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Keaton JM, Kamali Z, Xie T, Vaez A, Williams A, Goleva SB, Ani A, Evangelou E, Hellwege JN, Yengo L, Young WJ, Traylor M, Giri A, Zheng Z, Zeng J, Chasman DI, Morris AP, Caulfield MJ, Hwang SJ, Kooner JS, Conen D, Attia JR, Morrison AC, Loos RJF, Kristiansson K, Schmidt R, Hicks AA, Pramstaller PP, Nelson CP, Samani NJ, Risch L, Gyllensten U, Melander O, Riese H, Wilson JF, Campbell H, Rich SS, Psaty BM, Lu Y, Rotter JI, Guo X, Rice KM, Vollenweider P, Sundström J, Langenberg C, Tobin MD, Giedraitis V, Luan J, Tuomilehto J, Kutalik Z, Ripatti S, Salomaa V, Girotto G, Trompet S, Jukema JW, van der Harst P, Ridker PM, Giulianini F, Vitart V, Goel A, Watkins H, Harris SE, Deary IJ, van der Most PJ, Oldehinkel AJ, Keavney BD, Hayward C, Campbell A, Boehnke M, Scott LJ, Boutin T, Mamasoula C, Järvelin MR, Peters A, Gieger C, Lakatta EG, Cucca F, Hui J, Knekt P, Enroth S, De Borst MH, Polašek O, Concas MP, Catamo E, Cocca M, Li-Gao R, Hofer E, Schmidt H, Spedicati B, Waldenberger M, Strachan DP, Laan M, Teumer A, Dörr M, Gudnason V, Cook JP, Ruggiero D, Kolcic I, Boerwinkle E, Traglia M, Lehtimäki T, Raitakari OT, Johnson AD, Newton-Cheh C, Brown MJ, Dominiczak AF, Sever PJ, Poulter N, Chambers JC, Elosua R, Siscovick D, Esko T, Metspalu A, Strawbridge RJ, Laakso M, Hamsten A, Hottenga JJ, de Geus E, Morris AD, Palmer CNA, Nolte IM, Milaneschi Y, Marten J, Wright A, Zeggini E, Howson JMM, O'Donnell CJ, Spector T, Nalls MA, Simonsick EM, Liu Y, van Duijn CM, Butterworth AS, Danesh JN, Menni C, Wareham NJ, Khaw KT, Sun YV, Wilson PWF, Cho K, Visscher PM, Denny JC, Levy D, Edwards TL, Munroe PB, Snieder H, Warren HR. Genome-wide analysis in over 1 million individuals of European ancestry yields improved polygenic risk scores for blood pressure traits. Nat Genet 2024; 56:778-791. [PMID: 38689001 PMCID: PMC11096100 DOI: 10.1038/s41588-024-01714-w] [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: 03/01/2022] [Accepted: 03/11/2024] [Indexed: 05/02/2024]
Abstract
Hypertension affects more than one billion people worldwide. Here we identify 113 novel loci, reporting a total of 2,103 independent genetic signals (P < 5 × 10-8) from the largest single-stage blood pressure (BP) genome-wide association study to date (n = 1,028,980 European individuals). These associations explain more than 60% of single nucleotide polymorphism-based BP heritability. Comparing top versus bottom deciles of polygenic risk scores (PRSs) reveals clinically meaningful differences in BP (16.9 mmHg systolic BP, 95% CI, 15.5-18.2 mmHg, P = 2.22 × 10-126) and more than a sevenfold higher odds of hypertension risk (odds ratio, 7.33; 95% CI, 5.54-9.70; P = 4.13 × 10-44) in an independent dataset. Adding PRS into hypertension-prediction models increased the area under the receiver operating characteristic curve (AUROC) from 0.791 (95% CI, 0.781-0.801) to 0.826 (95% CI, 0.817-0.836, ∆AUROC, 0.035, P = 1.98 × 10-34). We compare the 2,103 loci results in non-European ancestries and show significant PRS associations in a large African-American sample. Secondary analyses implicate 500 genes previously unreported for BP. Our study highlights the role of increasingly large genomic studies for precision health research.
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Affiliation(s)
- Jacob M Keaton
- Center for Precision Health Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Zoha Kamali
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
- Department of Bioinformatics, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Tian Xie
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Ahmad Vaez
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
- Department of Bioinformatics, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Ariel Williams
- Center for Precision Health Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Slavina B Goleva
- Center for Precision Health Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Alireza Ani
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
- Department of Bioinformatics, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Evangelos Evangelou
- Department of Epidemiology and Biostatistics, Imperial College London, London, UK
- Department of Hygiene and Epidemiology, University of Ioannina Medical School, Ioannina, Greece
- Department of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Ioannina, Greece
| | - Jacklyn N Hellwege
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
- Biomedical Laboratory Research and Development, Tennessee Valley Healthcare System (626)/Vanderbilt University, Nashville, TN, USA
| | - Loic Yengo
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - William J Young
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Barts Heart Centre, St Bartholomew's Hospital, Barts Health NHS Trust, London, UK
| | - Matthew Traylor
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Department of Genetics, Novo Nordisk Research Centre Oxford, Oxford, UK
| | - Ayush Giri
- Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Division of Quantitative Sciences, Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Zhili Zheng
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
- Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Jian Zeng
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Daniel I Chasman
- Division of Preventive Medicine Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Andrew P Morris
- Centre for Genetics and Genomics Versus Arthritis, Centre for Musculoskeletal Research, The University of Manchester, Manchester, UK
| | - Mark J Caulfield
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- NIHR Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Shih-Jen Hwang
- Population Sciences Branch, NHLBI Framingham Heart Study, Framingham, MA, USA
- Department of Biostatistics, Boston University, Boston, MA, USA
| | - Jaspal S Kooner
- National Heart and Lung Institute, Imperial College London, London, UK
| | - David Conen
- Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - John R Attia
- Faculty of Health and Medicine, University of Newcastle, New Lambton Heights, Newcastle, New South Wales, Australia
| | - Alanna C Morrison
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Ruth J F Loos
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kati Kristiansson
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | | | - Andrew A Hicks
- Institute for Biomedicine, Eurac Research, Bolzano, Italy
- University of Lübeck, Lübeck, Germany
| | - Peter P Pramstaller
- Institute for Biomedicine, Eurac Research, Bolzano, Italy
- University of Lübeck, Lübeck, Germany
| | - Christopher P Nelson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Nilesh J Samani
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, Leicester, UK
| | - Lorenz Risch
- Faculty of Medical Sciences, Private University of the Principality of Liechtenstein, Triesen, Liechtenstein
- Department of Laboratory Medicine, Dr. Risch Anstalt, Vaduz, Liechtenstein
| | - Ulf Gyllensten
- Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Olle Melander
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
- Department of Internal Medicine, Skåne University Hospital, Malmö, Sweden
| | - Harriette Riese
- Interdisciplinary Center Psychopathology and Emotional Regulation (ICPE), Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - James F Wilson
- Centre for Global Health Research, Usher Institute, University of Edinburgh, Edinburgh, Scotland
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | - Harry Campbell
- Centre for Global Health Research, Usher Institute, University of Edinburgh, Edinburgh, Scotland
| | - Stephen S Rich
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, USA
| | - Bruce M Psaty
- Cardiovascular Health Research Unit, Departments of Medicine, Epidemiology, and Health Systems and Population Health, University of Washington, Seattle, WA, USA
| | - Yingchang Lu
- Vanderbilt Genetic Institute, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jerome I Rotter
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Xiuqing Guo
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Kenneth M Rice
- Department of Biostatistics, University of Washington, Seattle, WA, USA
