast Louisiana Veterans Health Care Network and Department of Medicine, Section of Nephrology, Department of Physiology, Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, Louisiana
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19
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Durant AC, Chasiotis H, Misyura L, Donini A. Aedes aegypti Rhesus glycoproteins contribute to ammonia excretion by larval anal papillae. ACTA ACUST UNITED AC 2016; 220:588-596. [PMID: 27885043 DOI: 10.1242/jeb.151084] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/21/2016] [Indexed: 02/06/2023]
Abstract
In larval Aedes aegypti, transcripts of the Rhesus-like glycoproteins AeRh50-1 and AeRh50-2 have been detected in the anal papillae, sites of ammonia (NH3/NH4+) excretion; however, these putative ammonia transporters have not been previously localized or functionally characterized. In this study, we show that the AeRh50s co-immunolocalize with apical V-type H+-ATPase as well as with basal Na+/K+-ATPase in the epithelium of anal papillae. The double-stranded RNA-mediated knockdown of AeRh50-1 and AeRh50-2 resulted in a significant reduction in AeRh50 protein abundance in the anal papillae, and this was coupled to decreased ammonia excretion. The knockdown of AeRh50-1 resulted in decreased hemolymph [NH4+] and pH whereas knockdown of AeRh50-2 had no effect on these parameters. We conclude that the AeRh50s are important contributors to ammonia excretion at the anal papillae of larval A. aegypti, which may be the basis for their ability to inhabit areas with high ammonia levels.
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Affiliation(s)
- Andrea C Durant
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Helen Chasiotis
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Lidiya Misyura
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Andrew Donini
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
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20
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Srivastava K, Polin H, Sheldon SL, Wagner FF, Grabmer C, Gabriel C, Denomme GA, Flegel WA. The DAU cluster: a comparative analysis of 18 RHD alleles, some forming partial D antigens. Transfusion 2016; 56:2520-2531. [PMID: 27480171 PMCID: PMC5499517 DOI: 10.1111/trf.13739] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 01/10/2023]
Abstract
BACKGROUND The Rh system is the most complex and polymorphic blood group system in humans with more than 460 alleles known for the RHD gene. The DAU cluster of RHD alleles is characterized by the single-nucleotide change producing the p.Thr379Met amino acid substitution. It is called the DAU-0 allele and has been postulated to be the primordial allele, from which all other alleles of the DAU cluster have eventually evolved. STUDY DESIGN AND METHODS For two novel DAU alleles, the nucleotide sequences of all 10 exons as well as adjacent intronic regions, including the 5' and 3' untranslated regions (UTR), were determined for the RHD and RHCE genes. A phylogenetic tree for all DAU alleles was established using the neighbor-joining method with Pan troglodytes as root. Standard hemagglutination and flow cytometry tests were performed. RESULTS We characterized two DAU alleles, DAU-11 and DAU-5.1, closely related to DAU-3 and DAU-5, respectively. A phylogenetic analysis of the 18 known DAU alleles indicated point mutations and interallelic recombination contributing to diversification of the DAU cluster. CONCLUSIONS The DAU alleles encode a group of RhD protein variants, some forming partial D antigens known to permit anti-D in carriers; all are expected to cause anti-D alloimmunization in recipients of red blood cell transfusions. The DAU alleles evolved through genomic point mutations and recombination. These results suggest that the cluster of DAU alleles represent a clade, which is concordant with our previous postulate that they derived from the primordial DAU-0 allele.
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Affiliation(s)
- Kshitij Srivastava
- Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Helene Polin
- Red Cross Transfusion Service of Upper Austria, Linz, Austria
| | - Sherry Lynne Sheldon
- Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | | | - Christoph Grabmer
- Department of Blood Group Serology and Transfusion Medicine, SALK-Paracelsus Medical University, Salzburg, Austria
| | - Christian Gabriel
- Red Cross Transfusion Service of Upper Austria, Linz, Austria
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria
| | | | - Willy Albert Flegel
- Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland.
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21
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Golovkina LL, Stremoukhova AG, Pushkina TD, Kalandarov RS, Atroshchenko GV, Vasilyeva MN, Surin VL, Salomashkina VV, Pshenichnikova OS, Miterev GY, Parovichnikova EN, Savchenko VG. [Molecular serological characteristics of weak D antigen types of the Rhesus system]. TERAPEVT ARKH 2016; 88:78-83. [PMID: 27459619 DOI: 10.17116/terarkh201688778-83] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
AIM to estimate the spread of weak D antigen types of the Rhesus system in the citizens of the Russian Federation and a possibility of serologically identifying these types. SUBJECTS AND METHODS The red blood cells and DNA of people with weakened expression of D antigen were investigated using erythrocyte agglutination reaction in salt medium (2 methods); agglutination reaction in the gel columns containing IgM + IgG anti-D antibodies, indirect antiglobulin test with IgG anti-D antibodies (2 methods); polymerase chain reaction to establish the type of weak D. RESULTS A rhesus phenotype was determined in 5100 people in 2014-2015. The weakened agglutinable properties of red blood cells were detected in 102 (2%) examinees. 63 examinees underwent genotyping to identify the variants of the weak D antigen, which identified 6 weak D types. There were the most common weak D types 3 (n=31 (49.2%)) and weak D type 1 (n=18 (28.6%)), including weak D type 1.1 in one (1.6%) case. The other 4 weak D antigen types were as follows: weak D type 2 (14.3% (n=9)), weak D type 15 (4.8% (n=3)), weak D type 4.2 (DAR) (1.6% (n=1)) and weak D type 6 (1.6% (n=1)). The antiglobulin test in the gel column containing antiglobulin serum was the most sensitive serological assay to identify the weak D antigen. Only a molecular test could establish weak D type 15 in 2 samples of red blood cells with Ccdee and ccdEe phenotypes. CONCLUSION The weak D antigen could be serologically identified in 96.8% of cases. When testing for weak D, particular attention should be given to people with the D-negative phenotype who had the C or E antigens. Our investigations conducted for the first time in Russia will be able to improve the immunological safety of red blood cell-containing medium transfusions for patients.
