1
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Cevheroğlu O, Demirbaş B, Öğütcü D, Murat M. ADGRG1, an adhesion G protein-coupled receptor, forms oligomers. FEBS J 2024; 291:2461-2478. [PMID: 38468592 DOI: 10.1111/febs.17117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 01/26/2024] [Accepted: 03/01/2024] [Indexed: 03/13/2024]
Abstract
G protein-coupled receptor (GPCR) oligomerization is a highly debated topic in the field. While initially believed to function as monomers, current literature increasingly suggests that these cell surface receptors, spanning almost all GPCR families, function as homo- or hetero-oligomers. Yet, the functional consequences of these oligomeric complexes remain largely unknown. Adhesion GPCRs (aGPCRs) present an intriguing family of receptors characterized by their large and multi-domain N-terminal fragments (NTFs), intricate activation mechanisms, and the prevalence of numerous splice variants in almost all family members. In the present study, bioluminescence energy transfer (BRET) and Förster resonance energy transfer (FRET) were used to study the homo-oligomerization of adhesion G protein-coupled receptor G1 (ADGRG1; also known as GPR56) and to assess the involvement of NTFs in these receptor complexes. Based on the results presented herein, we propose that ADGRG1 forms 7-transmembrane-driven homo-oligomers on the plasma membrane. Additionally, Stachel motif interactions appear to influence the conformation of these receptor complexes.
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Affiliation(s)
| | - Berkay Demirbaş
- Department of Biological Sciences, Middle East Technical University, Çankaya, Turkey
| | - Dilara Öğütcü
- Department of Biological Sciences, Middle East Technical University, Çankaya, Turkey
| | - Merve Murat
- Department of Biological Sciences, Middle East Technical University, Çankaya, Turkey
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2
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Kuhn CK, Stenzel U, Berndt S, Liebscher I, Schöneberg T, Horn S. The repertoire and structure of adhesion GPCR transcript variants assembled from publicly available deep-sequenced human samples. Nucleic Acids Res 2024; 52:3823-3836. [PMID: 38421639 DOI: 10.1093/nar/gkae145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/24/2024] [Accepted: 02/19/2024] [Indexed: 03/02/2024] Open
Abstract
Alternative splicing and multiple transcription start and termination sites can produce a diverse repertoire of mRNA transcript variants from a given gene. While the full picture of the human transcriptome is still incomplete, publicly available RNA datasets have enabled the assembly of transcripts. Using publicly available deep sequencing data from 927 human samples across 48 tissues, we quantified known and new transcript variants, provide an interactive, browser-based application Splice-O-Mat and demonstrate its relevance using adhesion G protein-coupled receptors (aGPCRs) as an example. On average, 24 different transcript variants were detected for each of the 33 human aGPCR genes, and several dominant transcript variants were not yet annotated. Variable transcription starts and complex exon-intron structures encode a flexible protein domain architecture of the N- and C termini and the seven-transmembrane helix domain (7TMD). Notably, we discovered the first GPCR (ADGRG7/GPR128) with eight transmembrane helices. Both the N- and C terminus of this aGPCR were intracellularly oriented, anchoring the N terminus in the plasma membrane. Moreover, the assessment of tissue-specific transcript variants, also for other gene classes, in our application may change the evaluation of disease-causing mutations, as their position in different transcript variants may explain tissue-specific phenotypes.
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Affiliation(s)
- Christina Katharina Kuhn
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Udo Stenzel
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Sandra Berndt
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
- Department of Biochemistry, School of Medicine, University of Global Health Equity (UGHE), PO Box 6955 Kigali, Rwanda
| | - Susanne Horn
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
- Institute of Translational Genomics, Helmholtz Zentrum München - German Research Center for Environmental Health, 85764 Neuherberg, Germany
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3
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Fam BSDO, Vargas-Pinilla P, Paré P, Landau L, Viscardi LH, Pissinatti A, Falótico T, Maestri R, Bortolini MC. Exploring the diversity of AVPR2 in Primates and its evolutionary implications. Genet Mol Biol 2023; 46:e20230045. [PMID: 37930141 PMCID: PMC10626583 DOI: 10.1590/1678-4685-gmb-2023-0045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 09/09/2023] [Indexed: 11/07/2023] Open
Abstract
The current study focuses on the investigation of AVPR2 (VTR2C) protein-coupled receptor variants specific to different primate taxa. AVPR2 is activated by the neurohormone AVP, which modulates physiological processes, including water homeostasis. Our findings reveal positive selection at three AVPR2 sites at positions 190, 250, and 346. Variation at position 250 is associated with human Congenital Nephrogenic Diabetes Insipidus (cNDI), a condition characterized by excessive water loss. Other 13 functional sites with potential adaptive relevance include positions 185, 202, 204, and 252 associated with cNDI. We identified SH3-binding motifs in AVPR2's ICL3 and N-terminus domains, with some losses observed in clades of Cercopithecidae, Callitrichinae, and Atelidae. SH3-binding motifs are crucial in regulating cellular physiology, indicating that the differences may be adaptive. Co-evolution was found between AVPR2 residues and those in the AVP signal peptide/Neurophysin-2 and AQP2, other molecules in the same signaling cascade. No significant correlation was found between these Primates' taxon-specific variants and the bioclimatic variables of the areas where they live. Distinct co-evolving amino acid sequences in functional sites were found in Platyrrhini and Catarrhini, which may have adaptive implications involving glucocorticoid hormones, suggesting varied selective pressures. Further studies are required to confirm these results.
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Affiliation(s)
- Bibiana Sampaio de Oliveira Fam
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
| | - Pedro Vargas-Pinilla
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
- Universidade de São Paulo, Faculdade de Medicina, Departamento de
Bioquímica e Imunologia, Ribeirão Preto, SP, Brazil
| | - Pâmela Paré
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
| | - Luane Landau
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
| | - Lucas H. Viscardi
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
| | | | - Tiago Falótico
- Universidade de São Paulo, Escola de Artes, Ciências e Humanidades,
São Paulo, SP, Brazil
| | - Renan Maestri
- Universidade Federal do Rio Grande do Sul, Departamento de Ecologia,
Laboratório de Ecomorfologia e Macroevolução, Porto Alegre, RS, Brazil
| | - Maria Cátira Bortolini
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
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4
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Mitgau J, Franke J, Schinner C, Stephan G, Berndt S, Placantonakis DG, Kalwa H, Spindler V, Wilde C, Liebscher I. The N Terminus of Adhesion G Protein–Coupled Receptor GPR126/ADGRG6 as Allosteric Force Integrator. Front Cell Dev Biol 2022; 10:873278. [PMID: 35813217 PMCID: PMC9259995 DOI: 10.3389/fcell.2022.873278] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 05/12/2022] [Indexed: 12/15/2022] Open
Abstract
The adhesion G protein–coupled receptor (aGPCR) GPR126/ADGRG6 plays an important role in several physiological functions, such as myelination or peripheral nerve repair. This renders the receptor an attractive pharmacological target. GPR126 is a mechano-sensor that translates the binding of extracellular matrix (ECM) molecules to its N terminus into a metabotropic intracellular signal. To date, the structural requirements and the character of the forces needed for this ECM-mediated receptor activation are largely unknown. In this study, we provide this information by combining classic second-messenger detection with single-cell atomic force microscopy. We established a monoclonal antibody targeting the N terminus to stimulate GPR126 and compared it to the activation through its known ECM ligands, collagen IV and laminin 211. As each ligand uses a distinct mode of action, the N terminus can be regarded as an allosteric module that can fine-tune receptor activation in a context-specific manner.
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Affiliation(s)
- Jakob Mitgau
- Rudolf Schönheimer Institute for Biochemistry, Molecular Biochemistry, University of Leipzig, Leipzig, Germany
| | - Julius Franke
- Rudolf Schönheimer Institute for Biochemistry, Molecular Biochemistry, University of Leipzig, Leipzig, Germany
| | - Camilla Schinner
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Gabriele Stephan
- Department of Neurosurgery, Kimmel Center for Stem Cell Biology, Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, United States
| | - Sandra Berndt
- Rudolf Schönheimer Institute for Biochemistry, Molecular Biochemistry, University of Leipzig, Leipzig, Germany
| | - Dimitris G. Placantonakis
- Department of Neurosurgery, Kimmel Center for Stem Cell Biology, Laura and Isaac Perlmutter Cancer Center, NYU Grossman School of Medicine, New York, NY, United States
| | - Hermann Kalwa
- Rudolf-Boehm-Institute for Pharmacology and Toxicology, University of Leipzig, Leipzig, Germany
| | - Volker Spindler
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Caroline Wilde
- Rudolf Schönheimer Institute for Biochemistry, Molecular Biochemistry, University of Leipzig, Leipzig, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute for Biochemistry, Molecular Biochemistry, University of Leipzig, Leipzig, Germany
- *Correspondence: Ines Liebscher,
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5
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Knapp B, Roedig J, Roedig H, Krzysko J, Horn N, Güler BE, Kusuluri DK, Yildirim A, Boldt K, Ueffing M, Liebscher I, Wolfrum U. Affinity Proteomics Identifies Interaction Partners and Defines Novel Insights into the Function of the Adhesion GPCR VLGR1/ADGRV1. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27103108. [PMID: 35630584 PMCID: PMC9146371 DOI: 10.3390/molecules27103108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 12/20/2022]
Abstract
The very large G-protein-coupled receptor 1 (VLGR1/ADGRV1) is the largest member of the adhesion G-protein-coupled receptor (ADGR) family. Mutations in VLGR1/ADGRV1 cause human Usher syndrome (USH), a form of hereditary deaf-blindness, and have been additionally linked to epilepsy. In the absence of tangible knowledge of the molecular function and signaling of VLGR1, the pathomechanisms underlying the development of these diseases are still unknown. Our study aimed to identify novel, previously unknown protein networks associated with VLGR1 in order to describe new functional cellular modules of this receptor. Using affinity proteomics, we have identified numerous new potential binding partners and ligands of VLGR1. Tandem affinity purification hits were functionally grouped based on their Gene Ontology terms and associated with functional cellular modules indicative of functions of VLGR1 in transcriptional regulation, splicing, cell cycle regulation, ciliogenesis, cell adhesion, neuronal development, and retinal maintenance. In addition, we validated the identified protein interactions and pathways in vitro and in situ. Our data provided new insights into possible functions of VLGR1, related to the development of USH and epilepsy, and also suggest a possible role in the development of other neuronal diseases such as Alzheimer’s disease.
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Affiliation(s)
- Barbara Knapp
- Institute of Molecular Physiology (ImP), Molecular Cell Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (B.K.); (J.R.); (H.R.); (J.K.); (B.E.G.); (D.K.K.); (A.Y.)
| | - Jens Roedig
- Institute of Molecular Physiology (ImP), Molecular Cell Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (B.K.); (J.R.); (H.R.); (J.K.); (B.E.G.); (D.K.K.); (A.Y.)
| | - Heiko Roedig
- Institute of Molecular Physiology (ImP), Molecular Cell Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (B.K.); (J.R.); (H.R.); (J.K.); (B.E.G.); (D.K.K.); (A.Y.)
| | - Jacek Krzysko
- Institute of Molecular Physiology (ImP), Molecular Cell Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (B.K.); (J.R.); (H.R.); (J.K.); (B.E.G.); (D.K.K.); (A.Y.)
| | - Nicola Horn
- Core Facility for Medical Bioanalytics, Institute for Ophthalmic Research, University of Tuebingen, 72076 Tuebingen, Germany; (N.H.); (K.B.); (M.U.)
| | - Baran E. Güler
- Institute of Molecular Physiology (ImP), Molecular Cell Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (B.K.); (J.R.); (H.R.); (J.K.); (B.E.G.); (D.K.K.); (A.Y.)
| | - Deva Krupakar Kusuluri
- Institute of Molecular Physiology (ImP), Molecular Cell Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (B.K.); (J.R.); (H.R.); (J.K.); (B.E.G.); (D.K.K.); (A.Y.)
| | - Adem Yildirim
- Institute of Molecular Physiology (ImP), Molecular Cell Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (B.K.); (J.R.); (H.R.); (J.K.); (B.E.G.); (D.K.K.); (A.Y.)
| | - Karsten Boldt
- Core Facility for Medical Bioanalytics, Institute for Ophthalmic Research, University of Tuebingen, 72076 Tuebingen, Germany; (N.H.); (K.B.); (M.U.)
| | - Marius Ueffing
- Core Facility for Medical Bioanalytics, Institute for Ophthalmic Research, University of Tuebingen, 72076 Tuebingen, Germany; (N.H.); (K.B.); (M.U.)
