1
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Xuan C, Xinxin F, Piao L, Wenbin K, Yingyin L, Chixiang L, Huayou Z. Identification of a novel RHCE*Ce (829G > A) allele associated with absence of C and e antigens expression. Transfus Med 2024. [PMID: 39087254 DOI: 10.1111/tme.13072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 07/15/2024] [Accepted: 07/24/2024] [Indexed: 08/02/2024]
Abstract
BACKGROUND The Rh blood group antigens are encoded by the RHD and RHCE genes, which possess a remarkable degree of polymorphism owing to their high homologous structures. These variants of the RH genes can lead to absence or weak expression of antigens. METHODS Analysis of RHCE genotyping by Polymerase Chain Reaction (PCR-SSP) method specific to detect c.48G, c.48C, 109 bp insertion of IVS2, c.201A and c.307C and RhCE phenotyping, were conducted in 316 Chinese patients in previous study. One patient with discrepancy typing result was collected for further RhCE serologic typing using microcolumn gel method and tube method in saline using monoclonal antibodies. PacBio sequencing was performed for RHCE, RHD and RHAG complete sequence analysis. 3D molecular models of the protein with the wild-type and mutant residue were generated using the DynaMut web server. The effect of the mutation on the protein function was predicted by PolyPhen-2 software. RESULTS One male patient of Chinese Han was detected with RHCE*C allele showed by PCR-SSP method but ccEE phenotype. Further PacBio sequencing identified one normal RHCE*cE allele and one RHCE*Ce allele carried a novel c.829G > A (p.Gly277Arg) variant, which the encoded amino acid located in the ninth transmembrane segment of RhCE protein. Crystallisation analysis of 3D molecular models revealed that the substitution at Arg277 leads to the formation of additional hydrogen bonds, including weak hydrogen bonds between multiple atoms. It also results in hydrophobic ion interactions between Arg277 and Ala244. This mutation is predicted to have a damaging effect on protein function. CONCLUSION One novel RHCE*Ce allele with c.829G > A (p.Gly277Arg) variant was identified to resulting in the absence or weak expression of C and e antigens.
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Affiliation(s)
- Ci Xuan
- Department of Transfusion Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
- Department of Blood Transfusion, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Fan Xinxin
- Department of Transfusion Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Lv Piao
- Department of Transfusion Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Kong Wenbin
- Department of Transfusion Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Liang Yingyin
- Department of Transfusion Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Liu Chixiang
- Department of Transfusion Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Zhou Huayou
- Department of Transfusion Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
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2
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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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3
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Pedini P, Filosa L, Bichel N, Picard C, Silvy M, Chiaroni J, Izard C, Laget L, Mazières S. Five-Years Review of RHCE Alleles Detected after Weak and/or Discrepant C Results in Southern France. Genes (Basel) 2022; 13:1058. [PMID: 35741820 PMCID: PMC9222276 DOI: 10.3390/genes13061058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/09/2022] [Accepted: 06/10/2022] [Indexed: 02/04/2023] Open
Abstract
Immunohematology laboratories are regularly facing transfusion issues due to serological weaknesses. Altered (partial) RH antigens account for most of them. In some situations, RHCE variant alleles are involved. Herein we present our three-step molecular exploration, with allele frequencies, that has efficiently untangled RH2 phenotype weaknesses and discrepancies in our 2017-2021 cohort. In the last 5 years, the PACA Corse EFS molecular platform received 265 samples from healthy blood donors or patients with C and C/e typing difficulties. The first-intention technique (DNA array and real time PCR for RHCE*CeRN research) detected RHCE variant alleles in 143 cases (54%). The RHCE alleles classically found in African populations were the most frequent, with RHCE*CeRN allele in 40 cases (15%) and (C)ces haplotype type 1 and 2 in 26 cases (10%). A "CE" effect haplotype was suspected in 56 cases, due to the uncommon DCE haplotype that may explain the low C expression. When there were no RHCE*Ce or RHCE*CE alleles, we then searched for RHD polymorphisms by DNA array. We detected the RHD*DAU5 and RHD*DIVa in 18 and 7 cases respectively, suggesting that C ambiguity is related to the presence of these alleles which has never been described with DAU5. If no variant RHCE and RHD alleles were detected, we finally sequenced the 10 exons of both RHCE and RHD genes according to the clinical context and found seven new RHCE alleles. Thus, this molecular strategy would improve the knowledge of RHCE variants' expression and, thus, optimize the transfusion management.
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Affiliation(s)
- Pascal Pedini
- Etablissement Français du Sang Provence-Alpes-Côte d’Azur-Corse, 13005 Marseille, France; (P.P.); (L.F.); (N.B.); (C.P.); (J.C.); (C.I.); (L.L.)