| | - Peter Vollenweider
- Department of Medicine, Internal Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Johan Sundström
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
- The George Institute for Global Health, University of New South Wales, Sydney, New South Wales, Australia
| | - Claudia Langenberg
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
- Computational Medicine, Berlin Institute of Health (BIH) at Charité - Universitätsmedizin Berlin, Berlin, Germany
- Precision Healthcare University Research Institute, Queen Mary University of London, London, UK
| | - Martin D Tobin
- Department of Health Sciences, University of Leicester, Leicester, UK
- Leicester NIHR Respiratory Biomedical Research Centre, Glenfield Hospital, Leicester, UK
| | - Vilmantas Giedraitis
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Jian'an Luan
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - Jaakko Tuomilehto
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
- Department of Public Health, University of Helsinki, Helsinki, Finland
- Diabetes Research Group, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Zoltan Kutalik
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Samuli Ripatti
- Institute for Molecular Medicine Finland (FIMM), HiLIFE, University of Helsinki, Helsinki, Finland
- Department of Public Health, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Veikko Salomaa
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Giorgia Girotto
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
- Institute for Maternal and Child Health - IRCCS, Burlo Garofolo, Trieste, Italy
| | - Stella Trompet
- Department Internal Medicine, Section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, the Netherlands
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
| | - J Wouter Jukema
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
- Netherlands Heart Institute, Utrecht, the Netherlands
| | - Pim van der Harst
- Department of Cardiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Paul M Ridker
- Division of Preventive Medicine Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Franco Giulianini
- Division of Preventive Medicine Brigham and Women's Hospital, Boston, MA, USA
| | - Veronique Vitart
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | - Anuj Goel
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Hugh Watkins
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Sarah E Harris
- Lothian Birth Cohorts Group, Department of Psychology, The University of Edinburgh, Edinburgh, UK
| | - Ian J Deary
- Lothian Birth Cohorts Group, Department of Psychology, The University of Edinburgh, Edinburgh, UK
| | - Peter J van der Most
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Albertine J Oldehinkel
- Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Bernard D Keavney
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- Manchester Heart Institute, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Caroline Hayward
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
- Centre for Genomic and Experimental Medicine, IGC, University of Edinburgh, Edinburgh, UK
| | - Archie Campbell
- Centre for Genomic and Experimental Medicine, IGC, University of Edinburgh, Edinburgh, UK
- Usher Institute, University of Edinburgh, Edinburgh, UK
| | - Michael Boehnke
- Department of Biostatistics, Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Laura J Scott
- Department of Biostatistics, Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Thibaud Boutin
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | | | - Marjo-Riitta Järvelin
- Department of Epidemiology and Biostatistics, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK
- Center for Life Course Health Research, Faculty of Medicine, University of Oulu, Oulu, Finland
- Unit of Primary Health Care, Oulu University Hospital, OYS, Oulu, Finland
| | - Annette Peters
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Lehrstuhl für Epidemiologie, Institut für Medizinische Informationsverarbeitung, Biometrie und Epidemiologie (IBE), Ludwig-Maximilians-Universität München, Neuherberg, Germany
| | - Christian Gieger
- Research Unit of Molecular Epidemiology, Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Francesco Cucca
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Monserrato, Italy
| | - Jennie Hui
- Busselton Population Medical Research Institute, Perth, Western Australia, Australia
- School of Population and Global Health, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Paul Knekt
- Population Health Unit, Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Stefan Enroth
- Department of Immunology, Genetics, and Pathology, Biomedical Center, Science for Life Laboratory (SciLifeLab) Uppsala, Uppsala University, Uppsala, Sweden
| | - Martin H De Borst
- Department of Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Ozren Polašek
- University of Split School of Medicine, Split, Croatia
- Algebra University College, Zagreb, Croatia
| | - Maria Pina Concas
- Institute for Maternal and Child Health - IRCCS, Burlo Garofolo, Trieste, Italy
| | - Eulalia Catamo
- Institute for Maternal and Child Health - IRCCS, Burlo Garofolo, Trieste, Italy
| | - Massimiliano Cocca
- Institute for Maternal and Child Health - IRCCS, Burlo Garofolo, Trieste, Italy
| | - Ruifang Li-Gao
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Edith Hofer
- Clinical Division of Neurogeriatrics, Department of Neurology, Medical University of Graz, Graz, Austria
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria
| | - Helena Schmidt
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Graz, Austria
| | - Beatrice Spedicati
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
| | - Melanie Waldenberger
- Research Unit of Molecular Epidemiology, Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - David P Strachan
- Population Health Sciences Institute St George's, University of London, London, UK
| | - Maris Laan
- Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia
| | - Alexander Teumer
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany
| | - Marcus Dörr
- DZHK (German Center for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany
- Department of Internal Medicine B, University Medicine Greifswald, Greifswald, Germany
| | - Vilmundur Gudnason
- Icelandic Heart Association, Kopavogur, Iceland
- Faculty of Medicine, University of Iceland, Kopavogur, Iceland
| | - James P Cook
- Department of Health Data Science, University of Liverpool, Liverpool, UK
| | - Daniela Ruggiero
- IRCCS Neuromed, Pozzilli, Italy
- Institute of Genetics and Biophysics - 'A. Buzzati-Traverso', National Research Council of Italy, Naples, Italy
| | - Ivana Kolcic
- Algebra University College, Zagreb, Croatia
- Department of Public Health, University of Split School of Medicine, Split, Croatia
| | - Eric Boerwinkle
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Michela Traglia
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Terho Lehtimäki
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere, Finland
- Department of Clinical Chemistry, Finnish Cardiovascular Research Center - Tampere, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Olli T Raitakari
- Centre for Population Health Research, University of Turku and Turku University Hospital, Turku, Finland
- Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland
| | - Andrew D Johnson
- Population Sciences Branch, NHLBI Framingham Heart Study, Framingham, MA, USA
- The Framingham Heart Study, Framingham, MA, USA
| | - Christopher Newton-Cheh
- Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Cardiovascular Research Center and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Morris J Brown
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Anna F Dominiczak
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Peter J Sever
- International Centre for Circulatory Health, Imperial College London, London, UK
| | - Neil Poulter
- School of Public Health, Imperial College London, London, UK
| | - John C Chambers
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Roberto Elosua
- Hospital del Mar Research Institute (IMIM), Barcelona, Spain
- CIBER Enfermedades Cardiovasculares (CIBERCV), Barcelona, Spain