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Faculty of Medicine, Leipzig University, 04103 Leipzig, Germany;
| | - Uwe Wolfrum
- Institute of Molecular Physiology (ImP), Molecular Cell Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (B.K.); (J.R.); (H.R.); (J.K.); (B.E.G.); (D.K.K.); (A.Y.)
- Correspondence:
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6
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Alhasan K, D'Alessandri-Silva C, Mongia A, Topaloglu R, Tasic V, Filler G. Young Adults With Hereditary Tubular Diseases: Practical Aspects for Adult-Focused Colleagues. Adv Chronic Kidney Dis 2022; 29:292-307. [PMID: 36084976 DOI: 10.1053/j.ackd.2021.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/07/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Recent advances in the management of kidney tubular diseases have resulted in a significant cohort of adolescents and young adults transitioning from pediatric- to adult-focused care. Most of the patients under adult-focused care have glomerular diseases, whereas rarer tubular diseases form a considerable proportion of pediatric patients. The purpose of this review is to highlight the clinical signs and symptoms of tubular disorders, as well as their diagnostic workup, including laboratory findings and imaging, during young adulthood. We will then discuss more common disorders such as cystinosis, cystinuria, distal kidney tubular acidosis, congenital nephrogenic diabetes insipidus, Dent disease, rickets, hypercalciuria, and syndromes such as Bartter, Fanconi, Gitelman, Liddle, and Lowe. This review is a practical guide on the diagnostic and therapeutic approach of tubular conditions affecting young adults who are transitioning to adult-focused care.
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Affiliation(s)
- Khalid Alhasan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Cynthia D'Alessandri-Silva
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, and Nephrology, Connecticut Children's Medical Center, Hartford, CT
| | - Anil Mongia
- Department of Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY
| | - Rezan Topaloglu
- Department of Paediatrics, Division of Pediatric Nephrology, Hacettepe University School of Medicine, Ankara, Turkey
| | - Velibor Tasic
- University Children's Hospital, Medical School, Skopje, North Macedonia
| | - Guido Filler
- Department of Paediatrics, Division of Pediatric Nephrology, Western University, London, ON, Canada; Department of Medicine, Western University, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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7
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Zimmermann A, Vu O, Brüser A, Sliwoski G, Marnett LJ, Meiler J, Schöneberg T. Mapping the binding sites of UDP and prostaglandin E2 glyceryl ester in the nucleotide receptor P2Y6. ChemMedChem 2022; 17:e202100683. [PMID: 35034430 PMCID: PMC9305961 DOI: 10.1002/cmdc.202100683] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/14/2022] [Indexed: 12/02/2022]
Abstract
Cyclooxygenase‐2 catalyzes the biosynthesis of prostaglandins from arachidonic acid and the biosynthesis of prostaglandin glycerol esters (PG‐Gs) from 2‐arachidonoylglycerol. PG‐Gs are mediators of several biological actions such as macrophage activation, hyperalgesia, synaptic plasticity, and intraocular pressure. Recently, the human UDP receptor P2Y6 was identified as a target for the prostaglandin E2 glycerol ester (PGE2‐G). Here, we show that UDP and PGE2‐G are evolutionary conserved endogenous agonists at vertebrate P2Y6 orthologs. Using sequence comparison of P2Y6 orthologs, homology modeling, and ligand docking studies, we proposed several receptor positions participating in agonist binding. Site‐directed mutagenesis and functional analysis of these P2Y6 mutants revealed that both UDP and PGE2‐G share in parts one ligand‐binding site. Thus, the convergent signaling of these two chemically very different agonists has already been manifested in the evolutionary design of the ligand‐binding pocket.
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Affiliation(s)
- Anne Zimmermann
- Leipzig University: Universitat Leipzig Rudolf Schönheimer Institute of Biochemistry GERMANY
| | - Oanh Vu
- Vanderbilt University Department of Chemistry UNITED STATES
| | - Antje Brüser
- Leipzig University: Universitat Leipzig Rudolf Schönheimer Institute of Biochemistry GERMANY
| | - Gregory Sliwoski
- Vanderbilt University School of Medicine Department of Biomedical Informatics UNITED STATES
| | - Lawrence J. Marnett
- Vanderbilt University School of Medicine Department of Biochemistry UNITED STATES
| | - Jens Meiler
- Leipzig University: Universitat Leipzig Institute of Drug discovery GERMANY
| | - Torsten Schöneberg
- Leipzig University: Universitat Leipzig Rudolf Schönheimer Institute of Biochemistry Johannisallee 30 04103 Leipzig GERMANY
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8
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Schöneberg T, Liebscher I. Mutations in G Protein-Coupled Receptors: Mechanisms, Pathophysiology and Potential Therapeutic Approaches. Pharmacol Rev 2020; 73:89-119. [PMID: 33219147 DOI: 10.1124/pharmrev.120.000011] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
There are approximately 800 annotated G protein-coupled receptor (GPCR) genes, making these membrane receptors members of the most abundant gene family in the human genome. Besides being involved in manifold physiologic functions and serving as important pharmacotherapeutic targets, mutations in 55 GPCR genes cause about 66 inherited monogenic diseases in humans. Alterations of nine GPCR genes are causatively involved in inherited digenic diseases. In addition to classic gain- and loss-of-function variants, other aspects, such as biased signaling, trans-signaling, ectopic expression, allele variants of GPCRs, pseudogenes, gene fusion, and gene dosage, contribute to the repertoire of GPCR dysfunctions. However, the spectrum of alterations and GPCR involvement is probably much larger because an additional 91 GPCR genes contain homozygous or hemizygous loss-of-function mutations in human individuals with currently unidentified phenotypes. This review highlights the complexity of genomic alteration of GPCR genes as well as their functional consequences and discusses derived therapeutic approaches. SIGNIFICANCE STATEMENT: With the advent of new transgenic and sequencing technologies, the number of monogenic diseases related to G protein-coupled receptor (GPCR) mutants has significantly increased, and our understanding of the functional impact of certain kinds of mutations has substantially improved. Besides the classical gain- and loss-of-function alterations, additional aspects, such as biased signaling, trans-signaling, ectopic expression, allele variants of GPCRs, uniparental disomy, pseudogenes, gene fusion, and gene dosage, need to be elaborated in light of GPCR dysfunctions and possible therapeutic strategies.
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Affiliation(s)
- Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig, Germany
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9
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Muresanu DF, Sharma A, Sahib S, Tian ZR, Feng L, Castellani RJ, Nozari A, Lafuente JV, Buzoianu AD, Sjöquist PO, Patnaik R, Wiklund L, Sharma HS. Diabetes exacerbates brain pathology following a focal blast brain injury: New role of a multimodal drug cerebrolysin and nanomedicine. PROGRESS IN BRAIN RESEARCH 2020; 258:285-367. [PMID: 33223037 DOI: 10.1016/bs.pbr.2020.09.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Blast brain injury (bBI) is a combination of several forces of pressure, rotation, penetration of sharp objects and chemical exposure causing laceration, perforation and tissue losses in the brain. The bBI is quite prevalent in military personnel during combat operations. However, no suitable therapeutic strategies are available so far to minimize bBI pathology. Combat stress induces profound cardiovascular and endocrine dysfunction leading to psychosomatic disorders including diabetes mellitus (DM). This is still unclear whether brain pathology in bBI could exacerbate in DM. In present review influence of DM on pathophysiology of bBI is discussed based on our own investigations. In addition, treatment with cerebrolysin (a multimodal drug comprising neurotrophic factors and active peptide fragments) or H-290/51 (a chain-breaking antioxidant) using nanowired delivery of for superior neuroprotection on brain pathology in bBI in DM is explored. Our observations are the first to show that pathophysiology of bBI is exacerbated in DM and TiO2-nanowired delivery of cerebrolysin induces profound neuroprotection in bBI in DM, not reported earlier. The clinical significance of our findings with regard to military medicine is discussed.
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Affiliation(s)
- Dafin F Muresanu
- Department of Clinical Neurosciences, University of Medicine & Pharmacy, Cluj-Napoca, Romania; "RoNeuro" Institute for Neurological Research and Diagnostic, Cluj-Napoca, Romania
| | - Aruna Sharma
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden.
| | - Seaab Sahib
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Z Ryan Tian
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Lianyuan Feng
- Department of Neurology, Bethune International Peace Hospital, Shijiazhuang, Hebei Province, China
| | - Rudy J Castellani
- Department of Pathology, University of Maryland, Baltimore, MD, United States
| | - Ala Nozari
- Anesthesiology & Intensive Care, Massachusetts General Hospital, Boston, MA, United States
| | - José Vicente Lafuente
- LaNCE, Department of Neuroscience, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain
| | - Anca D Buzoianu
- Department of Clinical Pharmacology and Toxicology, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Per-Ove Sjöquist
- Division of Cardiology, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Ranjana Patnaik
- Department of Biomaterials, School of Biomedical Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi, India
| | - Lars Wiklund
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden
| | - Hari Shanker Sharma
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden.
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10
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Schulze A, Kleinau G, Neumann S, Scheerer P, Schöneberg T, Brüser A. The intramolecular agonist is obligate for activation of glycoprotein hormone receptors. FASEB J 2020; 34:11243-11256. [PMID: 32648604 DOI: 10.1096/fj.202000100r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 01/15/2023]
Abstract
In contrast to most rhodopsin-like G protein-coupled receptors, the glycoprotein hormone receptors (GPHR) have a large extracellular N-terminus for hormone binding. The hormones do not directly activate the transmembrane domain but mediate their action via a, thus, far only partially known Tethered Agonistic LIgand (TALI). The existence of such an intramolecular agonist was initially indicated by site-directed mutation studies and activating peptides derived from the extracellular hinge region. It is still unknown precisely how TALI is involved in intramolecular signal transmission. We combined systematic mutagenesis studies at the luteinizing hormone receptor and the thyroid-stimulating hormone receptor (TSHR), stimulation with a drug-like agonist (E2) of the TSHR, and structural homology modeling to unravel the functional and structural properties defining the TALI region. Here, we report that TALI (a) is predisposed to constitutively activate GPHR, (b) can by itself rearrange GPHR into a fully active conformation, (c) stabilizes active GPHR conformation, and (d) is not involved in activation of the TSHR by E2. In the active state conformation, TALI forms specific interactions between the N-terminus and the transmembrane domain. We show that stabilization of an active state is dependent on TALI, including activation by hormones and constitutively activating mutations.
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Affiliation(s)
- Annelie Schulze
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Gunnar Kleinau
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Susanne Neumann
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Patrick Scheerer
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Antje Brüser
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
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11
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Eichler W, Lohrenz A, Simon K, Krohn S, Lange J, Bürger S, Liebscher I. The role of ADGRE5/CD97 in human retinal pigment epithelial cell growth and survival. Ann N Y Acad Sci 2019; 1456:64-79. [DOI: 10.1111/nyas.14210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 06/28/2019] [Accepted: 07/22/2019] [Indexed: 12/27/2022]
Affiliation(s)
| | | | - Kay‐Uwe Simon
- Rudolf Schönheimer Institute of Biochemistry, Molecular BiochemistryLeipzig University Leipzig Germany
| | - Sandra Krohn
- Clinic for Gastroenterology and Rheumatology, Hepatology SectionLeipzig University Leipzig Germany
| | - Johannes Lange
- Norwegian Center for Movement DisordersStavanger University Hospital Stavanger Norway
| | | | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Molecular BiochemistryLeipzig University Leipzig Germany
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12
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Genetic basis of functional variability in adhesion G protein-coupled receptors. Sci Rep 2019; 9:11036. [PMID: 31363148 PMCID: PMC6667449 DOI: 10.1038/s41598-019-46265-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 06/21/2019] [Indexed: 12/15/2022] Open
Abstract
The enormous sizes of adhesion G protein-coupled receptors (aGPCRs) go along with complex genomic exon-intron architectures giving rise to multiple mRNA variants. There is a need for a comprehensive catalog of aGPCR variants for proper evaluation of the complex functions of aGPCRs found in structural, in vitro and animal model studies. We used an established bioinformatics pipeline to extract, quantify and visualize mRNA variants of aGPCRs from deeply sequenced transcriptomes. Data analysis showed that aGPCRs have multiple transcription start sites even within introns and that tissue-specific splicing is frequent. On average, 19 significantly expressed transcript variants are derived from a given aGPCR gene. The domain architecture of the N terminus encoded by transcript variants often differs and N termini without or with an incomplete seven-helix transmembrane anchor as well as separate seven-helix transmembrane domains are frequently derived from aGPCR genes. Experimental analyses of selected aGPCR transcript variants revealed marked functional differences. Our analysis has an impact on a rational design of aGPCR constructs for structural analyses and gene-deficient mouse lines and provides new support for independent functions of both, the large N terminus and the transmembrane domain of aGPCRs.