- Biologie des Groupes Sanguins, EFS, CNRS, ADES, Aix Marseille University, 13005 Marseille, France;
| | - Lugdivine Filosa
- Etablissement Français du Sang Provence-Alpes-Côte d’Azur-Corse, 13005 Marseille, France; (P.P.); (L.F.); (N.B.); (C.P.); (J.C.); (C.I.); (L.L.)
| | - Nelly Bichel
- Etablissement Français du Sang Provence-Alpes-Côte d’Azur-Corse, 13005 Marseille, France; (P.P.); (L.F.); (N.B.); (C.P.); (J.C.); (C.I.); (L.L.)
| | - Christophe Picard
- Etablissement Français du Sang Provence-Alpes-Côte d’Azur-Corse, 13005 Marseille, France; (P.P.); (L.F.); (N.B.); (C.P.); (J.C.); (C.I.); (L.L.)
- Biologie des Groupes Sanguins, EFS, CNRS, ADES, Aix Marseille University, 13005 Marseille, France;
| | - Monique Silvy
- Biologie des Groupes Sanguins, EFS, CNRS, ADES, Aix Marseille University, 13005 Marseille, France;
| | - Jacques Chiaroni
- Etablissement Français du Sang Provence-Alpes-Côte d’Azur-Corse, 13005 Marseille, France; (P.P.); (L.F.); (N.B.); (C.P.); (J.C.); (C.I.); (L.L.)
- Biologie des Groupes Sanguins, EFS, CNRS, ADES, Aix Marseille University, 13005 Marseille, France;
| | - Caroline Izard
- Etablissement Français du Sang Provence-Alpes-Côte d’Azur-Corse, 13005 Marseille, France; (P.P.); (L.F.); (N.B.); (C.P.); (J.C.); (C.I.); (L.L.)
| | - Laurine Laget
- Etablissement Français du Sang Provence-Alpes-Côte d’Azur-Corse, 13005 Marseille, France; (P.P.); (L.F.); (N.B.); (C.P.); (J.C.); (C.I.); (L.L.)
| | - Stéphane Mazières
- Biologie des Groupes Sanguins, EFS, CNRS, ADES, Aix Marseille University, 13005 Marseille, France;
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4
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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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5
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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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6
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Abstract
During inflammatory response, blood leukocytes adhere to the endothelium. This process involves numerous adhesion molecules, including a transmembrane chemokine, CX3CL1, which behaves as a molecular cluster. How this cluster assembles and whether this association has a functional role remain unknown. The analysis of CX3CL1 clusters using native electrophoresis and single molecule fluorescence kinetics shows that CX3CL1 is a homo-oligomer of 3 to 7 monomers. Fluorescence recovery after photobleaching assays reveal that the CX3CL1-transmembrane domain peptide self-associates in both cellular and acellular lipid environments, while its random counterpart (i.e. peptide with the same residues in a different order) does not. This strongly indicates that CX3CL1 oligomerization is driven by its intrinsic properties. According to the molecular modeling, CX3CL1 does not associate in compact bundles but rather with monomers linearly assembled side by side. Finally, the CX3CL1 transmembrane peptide inhibits both the CX3CL1 oligomerization and the adhesive function, while its random counterpart does not. This demonstrates that CX3CL1 oligomerization is mandatory for its adhesive potency. Our results provide a new direction to control CX3CL1-dependent cellular adherence in key immune processes.
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7
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Filosa L, Izard C, Chiaroni J, Bailly P, Silvy M. Identification and characterization of three novel
RHCE*ce
variant alleles affecting Rhc (RH4) reactivity. Transfusion 2019; 59:2754-2755. [DOI: 10.1111/trf.15417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 05/06/2019] [Accepted: 05/12/2019] [Indexed: 11/27/2022]
Affiliation(s)
- Lugdivine Filosa
- Biologie des Groupes Sanguins Établissement Français du Sang PACA Corse Marseille France
- Biologie des Groupes Sanguins Aix Marseille Univ, CNRS, EFS, ADES Marseille France
- Laboratoire d'Immuno‐Hématologie receveur Établissement Français du Sang PACA Corse Marseille France
| | - Caroline Izard
- Laboratoire d'Immuno‐Hématologie receveur Établissement Français du Sang PACA Corse Marseille France
| | - Jacques Chiaroni
- Biologie des Groupes Sanguins Établissement Français du Sang PACA Corse Marseille France
- Biologie des Groupes Sanguins Aix Marseille Univ, CNRS, EFS, ADES Marseille France
- Laboratoire d'Immuno‐Hématologie receveur Établissement Français du Sang PACA Corse Marseille France
| | - Pascal Bailly
- Biologie des Groupes Sanguins Établissement Français du Sang PACA Corse Marseille France
- Biologie des Groupes Sanguins Aix Marseille Univ, CNRS, EFS, ADES Marseille France
| | - Monique Silvy
- Biologie des Groupes Sanguins Établissement Français du Sang PACA Corse Marseille France
- Biologie des Groupes Sanguins Aix Marseille Univ, CNRS, EFS, ADES Marseille France
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8
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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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9
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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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10
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From genetic variability to phenotypic expression of blood group systems. Transfus Clin Biol 2017; 24:472-475. [DOI: 10.1016/j.tracli.2017.06.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 06/07/2017] [Indexed: 01/06/2023]
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11
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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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12
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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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Filosa L, Beley S, Chiaroni J, Bailly P, Silvy M. New silent and weak D alleles: molecular characterization and associated antigen density. Transfusion 2016; 56:2154-5. [PMID: 27189905 DOI: 10.1111/trf.13655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/30/2016] [Accepted: 04/04/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Lugdivine Filosa
- Laboratoire d'Hématologie Moléculaire: Biologie des Groupes Sanguins, Établissement Français du Sang Alpes Méditerranée, Marseille, France
| | - Sophie Beley