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Affiliation(s)
- L L Golovkina
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - A G Stremoukhova
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - T D Pushkina
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - R S Kalandarov
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - G V Atroshchenko
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - M N Vasilyeva
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - V L Surin
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - V V Salomashkina
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - O S Pshenichnikova
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - G Yu Miterev
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - E N Parovichnikova
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
| | - V G Savchenko
- National Research Centre for Hematology, Ministry of Health of Russia, Moscow, Russia
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22
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Ogasawara K, Suzuki Y, Sasaki K, Osabe T, Isa K, Tsuneyama H, Uchikawa M, Satake M, Tadokoro K. Molecular basis for D− Japanese: identification of novel DEL and D− alleles. Vox Sang 2015; 109:359-65. [DOI: 10.1111/vox.12290] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/10/2015] [Accepted: 03/28/2015] [Indexed: 12/29/2022]
Affiliation(s)
- K. Ogasawara
- Japanese Red Cross Central Blood Institute; Tokyo Japan
| | - Y. Suzuki
- Japanese Red Cross Kanto-Koshinetsu Block Blood Center; Tokyo Japan
| | - K. Sasaki
- Japanese Red Cross Central Blood Institute; Tokyo Japan
| | - T. Osabe
- Japanese Red Cross Kanto-Koshinetsu Block Blood Center; Tokyo Japan
| | - K. Isa
- Japanese Red Cross Central Blood Institute; Tokyo Japan
| | - H. Tsuneyama
- Japanese Red Cross Kanto-Koshinetsu Block Blood Center; Tokyo Japan
| | - M. Uchikawa
- Japanese Red Cross Kanto-Koshinetsu Block Blood Center; Tokyo Japan
| | - M. Satake
- Japanese Red Cross Central Blood Institute; Tokyo Japan
| | - K. Tadokoro
- Japanese Red Cross Central Blood Institute; Tokyo Japan
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Lim MYT, Zimmer AM, Wood CM. Acute exposure to waterborne copper inhibits both the excretion and uptake of ammonia in freshwater rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol C Toxicol Pharmacol 2015; 168:48-54. [PMID: 25500421 DOI: 10.1016/j.cbpc.2014.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/24/2014] [Accepted: 12/02/2014] [Indexed: 01/02/2023]
Abstract
In freshwater fish, exposure to sub-lethal concentrations of waterborne copper (Cu) results in inhibitions of ammonia excretion (Jamm) and Na(+) uptake (J(Na)in), yet the mechanisms by which these occur are not fully understood. In the present study, rainbow trout (Oncorhynchus mykiss) fry exposed to 50μg/l Cu for 24h displayed a sustained 40% decrease in Jamm and a transient 60% decrease in J(Na)in. Previously, these effects have been attributed to inhibitions of gill Na(+)/K(+)-ATPase and/or carbonic anhydrase (CA) activities by Cu. Trout fry did not display significant reductions in the branchial activities of these enzymes or H(+)-ATPase over 24h Cu exposure. Recently, Rhesus (Rh) glycoproteins, bi-directional NH3 gas channels, have been implicated in the mechanism of Cu toxicity. Juvenile trout were exposed to nominal 0, 50, and 200μg/l Cu for 3-6h under control conditions (ammonia-free water) followed by 6h exposure to high environmental ammonia (HEA; 1.5mmol/l NH4HCO3). HEA led to significant ammonia uptake in control fish (0μg/l Cu), and exposure to 50 and 200μg/l Cu resulted in significant reductions of ammonia uptake during HEA exposure. This is the first evidence that Cu inhibits both the excretion and uptake of ammonia, implicating bi-directional Rh glycoproteins as a target for Cu toxicity. We propose a model whereby Rh blockade by Cu causes the sustained inhibition of Jamm and transient inhibition of J(Na)in, with H(+)-ATPase potentially aiding in J(Na)in recovery. More work is needed to elucidate the role of Rh proteins in sub-lethal Cu toxicity.