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13
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Hsiao CC, Chu TY, Wu CJ, van den Biggelaar M, Pabst C, Hébert J, Kuijpers TW, Scicluna BP, I KY, Chen TC, Liebscher I, Hamann J, Lin HH. The Adhesion G Protein-Coupled Receptor GPR97/ ADGRG3 Is Expressed in Human Granulocytes and Triggers Antimicrobial Effector Functions. Front Immunol 2018; 9:2830. [PMID: 30559745 PMCID: PMC6287011 DOI: 10.3389/fimmu.2018.02830] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 11/16/2018] [Indexed: 12/15/2022] Open
Abstract
The adhesion family of G protein-coupled receptors (aGPCRs) comprises 33 members in human, several of which are distinctly expressed and functionally involved in polymorphonuclear cells (PMNs). As former work indicated the possible presence of the aGPCR GPR97 in granulocytes, we studied its cellular distribution, molecular structure, signal transduction, and biological function in PMNs. RNA sequencing and mass-spectrometry revealed abundant RNA and protein expression of ADGRG3/GPR97 in granulocyte precursors and terminally differentiated neutrophilic, eosinophilic, and basophilic granulocytes. Using a newly generated GPR97-specific monoclonal antibody, we confirmed that endogenous GPR97 is a proteolytically processed, dichotomous, N-glycosylated receptor. GPR97 was detected in tissue-infiltrating PMNs and upregulated during systemic inflammation. Antibody ligation of GPR97 increased neutrophil reactive oxygen species production and proteolytic enzyme activity, which is accompanied by an increase in mitogen-activated protein kinases and IκBα phosphorylation. In-depth analysis of the GPR97 signaling cascade revealed a possible switch from basal Gαs/cAMP-mediated signal transduction to a Gαi-induced reduction in cAMP levels upon mutation-induced activation of the receptor, in combination with an increase in downstream effectors of Gβγ, such as SRE and NF-κB. Finally, ligation of GPR97 increased the bacteria uptake and killing activity of neutrophils. We conclude that the specific presence of GPR97 regulates antimicrobial activity in human granulocytes.
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Affiliation(s)
- Cheng-Chih Hsiao
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Tai-Ying Chu
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chia-Jung Wu
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Maartje van den Biggelaar
- Sanquin Research and Landsteiner Laboratory, Department of Plasma Proteins, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Caroline Pabst
- Department of Internal Medicine V, Heidelberg University, Heidelberg, Germany
| | - Josée Hébert
- Division of Hematology-Oncology and Leukemia Cell Bank of Quebec, Maisonneuve-Rosemont Hospital, Montreal, QC, Canada.,Department of Medicine, University of Montreal, Montreal, QC, Canada
| | - Taco W Kuijpers
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatric Hematology, Immunology and Infectious Diseases, Emma Children's Hospital, Amsterdam UMC, Amsterdam, Netherlands
| | - Brendon P Scicluna
- Department of Clinical Epidemiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Center for Experimental Molecular Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Kuan-Yu I
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tse-Ching Chen
- Department of Anatomic Pathology, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Jörg Hamann
- Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Hsi-Hsien Lin
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Anatomic Pathology, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan.,Chang Gung Immunology Consortium, Chang Gung Memorial Hospital-Linkou, Taoyuan, Taiwan
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14
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Erdem B, Schulz A, Saglar E, Deniz F, Schöneberg T, Mergen H. Functional characterization of AVPR2 mutants found in Turkish patients with nephrogenic diabetes insipidus. Endocr Connect 2018; 7:56-64. [PMID: 29117938 PMCID: PMC5744627 DOI: 10.1530/ec-17-0236] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 11/08/2017] [Indexed: 11/15/2022]
Abstract
Diabetes insipidus is a rare disorder characterized by an impairment in water balance because of the inability to concentrate urine. While central diabetes insipidus is caused by mutations in the AVP, the reason for genetically determined nephrogenic diabetes insipidus can be mutations in AQP2 or AVPR2 After release of AVP from posterior pituitary into blood stream, it binds to AVPR2, which is one of the receptors for AVP and is mainly expressed in principal cells of collecting ducts of kidney. Receptor activation increases cAMP levels in principal cells, resulting in the incorporation of AQP2 into the membrane, finally increasing water reabsorption. This pathway can be altered by mutations in AVPR2 causing nephrogenic diabetes insipidus. In this study, we functionally characterize four mutations (R68W, ΔR67-G69/G107W, V162A and T273M) in AVPR2, which were found in Turkish patients. Upon AVP stimulation, R68W, ΔR67-G69/G107W and T273M showed a significantly reduced maximum in cAMP response compared to wild-type receptor. All mutant receptor proteins were expressed at the protein level; however, R68W, ΔR67-G69/G107W and T273M were partially retained in the cellular interior. Immunofluorescence studies showed that these mutant receptors were trapped in ER and Golgi apparatus. The function of V162A was indistinguishable from the indicating other defects causing disease. The results are important for understanding the influence of mutations on receptor function and cellular trafficking. Therefore, characterization of these mutations provides useful information for further studies addressing treatment of intracellularly trapped receptors with cell-permeable antagonists to restore receptor function in patients with nephrogenic diabetes insipidus.
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Affiliation(s)
- Beril Erdem
- Department of BiologyFaculty of Science, Hacettepe University, Ankara, Turkey
| | - Angela Schulz
- Rudolf Schönheimer Institute of BiochemistryFaculty of Medicine, Leipzig University, Leipzig, Germany
| | - Emel Saglar
- Department of BiologyFaculty of Science, Hacettepe University, Ankara, Turkey
| | - Ferhat Deniz
- Department of EndocrinologySBÜ Sultan Abdülhamid Han Teaching Hospital, Istanbul, Turkey
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of BiochemistryFaculty of Medicine, Leipzig University, Leipzig, Germany
| | - Hatice Mergen
- Department of BiologyFaculty of Science, Hacettepe University, Ankara, Turkey
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15
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Scholz N, Guan C, Nieberler M, Grotemeyer A, Maiellaro I, Gao S, Beck S, Pawlak M, Sauer M, Asan E, Rothemund S, Winkler J, Prömel S, Nagel G, Langenhan T, Kittel RJ. Mechano-dependent signaling by Latrophilin/CIRL quenches cAMP in proprioceptive neurons. eLife 2017; 6. [PMID: 28784204 PMCID: PMC5548486 DOI: 10.7554/elife.28360] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/29/2017] [Indexed: 01/02/2023] Open
Abstract
Adhesion-type G protein-coupled receptors (aGPCRs), a large molecule family with over 30 members in humans, operate in organ development, brain function and govern immunological responses. Correspondingly, this receptor family is linked to a multitude of diverse human diseases. aGPCRs have been suggested to possess mechanosensory properties, though their mechanism of action is fully unknown. Here we show that the Drosophila aGPCR Latrophilin/dCIRL acts in mechanosensory neurons by modulating ionotropic receptor currents, the initiating step of cellular mechanosensation. This process depends on the length of the extended ectodomain and the tethered agonist of the receptor, but not on its autoproteolysis, a characteristic biochemical feature of the aGPCR family. Intracellularly, dCIRL quenches cAMP levels upon mechanical activation thereby specifically increasing the mechanosensitivity of neurons. These results provide direct evidence that the aGPCR dCIRL acts as a molecular sensor and signal transducer that detects and converts mechanical stimuli into a metabotropic response.
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Affiliation(s)
- Nicole Scholz
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany.,Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Chonglin Guan
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Matthias Nieberler
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Alexander Grotemeyer
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Isabella Maiellaro
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany.,Rudolf Virchow Center, DFG-Research Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Shiqiang Gao
- Department of Biology, Institute for Molecular Plant Physiology and Biophysics, University of Würzburg Biocenter, Würzburg, Germany
| | - Sebastian Beck
- Department of Biology, Institute for Molecular Plant Physiology and Biophysics, University of Würzburg Biocenter, Würzburg, Germany
| | - Matthias Pawlak
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of Würzburg Biocenter, Würzburg, Germany
| | - Esther Asan
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Sven Rothemund
- Core Unit Peptide Technologies, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Jana Winkler
- Rudolf Schönheimer Institute of Biochemistry, Division of Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Simone Prömel
- Rudolf Schönheimer Institute of Biochemistry, Division of Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Georg Nagel
- Department of Biology, Institute for Molecular Plant Physiology and Biophysics, University of Würzburg Biocenter, Würzburg, Germany
| | - Tobias Langenhan
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany.,Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Robert J Kittel
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
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16
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Brüser A, Zimmermann A, Crews BC, Sliwoski G, Meiler J, König GM, Kostenis E, Lede V, Marnett LJ, Schöneberg T. Prostaglandin E 2 glyceryl ester is an endogenous agonist of the nucleotide receptor P2Y 6. Sci Rep 2017; 7:2380. [PMID: 28539604 PMCID: PMC5443783 DOI: 10.1038/s41598-017-02414-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 04/10/2017] [Indexed: 11/10/2022] Open
Abstract
Cyclooxygenase-2 catalyses the biosynthesis of prostaglandins from arachidonic acid but also the biosynthesis of prostaglandin glycerol esters (PG-Gs) from 2-arachidonoylglycerol. Previous studies identified PG-Gs as signalling molecules involved in inflammation. Thus, the glyceryl ester of prostaglandin E2, PGE2-G, mobilizes Ca2+ and activates protein kinase C and ERK, suggesting the involvement of a G protein-coupled receptor (GPCR). To identify the endogenous receptor for PGE2-G, we performed a subtractive screening approach where mRNA from PGE2-G response-positive and -negative cell lines was subjected to transcriptome-wide RNA sequencing analysis. We found several GPCRs that are only expressed in the PGE2-G responder cell lines. Using a set of functional readouts in heterologous and endogenous expression systems, we identified the UDP receptor P2Y6 as the specific target of PGE2-G. We show that PGE2-G and UDP are both agonists at P2Y6, but they activate the receptor with extremely different EC50 values of ~1 pM and ~50 nM, respectively. The identification of the PGE2-G/P2Y6 pair uncovers the signalling mode of PG-Gs as previously under-appreciated products of cyclooxygenase-2.
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Affiliation(s)
- Antje Brüser
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103, Leipzig, Germany.
| | - Anne Zimmermann
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103, Leipzig, Germany
| | - Brenda C Crews
- Department of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, 37232-0146, USA
| | - Gregory Sliwoski
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN, 37232-8725, USA
| | - Jens Meiler
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232-8725, USA
| | - Gabriele M König
- Institute of Pharmaceutical Biology, University of Bonn, 53115, Bonn, Germany
| | - Evi Kostenis
- Institute of Pharmaceutical Biology, University of Bonn, 53115, Bonn, Germany
| | - Vera Lede
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103, Leipzig, Germany
| | - Lawrence J Marnett
- Department of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, 37232-0146, USA
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103, Leipzig, Germany.