- Laboratoire d'Hématologie Moléculaire: Biologie des Groupes Sanguins, Établissement Français du Sang Alpes Méditerranée, Marseille, France.,UMR 7268 ADÉS, Aix-Marseille Université-EFS-CNRS, Marseille, France
| | - Jacques Chiaroni
- Laboratoire d'Hématologie Moléculaire: Biologie des Groupes Sanguins, Établissement Français du Sang Alpes Méditerranée, Marseille, France.,UMR 7268 ADÉS, Aix-Marseille Université-EFS-CNRS, Marseille, France
| | - Pascal Bailly
- Laboratoire d'Hématologie Moléculaire: Biologie des Groupes Sanguins, Établissement Français du Sang Alpes Méditerranée, Marseille, France.,UMR 7268 ADÉS, Aix-Marseille Université-EFS-CNRS, Marseille, France
| | - Monique Silvy
- Laboratoire d'Hématologie Moléculaire: Biologie des Groupes Sanguins, Établissement Français du Sang Alpes Méditerranée, Marseille, France.,UMR 7268 ADÉS, Aix-Marseille Université-EFS-CNRS, Marseille, France
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14
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Stegmann TC, Veldhuisen B, Bijman R, Thurik FF, Bossers B, Cheroutre G, Jonkers R, Ligthart P, de Haas M, Haer-Wigman L, van der Schoot CE. Frequency and characterization of known and novel RHD variant alleles in 37 782 Dutch D-negative pregnant women. Br J Haematol 2016; 173:469-79. [PMID: 27018217 DOI: 10.1111/bjh.13960] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/14/2015] [Indexed: 11/30/2022]
Abstract
To guide anti-D prophylaxis, Dutch D- pregnant women are offered a quantitative fetal-RHD-genotyping assay to determine the RHD status of their fetus. This allowed us to determine the frequency of different maternal RHD variants in 37 782 serologically D- pregnant women. A variant allele is present in at least 0·96% of Dutch D- pregnant women The D- serology could be confirmed after further serological testing in only 54% of these women, which emphasizes the potential relevance of genotyping of blood donors. 43 different RHD variant alleles were detected, including 15 novel alleles (11 null-, 2 partial D- and 2 DEL-alleles). Of those novel null alleles, one allele contained a single missense mutation (RHD*443C>G) and one allele had a single amino acid deletion (RHD*424_426del). The D- phenotype was confirmed by transduction of human D- erythroblasts, consolidating that, for the first time, a single amino acid change or deletion causes the D- phenotype. Transduction also confirmed the phenotypes for the two new variant DEL-alleles (RHD*721A>C and RHD*884T>C) and the novel partial RHD*492C>A allele. Notably, in three additional cases the DEL phenotype was observed but sequencing of the coding sequence, flanking introns and promoter region revealed an apparently wild-type RHD allele without mutations.
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Affiliation(s)
- Tamara C Stegmann
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Barbera Veldhuisen
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.,Sanquin Diagnostic Services, Amsterdam, The Netherlands
| | - Renate Bijman
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Florentine F Thurik
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | - Remco Jonkers
- Sanquin Diagnostic Services, Amsterdam, The Netherlands
| | | | - Masja de Haas
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.,Sanquin Diagnostic Services, Amsterdam, The Netherlands
| | - Lonneke Haer-Wigman
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - C Ellen van der Schoot
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
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Yassai MB, Annen K, Bensing KM, Denomme GA. RHCE*cE94Gencodes variable expression of c (RH4). Transfusion 2015; 55:2519-20. [DOI: 10.1111/trf.13164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/07/2015] [Accepted: 04/12/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Maryam B. Yassai
- Diagnostic Laboratories; BloodCenter of Wisconsin; Milwaukee Wisconsin
| | - Kyle Annen
- Diagnostic Laboratories; BloodCenter of Wisconsin; Milwaukee Wisconsin
- Heartland Blood Centers; Aurora Illinois
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16
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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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17
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Suzuki A, Endo K, Kitano T. Phylogenetic positions of RH blood group-related genes in cyclostomes. Gene 2014; 543:22-7. [DOI: 10.1016/j.gene.2014.04.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 03/24/2014] [Accepted: 04/06/2014] [Indexed: 11/26/2022]
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18
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Custódio FL, Barbosa HJ, Dardenne LE. A multiple minima genetic algorithm for protein structure prediction. Appl Soft Comput 2014. [DOI: 10.1016/j.asoc.2013.10.029] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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19
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Goossens D, da Silva N, Metral S, Cortes U, Callebaut I, Picot J, Mouro-Chanteloup I, Cartron JP. Mice expressing RHAG and RHD human blood group genes. PLoS One 2013; 8:e80460. [PMID: 24260394 PMCID: PMC3832391 DOI: 10.1371/journal.pone.0080460] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 10/02/2013] [Indexed: 11/18/2022] Open
Abstract
Anti-RhD prophylaxis of haemolytic disease of the fetus and newborn (HDFN) is highly effective, but as the suppressive mechanism remains uncertain, a mouse model would be of interest. Here we have generated transgenic mice expressing human RhAG and RhD erythrocyte membrane proteins in the presence and, for human RhAG, in the absence, of mouse Rhag. Human RhAG associates with mouse Rh but not mouse Rhag on red blood cells. In Rhag knockout mice transgenic for human RHAG, the mouse Rh protein is “rescued” (re-expressed), and co-immunoprecipitates with human RhAG, indicating the presence of hetero-complexes which associate mouse and human proteins. RhD antigen was expressed from a human RHD gene on a BAC or from RHD cDNA under control of β-globin regulatory elements. RhD was never observed alone, strongly indicative that its expression absolutely depends on the presence of transgenic human RhAG. This first expression of RhD in mice is an important step in the creation of a mouse model of RhD allo-immunisation and HDFN, in conjunction with the Rh-Rhag knockout mice we have developed previously.