- Faculty of Medicine, University of Vic-Central University of Catalonia (UVic-UCC), Vic, Spain
| | | | - Tõnu Esko
- Institute of Genomics, University of Tartu, Tartu, Estonia
| | | | - Rona J Strawbridge
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK
- Health Data Research UK, Glasgow, UK
- Division of Cardiovascular Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Markku Laakso
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, Finland
- Kuopio University Hospital, Kuopio, Finland
| | - Anders Hamsten
- Division of Cardiovascular Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jouke-Jan Hottenga
- Department of Biological Psychology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, the Netherlands
| | - Eco de Geus
- Department of Biological Psychology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, the Netherlands
- Amsterdam Public Health Research Institute, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Andrew D Morris
- Data Science, University of Edinburgh, Edinburgh, UK
- Health Data Research UK, London, UK
| | - Colin N A Palmer
- Population Health and Genomics, School of Medicine, University of Dundee, Dundee, UK
| | - Ilja M Nolte
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Yuri Milaneschi
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Psychiatry, Amsterdam Public Health Research Institute, Amsterdam, the Netherlands
| | - Jonathan Marten
- Centre for Genomic and Experimental Medicine, IGC, University of Edinburgh, Edinburgh, UK
| | - Alan Wright
- Centre for Genomic and Experimental Medicine, IGC, University of Edinburgh, Edinburgh, UK
| | - Eleftheria Zeggini
- Institute of Translational Genomics, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- Technical University of Munich (TUM) and Klinikum Rechts der Isar, TUM School of Medicine, Munich, Germany
| | - Joanna M M Howson
- Department of Genetics, Novo Nordisk Research Centre Oxford, Oxford, UK
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Christopher J O'Donnell
- VA Boston Healthcare System, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tim Spector
- Department of Twin Research, King's College London, London, UK
| | - Mike A Nalls
- Center for Alzheimer's and Related Dementias, NIA/NINDS, NIH, Bethesda, MD, USA
- Laboratory of Neurogenetics, NIA, NIH, Bethesda, MD, USA
- DataTecnica LLC, Washington, DC, USA
| | - Eleanor M Simonsick
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Yongmei Liu
- Division of Cardiology, Duke University School of Medicine, Durham, NC, USA
| | - Cornelia M van Duijn
- Nuffield Department of Population Health, Big Data Institute, University of Oxford, Oxford, UK
| | - Adam S Butterworth
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, UK
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, UK
- Victor Phillip Dahdaleh Heart and Lung Research Institute, University of Cambridge, Cambridge, UK
- National Institute for Health and Care Research Blood and Transplant Research Unit in Donor Health and Behaviour, University of Cambridge, Cambridge, UK
| | - John N Danesh
- British Heart Foundation Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, UK
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, UK
- Victor Phillip Dahdaleh Heart and Lung Research Institute, University of Cambridge, Cambridge, UK
- National Institute for Health and Care Research Blood and Transplant Research Unit in Donor Health and Behaviour, University of Cambridge, Cambridge, UK
- Department of Human Genetics, The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Cristina Menni
- Department of Twin Research and Genetic Epidemiology, London, UK
| | | | - Kay-Tee Khaw
- Department of Public Health and Primary Care, University of Cambridge School of Clinical Medicine, Cambridge, UK
| | - Yan V Sun
- Department of Epidemiology, Emory University Rollins School of Public Health, Atlanta, Georgia, USA
- VA Atlanta Healthcare System, Decatur, GA, USA
| | - Peter W F Wilson
- Emory Clinical Cardiovascular Research Institute, Atlanta, GA, USA
- Massachusetts Veterans Epidemiology Research and Information Center (MAVERIC), VA Boston Healthcare System, Boston, MA, USA
| | - Kelly Cho
- Division of Aging, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
- Cardiovascular Health Research Unit, Departments of Medicine and Epidemiology, University of Washington, Seattle, WA, USA
| | - Peter M Visscher
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Joshua C Denny
- Center for Precision Health Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Daniel Levy
- Population Sciences Branch, NHLBI Framingham Heart Study, Framingham, MA, USA
- Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland
| | - Todd L Edwards
- Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Patricia B Munroe
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- NIHR Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Harold Snieder
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Helen R Warren
- Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
- NIHR Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
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Thagun C, Suzuki T, Kodama Y, Numata K. C-Terminal Domain Controls Protein Quality and Secretion of Spider Silk in Tobacco Cells. Adv Biol (Weinh) 2023; 7:e2300011. [PMID: 37409415 DOI: 10.1002/adbi.202300011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 05/15/2023] [Indexed: 07/07/2023]
Abstract
The remarkable mechanical strength and extensibility of spider dragline silk spidroins are attributed to the major ampullate silk proteins (MaSp). Although fragmented MaSp molecules have been extensively produced in various heterologous expression platforms for biotechnological applications, complete MaSp molecules are required to achieve instinctive spinning of spidroin fibers from aqueous solutions. Here, a plant cell-based expression platform for extracellular production of the entire MaSp2 protein is developed, which exhibits remarkable self-assembly properties to form spider silk nanofibrils. The engineered transgenic Bright-yellow 2 (BY-2) cell lines overexpressing recombinant secretory MaSp2 proteins yield 0.6-1.3 µg L-1 at 22 days post-inoculation, which is four times higher than those of cytosolic expressions. However, only 10-15% of these secretory MaSp2 proteins are discharged into the culture media. Surprisingly, expression of functional domain-truncated MaSp2 proteins lacking the C-terminal domain in transgenic BY-2 cells increases recombinant protein secretion incredibly, from 0.9 to 2.8 mg L-1 per day within 7 days. These findings demonstrate significant improvement in the extracellular production of recombinant biopolymers such as spider silk spidroins using plant cells. In addition, the results reveal the regulatory roles of the C-terminal domain of MaSp2 proteins in controlling their protein quality and secretion.
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Affiliation(s)
- Chonprakun Thagun
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, 321-8505, Japan
| | - Tomohiro Suzuki
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, 321-8505, Japan
| | - Yutaka Kodama
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, 321-8505, Japan
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
| | - Keiji Numata
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
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Perfilov MM, Zaitseva ER, Baleeva NS, Kublitski VS, Smirnov AY, Bogdanova YA, Krasnova SA, Myasnyanko IN, Mishin AS, Baranov MS. Meta-CF 3-Substituted Analogues of the GFP Chromophore with Remarkable Solvatochromism. Int J Mol Sci 2023; 24:9923. [PMID: 37373071 DOI: 10.3390/ijms24129923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
In this work, we have shown that the introduction of a trifluoromethyl group into the me-ta-position of arylidene imidazolones (GFP chromophore core) leads to a dramatic increase in their fluorescence in nonpolar and aprotic media. The presence of a pronounced solvent-dependent gradation of fluorescence intensity makes it possible to use these substances as fluorescent polarity sensors. In particular, we showed that one of the created compounds could be used for selective labeling of the endoplasmic reticulum of living cells.