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17
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Demberg LM, Winkler J, Wilde C, Simon KU, Schön J, Rothemund S, Schöneberg T, Prömel S, Liebscher I. Activation of Adhesion G Protein-coupled Receptors: AGONIST SPECIFICITY OF STACHEL SEQUENCE-DERIVED PEPTIDES. J Biol Chem 2017; 292:4383-4394. [PMID: 28154189 DOI: 10.1074/jbc.m116.763656] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/20/2017] [Indexed: 11/06/2022] Open
Abstract
Members of the adhesion G protein-coupled receptor (aGPCR) family carry an agonistic sequence within their large ectodomains. Peptides derived from this region, called the Stachel sequence, can activate the respective receptor. As the conserved core region of the Stachel sequence is highly similar between aGPCRs, the agonist specificity of Stachel sequence-derived peptides was tested between family members using cell culture-based second messenger assays. Stachel peptides derived from aGPCRs of subfamily VI (GPR110/ADGRF1, GPR116/ADGRF5) and subfamily VIII (GPR64/ADGRG2, GPR126/ADGRG6) are able to activate more than one member of the respective subfamily supporting their evolutionary relationship and defining them as pharmacological receptor subtypes. Extended functional analyses of the Stachel sequences and derived peptides revealed agonist promiscuity, not only within, but also between aGPCR subfamilies. For example, the Stachel-derived peptide of GPR110 (subfamily VI) can activate GPR64 and GPR126 (both subfamily VIII). Our results indicate that key residues in the Stachel sequence are very similar between aGPCRs allowing for agonist promiscuity of several Stachel-derived peptides. Therefore, aGPCRs appear to be pharmacologically more closely related than previously thought. Our findings have direct implications for many aGPCR studies, as potential functional overlap has to be considered for in vitro and in vivo studies. However, it also offers the possibility of a broader use of more potent peptides when the original Stachel sequence is less effective.
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Affiliation(s)
- Lilian M Demberg
- From the Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry and
| | - Jana Winkler
- From the Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry and
| | - Caroline Wilde
- From the Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry and
| | - Kay-Uwe Simon
- From the Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry and
| | - Julia Schön
- From the Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry and
| | - Sven Rothemund
- the Core Unit Peptide Technologies, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Torsten Schöneberg
- From the Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry and
| | - Simone Prömel
- From the Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry and
| | - Ines Liebscher
- From the Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry and
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18
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Ng HKH, Harikumar KG, Miller LJ, Chow BKC. Signaling Modification by GPCR Heteromer and Its Implication on X-Linked Nephrogenic Diabetes Insipidus. PLoS One 2016; 11:e0163086. [PMID: 27649563 PMCID: PMC5029868 DOI: 10.1371/journal.pone.0163086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 09/04/2016] [Indexed: 11/18/2022] Open
Abstract
The involvement of secretin (SCT) and secretin receptor (SCTR) in regulating body water homeostasis is well established. Identified as one of the vasopressin (Vp)-independent mechanisms in fluid balance, SCT regulates aquaporin 2 (AQP2) in the kidney distal collecting duct cells through activating intracellular cAMP production. This ability to bypass Vp-mediated water reabsorption in kidney implicates SCT’s potential to treat nephrogenic diabetes insipidus (NDI). Research on NDI in the past has largely been focused on the searching for mutations in vasopressin receptor 2 (AVPR2), while the functional relationship between SCTR, AVPR2 and NDI remains unclear. Here, we demonstrate the interaction between SCTR and AVPR2 to modulate cellular signaling in vitro. Interestingly, we show in this report that upon heteromer formation with SCTR, R137H, a NDI-causing AVPR2 mutant that is defective in trafficking to cell surface, can functionally be rescued. Our data may provide an explanation for this clinically mild case of NDI, and insights into the pathological development of NDI in the future.
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MESH Headings
- Animals
- CHO Cells
- Cricetinae
- Cricetulus
- Diabetes Insipidus, Nephrogenic/genetics
- Diabetes Insipidus, Nephrogenic/metabolism
- Gene Expression
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- Humans
- Mice
- Microscopy, Confocal
- Mutation
- Protein Binding
- Protein Multimerization
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Gastrointestinal Hormone/chemistry
- Receptors, Gastrointestinal Hormone/genetics
- Receptors, Gastrointestinal Hormone/metabolism
- Receptors, Vasopressin/chemistry
- Receptors, Vasopressin/genetics
- Receptors, Vasopressin/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction/genetics
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Affiliation(s)
- Hans K. H. Ng
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Kaleeckal G. Harikumar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona, 85259, United States of America
| | - Laurence J. Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona, 85259, United States of America
| | - Billy K. C. Chow
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
- * E-mail:
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19
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Fischer L, Wilde C, Schöneberg T, Liebscher I. Functional relevance of naturally occurring mutations in adhesion G protein-coupled receptor ADGRD1 (GPR133). BMC Genomics 2016; 17:609. [PMID: 27516204 PMCID: PMC4982218 DOI: 10.1186/s12864-016-2937-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 07/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A large number of human inherited and acquired diseases and phenotypes are caused by mutations in G protein-coupled receptors (GPCR). Genome-wide association studies (GWAS) have shown that variations in the ADGRD1 (GPR133) locus are linked with differences in metabolism, human height and heart frequency. ADGRD1 is a Gs protein-coupled receptor belonging to the class of adhesion GPCRs. RESULTS Analysis of more than 1000 sequenced human genomes revealed approximately 9000 single nucleotide polymorphisms (SNPs) in the human ADGRD1 as listed in public data bases. Approximately 2.4 % of these SNPs are located in exons resulting in 129 non-synonymous SNPs (nsSNPs) at 119 positions of ADGRD1. However, the functional relevance of those variants is unknown. In-depth characterization of these amino acid changes revealed several nsSNPs (A448D, Q600stop, C632fs [frame shift], A761E, N795K) causing full or partial loss of receptor function, while one nsSNP (F383S) significantly increased basal activity of ADGRD1. CONCLUSION Our results show that a broad spectrum of functionally relevant ADGRD1 variants is present in the human population which may cause clinically relevant phenotypes, while being compatible with life when heterozygous.
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Affiliation(s)
- Liane Fischer
- From the Section of Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, 04103, Leipzig, Germany
| | - Caroline Wilde
- From the Section of Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, 04103, Leipzig, Germany
| | - Torsten Schöneberg
- From the Section of Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, 04103, Leipzig, Germany.
| | - Ines Liebscher
- From the Section of Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, 04103, Leipzig, Germany.
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20
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Brüser A, Schulz A, Rothemund S, Ricken A, Calebiro D, Kleinau G, Schöneberg T. The Activation Mechanism of Glycoprotein Hormone Receptors with Implications in the Cause and Therapy of Endocrine Diseases. J Biol Chem 2015; 291:508-20. [PMID: 26582202 DOI: 10.1074/jbc.m115.701102] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Indexed: 11/06/2022] Open
Abstract
Glycoprotein hormones (GPHs) are the main regulators of the pituitary-thyroid and pituitary-gonadal axes. Selective interaction between GPHs and their cognate G protein-coupled receptors ensure specificity in GPH signaling. The mechanisms of how these hormones activate glycoprotein hormone receptors (GPHRs) or how mutations and autoantibodies can alter receptor function were unclear. Based on the hypothesis that GPHRs contain an internal agonist, we systematically screened peptide libraries derived from the ectodomain for agonistic activity on the receptors. We show that a peptide (p10) derived from a conserved sequence in the C-terminal part of the extracellular N terminus can activate all GPHRs in vitro and in GPHR-expressing tissues. Inactivating mutations in this conserved region or in p10 can inhibit activation of the thyroid-stimulating hormone receptor by autoantibodies. Our data suggest an activation mechanism where, upon extracellular ligand binding, this intramolecular agonist isomerizes and induces structural changes in the 7-transmembrane helix domain, triggering G protein activation. This mechanism can explain the pathophysiology of activating autoantibodies and several mutations causing endocrine dysfunctions such as Graves disease and hypo- and hyperthyroidism. Our findings highlight an evolutionarily conserved activation mechanism of GPHRs and will further promote the development of specific ligands useful to treat Graves disease and other dysfunctions of GPHRs.
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Affiliation(s)
| | | | | | - Albert Ricken
- Institute of Anatomy, Medical Faculty, University of Leipzig, 04103 Leipzig
| | - Davide Calebiro
- the Institute of Pharmacology and Toxicology & Bio-Imaging Center/Rudolf Virchow Center, University of Würzburg, 97078 Würzburg, and
| | - Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
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21
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Müller A, Winkler J, Fiedler F, Sastradihardja T, Binder C, Schnabel R, Kungel J, Rothemund S, Hennig C, Schöneberg T, Prömel S. Oriented Cell Division in the C. elegans Embryo Is Coordinated by G-Protein Signaling Dependent on the Adhesion GPCR LAT-1. PLoS Genet 2015; 11:e1005624. [PMID: 26505631 PMCID: PMC4624771 DOI: 10.1371/journal.pgen.1005624] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 10/01/2015] [Indexed: 12/20/2022] Open
Abstract
Orientation of spindles and cell division planes during development of many species ensures that correct cell-cell contacts are established, which is vital for proper tissue formation. This is a tightly regulated process involving a complex interplay of various signals. The molecular mechanisms underlying several of these pathways are still incompletely understood. Here, we identify the signaling cascade of the C. elegans latrophilin homolog LAT-1, an essential player in the coordination of anterior-posterior spindle orientation during the fourth round of embryonic cell division. We show that the receptor mediates a G protein-signaling pathway revealing that G-protein signaling in oriented cell division is not solely GPCR-independent. Genetic analyses showed that through the interaction with a Gs protein LAT-1 elevates intracellular cyclic AMP (cAMP) levels in the C. elegans embryo. Stimulation of this G-protein cascade in lat-1 null mutant nematodes is sufficient to orient spindles and cell division planes in the embryo in the correct direction. Finally, we demonstrate that LAT-1 is activated by an intramolecular agonist to trigger this cascade. Our data support a model in which a novel, GPCR-dependent G protein-signaling cascade mediated by LAT-1 controls alignment of cell division planes in an anterior-posterior direction via a metabotropic Gs-protein/adenylyl cyclase pathway by regulating intracellular cAMP levels. During embryogenesis an entire organism develops from a single cell. This process is vital for the formation of life, thus cell division occurs with a very distinct orientation and pattern that is tightly controlled by several signaling pathways. The mechanisms underlying these pathways are complex and not yet fully understood. In the roundworm Caenorhabditis elegans, a common genetic model, the patterns and orientations in which cells divide in the embryo have been well characterized offering an ideal model to study the molecular mechanisms involved. Here, we show that the signal mediated by the adhesion G protein-coupled receptor LAT-1 is based on cAMP. This second messenger is essential for the orientation of distinct cell division planes in the early embryo. Studies based on a lat-1 knockout mutant reveal that LAT-1 signaling affects the levels of the second messenger cAMP in the cells via a specific G protein. Thereby the receptor is activated by an intrinsic sequence. This pathway is the first one clearly shown to involve a G protein-coupled receptor-dependent G-protein signal in orientation of embryonic cell division, offering a novel level of regulation of this process among other described pathways.
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Affiliation(s)
- Antje Müller
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Jana Winkler
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Franziska Fiedler
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | | | - Claudia Binder
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Ralf Schnabel
- Institute of Genetics, TU Braunschweig, Braunschweig, Germany
| | - Jana Kungel
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Sven Rothemund
- Core Unit Peptide Technologies, Medical Faculty, Leipzig University, Leipzig, Germany
| | | | - Torsten Schöneberg
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Simone Prömel
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
- * E-mail:
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Cöster M, Biebermann H, Schöneberg T, Stäubert C. Evolutionary Conservation of 3-Iodothyronamine as an Agonist at the Trace Amine-Associated Receptor 1. Eur Thyroid J 2015; 4:9-20. [PMID: 26601069 PMCID: PMC4640299 DOI: 10.1159/000430839] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 04/21/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES The trace amine-associated receptor 1 (Taar1) is a Gs protein-coupled receptor activated by trace amines, such as β-phenylethylamine (β-PEA) and 3-iodothyronamine (T1AM). T1AM is an endogenous biogenic amine and thyroid hormone derivative that exerts several biological functions. However, the physiological relevance of T1AM acting via Taar1 is still under discussion. Therefore, we studied the structural and functional evolution of Taar1 in vertebrates to provide evidence for a conserved Taar1-mediated T1AM function. STUDY DESIGN We searched public sequence databases to retrieve Taar1 sequence information from vertebrates. We cloned and functionally characterized Taar1 from selected vertebrate species using cAMP assays to determine the evolutionary conservation of T1AM action at Taar1. RESULTS We found intact open reading frames of Taar1 in more than 100 vertebrate species, including mammals, sauropsids and amphibians. Evolutionary conservation analyses of Taar1 protein sequences revealed a high variation in amino acid residues proposed to be involved in agonist binding, especially in rodent Taar1 orthologs. Functional characterization showed that T1AM, β-PEA and p-tyramine (p-Tyr) act as agonists at all tested orthologs, but EC50 values of T1AM at rat Taar1 differed significantly when compared to all other tested vertebrate Taar1. CONCLUSIONS The high structural conservation of Taar1 throughout vertebrate evolution highlights the physiological relevance of Taar1, but species-specific differences in T1AM potency at Taar1 orthologs suggest a specialization of rat Taar1 for T1AM recognition. In contrast, β-PEA and p-Tyr potencies were rather conserved throughout all tested Taar1 orthologs. We provide evidence that the observed differences in potency are related to differences in constraint during Taar1 evolution.