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Affiliation(s)
- Dominique Goossens
- Institut National de la Transfusion Sanguine, Paris, France
- Inserm UMR_S 665, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, UMR-S665, Paris, France
- * E-mail:
| | - Nelly da Silva
- Institut National de la Transfusion Sanguine, Paris, France
| | - Sylvain Metral
- Institut National de la Transfusion Sanguine, Paris, France
| | - Ulrich Cortes
- Institut National de la Transfusion Sanguine, Paris, France
| | - Isabelle Callebaut
- IInstitut de Minéralogie et de Physique des milieux Condensés UMR 7590 CNRS, Université Pierre et Marie Curie, Paris, France
| | - Julien Picot
- Institut National de la Transfusion Sanguine, Paris, France
- Inserm UMR_S 665, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, UMR-S665, Paris, France
| | - Isabelle Mouro-Chanteloup
- Institut National de la Transfusion Sanguine, Paris, France
- Inserm UMR_S 665, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, UMR-S665, Paris, France
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20
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Le Gac G, Ka C, Joubrel R, Gourlaouen I, Lehn P, Mornon JP, Férec C, Callebaut I. Structure-function analysis of the human ferroportin iron exporter (SLC40A1): effect of hemochromatosis type 4 disease mutations and identification of critical residues. Hum Mutat 2013; 34:1371-80. [PMID: 23784628 DOI: 10.1002/humu.22369] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 06/06/2013] [Indexed: 11/06/2022]
Abstract
Ferroportin (SLC40A1) is the only known iron exporter in mammals and is considered a key coordinator of the iron balance between intracellular and systemic iron homeostasis. However, the structural organization of ferroportin in the lipid bilayer remains controversial and very little is known about the mechanism underlying iron egress. In the present study, we have developed an approach based on comparative modeling, which has led to the construction of a model of the three-dimensional (3D) structure of ferroportin by homology to the crystal structure of a Major Facilitator Superfamily member (EmrD). This model predicts atomic details for the organization of ferroportin transmembrane helices and is in agreement with our current understanding of the ferroportin function and its interaction with hepcidin. Using in vitro experiments, we demonstrate that this model can be used to identify novel critical amino acids. In particular, we show that the tryptophan residue 42 (p.Trp42), which is localized within the extracellular end of the ferroportin pore, is likely involved in both the iron export function and in the mechanism of inhibition by hepcidin. Thus, our 3D model provides a new perspective for understanding the molecular basis of ferroportin functions and dysfunctions.
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Affiliation(s)
- Gérald Le Gac
- Inserm UMR1078, Université de Brest, SFR SnInBioS, Centre Hospitalier Régional Universitaire - Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Etablissement Français du Sang - Bretagne, Brest, France
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21
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Olivella M, Gonzalez A, Pardo L, Deupi X. Relation between sequence and structure in membrane proteins. Bioinformatics 2013; 29:1589-92. [PMID: 23677941 DOI: 10.1093/bioinformatics/btt249] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
MOTIVATION Integral polytopic membrane proteins contain only two types of folds in their transmembrane domains: α-helix bundles and β-barrels. The increasing number of available crystal structures of these proteins permits an initial estimation of how sequence variability affects the structure conservation in their transmembrane domains. We, thus, aim to determine the pairwise sequence identity necessary to maintain the transmembrane molecular architectures compatible with the hydrophobic nature of the lipid bilayer. RESULTS Root-mean-square deviation (rmsd) and sequence identity were calculated from the structural alignments of pairs of homologous polytopic membrane proteins sharing the same fold. Analysis of these data reveals that transmembrane segment pairs with sequence identity in the so-called 'twilight zone' (20-35%) display high-structural similarity (rmsd < 1.5 Å). Moreover, a large group of β-barrel pairs with low-sequence identity (<20%) still maintain a close structural similarity (rmsd < 2.5 Å). Thus, we conclude that fold preservation in transmembrane regions requires less sequence conservation than for globular proteins. These findings have direct implications in homology modeling of evolutionary-related membrane proteins. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Mireia Olivella
- Grup de Recerca en Bioinformàtica i Estadística Mèdica, Departament de Biologia de Sistemes, Escola Politècnica Superior, Universitat de Vic, 08500 Vic, Barcelona, Catalonia, Spain.