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Affiliation(s)
- Maxim M Perfilov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Elvira R Zaitseva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Nadezhda S Baleeva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Vadim S Kublitski
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Alexander Yu Smirnov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
- Center of Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoi Blvd. 30, Bld. 1, Moscow 121205, Russia
| | - Yulia A Bogdanova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Svetlana A Krasnova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Ivan N Myasnyanko
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Alexander S Mishin
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
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4
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Krajewska M, Szewczyk A, Kulawiak B, Koprowski P. Pharmacological Characterization of a Recombinant Mitochondrial ROMK2 Potassium Channel Expressed in Bacteria and Reconstituted in Planar Lipid Bilayers. MEMBRANES 2023; 13:360. [PMID: 36984747 PMCID: PMC10052516 DOI: 10.3390/membranes13030360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 06/18/2023]
Abstract
In the inner mitochondrial membrane, several potassium channels that play a role in cell life and death have been identified. One of these channels is the ATP-regulated potassium channel (mitoKATP). The ROMK2 potassium channel is a potential molecular component of the mitoKATP channel. The current study aimed to investigate the pharmacological modulation of the activity of the ROMK2 potassium channel expressed in Escherichia coli bacteria. ROMK2 was solubilized in polymer nanodiscs and incorporated in planar lipid bilayers. The impact of known mitoKATP channel modulators on the activity of the ROMK2 was characterized. We found that the ROMK2 channel was activated by the mitoKATP channel opener diazoxide and blocked by mitoKATP inhibitors such as ATP/Mg2+, 5-hydroxydecanoic acid, and antidiabetic sulfonylurea glibenclamide. These results indicate that the ROMK2 potassium protein may be a pore-forming subunit of mitoKATP and that the impact of channel modulators is not related to the presence of accessory proteins.
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Affiliation(s)
- Milena Krajewska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
- Interdisciplinary Laboratory of Molecular Biology and Biophysics, Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Piotr Koprowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
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5
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Orthogonally-tunable and ER-targeting fluorophores detect avian influenza virus early infection. Nat Commun 2022; 13:5841. [PMID: 36192426 PMCID: PMC9529605 DOI: 10.1038/s41467-022-33586-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 09/23/2022] [Indexed: 11/08/2022] Open
Abstract
Cell-based assays can monitor virus infection at a single-cell level with high sensitivity and cost-efficiency. For this purpose, it is crucial to develop molecular probes that respond selectively to physiological changes in live cells. We report stimuli-responsive light-emitters built on a T-shaped benzimidazole platform, and consecutive borylation reactions to produce a library of homologs displaying systematic changes in fluorescence quantum yield and environmental sensitivity. We find that certain fluorophores localize selectively at the endoplasmic reticulum, and interact with proteins involved in the stress signaling pathways. Notably, the mono-borylated compound responds selectively to the stress conditions by enhancing fluorescence, and detects avian influenza virus infection at the single-cell level. Our findings demonstrate the unprecedented practical utility of the stress-responsive molecular probes to differentiate cellular states for early diagnosis. Methods to detect and distinguish the early stage of viral infection often involve complicated and time-consuming protocols. Here, the authors disclose a class of fluorescent molecules that enable fast detection of avian influenza virus infection by selectively localizing at the endoplasmic reticulum in the cell.
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Song L, Barrett DG, Cox KL, Efanov AM, Syed SK, Tomandl D, Willard FS. A High-Throughput Assay for the Pancreatic Islet Beta-Cell Potassium Channel: Use in the Pharmacological Characterization of Insulin Secretagogues Identified from Phenotypic Screening. Assay Drug Dev Technol 2020; 19:27-37. [PMID: 33164547 DOI: 10.1089/adt.2020.1011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Phenotypic screening is a neoclassical approach for drug discovery. We conducted phenotypic screening for insulin secretion enhancing agents using INS-1E insulinoma cells as a model system for pancreatic beta-cells. A principal regulator of insulin secretion in beta-cells is the metabolically regulated potassium channel Kir6.2/SUR1 complex. To characterize hit compounds, we developed an assay to quantify endogenous potassium channel activity in INS-1E cells. We quantified ligand-regulated potassium channel activity in INS-1E cells using fluorescence imaging and thallium flux. Potassium channel activity was metabolically regulated and coupled to insulin secretion. The pharmacology of channel opening agents (diazoxide) and closing agents (sulfonylureas) was used to validate the applicability of the assay. A precise high-throughput assay was enabled, and phenotypic screening hits were triaged to enable a higher likelihood of discovering chemical matter with novel and useful mechanisms of action.
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Affiliation(s)
- Luyan Song
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - David G Barrett
- Discovery Chemistry, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Karen L Cox
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Alexander M Efanov
- Diabetes and Complications Therapeutic Area, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Samreen K Syed
- Diabetes and Complications Therapeutic Area, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Dirk Tomandl
- Discovery Informatics, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Francis S Willard
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
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7
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Mohamed E, Sierra RA, Trillo-Tinoco J, Cao Y, Innamarato P, Payne KK, de Mingo Pulido A, Mandula J, Zhang S, Thevenot P, Biswas S, Abdalla SK, Costich TL, Hänggi K, Anadon CM, Flores ER, Haura EB, Mehrotra S, Pilon-Thomas S, Ruffell B, Munn DH, Cubillos-Ruiz JR, Conejo-Garcia JR, Rodriguez PC. The Unfolded Protein Response Mediator PERK Governs Myeloid Cell-Driven Immunosuppression in Tumors through Inhibition of STING Signaling. Immunity 2020; 52:668-682.e7. [PMID: 32294407 DOI: 10.1016/j.immuni.2020.03.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 01/14/2020] [Accepted: 03/12/2020] [Indexed: 12/21/2022]
Abstract
The primary mechanisms supporting immunoregulatory polarization of myeloid cells upon infiltration into tumors remain largely unexplored. Elucidation of these signals could enable better strategies to restore protective anti-tumor immunity. Here, we investigated the role of the intrinsic activation of the PKR-like endoplasmic reticulum (ER) kinase (PERK) in the immunoinhibitory actions of tumor-associated myeloid-derived suppressor cells (tumor-MDSCs). PERK signaling increased in tumor-MDSCs, and its deletion transformed MDSCs into myeloid cells that activated CD8+ T cell-mediated immunity against cancer. Tumor-MDSCs lacking PERK exhibited disrupted NRF2-driven antioxidant capacity and impaired mitochondrial respiratory homeostasis. Moreover, reduced NRF2 signaling in PERK-deficient MDSCs elicited cytosolic mitochondrial DNA elevation and, consequently, STING-dependent expression of anti-tumor type I interferon. Reactivation of NRF2 signaling, conditional deletion of STING, or blockade of type I interferon receptor I restored the immunoinhibitory potential of PERK-ablated MDSCs. Our findings demonstrate the pivotal role of PERK in tumor-MDSC functionality and unveil strategies to reprogram immunosuppressive myelopoiesis in tumors to boost cancer immunotherapy.