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Affiliation(s)
| | - Alex M Zimmer
- Department of Biology, McMaster University, Hamilton L8S 4K1, ON, Canada.
| | - Chris M Wood
- Department of Biology, McMaster University, Hamilton L8S 4K1, ON, Canada; Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, BC, Canada.
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24
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Nakhoul NL, Lee Hamm L. The challenge of determining the role of Rh glycoproteins in transport of NH3and NH4+. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/wmts.105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Nazih L. Nakhoul
- Department of Physiology; Tulane University Medical School; New Orleans LA USA
- Department of Medicine, Section of Nephrology; Tulane University Medical School; New Orleans LA USA
| | - L. Lee Hamm
- Department of Medicine, Section of Nephrology; Tulane University Medical School; New Orleans LA USA
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25
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Characteristics of mammalian Rh glycoproteins (SLC42 transporters) and their role in acid-base transport. Mol Aspects Med 2013; 34:629-37. [PMID: 23506896 DOI: 10.1016/j.mam.2012.05.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 04/16/2012] [Indexed: 01/06/2023]
Abstract
The mammalian Rh glycoproteins belong to the solute transporter family SLC42 and include RhAG, present in red blood cells, and two non-erythroid members RhBG and RhCG that are expressed in various tissues, including kidney, liver, skin and the GI tract. The Rh proteins in the red blood cell form an "Rh complex" made up of one D-subunit, one CE-subunit and two RhAG subunits. The Rh complex has a well-known antigenic effect but also contributes to the stability of the red cell membrane. RhBG and RhCG are related to the NH4(+) transporters of the yeast and bacteria but their exact function is yet to be determined. This review describes the expression and molecular properties of these membrane proteins and their potential role as NH3/NH4(+) and CO2 transporters. The likelihood that these proteins transport gases such as CO2 or NH3 is novel and significant. The review also describes the physiological importance of these proteins and their relevance to human disease.
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Affiliation(s)
- Geoff Daniels
- International Blood Group Reference Laboratory; NHS Blood and Transplant; Bristol UK
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Abstract
Renal ammonia metabolism and transport mediates a central role in acid-base homeostasis. In contrast to most renal solutes, the majority of renal ammonia excretion derives from intrarenal production, not from glomerular filtration. Renal ammoniagenesis predominantly results from glutamine metabolism, which produces 2 NH4(+) and 2 HCO3(-) for each glutamine metabolized. The proximal tubule is the primary site for ammoniagenesis, but there is evidence for ammoniagenesis by most renal epithelial cells. Ammonia produced in the kidney is either excreted into the urine or returned to the systemic circulation through the renal veins. Ammonia excreted in the urine promotes acid excretion; ammonia returned to the systemic circulation is metabolized in the liver in a HCO3(-)-consuming process, resulting in no net benefit to acid-base homeostasis. Highly regulated ammonia transport by renal epithelial cells determines the proportion of ammonia excreted in the urine versus returned to the systemic circulation. The traditional paradigm of ammonia transport involving passive NH3 diffusion, protonation in the lumen and NH4(+) trapping due to an inability to cross plasma membranes is being replaced by the recognition of limited plasma membrane NH3 permeability in combination with the presence of specific NH3-transporting and NH4(+)-transporting proteins in specific renal epithelial cells. Ammonia production and transport are regulated by a variety of factors, including extracellular pH and K(+), and by several hormones, such as mineralocorticoids, glucocorticoids and angiotensin II. This coordinated process of regulated ammonia production and transport is critical for the effective maintenance of acid-base homeostasis.
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Affiliation(s)
- I David Weiner
- Nephrology and Hypertension Section, NF/SGVHS, Gainesville, Florida, USA.
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Ullmann RT, Andrade SLA, Ullmann GM. Thermodynamics of transport through the ammonium transporter Amt-1 investigated with free energy calculations. J Phys Chem B 2012; 116:9690-703. [PMID: 22804733 DOI: 10.1021/jp305440f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Amt-1 from Archaeoglobus fulgidus (AfAmt-1) belongs to the Amt/Rh family of ammonium/ammonia transporting membrane proteins. The transport mode and the precise microscopic permeation mechanism utilized by these proteins are intensely debated. Open questions concern the identity of the transported substrate (ammonia and/or ammonium) and whether the transport is passive or active. To address these questions, we studied the overall thermodynamics of the different transport modes as a function of the environmental conditions. Then, we investigated the thermodynamics of the underlying microscopic transport mechanisms with free energy calculations within a continuum electrostatics model. The formalism developed for this purpose is of general utility in the calculation of binding free energies for ligands with multiple protonation forms or other binding forms. The results of our calculations are compared to the available experimental and theoretical data on Amt/Rh proteins and discussed in light of the current knowledge on the physiological conditions experienced by microorganisms and plants. We found that microscopic models of electroneutral and electrogenic transport modes are in principle thermodynamically viable. However, only the electrogenic variants have a net thermodynamic driving force under the physiological conditions experienced by microorganisms and plants. Thus, the transport mechanism of AfAmt-1 is most likely electrogenic.