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22
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Silvy M, Chapel-Fernandes S, Callebaut I, Beley S, Durousseau C, Simon S, Lauroua P, Dubosc-Marchenay N, Babault C, Mouchet C, Ferrera V, Chiaroni J, Bailly P. Characterization of novel RHD alleles: relationship between phenotype, genotype, and trimeric architecture. Transfusion 2012; 52:2020-9. [DOI: 10.1111/j.1537-2995.2011.03544.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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23
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Genetet S, Ripoche P, Picot J, Bigot S, Delaunay J, Armari-Alla C, Colin Y, Mouro-Chanteloup I. Human RhAG ammonia channel is impaired by the Phe65Ser mutation in overhydrated stomatocytic red cells. Am J Physiol Cell Physiol 2011; 302:C419-28. [PMID: 22012326 DOI: 10.1152/ajpcell.00092.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In red cells, Rh-associated glycoprotein (RhAG) acts as an ammonia channel, as demonstrated by stopped-flow analysis of ghost intracellular pH (pH(i)) changes. Recently, overhydrated hereditary stomatocytosis (OHSt), a rare dominantly inherited hemolytic anemia, was found to be associated with a mutation (Phe65Ser or Ile61Arg) in RHAG. Ghosts from the erythrocytes of four of the OHSt patients with a Phe65Ser mutation were resealed with a pH-sensitive probe and submitted to ammonium gradients. Alkalinization rate constants, reflecting NH(3) transport through the channel and NH(3) diffusion unmediated by RhAG, were deduced from time courses of fluorescence changes. After subtraction of the constant value found for Rh(null) lacking RhAG, we observed that alkalinization rate constant values decreased ∼50% in OHSt compared with those of controls. Similar RhAG expression levels were found in control and OHSt. Since half of the expressed RhAG in OHSt most probably corresponds to the mutated form of RhAG, as expected from the OHSt heterozygous status, this dramatic decrease can be therefore related to the loss of function of the Phe65Ser-mutated RhAG monomer.
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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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Hwang PP, Lee TH, Lin LY. Ion regulation in fish gills: recent progress in the cellular and molecular mechanisms. Am J Physiol Regul Integr Comp Physiol 2011; 301:R28-47. [PMID: 21451143 DOI: 10.1152/ajpregu.00047.2011] [Citation(s) in RCA: 310] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Fish encounter harsh ionic/osmotic gradients on their aquatic environments, and the mechanisms through which they maintain internal homeostasis are more challenging compared with those of terrestrial vertebrates. Gills are one of the major organs conducting the internal ionic and acid-base regulation, with specialized ionocytes as the major cells carrying out active transport of ions. Exploring the iono/osmoregulatory mechanisms in fish gills, extensive literature proposed several models, with many conflicting or unsolved issues. Recent studies emerged, shedding light on these issues with new opened windows on other aspects, on account of available advanced molecular/cellular physiological approaches and animal models. Respective types of ionocytes and ion transporters, and the relevant regulators for the mechanisms of NaCl secretion, Na(+) uptake/acid secretion/NH(4)(+) excretion, Ca(2+) uptake, and Cl(-) uptake/base secretion, were identified and functionally characterized. These new ideas broadened our understanding of the molecular/cellular mechanisms behind the functional modification/regulation of fish gill ion transport during acute and long-term acclimation to environmental challenges. Moreover, a model for the systematic and local carbohydrate energy supply to gill ionocytes during these acclimation processes was also proposed. These provide powerful platforms to precisely study transport pathways and functional regulation of specific ions, transporters, and ionocytes; however, very few model species were established so far, whereas more efforts are needed in other species.
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Affiliation(s)
- Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei 115, Taiwan.