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Affiliation(s)
- Maxi Cöster
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Heike Biebermann
- Institut für Experimenelle Pädiatrische Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Torsten Schöneberg
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Claudia Stäubert
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
- *Claudia Stäubert, Institute of Biochemistry, Molecular Biochemistry, Faculty of Medicine, University of Leipzig, Johannisallee 30, DE-04103 Leipzig (Germany), E-Mail
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23
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Identification of the tethered peptide agonist of the adhesion G protein-coupled receptor GPR64/ADGRG2. Biochem Biophys Res Commun 2015; 464:743-7. [DOI: 10.1016/j.bbrc.2015.07.020] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 07/03/2015] [Indexed: 11/22/2022]
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24
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Liebscher I, Schön J, Petersen SC, Fischer L, Auerbach N, Demberg LM, Mogha A, Cöster M, Simon KU, Rothemund S, Monk KR, Schöneberg T. A tethered agonist within the ectodomain activates the adhesion G protein-coupled receptors GPR126 and GPR133. Cell Rep 2014; 9:2018-26. [PMID: 25533341 DOI: 10.1016/j.celrep.2014.11.036] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/10/2014] [Accepted: 11/22/2014] [Indexed: 01/08/2023] Open
Abstract
Adhesion G protein-coupled receptors (aGPCRs) comprise the second largest yet least studied class of the GPCR superfamily. aGPCRs are involved in many developmental processes and immune and synaptic functions, but the mode of their signal transduction is unclear. Here, we show that a short peptide sequence (termed the Stachel sequence) within the ectodomain of two aGPCRs (GPR126 and GPR133) functions as a tethered agonist. Upon structural changes within the receptor ectodomain, this intramolecular agonist is exposed to the seven-transmembrane helix domain, which triggers G protein activation. Our studies show high specificity of a given Stachel sequence for its receptor. Finally, the function of Gpr126 is abrogated in zebrafish with a mutated Stachel sequence, and signaling is restored in hypomorphic gpr126 zebrafish mutants upon exogenous Stachel peptide application. These findings illuminate a mode of aGPCR activation and may prompt the development of specific ligands for this currently untargeted GPCR family.
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Affiliation(s)
- Ines Liebscher
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany; Novo Nordisk Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
| | - Julia Schön
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Sarah C Petersen
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Liane Fischer
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Nina Auerbach
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lilian Marie Demberg
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Amit Mogha
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Maxi Cöster
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Kay-Uwe Simon
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Sven Rothemund
- Core Unit Peptide Technologies, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Kelly R Monk
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Torsten Schöneberg
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany.
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Gpr126 functions in Schwann cells to control differentiation and myelination via G-protein activation. J Neurosci 2014; 33:17976-85. [PMID: 24227709 DOI: 10.1523/jneurosci.1809-13.2013] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The myelin sheath surrounding axons ensures that nerve impulses travel quickly and efficiently, allowing for the proper function of the vertebrate nervous system. We previously showed that the adhesion G-protein-coupled receptor (aGPCR) Gpr126 is essential for peripheral nervous system myelination, although the molecular mechanisms by which Gpr126 functions were incompletely understood. aGPCRs are a significantly understudied protein class, and it was unknown whether Gpr126 couples to G-proteins. Here, we analyze Dhh(Cre);Gpr126(fl/fl) conditional mutants, and show that Gpr126 functions in Schwann cells (SCs) for radial sorting of axons and myelination. Furthermore, we demonstrate that elevation of cAMP levels or protein kinase A activation suppresses myelin defects in Gpr126 mouse mutants and that cAMP levels are reduced in conditional Gpr126 mutant peripheral nerve. Finally, we show that GPR126 directly increases cAMP by coupling to heterotrimeric G-proteins. Together, these data support a model in which Gpr126 functions in SCs for proper development and myelination and provide evidence that these functions are mediated via G-protein-signaling pathways.
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26
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Guernsey MW, Ritscher L, Miller MA, Smith DA, Schöneberg T, Shapiro MD. A Val85Met mutation in melanocortin-1 receptor is associated with reductions in eumelanic pigmentation and cell surface expression in domestic rock pigeons (Columba livia). PLoS One 2013; 8:e74475. [PMID: 23977400 PMCID: PMC3744500 DOI: 10.1371/journal.pone.0074475] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 08/02/2013] [Indexed: 12/28/2022] Open
Abstract
Variation in the melanocortin-1 receptor (Mc1r) is associated with pigmentation diversity in wild and domesticated populations of vertebrates, including several species of birds. Among domestic bird species, pigmentation variation in the rock pigeon (Columbalivia) is particularly diverse. To determine the potential contribution of Mc1r variants to pigment diversity in pigeons, we sequenced Mc1r in a wide range of pigeon breeds and identified several single nucleotide polymorphisms, including a variant that codes for an amino acid substitution (Val85Met). In contrast to the association between Val85Met and eumelanism in other avian species, this change was associated with pheomelanism in pigeons. In vitro cAMP accumulation and protein expression assays revealed that Val85Met leads to decreased receptor function and reduced cell surface expression of the mutant protein. The reduced in vitro function is consistent with the observed association with reduced eumelanic pigmentation. Comparative genetic and cellular studies provide important insights about the range of mechanisms underlying diversity among vertebrates, including different phenotypic associations with similar mutations in different species.
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Affiliation(s)
- Michael W. Guernsey
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Lars Ritscher
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Matthew A. Miller
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Daniel A. Smith
- Department of Chemistry, Goshen College, Goshen, Indiana, United States of America
| | - Torsten Schöneberg
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Michael D. Shapiro
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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27
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Stäubert C, Bohnekamp J, Schöneberg T. Determinants involved in subtype-specific functions of rat trace amine-associated receptors 1 and 4. Br J Pharmacol 2013; 168:1266-78. [PMID: 23072560 DOI: 10.1111/bph.12020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 09/26/2012] [Accepted: 10/07/2012] [Indexed: 01/14/2023] Open
Abstract
AIMS The trace amine-associated receptor (Taar) family displays high species- and subtype-specific pharmacology. Several trace amines such as β-phenylethylamine (β-PEA), p-tyramine and tryptamine are agonists at TA(1) but poorly activate rat and mouse Taar4. PRINCIPAL RESULTS Using rat TA(1) and Taar4 chimera, we identified determinants in transmembrane helices 3 and 6, which, when replaced by the corresponding portion of rat TA(1) , can rescue cell surface expression of rat Taar4. When expressed at the cell surface, rat Taar4 pharmacology was very similar to that of TA(1) and coupled to the Gα(s) -protein/AC pathway. Our data suggest that binding pockets of Taar for surrogate agonists overlap between paralogs. CONCLUSIONS This implicates that the repertoire of Taar ensures functional redundancy, tissue- and cell-specific expression and/or different downstream signalling rather than different agonist specificity.
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Affiliation(s)
- C Stäubert
- Institute of Biochemistry, Medical Faculty, University Leipzig, Leipzig, Germany
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28
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Armstrong SP, Seeber RM, Ayoub MA, Feldman BJ, Pfleger KDG. Characterization of three vasopressin receptor 2 variants: an apparent polymorphism (V266A) and two loss-of-function mutations (R181C and M311V). PLoS One 2013; 8:e65885. [PMID: 23762448 PMCID: PMC3675069 DOI: 10.1371/journal.pone.0065885] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 04/30/2013] [Indexed: 02/01/2023] Open
Abstract
Arginine vasopressin (AVP) is released from the posterior pituitary and controls water homeostasis. AVP binding to vasopressin V2 receptors (V2Rs) located on kidney collecting duct epithelial cells triggers activation of Gs proteins, leading to increased cAMP levels, trafficking of aquaporin-2 water channels, and consequent increased water permeability and antidiuresis. Typically, loss-of-function V2R mutations cause nephrogenic diabetes insipidus (NDI), whereas gain-of-function mutations cause nephrogenic syndrome of inappropriate antidiuresis (NSIAD). Here we provide further characterization of two mutant V2Rs, R181C and M311V, reported to cause complete and partial NDI respectively, together with a V266A variant, in a patient diagnosed with NSIAD. Our data in HEK293FT cells revealed that for cAMP accumulation, AVP was about 500- or 30-fold less potent at the R181C and M311V mutants than at the wild-type receptor respectively (and about 4000- and 60-fold in COS7 cells respectively). However, in contrast to wild type V2R, the R181C mutant failed to increase inositol phosphate production, while with the M311V mutant, AVP exhibited only partial agonism in addition to a 37-fold potency decrease. Similar responses were detected in a BRET assay for β-arrestin recruitment, with the R181C receptor unresponsive to AVP, and partial agonism with a 23-fold decrease in potency observed with M311V in both HEK293FT and COS7 cells. Notably, the V266A V2R appeared functionally identical to the wild-type receptor in all assays tested, including cAMP and inositol phosphate accumulation, β-arrestin interaction, and in a BRET assay of receptor ubiquitination. Each receptor was expressed at comparable levels. Hence, the M311V V2R retains greater activity than the R181C mutant, consistent with the milder phenotype of NDI associated with this mutant. Notably, the R181C mutant appears to be a Gs protein-biased receptor incapable of signaling to inositol phosphate or recruiting β-arrestin. The etiology of NSIAD in the patient with V266A V2R remains unknown.
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MESH Headings
- Animals
- Aquaporin 2/genetics
- Aquaporin 2/metabolism
- Arginine Vasopressin/metabolism
- Arrestins/genetics
- Arrestins/metabolism
- COS Cells
- Chlorocebus aethiops
- Cyclic AMP/metabolism
- Diabetes Insipidus, Nephrogenic/genetics
- Diabetes Insipidus, Nephrogenic/metabolism
- Diabetes Insipidus, Nephrogenic/pathology
- GTP-Binding Protein alpha Subunits, Gs/genetics
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- Gene Expression Regulation
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- Genetic Diseases, X-Linked/pathology
- HEK293 Cells
- Humans
- Inappropriate ADH Syndrome/genetics
- Inappropriate ADH Syndrome/metabolism
- Inappropriate ADH Syndrome/pathology
- Inositol Phosphates/metabolism
- Mutation
- Polymorphism, Genetic
- Receptors, Vasopressin/genetics
- Receptors, Vasopressin/metabolism
- Signal Transduction
- beta-Arrestins
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Affiliation(s)
- Stephen P. Armstrong
- Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia, Australia
| | - Ruth M. Seeber
- Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia, Australia
| | - Mohammed Akli Ayoub
- Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia, Australia
- Protein Research Chair - Department of Biochemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Brian J. Feldman
- Pediatric Endocrinology, Department of Pediatrics, Stanford University, Stanford, California, United States of America
| | - Kevin D. G. Pfleger
- Laboratory for Molecular Endocrinology-G Protein-Coupled Receptors, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, Perth, Western Australia, Australia
- * E-mail:
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29
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Fu Y, Cheetham T, Bourn D, Orwoll E, Cohen DM. Functional polymorphisms affecting the clinically important arginine-137 residue of AVPR2 do not influence serum sodium concentration at the population level. Physiol Genomics 2013; 45:210-6. [PMID: 23362144 DOI: 10.1152/physiolgenomics.00161.2012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The protein product of the AVPR2 gene, coding for the arginine vasopressin receptor type 2, is essential for vasopressin-dependent concentration of the urine. The arginine residue at position 137 in the protein product of this gene is uniquely pivotal for function. The R137H mutant inactivates the receptor conferring congenital nephrogenic diabetes insipidus, whereas activating mutations at this same residue (i.e., R137C and R137L) confer pathological water retention in the nephrogenic syndrome of inappropriate antidiuresis. These mutations were discovered in human subjects with conspicuous phenotypes in clinical water balance. Prevalence of these polymorphisms among asymptomatic individuals has not been assessed, nor has their contribution to broad interindividual variation in serum sodium concentration; no data addressing minor allele frequency are available. We genotyped two large cohorts using a validated high-throughput Pyrosequencing-based assay that we designed to capture the totality of pathological variation at this important residue. In the Osteoporotic Fractures in Men (MrOS) Study, all participants were male (i.e., hemizygous for AVPR2 gene on the X-chromosome), and participants were oversampled at the extremes of the population distribution for serum sodium concentration. In the Offspring Cohort of the Framingham Heart Study, male and female participants were genotyped. No pathological variants affecting R137 were detected among the 5,142 AVPR2 alleles successfully genotyped. Even at the population extremes of serum sodium distribution, we estimate minor allele frequency < 0.06%. We conclude that these disease-associated variants are exceedingly uncommon and do not contribute broadly to interindividual variability in serum sodium concentration or to its heritability.