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Affiliation(s)
- Eslam Mohamed
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Rosa A Sierra
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | | | - Yu Cao
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Patrick Innamarato
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Kyle K Payne
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Alvaro de Mingo Pulido
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Jessica Mandula
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Shuzhong Zhang
- Center for Microbial Pathogenesis, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Paul Thevenot
- Institute of Translational Research, Ochsner Health System, New Orleans, LA 70121, USA
| | - Subir Biswas
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Sarah K Abdalla
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Tara Lee Costich
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Kay Hänggi
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Carmen M Anadon
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Elsa R Flores
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Eric B Haura
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Shikhar Mehrotra
- Department of Surgery, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Shari Pilon-Thomas
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Brian Ruffell
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - David H Munn
- Department of Pediatrics, Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA
| | - Juan R Cubillos-Ruiz
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY 10065, USA; Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10065, USA
| | - Jose R Conejo-Garcia
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
| | - Paulo C Rodriguez
- Department of Immunology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA.
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9
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Wang T, Nakagawa S, Miyake T, Setsu G, Kunisue S, Goto K, Hirasawa A, Okamura H, Yamaguchi Y, Doi M. Identification and functional characterisation of N-linked glycosylation of the orphan G protein-coupled receptor Gpr176. Sci Rep 2020; 10:4429. [PMID: 32157140 PMCID: PMC7064540 DOI: 10.1038/s41598-020-61370-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 02/26/2020] [Indexed: 12/13/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are important drug targets with diverse therapeutic applications. However, there are still more than a hundred orphan GPCRs, whose protein functions and biochemical features remain unidentified. Gpr176 encodes a class-A orphan GPCR that has a role in circadian clock regulation in mouse hypothalamus and is also implicated in human breast cancer transcriptional response. Here we show that Gpr176 is N-glycosylated. Peptide-N-glycosidase treatment of mouse hypothalamus extracts revealed that endogenous Gpr176 undergoes N-glycosylation. Using a heterologous expression system, we show that N-glycosylation occurs at four conserved asparagine residues in the N-terminal region of Gpr176. Deficient N-glycosylation due to mutation of these residues reduced the protein expression of Gpr176. At the molecular function level, Gpr176 has constitutive, agonist-independent activity that leads to reduced cAMP synthesis. Although deficient N-glycosylation did not compromise this intrinsic activity, the resultant reduction in protein expression was accompanied by attenuation of cAMP-repressive activity in the cells. We also demonstrate that human GPR176 is N-glycosylated. Importantly, missense variations in the conserved N-glycosylation sites of human GPR176 (rs1473415441; rs761894953) affected N-glycosylation and thereby attenuated protein expression and cAMP-repressive activity in the cells. We show that N-glycosylation is a prerequisite for the efficient protein expression of functional Gpr176/GPR176.
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Affiliation(s)
- Tianyu Wang
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Shumpei Nakagawa
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Takahito Miyake
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Genzui Setsu
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Sumihiro Kunisue
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Kaoru Goto
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Akira Hirasawa
- Department of Genomic Drug Discovery Science, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Hitoshi Okamura
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan.,Laboratory of Molecular Brain Science, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Yoshiaki Yamaguchi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan
| | - Masao Doi
- Department of Systems Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyō-ku, Kyoto, 606-8501, Japan.
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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Sikimic J, McMillen TS, Bleile C, Dastvan F, Quast U, Krippeit-Drews P, Drews G, Bryan J. ATP binding without hydrolysis switches sulfonylurea receptor 1 (SUR1) to outward-facing conformations that activate K ATP channels. J Biol Chem 2018; 294:3707-3719. [PMID: 30587573 DOI: 10.1074/jbc.ra118.005236] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 12/19/2018] [Indexed: 11/06/2022] Open
Abstract
Neuroendocrine-type ATP-sensitive K+ (KATP) channels are metabolite sensors coupling membrane potential with metabolism, thereby linking insulin secretion to plasma glucose levels. They are octameric complexes, (SUR1/Kir6.2)4, comprising sulfonylurea receptor 1 (SUR1 or ABCC8) and a K+-selective inward rectifier (Kir6.2 or KCNJ11). Interactions between nucleotide-, agonist-, and antagonist-binding sites affect channel activity allosterically. Although it is hypothesized that opening these channels requires SUR1-mediated MgATP hydrolysis, we show here that ATP binding to SUR1, without hydrolysis, opens channels when nucleotide antagonism on Kir6.2 is minimized and SUR1 mutants with increased ATP affinities are used. We found that ATP binding is sufficient to switch SUR1 alone between inward- or outward-facing conformations with low or high dissociation constant, KD , values for the conformation-sensitive channel antagonist [3H]glibenclamide ([3H]GBM), indicating that ATP can act as a pure agonist. Assembly with Kir6.2 reduced SUR1's KD for [3H]GBM. This reduction required the Kir N terminus (KNtp), consistent with KNtp occupying a "transport cavity," thus positioning it to link ATP-induced SUR1 conformational changes to channel gating. Moreover, ATP/GBM site coupling was constrained in WT SUR1/WT Kir6.2 channels; ATP-bound channels had a lower KD for [3H]GBM than ATP-bound SUR1. This constraint was largely eliminated by the Q1179R neonatal diabetes-associated mutation in helix 15, suggesting that a "swapped" helix pair, 15 and 16, is part of a structural pathway connecting the ATP/GBM sites. Our results suggest that ATP binding to SUR1 biases KATP channels toward open states, consistent with SUR1 variants with lower KD values causing neonatal diabetes, whereas increased KD values cause congenital hyperinsulinism.
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Affiliation(s)
- Jelena Sikimic
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Timothy S McMillen
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
| | - Cita Bleile
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Frank Dastvan
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
| | - Ulrich Quast
- Department of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, D-72074 Tübingen, Germany
| | - Peter Krippeit-Drews
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Gisela Drews
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Joseph Bryan
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
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12
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McClenaghan C, Hanson A, Sala-Rabanal M, Roessler HI, Josifova D, Grange DK, van Haaften G, Nichols CG. Cantu syndrome-associated SUR2 (ABCC9) mutations in distinct structural domains result in K ATP channel gain-of-function by differential mechanisms. J Biol Chem 2017; 293:2041-2052. [PMID: 29275331 DOI: 10.1074/jbc.ra117.000351] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/20/2017] [Indexed: 12/25/2022] Open
Abstract
The complex disorder Cantu syndrome (CS) arises from gain-of-function mutations in either KCNJ8 or ABCC9, the genes encoding the Kir6.1 and SUR2 subunits of ATP-sensitive potassium (KATP) channels, respectively. Recent reports indicate that such mutations can increase channel activity by multiple molecular mechanisms. In this study, we determined the mechanism by which KATP function is altered by several substitutions in distinct structural domains of SUR2: D207E in the intracellular L0-linker and Y985S, G989E, M1060I, and R1154Q/R1154W in TMD2. We engineered substitutions at their equivalent positions in rat SUR2A (D207E, Y981S, G985E, M1056I, and R1150Q/R1150W) and investigated functional consequences using macroscopic rubidium (86Rb+) efflux assays and patch-clamp electrophysiology. Our results indicate that D207E increases KATP channel activity by increasing intrinsic stability of the open state, whereas the cluster of Y981S/G985E/M1056I substitutions, as well as R1150Q/R1150W, augmented Mg-nucleotide activation. We also tested the responses of these channel variants to inhibition by the sulfonylurea drug glibenclamide, a potential pharmacotherapy for CS. None of the D207E, Y981S, G985E, or M1056I substitutions had a significant effect on glibenclamide sensitivity. However, Gln and Trp substitution at Arg-1150 significantly decreased glibenclamide potency. In summary, these results provide additional confirmation that mutations in CS-associated SUR2 mutations result in KATP gain-of-function. They help link CS genotypes to phenotypes and shed light on the underlying molecular mechanisms, including consequences for inhibitory drug sensitivity, insights that may inform the development of therapeutic approaches to manage CS.