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26
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27
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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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29
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van den Akker E, Satchwell TJ, Williamson RC, Toye AM. Band 3 multiprotein complexes in the red cell membrane; of mice and men. Blood Cells Mol Dis 2010; 45:1-8. [DOI: 10.1016/j.bcmd.2010.02.019] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 02/04/2010] [Indexed: 02/02/2023]
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30
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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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31
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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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32
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Mouro-Chanteloup I, Cochet S, Chami M, Genetet S, Zidi-Yahiaoui N, Engel A, Colin Y, Bertrand O, Ripoche P. Functional reconstitution into liposomes of purified human RhCG ammonia channel. PLoS One 2010; 5:e8921. [PMID: 20126667 PMCID: PMC2812482 DOI: 10.1371/journal.pone.0008921] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 01/08/2010] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Rh glycoproteins (RhAG, RhBG, RhCG) are members of the Amt/Mep/Rh family which facilitate movement of ammonium across plasma membranes. Changes in ammonium transport activity following expression of Rh glycoproteins have been described in different heterologous systems such as yeasts, oocytes and eukaryotic cell lines. However, in these complex systems, a potential contribution of endogenous proteins to this function cannot be excluded. To demonstrate that Rh glycoproteins by themselves transport NH(3), human RhCG was purified to homogeneity and reconstituted into liposomes, giving new insights into its channel functional properties. METHODOLOGY/PRINCIPAL FINDINGS An HA-tag introduced in the second extracellular loop of RhCG was used to purify to homogeneity the HA-tagged RhCG glycoprotein from detergent-solubilized recombinant HEK293E cells. Electron microscopy analysis of negatively stained purified RhCG-HA revealed, after image processing, homogeneous particles of 9 nm diameter with a trimeric protein structure. Reconstitution was performed with sphingomyelin, phosphatidylcholine and phosphatidic acid lipids in the presence of the C(12)E(8) detergent which was subsequently removed by Biobeads. Control of protein incorporation was carried out by freeze-fracture electron microscopy. Particle density in liposomes was a function of the Lipid/Protein ratio. When compared to empty liposomes, ammonium permeability was increased two and three fold in RhCG-proteoliposomes, depending on the Lipid/Protein ratio (1/300 and 1/150, respectively). This strong NH(3) transport was reversibly inhibited by mercuric and copper salts and exhibited a low Arrhenius activation energy. CONCLUSIONS/SIGNIFICANCE This study allowed the determination of ammonia permeability per RhCG monomer, showing that the apparent Punit(NH3) (around 1x10(-3) microm(3)xs(-1)) is close to the permeability measured in HEK293E cells expressing a recombinant human RhCG (1.60x10(-3) microm(3)xs(-1)), and in human red blood cells endogenously expressing RhAG (2.18x10(-3) microm(3)xs(-1)). The major finding of this study is that RhCG protein is active as an NH(3) channel and that this function does not require any protein partner.
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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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Lin Y, Pavenski K, Saidenberg E, Branch DR. Blood Group Antigens and Normal Red Blood Cell Physiology: A Canadian Blood Services Research and Development Symposium. Transfus Med Rev 2009; 23:292-309. [DOI: 10.1016/j.tmrv.2009.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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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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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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Kirsten JH, Xiong Y, Davis CT, Singleton CK. Subcellular localization of ammonium transporters in Dictyostelium discoideum. BMC Cell Biol 2008; 9:71. [PMID: 19108721 PMCID: PMC2653498 DOI: 10.1186/1471-2121-9-71] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 12/24/2008] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND With the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional purposes. Dictyostelium discoideum has three ammonium transporters, Amts A, B and C. Our present work used fluorescent fusion proteins to determine the cellular localization of the Amts and tested the hypothesis that the transporters mediate removal of ammonia generated endogenously from the elevated protein catabolism common to many protists. RESULTS Using RFP and YFP fusion constructs driven by the actin 15 promoter, we found that the three ammonium transporters were localized on the plasma membrane and on the membranes of subcellular organelles. AmtA and AmtB were localized on the membranes of endolysosomes and phagosomes, with AmtB further localized on the membranes of contractile vacuoles. AmtC also was localized on subcellular organelles when it was stabilized by coexpression with either the AmtA or AmtB fusion transporter. The three ammonium transporters exported ammonia linearly with regard to time during the first 18 hours of the developmental program as revealed by reduced export in the null strains. The fluorescently tagged transporters rescued export when expressed in the null strains, and thus they were functional transporters. CONCLUSION Unlike ammonium transporters in most organisms, which import NH3/NH4+ as a nitrogen source, those of Dictyostelium export ammonia/ammonium as a waste product from extensive catabolism of exogenously derived and endogenous proteins. Localization on proteolytic organelles and on the neutral contractile vacuole suggests that Dictyostelium ammonium transporters may have unique subcellular functions and play a role in the maintenance of intracellular ammonium distribution. A lack of correlation between the null strain phenotypes and ammonia excretion properties of the ammonium transporters suggests that it is not the excretion function that is important for coupling ammonia levels to the slug versus culmination choice, but rather a sensor and/or signaling function of these proteins that is important.