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Affiliation(s)
- Yi Fu
- Division of Nephrology & Hypertension, Oregon Health & Science University, Portland, OR 97239, USA
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30
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Abstract
Lyso-PS (lyso-phosphatidylserine) has been shown to activate the G(i/o)-protein-coupled receptor GPR34. Since in vitro and in vivo studies provided controversial results in assigning lyso-PS as the endogenous agonist for GPR34, we investigated the evolutionary conservation of agonist specificity in more detail. Except for some fish GPR34 subtypes, lyso-PS has no or very weak agonistic activity at most vertebrate GPR34 orthologues investigated. Using chimaeras we identified single positions in the second extracellular loop and the transmembrane helix 5 of carp subtype 2a that, if transferred to the human orthologue, enabled lyso-PS to activate the human GPR34. Significant improvement of agonist efficacy by changing only a few positions strongly argues against the hypothesis that nature optimized GPR34 as the receptor for lyso-PS. Phylogenetic analysis revealed several positions in some fish GPR34 orthologues which are under positive selection. These structural changes may indicate functional specification of these orthologues which can explain the species- and subtype-specific pharmacology of lyso-PS. Furthermore, we identified aminoethyl-carbamoyl ATP as an antagonist of carp GPR34, indicating ligand promiscuity with non-lipid compounds. The results of the present study suggest that lyso-PS has only a random agonistic activity at some GPR34 orthologues and the search for the endogenous agonist should consider additional chemical entities.
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31
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Cöster M, Wittkopf D, Kreuchwig A, Kleinau G, Thor D, Krause G, Schöneberg T. Using ortholog sequence data to predict the functional relevance of mutations in G‐protein‐coupled receptors. FASEB J 2012; 26:3273-81. [DOI: 10.1096/fj.12-203737] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Maxi Cöster
- Molecular Biochemistry, Institute of Biochemistry, Medical FacultyUniversity of Leipzig Leipzig Germany
| | - Doreen Wittkopf
- Molecular Biochemistry, Institute of Biochemistry, Medical FacultyUniversity of Leipzig Leipzig Germany
| | | | - Gunnar Kleinau
- Institute of Experimental Pediatric EndocrinologyCharité Universitätsmedizin Berlin Berlin Germany
| | - Doreen Thor
- Molecular Biochemistry, Institute of Biochemistry, Medical FacultyUniversity of Leipzig Leipzig Germany
| | - Gerd Krause
- Leibniz Institute for Molecular Pharmacology Berlin Germany
| | - Torsten Schöneberg
- Molecular Biochemistry, Institute of Biochemistry, Medical FacultyUniversity of Leipzig Leipzig Germany
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Takahashi K, Makita N, Manaka K, Hisano M, Akioka Y, Miura K, Takubo N, Iida A, Ueda N, Hashimoto M, Fujita T, Igarashi T, Sekine T, Iiri T. V2 vasopressin receptor (V2R) mutations in partial nephrogenic diabetes insipidus highlight protean agonism of V2R antagonists. J Biol Chem 2011; 287:2099-106. [PMID: 22144672 DOI: 10.1074/jbc.m111.268797] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inactivating mutations of the V2 vasopressin receptor (V2R) cause cross-linked congenital nephrogenic diabetes insipidus (NDI), resulting in renal resistance to the antidiuretic hormone AVP. In two families showing partial NDI, characterized by an apparently normal response to diagnostic tests and an increase in the basal ADH levels suggesting AVP resistance, we have identified two V2R mutations, Ser-333del and Y128S. Both mutant V2Rs, when expressed in COS-7 cells, show partial defects in vasopressin-stimulated cAMP accumulation and intracellular localization. The inhibition of internalization does not rescue their localization. In contrast, the non-peptide V2R antagonists OPC41061 and OPC31260 partially rescue the membrane localization and basal function of these V2R mutants, whereas they inhibit the basal activity of the wild-type V2R. These results indicate that a partial loss of function of Ser-333del and Y128S mutant V2Rs results from defective membrane trafficking. These findings further indicate that V2R antagonists can act as protean agonists, serving as pharmacological chaperones for inactivating V2R mutants and also as inverse agonists of wild-type receptors. We speculate that this protean agonism could underlie the possible dual beneficial effects of the V2R antagonist: improvement of hyponatremia with heart failure or polycystic kidney disease and potential rescue of NDI.
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Affiliation(s)
- Kazuhiro Takahashi
- Department of Pediatrics, The University of Tokyo, Tokyo 113-8655, Japan
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Bohnekamp J, Schöneberg T. Cell adhesion receptor GPR133 couples to Gs protein. J Biol Chem 2011; 286:41912-41916. [PMID: 22025619 DOI: 10.1074/jbc.c111.265934] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Adhesion G protein-coupled receptors (GPCR), with their very large and complex N termini, are thought to participate in cell-cell and cell-matrix interactions and appear to be highly relevant in several developmental processes. Their intracellular signaling is still poorly understood. Here we demonstrate that GPR133, a member of the adhesion GPCR subfamily, activates the G(s) protein/adenylyl cyclase pathway. The presence of the N terminus and the cleavage at the GPCR proteolysis site are not required for G protein signaling. G(s) protein coupling was verified by Gα(s) knockdown with siRNA, overexpression of Gα(s), co-expression of the chimeric Gq(s4) protein that routes GPR133 activity to the phospholipase C/inositol phosphate pathway, and missense mutation within the transmembrane domain that abolished receptor activity without changing cell surface expression. It is likely that not only GPR133 but also other adhesion GPCR signal via classical receptor/G protein-interaction.
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Affiliation(s)
- Jens Bohnekamp
- Section of Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Torsten Schöneberg
- Section of Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany.
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34
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Böselt I, Tramma D, Kalamitsou S, Niemeyer T, Nykänen P, Gräf KJ, Krude H, Marenzi KS, Di Candia S, Schöneberg T, Schulz A. Functional characterization of novel loss-of-function mutations in the vasopressin type 2 receptor gene causing nephrogenic diabetes insipidus. Nephrol Dial Transplant 2011; 27:1521-8. [PMID: 21917732 DOI: 10.1093/ndt/gfr487] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND X-linked nephrogenic diabetes insipidus (NDI) is a rare polyuric disorder caused by inactivating mutations in the arginine vasopressin receptor Type 2 (AVPR2) gene. METHODS NDI patients from six unrelated families were subjected to mutational analysis of the AVPR2 gene. In-depth in vitro characterization of novel AVPR2 mutants by a combination of functional and immunological techniques provided further insight into molecular mechanisms causing receptor dysfunction. RESULTS Mutational analysis revealed four novel (A89P, G107R, Q174R, W208X) and three recurrent (V277A, R337X, ΔR247-G250) mutations within the AVPR2 gene. One family carried the missense mutation R337X and a 12-bp deletion (ΔR247-G250), corresponding to a fragment in the third intracellular loop (ICL3), which was not genetically linked to R337X. The functionally tested missense mutations A89P, G107R and Q174R led to reduced receptor cell surface expression in transfected COS-7 cells, most probably due to misfolding and intracellular retention, and consequently to reduction or loss of agonist-mediated cyclic adenosine monophosphate formation. Deletion of R247-G250 had no effect on receptor function in vitro. Comparison with other mammalian AVPR2 orthologs showed that this part of the ICL3 is structurally not conserved and, therefore, less relevant for receptor function. In contrast, all missense mutations (A89P, G107R, Q174R, V277A) affect receptor positions that were fully preserved during mammalian evolution. CONCLUSION Our results provide valuable information about residues critical for AVPR2 folding, trafficking and function and proof that these mutations are responsible for causing NDI in the affected subjects.
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Affiliation(s)
- Iris Böselt
- Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
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Böselt I, Römpler H, Hermsdorf T, Thor D, Busch W, Schulz A, Schöneberg T. Involvement of the V2 vasopressin receptor in adaptation to limited water supply. PLoS One 2009; 4:e5573. [PMID: 19440390 PMCID: PMC2680020 DOI: 10.1371/journal.pone.0005573] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Accepted: 04/06/2009] [Indexed: 01/11/2023] Open
Abstract
Mammals adapted to a great variety of habitats with different accessibility to water. In addition to changes in kidney morphology, e.g. the length of the loops of Henle, several hormone systems are involved in adaptation to limited water supply, among them the renal-neurohypophysial vasopressin/vasopressin receptor system. Comparison of over 80 mammalian V2 vasopressin receptor (V2R) orthologs revealed high structural and functional conservation of this key component involved in renal water reabsorption. Although many mammalian species have unlimited access to water there is no evidence for complete loss of V2R function indicating an essential role of V2R activity for survival even of those species. In contrast, several marsupial V2R orthologs show a significant increase in basal receptor activity. An increased vasopressin-independent V2R activity can be interpreted as a shift in the set point of the renal-neurohypophysial hormone circuit to realize sufficient water reabsorption already at low hormone levels. As found in other desert mammals arid-adapted marsupials show high urine osmolalities. The gain of basal V2R function in several marsupials may contribute to the increased urine concentration abilities and, therefore, provide an advantage to maintain water and electrolyte homeostasis under limited water supply conditions.
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Affiliation(s)
- Iris Böselt
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Holger Römpler
- Rudolf-Böhm-Institute of Pharmacology and Toxicology, Medical Faculty, University of Leipzig, Leipzig, Germany
- Department of Organismic and Evolutionary Biology and the Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Thomas Hermsdorf
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Doreen Thor
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Wibke Busch
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Angela Schulz
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Torsten Schöneberg
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
- * E-mail:
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Spanakis E, Milord E, Gragnoli C. AVPR2 variants and mutations in nephrogenic diabetes insipidus: review and missense mutation significance. J Cell Physiol 2008; 217:605-17. [PMID: 18726898 DOI: 10.1002/jcp.21552] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Almost 90% of nephrogenic diabetes insipidus (NDI) is due to mutations in the arginine-vasopressin receptor 2 gene (AVPR2). We retrospectively examined all the published mutations/variants in AVPR2. We planned to perform a comprehensive review of all the AVPR2 mutations/variants and to test whether any amino acid change causing a missense mutation is significantly more or less common than others. We performed a Medline search and collected detailed information regarding all AVPR2 mutations and variants. We performed a frequency comparison between mutated and wild-type amino acids and codons. We predicted the mutation effect or reported it based on published in vitro studies. We also reported the ethnicity of each mutation/variant carrier. In summary, we identified 211 AVPR2 mutations which cause NDI in 326 families and 21 variants which do not cause NDI in 71 NDI families. We described 15 different types of mutations including missense, frameshift, inframe deletion, deletion, insertion, nonsense, duplication, splicing and combined mutations. The missense mutations represent the 55.83% of all the NDI published families. Arginine and tyrosine are significantly (P = 4.07E-08 and P = 3.27E-04, respectively) the AVPR2 most commonly mutated amino acids. Alanine and glutamate are significantly (P = 0.009 and P = 0.019, respectively) the least mutated AVPR2 amino acids. The spectrum of mutations varies from rare gene variants or polymorphisms not causing NDI to rare mutations causing NDI, among which arginine and tyrosine are the most common missense. The AVPR2 mutations are spread world-wide. Our study may serve as an updated review, comprehensive of all AVPR2 variants and specific gene locations. J. Cell. Physiol. 217: 605-617, 2008. (c) 2008 Wiley-Liss, Inc.