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Affiliation(s)
- R Thomas Ullmann
- Structural Biology/Bioinformatics, University of Bayreuth, Universitätsstrasse 30, BGI, 95447 Bayreuth, Germany.
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Jeremy KP, Plummer ZE, Head DJ, Madgett TE, Sanders KL, Wallington A, Storry JR, Gilsanz F, Delaunay J, Avent ND. 4.1R-deficient human red blood cells have altered phosphatidylserine exposure pathways and are deficient in CD44 and CD47 glycoproteins. Haematologica 2011; 94:1354-61. [PMID: 19794081 DOI: 10.3324/haematol.2009.006585] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Protein 4.1R is an important component of the red cell membrane skeleton. It imparts structural integrity and has transmembrane signaling roles by direct interactions with transmembrane proteins and other membrane skeletal components, notably p55 and calmodulin. DESIGN AND METHODS Spontaneous and ligation-induced phosphatidylserine exposure on erythrocytes from two patients with 4.1R deficiency were studied, using CD47 glycoprotein and glycophorin C as ligands. We also looked for protein abnormalities in the 4.1R-based multiprotein complex. RESULTS Phosphatidylserine exposure was significantly increased in 4.1R-deficient erythrocytes obtained from the two different individuals when ligands to CD47 glycoprotein were bound. Spontaneous phosphatidylserine exposure was normal. 4.1R, glycophorin C and p55 were missing or sharply reduced. Furthermore there was an alteration or deficiency of CD47 glycoprotein and a lack of CD44 glycoprotein. Based on a recent study in 4.1R-deficient mice, we found that there are clear functional differences between interactions of human red cell 4.1R and its murine counterpart. CONCLUSIONS Glycophorin C is known to bind 4.1R, and we have defined previously that it also binds CD47. From our evidence, we suggest that 4.1R plays a role in the phosphatidylserine exposure signaling pathway that is of fundamental importance in red cell turnover. The linkage of CD44 to 4.1R may be relevant to this process.
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Ye L, Wang P, Gao H, Zhang J, Wang C, Li Q, Han S, Guo Z, Yang Y, Zhu Z. Partial D phenotypes and genotypes in the Chinese population. Transfusion 2011; 52:241-6. [DOI: 10.1111/j.1537-2995.2011.03266.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tian L, Song N, Yao ZQ, Huang M, Hou L. A family study of the Chinese Rhnull individual of the regulator type: a novel single missense mutation identified in RHAG gene. Transfusion 2011; 51:2686-9. [DOI: 10.1111/j.1537-2995.2011.03218.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Lamoureux G, Javelle A, Baday S, Wang S, Bernèche S. Transport mechanisms in the ammonium transporter family. Transfus Clin Biol 2010; 17:168-75. [DOI: 10.1016/j.tracli.2010.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 06/14/2010] [Indexed: 02/09/2023]
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Huang CH, Ye M. The Rh protein family: gene evolution, membrane biology, and disease association. Cell Mol Life Sci 2010; 67:1203-18. [PMID: 19953292 PMCID: PMC11115862 DOI: 10.1007/s00018-009-0217-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 11/10/2009] [Accepted: 11/12/2009] [Indexed: 11/25/2022]
Abstract
The Rh (Rhesus) genes encode a family of conserved proteins that share a structural fold of 12 transmembrane helices with members of the major facilitator superfamily. Interest in this family has arisen from the discovery of Rh factor's involvement in hemolytic disease in the fetus and newborn, and of its homologs widely expressed in epithelial tissues. The Rh factor and Rh-associated glycoprotein (RhAG), with epithelial cousins RhBG and RhCG, form four subgroups conferring upon vertebrates a genealogical commonality. The past decade has heralded significant advances in understanding the phylogenetics, allelic diversity, crystal structure, and biological function of Rh proteins. This review describes recent progress on this family and the molecular insights gleaned from its gene evolution, membrane biology, and disease association. The focus is on its long evolutionary history and surprising structural conservation from prokaryotes to humans, pointing to the importance of its functional role, related to but distinct from ammonium transport proteins.