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Affiliation(s)
- Janet H Kirsten
- Department of Biological Sciences, Vanderbilt University, VU Station B 351634, Nashville TN 37235-1634, USA
| | - Yanhua Xiong
- Department of Biological Sciences, Vanderbilt University, VU Station B 351634, Nashville TN 37235-1634, USA
| | - Carter T Davis
- LSU School of Medicine – New Orleans, 2020 Gravier Street, New Orleans, LA 70112, USA
| | - Charles K Singleton
- Department of Biological Sciences, Vanderbilt University, VU Station B 351634, Nashville TN 37235-1634, USA
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Nawata CM, Wood CM. The effects of CO2 and external buffering on ammonia excretion and Rhesus glycoprotein mRNA expression in rainbow trout. ACTA ACUST UNITED AC 2008; 211:3226-36. [PMID: 18840656 DOI: 10.1242/jeb.020396] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Rhesus (Rh) proteins were recently characterized as ammonia gas (NH(3)) channels. Studies indicate, however, that Rh proteins also facilitate CO2 transport in a green alga and in human erythrocytes. Previously, we reported that Rh mRNA expression in various rainbow trout tissues responded to high environmental ammonia. To determine whether or not Rh proteins may also be involved in CO2 transport in rainbow trout, we examined the effects of a 12 h exposure to external hypercapnia (1% CO2 in air) on Rh mRNA expression in the gill, skin and erythrocytes. External hypercapnic conditions lowered the water pH and facilitated ammonia excretion; therefore, we also studied the effects of hypercapnia and normocapnia in the presence of 10 mmol l(-1) Hepes-buffered water. Hepes treatment prevented water acidification, but resulted in elevated plasma ammonia levels and reduced ammonia excretion rates. Hypercapnia exposure without buffering did not elicit changes in Rh mRNA expression in the gill or skin. However, Rhcg2 mRNA expression was downregulated in the gills and upregulated in the skin of both normocapnia- and hypercapnia-exposed fish in Hepes-buffered water. mRNA expression of a newly cloned Rhbg2 cDNA was downregulated in the skin of fish exposed to buffered water, and Rhag mRNA expression in erythrocytes was decreased with exposure to normocapnia in buffered water but not with hypercapnia exposure in either buffered or unbuffered water. With the aid of Hepes buffering, we were able to observe the effects of both CO2 and ammonia on Rh mRNA expression. Overall, we conclude that high CO2 did not directly elicit changes in Rh mRNA transcription levels in the gill and skin, and that the changes observed probably reflect responses to high plasma ammonia, mirroring those in trout exposed to high environmental ammonia. Therefore a dual function for gill and skin Rh proteins in CO2 and ammonia transport is not evident from these results. Rhag expression, however, responded differentially to high CO2 and high ammonia, suggesting a possible dual role in the erythrocytes.
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Affiliation(s)
- C Michele Nawata
- Department of Biology, McMaster University, Hamilton, Ontario, Canada.
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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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González-Díaz H, González-Díaz Y, Santana L, Ubeira FM, Uriarte E. Proteomics, networks and connectivity indices. Proteomics 2008; 8:750-78. [DOI: 10.1002/pmic.200700638] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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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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Cherif-Zahar B, Durand A, Schmidt I, Hamdaoui N, Matic I, Merrick M, Matassi G. Evolution and functional characterization of the RH50 gene from the ammonia-oxidizing bacterium Nitrosomonas europaea. J Bacteriol 2007; 189:9090-100. [PMID: 17921289 PMCID: PMC2168606 DOI: 10.1128/jb.01089-07] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 09/04/2007] [Indexed: 12/31/2022] Open
Abstract
The family of ammonia and ammonium channel proteins comprises the Amt proteins, which are present in all three domains of life with the notable exception of vertebrates, and the homologous Rh proteins (Rh50 and Rh30) that have been described thus far only in eukaryotes. The existence of an RH50 gene in bacteria was first revealed by the genome sequencing of the ammonia-oxidizing bacterium Nitrosomonas europaea. Here we have used a phylogenetic approach to study the evolution of the N. europaea RH50 gene, and we show that this gene, probably as a component of an integron cassette, has been transferred to the N. europaea genome by horizontal gene transfer. In addition, by functionally characterizing the Rh50(Ne) protein and the corresponding knockout mutant, we determined that NeRh50 can mediate ammonium uptake. The RH50(Ne) gene may thus have replaced functionally the AMT gene, which is missing in the genome of N. europaea and may be regarded as a case of nonorthologous gene displacement.
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Christiansen M, Samuelsen B, Christiansen L, Morbjerg T, Bredahl C, Grunnet N. Correlation between serology and genetics of weak D types in Denmark. Transfusion 2007; 48:187-93. [PMID: 17900277 DOI: 10.1111/j.1537-2995.2007.01504.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND To date more than 100 variant D types have been reported and the frequencies vary among populations. Blood donor typing should reveal all donors expressing D antigens, while patient typing should prevent the development of anti-D in patients with a D- or variant D blood type. Serotyping is the standard method to assign transfusion strategies, whereas molecular classification offers a more specific grouping of weak and partial D. STUDY DESIGN AND METHODS Blood donor and patient samples with discrepant results of D phenotyping were collected to investigate the frequency of weak D subtypes in Denmark and to evaluate currently used serologic methods. RESULTS Nine different weak D types were identified among the 101 samples. Weak D Types 1, 2, and 3 constituted 80 percent of the analyzed samples and 10 percent of the samples identified as weak D from serology were actually partial D. CONCLUSION The distribution of weak D types in Denmark was found to resemble the distribution in Northern Germany in respect to the three most prevalent weak D types. Correctly defining all samples that show weak reactions in D typing as weak D or partial D is not possible with serotyping alone; genotyping offers the only exact categorization. Serology is superior for routine blood typing, however.
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Affiliation(s)
- Mette Christiansen
- Department of Clinical Immunology, Aarhus University hospital, Skejby, Denmark.