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Affiliation(s)
- Elias Spanakis
- Laboratory of Molecular Genetics of Complex and Monogenic Disorders, Department of Medicine and Cellular & Molecular Physiology, M. S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA
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Stäubert C, Tarnow P, Brumm H, Pitra C, Gudermann T, Grüters A, Schöneberg T, Biebermann H, Römpler H. Evolutionary aspects in evaluating mutations in the melanocortin 4 receptor. Endocrinology 2007; 148:4642-8. [PMID: 17628007 DOI: 10.1210/en.2007-0138] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
More than 70 missense mutations have been identified in the human melanocortin 4 receptor (MC4R), and many of them have been associated with obesity. In a number of cases, the causal link between mutations in MC4R and obesity is controversially discussed. Here, we mined evolution as an additional source of structural information that may help to evaluate the functional relevance of naturally occurring variations in MC4R. The sequence information of more than 60 MC4R orthologs enabled us to identify residues that are important for maintaining receptor function. More than 90% of all inactivating mutations found in obese patients were located at amino acid positions that are highly conserved during 450 million years of MC4R evolution in vertebrates. However, for a reasonable number of MC4R variants, we found no correlation between structural conservation of the mutated position and the reported functional consequence. By re-evaluating selected mutations in the MC4R, we demonstrate the usefulness of combining functional and evolutionary approaches.
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Affiliation(s)
- Claudia Stäubert
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, 04103 Leipzig, Germany
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Schulz A, Römpler H, Mitschke D, Thor D, Schliebe N, Hermsdorf T, Strotmann R, Sangkuhl K, Schöneberg T. Molecular basis and clinical features of nephrogenic diabetes insipidus. Expert Rev Endocrinol Metab 2006; 1:727-741. [PMID: 30754158 DOI: 10.1586/17446651.1.6.727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Maintenance of water and electrolyte homeostasis is central to mammalian survival and, therefore, under stringent hormonal control. Water homeostasis is achieved by balancing fluid intake with water excretion, governed by the antidiuretic action of arginine vasopressin. Arginine vasopressin stimulation of renal V2 vasopressin receptors in the basolateral membrane of principal cells induces aquaporin-2-mediated water reabsorption in the kidney. The importance of this system is apparent when mutations inactivate V2 vasopressin receptors and aquaporin-2 and cause the clinical phenotype of nephrogenic diabetes insipidus. To date, over 190 mutations in the V2 vasopressin receptors gene (AVPR2) and approximately 38 mutations in the aquaporin-2 gene have been identified in patients with inherited nephrogenic diabetes insipidus. Extensive in vitro expression and mutagenesis studies of V2 vasopressin receptors and aquaporin-2 have provided detailed insights into the molecular mechanisms of G-protein-coupled receptor and water channel dysfunction per se. Targeted deletions of AVPR2 and AQP2 in mice have extended the knowledge of nephrogenic diabetes insipidus pathophysiology and have stimulated testing of old and new ideas to therapeutically restore normal kidney function in animal models and patients with this disease. In this review, we summarize the current knowledge relevant to understand the molecular basis of inherited nephrogenic diabetes insipidus forms and the rationales for the current pharmacological treatment of patients with this illness.
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Affiliation(s)
- Angela Schulz
- a University of Leipzig, Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103, Leipzig, Germany.
| | - Holger Römpler
- b University of Leipzig, Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103, Leipzig, Germany.
| | - Doreen Mitschke
- c University of Leipzig, Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103, Leipzig, Germany.
| | - Doreen Thor
- d University of Leipzig, Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103, Leipzig, Germany.
| | - Nicole Schliebe
- e University of Leipzig, Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103, Leipzig, Germany.
| | - Thomas Hermsdorf
- f University of Leipzig, Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103, Leipzig, Germany.
| | - Rainer Strotmann
- g University of Leipzig, Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103, Leipzig, Germany.
| | - Katrin Sangkuhl
- h Division of Reproductive Biology, Department of Obstetrics and Gynecology, Stanford University Medical Center, California, USA.
| | - Torsten Schöneberg
- i University of Leipzig, Molecular Biochemistry, Medical Faculty, Johannisallee 30, 04103 Leipzig, Germany.
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Tao YX. Inactivating mutations of G protein-coupled receptors and diseases: Structure-function insights and therapeutic implications. Pharmacol Ther 2006; 111:949-73. [PMID: 16616374 DOI: 10.1016/j.pharmthera.2006.02.008] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Accepted: 02/21/2006] [Indexed: 12/20/2022]
Abstract
Since the discovery of the first rhodopsin mutation that causes retinitis pigmentosa in 1990, significant progresses have been made in elucidating the pathophysiology of diseases caused by inactivating mutations of G protein-coupled receptors (GPCRs). This review aims to compile the compelling evidence accumulated during the past 15 years demonstrating the etiologies of more than a dozen diseases caused by inactivating GPCR mutations. A generalized classification scheme, based on the life cycle of GPCRs, is proposed. Insights gained through detailed studies of these naturally occurring mutations into the structure-function relationship of these receptors are reviewed. Therapeutic approaches directed against the different classes of mutants are being developed. Since intracellular retention emerges as the most common defect, recent progresses aimed at correcting this defect through membrane permeable pharmacological chaperones are highlighted.
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MESH Headings
- Animals
- Diabetes Insipidus, Nephrogenic/etiology
- Dwarfism/etiology
- Humans
- Hypogonadism/etiology
- Mutation
- Obesity/etiology
- Receptor, Melanocortin, Type 1/genetics
- Receptor, Melanocortin, Type 2/genetics
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Parathyroid Hormone, Type 1/genetics
- Receptors, CCR5/genetics
- Receptors, Calcium-Sensing/genetics
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/physiology
- Receptors, LHRH/genetics
- Receptors, Vasopressin/genetics
- Retinitis Pigmentosa/etiology
- Rhodopsin/genetics
- Structure-Activity Relationship
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, 213 Greene Hall, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
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Robben JH, Knoers NVAM, Deen PMT. Cell biological aspects of the vasopressin type-2 receptor and aquaporin 2 water channel in nephrogenic diabetes insipidus. Am J Physiol Renal Physiol 2006; 291:F257-70. [PMID: 16825342 DOI: 10.1152/ajprenal.00491.2005] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In the renal collecting duct, water reabsorption is regulated by the antidiuretic hormone vasopressin (AVP). Binding of this hormone to the vasopressin V2 receptor (V2R) leads to insertion of aquaporin-2 (AQP2) water channels in the apical membrane, thereby allowing water reabsorption from the pro-urine to the interstitium. The disorder nephrogenic diabetes insipidus (NDI) is characterized by the kidney's inability to concentrate pro-urine in response to AVP, which is mostly acquired due to electrolyte disturbances or lithium therapy. Alternatively, NDI is inherited in an X-linked or autosomal fashion due to mutations in the genes encoding V2R or AQP2, respectively. This review describes the current knowledge of the cell biological causes of NDI and how these defects may explain the patients' phenotypes. Also, the increased understanding of these cellular defects in NDI has opened exciting initiatives in the development of novel therapies for NDI, which are extensively discussed in this review.
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MESH Headings
- Amino Acid Sequence
- Aquaporin 2/genetics
- Aquaporin 2/physiology
- DNA/genetics
- Diabetes Insipidus, Nephrogenic/etiology
- Diabetes Insipidus, Nephrogenic/genetics
- Diabetes Insipidus, Nephrogenic/physiopathology
- Diabetes Insipidus, Nephrogenic/therapy
- Gene Expression Regulation/physiology
- Genetic Diseases, X-Linked/etiology
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/physiopathology
- Genetic Diseases, X-Linked/therapy
- Humans
- Molecular Sequence Data
- Mutation/genetics
- Mutation/physiology
- Receptors, Vasopressin/genetics
- Receptors, Vasopressin/physiology
- Vasopressins/physiology
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Affiliation(s)
- Joris H Robben
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences and Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Römpler H, Yu HT, Arnold A, Orth A, Schöneberg T. Functional consequences of naturally occurring DRY motif variants in the mammalian chemoattractant receptor GPR33. Genomics 2006; 87:724-32. [PMID: 16595170 DOI: 10.1016/j.ygeno.2006.02.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 01/30/2006] [Accepted: 02/14/2006] [Indexed: 11/24/2022]
Abstract
Most members of the large family of rhodopsin-like G-protein-coupled receptors possess an evolutionarily conserved Asp-Arg-Tyr (DRY) motif in the C-terminal region of the third transmembrane domain. Mutations of residues within this motif usually abolish receptor function and, when they occur naturally, can even cause human diseases. By analyzing over 100 mammalian orthologs of the chemoattractant receptor GPR33 we identified several polymorphic and fixed sequence variations within the DRY motif. Unexpectedly, the naturally occurring mutation of Arg(3.50) to His in mouse GPR33 showed no difference from the wild-type receptor in several functional tests. Sequence analysis of GPR33 from Asian house mice revealed the polymorphic existence of Arg(3.50) and His(3.50) alleles in wild-trapped populations, further supporting the functional equivalence of both allelic variants. In contrast, the Arg(3.50) to Gly mutation found in hamster GPR33 inactivates the receptor and may have contributed to pseudogenization of this gene in this species. Functional data with GPR33 variants indicate different receptor- and context-specific consequences of DRY mutations. Our study also reveals GPR33 as a new example illustrating missense mutations as a first step in the pseudogenization process.
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Affiliation(s)
- Holger Römpler
- Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Johannisallee 30, 04103 Leipzig, Germany
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42
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Grosse J, Tarnow P, Römpler H, Schneider B, Sedlmeier R, Huffstadt U, Korthaus D, Nehls M, Wattler S, Schöneberg T, Biebermann H, Augustin M. N-ethyl-N-nitrosourea-based generation of mouse models for mutant G protein-coupled receptors. Physiol Genomics 2006; 26:209-17. [PMID: 16720677 DOI: 10.1152/physiolgenomics.00289.2005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chemical random mutagenesis techniques with the germ line supermutagen N-ethyl-N-nitrosourea (ENU) have been established to provide comprehensive collections of mouse models, which were then mined and analyzed in phenotype-driven studies. Here, we applied ENU mutagenesis in a high-throughput fashion for a gene-driven identification of new mutations. Selected members of the large superfamily of G protein-coupled receptors (GPCR), melanocortin type 3 (Mc3r) and type 4 (Mc4r) receptors, and the orphan chemoattractant receptor GPR33, were used as model targets to prove the feasibility of this approach. Parallel archives of DNA and sperm from mice mutagenized with ENU were screened for mutations in these GPCR, and in vitro assays served as a preselection step before in vitro fertilization was performed to generate the appropriate mouse model. For example, mouse models for inherited obesity were established by selecting fully or partially inactivating mutations in Mc4r. Our technology described herein has the potential to provide mouse models for a GPCR dysfunction of choice within <4 mo and can be extended to other gene classes of interest.