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Affiliation(s)
- Cheng-Han Huang
- Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
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36
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Christiansen M, Sørensen BS, Grunnet N. RHD positive among C/E+ and D− blood donors in Denmark. Transfusion 2010; 50:1460-4. [DOI: 10.1111/j.1537-2995.2010.02611.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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37
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Peyrard T, Pham BN, Poupel S, Martin-Blanc S, Auxerre C, Kappler-Gratias S, Bonin P, Rouger P, Le Pennec PY. Alloanti-c/ce in a c+ceAR/Cepatient suggests that the rareRHCE*ceARallele (ceAR) encodes a partial c antigen. Transfusion 2009; 49:2406-11. [DOI: 10.1111/j.1537-2995.2009.02308.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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38
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Goossens D, Trinh-Trang-Tan MM, Debbia M, Ripoche P, Vilela-Lamego C, Louache F, Vainchenker W, Colin Y, Cartron JP. Generation and characterisation of Rhd and Rhag null mice. Br J Haematol 2009; 148:161-72. [PMID: 19807729 DOI: 10.1111/j.1365-2141.2009.07928.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mouse Rhd* and Rhag* genes were targeted using insertional vectors; the resulting knockout mice, and double-knockout descendants, were analysed. Rhag glycoprotein deficiency entailed defective assembly of the erythroid Rh complex with complete loss of Rh and intercellular adhesion molecule 4 (ICAM-4), but not CD47, expression. Absence of the Rh protein induced a loss of ICAM-4, and only a moderate reduction of Rhag expression. Double knockout phenotype was similar to that of Rhag targeted mice. Rhd and Rhag deficient mice exhibited neither the equivalent of human Rh(null) haemolytic anaemia nor any clinical or cellular abnormalities. Rhd-/- and Rhag-/- erythrocytes showed decreased basal adhesion to an endothelial cell line resulting from defective ICAM-4 membrane expression. There was no difference in recovery from phenylhydrazine-induced haematopoietic stress for double knockout mice as compared to controls, suggesting that ICAM-4 might be dispensable during stress erythropoiesis. Ammonia and methylammonia transport in erythrocytes was severely impaired in Rhag-/- but only slightly in Rhd-/- animals that significantly expressed Rhag, supporting the view that RhAG and Rhag, but not Rh, may act as ammonium transporters in human and mouse erythrocytes. These knockout mice should prove useful for further dissecting the physiological roles of Rh and Rhag proteins in the red cell membrane.
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Affiliation(s)
- Dominique Goossens
- Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, Paris, France.
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Tilley L, Green C, Poole J, Gaskell A, Ridgwell K, Burton NM, Uchikawa M, Tsuneyama H, Ogasawara K, Akkøk CA, Daniels G. A new blood group system, RHAG: three antigens resulting from amino acid substitutions in the Rh-associated glycoprotein. Vox Sang 2009; 98:151-9. [PMID: 19744193 DOI: 10.1111/j.1423-0410.2009.01243.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVES Rh-associated glycoprotein (RhAG) is closely associated with the Rh proteins in the red cell membrane. Two high frequency antigens (Duclos and DSLK) and one low frequency antigen (Ol(a)) have serological characteristics suggestive of expression on RhAG. MATERIALS AND METHODS RHAG was sequenced from the DNA of one Duclos-negative, one DSLK-negative, and two Ol(a+) individuals. Recombinant protein was expressed in HEK 293 cells. Protein models with RhAG subunits were constructed. RESULTS The original Duclos-negative patient was homozygous for RHAG 316C>G, encoding Gln106Glu. HEK 293 cells expressing Gln106Glu mutant RhAG did not react with anti-Duclos. An individual with DSLK-negative red cells was homozygous for 490A>C, encoding Lys164Gln. Two Ol(a+) members of the original Norwegian family were heterozygous for 680C>T, encoding Ser227Leu. A Japanese donor with Rh(mod) phenotype had Ol(a+) red cells and was homozygous for 680C>T. CONCLUSION The three red cell antigens encoded by RHAG form the RHAG blood group system: Duclos is RHAG1 (030001); Ol(a) is RHAG2 (030002); and DSLK is provisionally RHAG3 (030003).
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Affiliation(s)
- L Tilley
- International Blood Group Reference Laboratory and Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK
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40
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Zidi-Yahiaoui N, Callebaut I, Genetet S, Le Van Kim C, Cartron JP, Colin Y, Ripoche P, Mouro-Chanteloup I. Functional analysis of human RhCG: comparison with E. coli ammonium transporter reveals similarities in the pore and differences in the vestibule. Am J Physiol Cell Physiol 2009; 297:C537-47. [DOI: 10.1152/ajpcell.00137.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Rh glycoproteins are members of the ammonium transporter (Amt)/methylamine permease (Mep)/Rh family facilitating movement of NH3 across plasma membranes. Homology models constructed on the basis of the experimental structures of Escherichia coli AmtB and Nitrosomonas europaea Rh50 indicated a channel structure for human RhA (RhAG), RhB (RhBG), and RhC (RhCG) glycoproteins in which external and internal vestibules are linked by a pore containing two strictly conserved histidines. The pore entry is constricted by two highly conserved phenylalanines, “twin-Phe.” In this study, RhCG function was investigated by stopped-flow spectrofluorometry measuring kinetic pH variations in HEK293E cells in the presence of an ammonium gradient. The apparent unitary NH3 permeability of RhCG was determined and was found to be close to that of AmtB. With a site-directed mutagenesis approach, critical residues involved in Rh NH3 channel activity were highlighted. In the external vestibule, the importance of both the charge and the conformation of the conserved aspartic acid was shown. In contrast to AmtB, individual mutations of each phenylalanine of the twin-Phe impaired the function while the removal of both resulted in recovery of the transport activity. The impact of the mutations suggests that, although having a common function and a similar channel structure, bacterial AmtB and human Rh vary in several aspects of the NH3 transport mechanisms.