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Affiliation(s)
| | - Alex Hanson
- From the Departments of Cell Biology and Physiology and
| | | | - Helen I Roessler
- the Department of Medical Genetics, University Medical Center Utrecht, Postbus 85500, 3508 GA Utrecht, The Netherlands, and
| | - Dragana Josifova
- the Guy's and St. Thomas NHS Trust, Clinical Genetics Department, Great Maze Pond, London SE1 9RT, United Kingdom
| | - Dorothy K Grange
- Pediatrics, Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Gijs van Haaften
- the Department of Medical Genetics, University Medical Center Utrecht, Postbus 85500, 3508 GA Utrecht, The Netherlands, and
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13
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Li N, Wu JX, Ding D, Cheng J, Gao N, Chen L. Structure of a Pancreatic ATP-Sensitive Potassium Channel. Cell 2017; 168:101-110.e10. [DOI: 10.1016/j.cell.2016.12.028] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 10/20/2022]
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14
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McDonald L, Liu B, Taraboletti A, Whiddon K, Shriver LP, Konopka M, Liu Q, Pang Y. Fluorescent flavonoids for endoplasmic reticulum cell imaging. J Mater Chem B 2016. [PMID: 28626582 DOI: 10.1039/c6tb02456d] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Visualization of subcellular organelles in vivo is critical for basic biomedical research and clinical applications. Two new flavonoids with an amide substituent were synthesized and characterized. The flavonoids were nearly non-fluorescent in aqueous environment, but exhibited two emission peaks (one λem at 495-536 nm and the other at 570-587 nm) in organic solvents, which were assigned to the excited normal (N*) and tautomer (T*) emission. When the dyes were examined on oligodendrocyte cells, they were found to selectively accumulate in the endoplasmic reticulum (ER), a eukaryotic organelle involved in lipid and protein synthesis, giving fluorescence turn-on. The ER-selective flavonoids could be a valuable tool due to its low molecular mass (<500), large Stokes' shift, low toxicity, and biocompatibility.
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Affiliation(s)
- Lucas McDonald
- Department of Chemistry, University of Akron, Akron, Ohio 44325, USA
| | - Bin Liu
- Department of Chemistry, University of Akron, Akron, Ohio 44325, USA
| | | | - Kyle Whiddon
- Department of Chemistry, University of Akron, Akron, Ohio 44325, USA
| | - Leah P Shriver
- Department of Chemistry, University of Akron, Akron, Ohio 44325, USA.,Department of Biology, University of Akron, Akron, Ohio 44325, USA
| | - Michael Konopka
- Department of Chemistry, University of Akron, Akron, Ohio 44325, USA
| | - Qin Liu
- Department of Biology, University of Akron, Akron, Ohio 44325, USA
| | - Yi Pang
- Department of Chemistry, University of Akron, Akron, Ohio 44325, USA
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15
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Kaiser G, De Niz M, Zuber B, Burda PC, Kornmann B, Heussler VT, Stanway RR. High resolution microscopy reveals an unusual architecture of the Plasmodium berghei endoplasmic reticulum. Mol Microbiol 2016; 102:775-791. [PMID: 27566438 DOI: 10.1111/mmi.13490] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2016] [Indexed: 02/04/2023]
Abstract
To fuel the tremendously fast replication of Plasmodium liver stage parasites, the endoplasmic reticulum (ER) must play a critical role as a major site of protein and lipid biosynthesis. In this study, we analysed the parasite's ER morphology and function. Previous studies exploring the parasite ER have mainly focused on the blood stage. Visualizing the Plasmodium berghei ER during liver stage development, we found that the ER forms an interconnected network throughout the parasite with perinuclear and peripheral localizations. Surprisingly, we observed that the ER additionally generates huge accumulations. Using stimulated emission depletion microscopy and serial block-face scanning electron microscopy, we defined ER accumulations as intricate dense networks of ER tubules. We provide evidence that these accumulations are functional subdivisions of the parasite ER, presumably generated in response to elevated demands of the parasite, potentially consistent with ER stress. Compared to higher eukaryotes, Plasmodium parasites have a fundamentally reduced unfolded protein response machinery for reacting to ER stress. Accordingly, parasite development is greatly impaired when ER stress is applied. As parasites appear to be more sensitive to ER stress than are host cells, induction of ER stress could potentially be used for interference with parasite development.
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Affiliation(s)
- Gesine Kaiser
- Institute of Cell Biology, University of Bern, Baltzerstr. 4, 3012 Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland
| | - Mariana De Niz
- Institute of Cell Biology, University of Bern, Baltzerstr. 4, 3012 Bern, Switzerland.,Wellcome Trust Center for Molecular Parasitology, G12 8TA, Glasgow, UK
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland
| | - Paul-Christian Burda
- Institute of Cell Biology, University of Bern, Baltzerstr. 4, 3012 Bern, Switzerland
| | - Benoît Kornmann
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, 8093, Zürich, Switzerland
| | - Volker T Heussler
- Institute of Cell Biology, University of Bern, Baltzerstr. 4, 3012 Bern, Switzerland
| | - Rebecca R Stanway
- Institute of Cell Biology, University of Bern, Baltzerstr. 4, 3012 Bern, Switzerland
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16
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Molecular action of sulphonylureas on KATP channels: a real partnership between drugs and nucleotides. Biochem Soc Trans 2016; 43:901-7. [PMID: 26517901 PMCID: PMC4613533 DOI: 10.1042/bst20150096] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sulphonylureas stimulate insulin secretion from pancreatic β-cells primarily by closing ATP-sensitive K+ channels in the β-cell plasma membrane. The mechanism of channel inhibition by these drugs is unusually complex. As direct inhibitors of channel activity, sulphonylureas act only as partial antagonists at therapeutic concentrations. However, they also exert an additional indirect inhibitory effect via modulation of nucleotide-dependent channel gating. In this review, we summarize current knowledge and recent advances in our understanding of the molecular mechanism of action of these drugs.