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MESH Headings
- Alkylating Agents/toxicity
- Animals
- COS Cells
- Chlorocebus aethiops
- DNA Mutational Analysis/methods
- Disease Models, Animal
- Enzyme-Linked Immunosorbent Assay
- Ethylnitrosourea/toxicity
- Female
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Mutagenesis/drug effects
- Mutation/genetics
- Phylogeny
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/physiology
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/physiology
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/physiology
- Signal Transduction/physiology
- Transfection
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Schöneberg T, Schulz A, Biebermann H, Hermsdorf T, Römpler H, Sangkuhl K. Mutant G-protein-coupled receptors as a cause of human diseases. Pharmacol Ther 2004; 104:173-206. [PMID: 15556674 DOI: 10.1016/j.pharmthera.2004.08.008] [Citation(s) in RCA: 231] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
G-protein-coupled receptors (GPCR) are involved in directly and indirectly controlling an extraordinary variety of physiological functions. Their key roles in cellular communication have made them the target for more than 60% of all currently prescribed drugs. Mutations in GPCR can cause acquired and inherited diseases such as retinitis pigmentosa (RP), hypo- and hyperthyroidism, nephrogenic diabetes insipidus, several fertility disorders, and even carcinomas. To date, over 600 inactivating and almost 100 activating mutations in GPCR have been identified which are responsible for more than 30 different human diseases. The number of human disorders is expected to increase given the fact that over 160 GPCR have been targeted in mice. Herein, we summarize the current knowledge relevant to understanding the molecular basis of GPCR function, with primary emphasis on the mechanisms underlying GPCR malfunction responsible for different human diseases.
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Affiliation(s)
- Torsten Schöneberg
- Institute of Biochemistry, Department of Molecular Biochemistry (Max-Planck-Institute Interim), Medical Faculty, University of Leipzig, Deutscher Platz 6, 04103 Leipzig, Germany.
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Tarnow P, Schoneberg T, Krude H, Gruters A, Biebermann H. Mutationally Induced Disulfide Bond Formation within the Third Extracellular Loop Causes Melanocortin 4 Receptor Inactivation in Patients with Obesity. J Biol Chem 2003; 278:48666-73. [PMID: 14504270 DOI: 10.1074/jbc.m309941200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
By screening patients with severe early onset obesity for mutations within the melanocortin 4 receptor (MC4R) gene, we have identified a missense mutation (C271R) that occurs homozygous in two siblings with obesity. In-depth functional characterization of C271R revealed a right-shifted concentration response curve due to lower affinity to natural and synthetic MC4R agonists and a reduced cell surface expression. Cys-271 is located in the third extracellular loop. Here, we provide evidence that Cys-271 forms an intra-loop disulfide bond with Cys-277. Unexpectedly, we found that loss of receptor function is not only caused by the disruption of this disulfide bridge. Our data strongly support a new mechanism in which the receptor malfunction in the C271R mutant is induced by formation of a functionally disastrous disulfide bridge between Cys-277 and a third Cys residue at position 279. Mutational and chemical disruption of this improper disulfide bond was able to restore normal receptor potency. By demonstrating that a loss of a disulfide bond-participating Cys residue can favor a functionally disastrous disulfide bond, we now add a new mechanism of how Cys residues can be involved in G-protein-coupled receptor malfunction.
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MESH Headings
- Adolescent
- Adult
- Amino Acid Sequence
- Child
- Disulfides/chemistry
- Female
- Humans
- Male
- Molecular Sequence Data
- Mutation, Missense
- Obesity/metabolism
- Pedigree
- Radioligand Assay
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/chemistry
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Sequence Homology, Amino Acid
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Affiliation(s)
- Patrick Tarnow
- Otto Heubner Centrum für Kinderheilkunde und Jugendmedizin, Pädiatrische Endokrinologie, Charité Campus Virchow-Klinikum, Humboldt-Universität zu Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
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Kalenga K, Persu A, Goffin E, Lavenne-Pardonge E, van Cangh PJ, Bichet DG, Devuyst O. Intrafamilial phenotype variability in nephrogenic diabetes insipidus. Am J Kidney Dis 2002; 39:737-43. [PMID: 11920339 DOI: 10.1053/ajkd.2002.31993] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
X-Linked nephrogenic diabetes insipidus (NDI), which accounts for 90% of inherited cases of NDI, is caused by mutations in the AVPR2 gene that encodes the arginine vasopressin (AVP) receptor type 2 (V2R). The V2R mediates the antidiuretic action of AVP in principal cells of the collecting duct. To date, only three AVPR2 mutations (P322S, D85N, and G201D) have been associated with a mild NDI phenotype, and intrafamilial phenotype variability has not been reported in affected males. We describe a novel Belgian family with X-linked NDI caused by substitution of a histidine for an arginine at position 137 (R137H) of AVPR2. This mutation has been identified in two brothers and their mother. The R137H mutation results in a failure of V2R to stimulate adenylate cyclase and has been associated consistently with severe NDI and the inability to increase urinary osmolality to greater than plasma osmolality during water deprivation and/or infusion of 1-desamino-8-d-arginine vasopressin. Detailed examination of the two affected brothers showed the typical NDI phenotype in the 45-year-old proband, whereas a milder clinical phenotype associated with significant urinary concentrating ability during water deprivation was documented in the 33-year-old brother. Thus, in this family, the R137H mutation is associated with either a mild or severe NDI phenotype. Mechanisms that might account for these findings include genetic and/or environmental modifiers.
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Affiliation(s)
- Karine Kalenga
- Division of Nephrology, Université Catholique de Louvain Medical School, Brussels, Belgium
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46
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Abstract
Nephrogenic diabetes insipidus, which can be inherited or acquired, is characterized by an inability to concentrate urine despite normal or elevated plasma concentrations of the antidiuretic hormone arginine vasopressin. Polyuria, with hyposthenuria, and polydipsia are the cardinal clinical manifestations of the disease. About 90% of patients with congenital nephrogenic diabetes insipidus are males with the X-linked recessive form of the disease (OMIM 304800) who have mutations in the arginine vasopressin receptor 2 gene (AVPR2), which codes for the vasopressin V2 receptor. The gene is located in chromosomal region Xq28. In <10% of the families studied, congenital nephrogenic diabetes insipidus has an autosomal-recessive or autosomal-dominant (OMIM 222000 and 125800, respectively) mode of inheritance. Mutations have been identified in the aquaporin-2 gene (AQP2), which is located in chromosome region 12q13 and codes for the vasopressin-sensitive water channel. When studied in vitro, most AVPR2 mutations result in receptors that are trapped intracellularly and are unable to reach the plasma membrane. A few mutant receptors reach the cell surface but are unable to bind arginine vasopressin or to properly trigger an intracellular cyclic AMP signal. Similarly, aquaporin-2 mutant proteins are misrouted and cannot be expressed at the luminal membrane. Chemical or pharmacological chaperones have been found to reverse the intracellular retention of aquaporin-2 and arginine vasopressin receptor 2 mutant proteins. Because many hereditary diseases stem from the intracellular retention of otherwise functional proteins, this mechanism may offer a new therapeutic approach to the treatment of those diseases that result from errors in protein kinesis.
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Affiliation(s)
- J P Morello
- Department of Biochemistry, Université de Montréal, Montreal, Quebec, Canada.
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Barak LS, Oakley RH, Laporte SA, Caron MG. Constitutive arrestin-mediated desensitization of a human vasopressin receptor mutant associated with nephrogenic diabetes insipidus. Proc Natl Acad Sci U S A 2001; 98:93-8. [PMID: 11134505 PMCID: PMC14550 DOI: 10.1073/pnas.98.1.93] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Agonist-dependent desensitization and internalization of G protein-coupled receptors (GPCR) are mediated by the binding of arrestins to phosphorylated receptors. The affinity of arrestins for the phosphorylated GPCR regulates the ability of the internalized receptor to be dephosphorylated and recycled back to the plasma membrane. In this study, we show that the naturally occurring loss of function vasopressin receptor mutation R137H, which is associated with familial nephrogenic diabetes insipidus, induces constitutive arrestin-mediated desensitization. In contrast to the wild-type vasopressin receptor, the nonsignaling R137H receptor is phosphorylated and sequestered in arrestin-associated intracellular vesicles even in the absence of agonist. Eliminating molecular determinants on the receptor that promote high affinity arrestin-receptor interaction reestablishes plasma membrane localization and the ability of the mutated receptors to signal. These findings suggest that unregulated desensitization can contribute to the etiology of a GPCR-based disease, implying that pharmacological targeting of GPCR desensitization may be therapeutically beneficial.
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Affiliation(s)
- L S Barak
- Howard Hughes Medical Institute Laboratories and Departments of Cell Biology and Medicine, Duke University Medical Center, Durham, NC 27710, USA
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Constitutive arrestin-mediated desensitization of a human vasopressin receptor mutant associated with nephrogenic diabetes insipidus. Proc Natl Acad Sci U S A 2001. [PMID: 11134505 PMCID: PMC14550 DOI: 10.1073/pnas.011303698] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Agonist-dependent desensitization and internalization of G protein-coupled receptors (GPCR) are mediated by the binding of arrestins to phosphorylated receptors. The affinity of arrestins for the phosphorylated GPCR regulates the ability of the internalized receptor to be dephosphorylated and recycled back to the plasma membrane. In this study, we show that the naturally occurring loss of function vasopressin receptor mutation R137H, which is associated with familial nephrogenic diabetes insipidus, induces constitutive arrestin-mediated desensitization. In contrast to the wild-type vasopressin receptor, the nonsignaling R137H receptor is phosphorylated and sequestered in arrestin-associated intracellular vesicles even in the absence of agonist. Eliminating molecular determinants on the receptor that promote high affinity arrestin-receptor interaction reestablishes plasma membrane localization and the ability of the mutated receptors to signal. These findings suggest that unregulated desensitization can contribute to the etiology of a GPCR-based disease, implying that pharmacological targeting of GPCR desensitization may be therapeutically beneficial.
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Affiliation(s)
- P M Deen
- Department of Cell Physiology, University of Nijmegen, The Netherlands.
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Albertazzi E, Zanchetta D, Barbier P, Faranda S, Frattini A, Vezzoni P, Procaccio M, Bettinelli A, Guzzi F, Parenti M, Chini B. Nephrogenic diabetes insipidus: functional analysis of new AVPR2 mutations identified in Italian families. J Am Soc Nephrol 2000; 11:1033-1043. [PMID: 10820167 DOI: 10.1681/asn.v1161033] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The aim of this study was to identify loss-of-function mutations of the V2 vasopressin receptor gene (AVPR2) in Italian patients affected by X-linked nephrogenic diabetes insipidus (NDI). Mutations were found in 15 of the 18 unrelated families investigated: nine of these mutations were previously unknown, including two affecting residues located in regions known to be important for determining the pharmacologic properties of the receptor, which were therefore functionally investigated. The first (A84D) involves a residue located near an aspartic acid (D85) that is highly conserved in all G protein-coupled receptors and that is believed to play a role in the process of their isomerization into functionally active and inactive states. The present study indicates that this mutation not only affects receptor folding in such a way as to lead to its retention inside the intracellular compartments but, as expected, also has profound effects on its binding and coupling properties. The second was a mutation of a tryptophan located at the beginning of the first extracellular loop (W99R) that greatly impaired the binding properties of the receptor and had a minor effect on its intracellular routing. Molecular analysis of the first extracellular loop bearing this mutation suggests that this residue plays a fundamental role in stabilizing the peptide/receptor interactions responsible for the high-affinity binding of agonists to the V2 receptor.
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Affiliation(s)
- Elena Albertazzi
- Consiglio Nazionale delle Ricerche Cellular and Molecular Pharmacology Center, Milan, Italy
| | - Deborah Zanchetta
- Consiglio Nazionale delle Ricerche Cellular and Molecular Pharmacology Center, Milan, Italy
| | - Pascaline Barbier
- Consiglio Nazionale delle Ricerche Cellular and Molecular Pharmacology Center, Milan, Italy
| | - Sara Faranda
- Consiglio Nazionale delle Ricerche Institute of Advanced Biomedical Technologies, Milan, Italy
| | - Annalisa Frattini
- Consiglio Nazionale delle Ricerche Institute of Advanced Biomedical Technologies, Milan, Italy
| | - Paolo Vezzoni
- Consiglio Nazionale delle Ricerche Institute of Advanced Biomedical Technologies, Milan, Italy
| | | | | | - Francesca Guzzi
- Department of Pharmacology, University of Milan, Milan, Italy
| | - Marco Parenti
- Department of Pharmacology, University of Milan, Milan, Italy
| | - Bice Chini
- Consiglio Nazionale delle Ricerche Cellular and Molecular Pharmacology Center, Milan, Italy
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