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Affiliation(s)
- Nedjma Zidi-Yahiaoui
- Institut National de la Santé et de la Recherche Médicale, UMR-S665,
- Institut National de la Transfusion Sanguine,
- Université Paris Diderot-Paris 7, and
| | - Isabelle Callebaut
- Centre National de la Recherche Scientifique, UMR7590, Université Pierre et Marie Curie Paris 6, Paris France
| | - Sandrine Genetet
- Institut National de la Santé et de la Recherche Médicale, UMR-S665,
- Institut National de la Transfusion Sanguine,
- Université Paris Diderot-Paris 7, and
| | - Caroline Le Van Kim
- Institut National de la Santé et de la Recherche Médicale, UMR-S665,
- Institut National de la Transfusion Sanguine,
- Université Paris Diderot-Paris 7, and
| | - Jean-Pierre Cartron
- Institut National de la Santé et de la Recherche Médicale, UMR-S665,
- Institut National de la Transfusion Sanguine,
- Université Paris Diderot-Paris 7, and
| | - Yves Colin
- Institut National de la Santé et de la Recherche Médicale, UMR-S665,
- Institut National de la Transfusion Sanguine,
- Université Paris Diderot-Paris 7, and
| | - Pierre Ripoche
- Institut National de la Santé et de la Recherche Médicale, UMR-S665,
- Institut National de la Transfusion Sanguine,
- Université Paris Diderot-Paris 7, and
| | - Isabelle Mouro-Chanteloup
- Institut National de la Santé et de la Recherche Médicale, UMR-S665,
- Institut National de la Transfusion Sanguine,
- Université Paris Diderot-Paris 7, and
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Daniels G. The molecular genetics of blood group polymorphism. Hum Genet 2009; 126:729-42. [PMID: 19727826 DOI: 10.1007/s00439-009-0738-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 08/19/2009] [Indexed: 02/07/2023]
Abstract
Over 300 blood group specificities on red cells have been identified, many of which are polymorphic. The molecular mechanisms responsible for these polymorphisms are diverse, though many simply represent single nucleotide polymorphisms (SNPs). Other mechanisms include the following: gene deletion; single nucleotide deletion and sequence duplication, which introduce reading-frame shifts; nonsense mutation; intergenic recombination between closely linked genes, giving rise to hybrid genes and hybrid proteins; and a SNP in the promoter region of a blood group gene. Examples of these various genetic mechanisms are taken from the ABO, Rh, Kell, and Duffy blood group systems. Null phenotypes, in which no antigens of a blood group system are expressed, are not generally polymorphic, but provide good examples of the effect of inactivating mutations on blood group expression. As natural human 'knock-outs', null phenotypes provide useful clues to the functions of blood group antigens. Knowledge of the molecular backgrounds of blood group polymorphisms provides a means to predict blood group phenotypes from genomic DNA. This has two main applications in transfusion medicine: determination of foetal blood groups to assess whether the foetus is at risk from haemolytic disease and ascertainment of blood group phenotypes in multiply transfused, transfusion-dependent patients, where serological tests are precluded by the presence of donor red cells. Other applications are being developed for the future.
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Affiliation(s)
- Geoff Daniels
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Filton, Bristol, UK.
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42
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Flegel WA, von Zabern I, Doescher A, Wagner FF, Strathmann KP, Geisen C, Palfi M, Písacka M, Poole J, Polin H, Gabriel C, Avent ND. D variants at the RhD vestibule in the weak D type 4 and Eurasian D clusters. Transfusion 2009; 49:1059-69. [PMID: 19309476 PMCID: PMC10710224 DOI: 10.1111/j.1537-2995.2009.02102.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND One branch of the RHD phylogenetic tree is represented by the weak D type 4 cluster of alleles with F223V as the primordial amino acid substitution. F223V as well as a large number of further substitutions causing D variants are located at the extracellular RhD protein vestibule, which represents the entrance to the transmembraneous channel of the RhD protein. STUDY DESIGN AND METHODS RHD and RHCE nucleotide sequences were determined from genomic DNA and cDNA. D epitope patterns were established with commercial monoclonal anti-D panels. RESULTS The RHD alleles DOL-1 and DOL-2 had the two amino acid substitutions M170T (509T>C) and F223V (667T>G) in common. DOL-2 harbored the additional substitution L378V (1132C>G). Both alleles were observed in Africans and are probably evolutionary related. DMI carried M170I (510G>A), which differed from the DOL-typical substitution. DFW and DFL harbored the substitutions H166P (497A>C) and Y165C (494A>G). The antigen densities of DOL-1, DFL, and DFW were only moderately reduced. CONCLUSION DOL-1 and DOL-2 belong to the weak D type 4 cluster of RHD alleles. Together with DMI, DFL, and DFW they represent D variants with amino acid substitutions located at extracellular loops 3 or 4 lining the RhD protein vestibule. These substitutions were of minor influence on antigen density while adjacent substitutions in the transmembraneous section caused weak D antigen expression. All these D variants were partial D and alloanti-D immunizations have been observed in DOL-1, DMI, and DFL carriers. The substitution at position 170 causes partial D although located deep in the vestibule.
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Affiliation(s)
- Willy A Flegel
- Institute for Transfusion Medicine, University Hospital, Ulm, Germany.