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17
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Qian L, Zhang CW, Mao Y, Li L, Gao N, Lim KL, Xu QH, Yao SQ. Two-Photon Enzymatic Probes Visualizing Sub-cellular/Deep-brain Caspase Activities in Neurodegenerative Models. Sci Rep 2016; 6:26385. [PMID: 27210613 PMCID: PMC4876444 DOI: 10.1038/srep26385] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 04/29/2016] [Indexed: 01/23/2023] Open
Abstract
Caspases work as a double-edged sword in maintaining cell homeostasis. Highly regulated caspase activities are essential during animal development, but dysregulation might lead to different diseases, e.g. extreme caspase activation is known to promote neurodegeneration. At present, visualization of caspase activation has mostly remained at the cellular level, in part due to a lack of cell-permeable imaging probes capable of direct, real-time investigations of endogenous caspase activities in deep tissues. Herein, we report a suite of two-photon, small molecule/peptide probes which enable sensitive and dynamic imaging of individual caspase activities in neurodegenerative models under physiological conditions. With no apparent toxicity and the ability of imaging endogenous caspases both in different subcellular organelles of mammalian cells and in brain tissues, these probes serve as complementary tools to conventional histological analysis. They should facilitate future explorations of caspases at molecular, cellular and organism levels and inspire development of novel two-photon probes against other enzymes.
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Affiliation(s)
- Linghui Qian
- Department of Chemistry, National University of Singapore, 117543, Singapore
| | - Cheng-Wu Zhang
- Key Laboratory of Flexible Electronics &Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816, P. R. China.,National Neuroscience Institute, 308433, Singapore
| | - Yanli Mao
- Department of Chemistry, National University of Singapore, 117543, Singapore
| | - Lin Li
- Key Laboratory of Flexible Electronics &Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Nengyue Gao
- Department of Chemistry, National University of Singapore, 117543, Singapore
| | | | - Qing-Hua Xu
- Department of Chemistry, National University of Singapore, 117543, Singapore
| | - Shao Q Yao
- Department of Chemistry, National University of Singapore, 117543, Singapore
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18
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Abstract
KATP channels are integral to the functions of many cells and tissues. The use of electrophysiological methods has allowed for a detailed characterization of KATP channels in terms of their biophysical properties, nucleotide sensitivities, and modification by pharmacological compounds. However, even though they were first described almost 25 years ago (Noma 1983, Trube and Hescheler 1984), the physiological and pathophysiological roles of these channels, and their regulation by complex biological systems, are only now emerging for many tissues. Even in tissues where their roles have been best defined, there are still many unanswered questions. This review aims to summarize the properties, molecular composition, and pharmacology of KATP channels in various cardiovascular components (atria, specialized conduction system, ventricles, smooth muscle, endothelium, and mitochondria). We will summarize the lessons learned from available genetic mouse models and address the known roles of KATP channels in cardiovascular pathologies and how genetic variation in KATP channel genes contribute to human disease.
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Affiliation(s)
- Monique N Foster
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - William A Coetzee
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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19
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Rivera-Fuentes P, Lippard SJ. Metal-based optical probes for live cell imaging of nitroxyl (HNO). Acc Chem Res 2015; 48:2927-34. [PMID: 26550842 DOI: 10.1021/acs.accounts.5b00388] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nitroxyl (HNO) is a biological signaling agent that displays distinctive reactivity compared to nitric oxide (NO). As a consequence, these two reactive nitrogen species trigger different physiological responses. Selective detection of HNO over NO has been a challenge for chemists, and several fluorogenic molecular probes have been recently developed with that goal in mind. Common constructs take advantage of the HNO-induced reduction of Cu(II) to Cu(I). The sensing mechanism of such probes relies on the ability of the unpaired electron in a d orbital of the Cu(II) center to quench the fluorescence of a photoemissive ligand by either an electron or energy transfer mechanism. Experimental and theoretical mechanistic studies suggest that proton-coupled electron transfer mediates this process, and careful tuning of the copper coordination environment has led to sensors with optimized selectivity and kinetics. The current optical probes cover the visible and near-infrared regions of the spectrum. This palette of sensors comprises structurally and functionally diverse fluorophores such as coumarin (blue/green emission), boron dipyrromethane (BODIPY, green emission), benzoresorufin (red emission), and dihydroxanthenes (near-infrared emission). Many of these sensors have been successfully applied to detect HNO production in live cells. For example, copper-based optical probes have been used to detect HNO production in live mammalian cells that have been treated with H2S and various nitrosating agents. These studies have established a link between HSNO, the smallest S-nitrosothiol, and HNO. In addition, a near-infrared HNO sensor has been used to perform multicolor/multianalyte microscopy, revealing that exogenously applied HNO elevates the concentration of intracellular mobile zinc. This mobilization of zinc ions is presumably a consequence of nitrosation of cysteine residues in zinc-chelating proteins such as metallothionein. Future challenges for the optical imaging of HNO include devising probes that can detect HNO reversibly, especially because ratiometric imaging can only report equilibrium concentrations when the sensing event is reversible. Another important aspect that needs to be addressed is the creation of probes that can sense HNO in specific subcellular locations. These tools would be useful to identify the organelles in which HNO is produced in mammalian cells and probe the intracellular signaling networks in which this reactive nitrogen species is involved. In addition, near-infrared emitting probes might be applied to detect HNO in thicker specimens, such as acute tissue slices and even live animals, enabling the investigation of the roles of HNO in physiological or pathological conditions in multicellular systems.
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Affiliation(s)
- Pablo Rivera-Fuentes
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Stephen J. Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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20
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Ahmad A, Khan RMA, Alkharfy KM. Development and Validation of RP-HPLC Method for Simultaneous Estimation of Glibenclamide and Thymoquinone in Rat Plasma and Its Application to Pharmacokinetics. ACTA CHROMATOGR 2015. [DOI: 10.1556/achrom.27.2015.3.3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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21
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Proks P, de Wet H, Ashcroft FM. Sulfonylureas suppress the stimulatory action of Mg-nucleotides on Kir6.2/SUR1 but not Kir6.2/SUR2A KATP channels: a mechanistic study. ACTA ACUST UNITED AC 2015; 144:469-86. [PMID: 25348414 PMCID: PMC4210431 DOI: 10.1085/jgp.201411222] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sulfonylureas suppress the stimulatory effect of Mg-nucleotides on recombinant β-cell (Kir6.2/SUR1) but not cardiac (Kir6.2/SUR2A) KATP channels. Sulfonylureas, which stimulate insulin secretion from pancreatic β-cells, are widely used to treat both type 2 diabetes and neonatal diabetes. These drugs mediate their effects by binding to the sulfonylurea receptor subunit (SUR) of the ATP-sensitive K+ (KATP) channel and inducing channel closure. The mechanism of channel inhibition is unusually complex. First, sulfonylureas act as partial antagonists of channel activity, and second, their effect is modulated by MgADP. We analyzed the molecular basis of the interactions between the sulfonylurea gliclazide and Mg-nucleotides on β-cell and cardiac types of KATP channel (Kir6.2/SUR1 and Kir6.2/SUR2A, respectively) heterologously expressed in Xenopus laevis oocytes. The SUR2A-Y1206S mutation was used to confer gliclazide sensitivity on SUR2A. We found that both MgATP and MgADP increased gliclazide inhibition of Kir6.2/SUR1 channels and reduced inhibition of Kir6.2/SUR2A-Y1206S. The latter effect can be attributed to stabilization of the cardiac channel open state by Mg-nucleotides. Using a Kir6.2 mutation that renders the KATP channel insensitive to nucleotide inhibition (Kir6.2-G334D), we showed that gliclazide abolishes the stimulatory effects of MgADP and MgATP on β-cell KATP channels. Detailed analysis suggests that the drug both reduces nucleotide binding to SUR1 and impairs the efficacy with which nucleotide binding is translated into pore opening. Mutation of one (or both) of the Walker A lysines in the catalytic site of the nucleotide-binding domains of SUR1 may have a similar effect to gliclazide on MgADP binding and transduction, but it does not appear to impair MgATP binding. Our results have implications for the therapeutic use of sulfonylureas.