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Flegel WA, von Zabern I, Doescher A, Wagner FF, Vytisková J, Písacka M. DCS-1, DCS-2, and DFV share amino acid substitutions at the extracellular RhD protein vestibule. Transfusion 2007; 48:25-33. [PMID: 17900276 DOI: 10.1111/j.1537-2995.2007.01506.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND RhD and RhCE are structurally related to ammonium transporter proteins, yet their physiologic function remains unclear. Recent three-dimensional homology modeling with Escherichia coli AmtB as a template defined a putative transmembraneous channel. Three RhD variants with amino acid substitutions located at the extracellular channel aperture are described. STUDY DESIGN AND METHODS Blood samples were selected because of serologic abnormalities. RHD, RHCE, and LW nucleotide sequences were determined from genomic DNA. D epitope patterns were established with monoclonal anti-D panels. Three-dimensional Rh structures were calculated by alignment to AmtB. RESULTS The RHD allele DCS-1 was found to carry the two amino acid substitutions F223V (667T > G) and A226P (676G > C) caused by missense mutations in RHD exon 5. This study compared DCS-1 with the D variants DFV (F223V) and DCS-2 (A226P), harboring solely one or the other of the two substitutions. All three D variants were associated with a cDE haplotype. The antigen densities were approximately 3,000 D antigens per red blood cell for DCS-1, 800 for DCS-2, and 9,300 for DFV. DCS-1 and DCS-2 were partial D, because they lacked distinct epitopes. DFV presented as an almost normal D phenotype; the sample contained allo-anti-LW(a). The D(w) antigen was absent from DCS-1, DFV, and DAU-4, but expressed by DAU-5. CONCLUSION DCS-1, DCS-2, and DFV carry amino acid substitutions at the extracellular vestibule, visualized by 3-dimensional modeling. Proline at position 226 greatly influenced the D antigen density and may reduce the RhD membrane integration. Although the F223V substitution is regarded as the initial event in the evolution of the weak D Type 4 cluster, the current DFV allele probably evolved independently, as evident from different RHCE haplotypes.
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Affiliation(s)
- Willy A Flegel
- Institute for Transfusion Medicine, University Hospital Ulm, Ulm Germany.
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Endeward V, Cartron JP, Ripoche P, Gros G. RhAG protein of the Rhesus complex is a CO2channel in the human red cell membrane. FASEB J 2007; 22:64-73. [PMID: 17712059 DOI: 10.1096/fj.07-9097com] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We have determined CO2 permeabilities, P(CO2), of red cells of normal human blood and of blood deficient in various blood group proteins by a previously described mass spectrometric technique. While P(CO2) of normal red cells is approximately 0.15 cm/s, we find in red blood cells (RBCs) lacking the Rh protein complex (Rh(null)) a significantly reduced P(CO2) of 0.07 cm/s +/-0.02 cm/s (P<0.02). This value is similar to the value we have reported previously for RBCs lacking aquaporin-1 protein (AQP-1(null)), suggesting that each of the Rh and AQP-1 proteins is responsible for approximately 1/2 of the normal CO2 permeability of the RBC membrane. Four other blood group deficiencies tested lack diverse membrane proteins but exhibit normal CO2 permeability. The CO2 pathway constituted by Rh proteins was inhibitable at pH(e)= 7.4 by NH4Cl with an I50 of approximately 10 mM corresponding to an I50 for NH3 of approximately 0.3 mM. The pathway independent of Rh proteins, presumably that constituted by AQP-1, was not inhibitable by NH4Cl/NH3. However, both pathways were strongly inhibited by DIDS, which accounts for the marked inhibitory effect of DIDS on normal P(CO2), while in contrast another AE1 inhibitor, DiBAC, does not inhibit P(CO2), although it markedly reduces P(HCO3-). We conclude that Rh protein, presumably the Rh-associated glycoprotein RhAG, possesses a gas channel that allows passage of CO2 in addition to NH3.
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Affiliation(s)
- Volker Endeward
- Abt. Vegetative Physiologie Medizinische Hochschule Hannover, 30623-Hannover, Germany
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Javelle A, Lupo D, Li XD, Merrick M, Chami M, Ripoche P, Winkler FK. Structural and mechanistic aspects of Amt/Rh proteins. J Struct Biol 2007; 158:472-81. [PMID: 17368911 DOI: 10.1016/j.jsb.2007.01.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 01/08/2007] [Accepted: 01/13/2007] [Indexed: 12/14/2022]
Abstract
Amt/Rh proteins, which mediate movement of ammonium across cell membranes, are spread throughout the three kingdoms of life. Most functional studies on various members of the family have been performed using cellular assays in heterologous expression systems, which are, however, not very well suited for detailed mechanistic studies. Although now generally considered to be ammonia conducting channels, based on a number of experimental studies and structural insights, the possibility remains that some plant Amts facilitate net ammonium ion transport. The Escherichia coli channel AmtB has become the model system of choice for analysis of the mechanism of ammonia conductance, increasingly also through molecular dynamics simulations. Further progress in a more detailed mechanistic understanding of these proteins requires a reliable in vitro assay using purified protein, allowing quantitative kinetic measurements under a variety of experimental conditions for different Amt/Rh proteins, including mutants. Here, we critically review the existing functional data in the context of the most interesting and unresolved mechanistic questions and we present our results, obtained using an in vitro assay set up with the purified E. coli channel AmtB.
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Affiliation(s)
- Arnaud Javelle
- Biomolecular Research, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
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