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Lin Y, Cao Z, Mo Y. Functional role of Asp160 and the deprotonation mechanism of ammonium in the Escherichia coli ammonia channel protein AmtB. J Phys Chem B 2009; 113:4922-9. [PMID: 19278252 PMCID: PMC2676109 DOI: 10.1021/jp810651m] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Molecular dynamics simulations on the wild-type AmtB protein and its D160A homology model have been performed. Although no significant structural changes due to the mutation of Asp160 were observed, calculations confirmed the critical role of Asp160 for the recognition and binding of NH(4)(+) in AmtB. The carboxyl group of Asp160 is approximately 8 A from NH(4)(+), but their favorable through-space electrostatic interaction is further enhanced by a hydrogen bond chain involving Ala162 (the backbone carbonyl group) and Gly163 (the backbone amide group). This explains the occurrence of the second binding site in AmtB which does not exist in the D160A mutant, as shown in the computed energy profiles. As the initially buried carboxyl group of Asp160 links to the ammonium ion in the periplasmic binding vestibule through a chain of water molecules, a likely deprotonation venue thus is from ammonium to Asp160. Combined QM(PM3)/MM molecular dynamics simulations showed that indeed Asp160 can serve as the proton acceptor and the overall proton transfer process needs to overcome a barrier of merely 7.7 kcal/mol, which is in good agreement with our previous QM(DFT)/MM optimizations. Significantly, the proton transfer adopts an unconventional mechanism by migrating the negative charge from the carboxyl group of Asp160 to NH(4)(+) via two water molecules, which can be illustrated as -CO(2)(-)...H(2)O...H(2)O...NH(4)(+) --> -COOH...H(2)O...OH(-)...NH(4)(+) --> -COOH...H(2)O...H(2)O...NH(3). Apparently, this is also a charge recombination process and thus is exothermic.
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Affiliation(s)
- Yuchun Lin
- Department of Chemistry, Western Michigan University, Kalamazoo, MI 49008, USA
| | - Zexing Cao
- Department of Chemistry, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
| | - Yirong Mo
- Department of Chemistry, Western Michigan University, Kalamazoo, MI 49008, USA
- Department of Chemistry, the State Key Laboratory for Physical Chemistry of Solid States, Center for Theoretical Chemistry, Xiamen University, Xiamen, Fujian 361005, P. R. China
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Elevated CO2 levels affect development, motility, and fertility and extend life span in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2009; 106:4024-9. [PMID: 19237558 DOI: 10.1073/pnas.0900309106] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hypercapnia (high CO(2) levels) occurs in a number of lung diseases and it is associated with worse outcomes in patients with chronic obstructive lung disease (COPD). However, it is largely unknown how hypercapnia is sensed and responds in nonneuronal cells. Here, we used C. elegans to study the response to nonanesthetic CO(2) levels and show that levels exceeding 9% induce aberrant motility that is accompanied by age-dependent deterioration of body muscle organization, slowed development, reduced fertility and increased life span. These effects occur independently of the IGF-R, dietary restriction, egg laying or mitochondrial-induced aging pathways. Transcriptional profiling analysis shows specific and dynamic changes in gene expression after 1, 6, or 72 h of exposure to 19% CO(2) including increased transcription of several 7-transmembrane domain and innate immunity genes and a reduction in transcription of many of the MSP genes. Together, these results suggest specific physiological and molecular responses to hypercapnia, which appear to be independent of early heat shock and HIF mediated pathways.
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The monovalent cation leak in overhydrated stomatocytic red blood cells results from amino acid substitutions in the Rh-associated glycoprotein. Blood 2009; 113:1350-7. [DOI: 10.1182/blood-2008-07-171140] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
AbstractOverhydrated hereditary stomatocytosis (OHSt) is a rare dominantly inherited hemolytic anemia characterized by a profuse membrane leak to monovalent cations. Here, we show that OHSt red cell membranes contain slightly reduced amounts of Rh-associated glycoprotein (RhAG), a putative gas channel protein. DNA analysis revealed that the OHSt patients have 1 of 2 heterozygous mutations (t182g, t194c) in RHAG that lead to substitutions of 2 highly conserved amino acids (Ile61Arg, Phe65Ser). Unexpectedly, expression of wild-type RhAG in Xenopus laevis oocytes induced a monovalent cation leak; expression of the mutant RhAG proteins induced a leak about 6 times greater than that in wild type. RhAG belongs to the ammonium transporter family of proteins that form pore-like structures. We have modeled RhAG on the homologous Nitrosomonas europaea Rh50 protein and shown that these mutations are likely to lead to an opening of the pore. Although the function of RhAG remains controversial, this first report of functional RhAG mutations supports a role for RhAG as a cation pore.
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Abstract
The molecular background of blood group antigen expression of the major clinically significant blood group antigens has been largely accomplished. Despite this large body of work, blood group phenotype prediction by genotyping has a marginal supporting role in the routine blood bank. It has however had a major impact in the prenatal determination of fetal blood group status in the management of haemolytic disease of the fetus and newborn. In the past few years several high throughput systems have been in development that have the potential capacity to perform genotyping on a mass scale. Such systems have been designed for use on donor- and patient-derived DNA and provide much more comprehensive information regarding an individuals blood group than is possible by using serological methods alone. DNA-based typing methodology is easier to standardize than serology and has the potential to replace it as a front line diagnostic in blood banks. This review overviews the current situation in this area and attempts to predict how blood group genotyping will evolve in the future.
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Affiliation(s)
- Neil D Avent
- Centre for Research in Biomedicine and UWE, Bristol Genomics Research Institute, Faculty of Health and Life Sciences, University of the West of England, Bristol, UK.
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Sohet F, Colin Y, Genetet S, Ripoche P, Métral S, Le Van Kim C, Lopez C. Phosphorylation and ankyrin-G binding of the C-terminal domain regulate targeting and function of the ammonium transporter RhBG. J Biol Chem 2008; 283:26557-67. [PMID: 18635543 DOI: 10.1074/jbc.m803120200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
RhBG, a human member of the Amt/Mep/Rh/superfamily of ammonium transporters, has been shown to facilitate NH(3) transport and to be anchored to the basolateral plasma membrane of kidney epithelial cells, via ankyrin-G. We showed here that triple alanine substitution of the (419)FLD(421) sequence, which links the cytoplasmic C-terminal domain of RhBG to ankyrin-G, not only disrupted the interaction of RhBG with the spectrin-based skeleton but also delayed its cell surface expression, decreased its plasma membrane stability, and abolished its NH(3) transport function in epithelial cell lines. Similarly, we demonstrated that both anchoring to the membrane skeleton and ammonium transport activity are regulated by the phosphorylation status of the C-terminal tail of RhBG. Tyrosine 429, which belongs to the previously reported YED basolateral targeting signal of RhBG, was demonstrated to be phosphorylated in vitro using purified Src and Syk kinases and ex vivo by analyzing the effect of pervanadate treatment on wild-type RhBG or Y429A mutants. Then, we showed that Y429D and Y429E mutations, mimicking constitutive phosphorylation, abolished NH(3) transport and enhanced Triton X-100 solubilization of RhBG from the cell membrane. In contrast, the nonphosphorylated/nonphosphorylatable Y429A and Y429F mutants behaved the same as wild-type RhBG. Conversely, Y/A or Y/F but not Y/E or Y/D mutations of residue 429 abolished the exclusive basolateral localization of RhBG in polarized epithelial cells. All these results led to a model in which targeting and ammonium transport function of RhBG are regulated by both phosphorylation and membrane skeleton binding of the C-terminal cytoplasmic domain.
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Affiliation(s)
- Fabien Sohet
- INSERM, U665, Paris F-75015, the Institut National de la Transfusion Sanguine, 6 Rue Alexandre Cabanel, Paris F-75015, France
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Lupo D, Li XD, Durand A, Tomizaki T, Cherif-Zahar B, Matassi G, Merrick M, Winkler FK. The 1.3-A resolution structure of Nitrosomonas europaea Rh50 and mechanistic implications for NH3 transport by Rhesus family proteins. Proc Natl Acad Sci U S A 2007; 104:19303-8. [PMID: 18032606 PMCID: PMC2148285 DOI: 10.1073/pnas.0706563104] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Indexed: 12/19/2022] Open
Abstract
The Rhesus (Rh) proteins are a family of integral membrane proteins found throughout the animal kingdom that also occur in a number of lower eukaryotes. The significance of Rh proteins derives from their presence in the human red blood cell membrane, where they constitute the second most important group of antigens used in transfusion medicine after the ABO group. Rh proteins are related to the ammonium transport (Amt) protein family and there is considerable evidence that, like Amt proteins, they function as ammonia channels. We have now solved the structure of a rare bacterial homologue (from Nitrosomonas europaea) of human Rh50 proteins at a resolution of 1.3 A. The protein is a trimer, and analysis of its subunit interface strongly argues that all Rh proteins are likely to be homotrimers and that the human erythrocyte proteins RhAG and RhCE/D are unlikely to form heterooligomers as previously proposed. When compared with structures of bacterial Amt proteins, NeRh50 shows several distinctive features of the substrate conduction pathway that support the concept that Rh proteins have much lower ammonium affinities than Amt proteins and might potentially function bidirectionally.
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Affiliation(s)
- Domenico Lupo
- *Biomolecular Research, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Xiao-Dan Li
- *Biomolecular Research, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Anne Durand
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Takashi Tomizaki
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Baya Cherif-Zahar
- Université Paris Descartes, Institut National de la Santé et de la Recherche Médicale U845, Faculté de Medecine René Descartes, F-75015 Paris, France; and
| | - Giorgio Matassi
- Institut Jacques Monod Centre National de la Recherche Scientifique-Unite Mixte de Recherche 7592, Université Paris 6 et Université Paris 7, 2 Place Jussieu, 75251 Paris Cedex 05, France
| | - Mike Merrick
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Fritz K. Winkler
- *Biomolecular Research, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
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