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Affiliation(s)
- Peter Proks
- Oxford Centre for Gene Function and Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, England, UK Oxford Centre for Gene Function and Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, England, UK
| | - Heidi de Wet
- Oxford Centre for Gene Function and Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, England, UK Oxford Centre for Gene Function and Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, England, UK
| | - Frances M Ashcroft
- Oxford Centre for Gene Function and Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, England, UK Oxford Centre for Gene Function and Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, England, UK
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22
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Kistler HC, Broz K. Cellular compartmentalization of secondary metabolism. Front Microbiol 2015; 6:68. [PMID: 25709603 PMCID: PMC4321598 DOI: 10.3389/fmicb.2015.00068] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/20/2015] [Indexed: 12/26/2022] Open
Abstract
Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g., amino acids, acetyl CoA, NADPH), enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported.
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Affiliation(s)
- H. Corby Kistler
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, University of MinnesotaSaint Paul, MN, USA
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23
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Devaraneni PK, Martin GM, Olson EM, Zhou Q, Shyng SL. Structurally distinct ligands rescue biogenesis defects of the KATP channel complex via a converging mechanism. J Biol Chem 2015; 290:7980-91. [PMID: 25637631 DOI: 10.1074/jbc.m114.634576] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Small molecules that correct protein misfolding and misprocessing defects offer a potential therapy for numerous human diseases. However, mechanisms underlying pharmacological correction of such defects, especially in heteromeric complexes with structurally diverse constituent proteins, are not well understood. Here we investigate how two chemically distinct compounds, glibenclamide and carbamazepine, correct biogenesis defects in ATP-sensitive potassium (KATP) channels composed of sulfonylurea receptor 1 (SUR1) and Kir6.2. We present evidence that despite structural differences, carbamazepine and glibenclamide compete for binding to KATP channels, and both drugs share a binding pocket in SUR1 to exert their effects. Moreover, both compounds engage Kir6.2, in particular the distal N terminus of Kir6.2, which is involved in normal channel biogenesis, for their chaperoning effects on SUR1 mutants. Conversely, both drugs can correct channel biogenesis defects caused by Kir6.2 mutations in a SUR1-dependent manner. Using an unnatural, photocross-linkable amino acid, azidophenylalanine, genetically encoded in Kir6.2, we demonstrate in living cells that both drugs promote interactions between the distal N terminus of Kir6.2 and SUR1. These findings reveal a converging pharmacological chaperoning mechanism wherein glibenclamide and carbamazepine stabilize the heteromeric subunit interface critical for channel biogenesis to overcome defective biogenesis caused by mutations in individual subunits.
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Affiliation(s)
- Prasanna K Devaraneni
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Gregory M Martin
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Erik M Olson
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Qing Zhou
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Show-Ling Shyng
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
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24
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Ortiz D, Bryan J. Neonatal Diabetes and Congenital Hyperinsulinism Caused by Mutations in ABCC8/SUR1 are Associated with Altered and Opposite Affinities for ATP and ADP. Front Endocrinol (Lausanne) 2015; 6:48. [PMID: 25926814 PMCID: PMC4397924 DOI: 10.3389/fendo.2015.00048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 03/21/2015] [Indexed: 12/28/2022] Open
Abstract
ATP-sensitive K(+) (KATP) channels composed of potassium inward-rectifier type 6.2 and sulfonylurea receptor type 1 subunits (Kir6.2/SUR1)4 are expressed in various cells in the brain and endocrine pancreas where they couple metabolic status to membrane potential. In β-cells, increases in cytosolic [ATP/ADP]c inhibit KATP channel activity, leading to membrane depolarization and exocytosis of insulin granules. Mutations in ABCC8 (SUR1) or KCNJ11 (Kir6.2) can result in gain or loss of channel activity and cause neonatal diabetes (ND) or congenital hyperinsulinism (CHI), respectively. SUR1 is reported to be a Mg(2+)-dependent ATPase. A prevailing model posits that ATP hydrolysis at SUR1 is required to stimulate openings of the pore. However, recent work shows nucleotide binding, without hydrolysis, is sufficient to switch SUR1 to stimulatory conformations. The actions of nucleotides, ATP and ADP, on ND (SUR1E1506D) and CHI (SUR1E1506K) mutants, without Kir6.2, were compared to assess both models. Both substitutions significantly impair hydrolysis in SUR1 homologs. SUR1E1506D has greater affinity for MgATP than wildtype; SUR1E1506K has reduced affinity. Without Mg(2+), SUR1E1506K has a greater affinity for ATP(4-) consistent with electrostatic attraction between ATP(4-), unshielded by Mg(2+), and the basic lysine. Further analysis of ND and CHI ABCC8 mutants in the second transmembrane and nucleotide-binding domains (TMD2 and NBD2) found a relation between their affinities for ATP (±Mg(2+)) and their clinical phenotype. Increased affinity for ATP is associated with ND; decreased affinity with CHI. In contrast, MgADP showed a weaker relationship. Diazoxide, known to reduce insulin release in some CHI cases, potentiates switching of CHI mutants from non-stimulatory to stimulatory states consistent with diazoxide stabilizing a nucleotide-bound conformation. The results emphasize the greater importance of nucleotide binding vs. hydrolysis in the regulation of KATP channels in vivo.
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Affiliation(s)
- David Ortiz
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Joseph Bryan
- Pacific Northwest Diabetes Research Institute, Seattle, WA, USA
- *Correspondence: Joseph Bryan, Pacific Northwest Diabetes Research Institute, 720 Broadway, Seattle, WA 98122, USA e-mail:
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25
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Khodaee N, Ghasemi M, Saghiri R, Eliassi A. Endoplasmic reticulum membrane potassium channel dysfunction in high fat diet induced stress in rat hepatocytes. EXCLI JOURNAL 2014; 13:1075-87. [PMID: 26417322 PMCID: PMC4464507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 08/20/2014] [Indexed: 11/02/2022]
Abstract
In a previous study we reported the presence of a large conductance K(+) channel in the membrane of endoplasmic reticulum (ER) from rat hepatocytes. The channel open probability (Po) appeared voltage dependent and reached to a minimum 0.2 at +50 mV. Channel activity in this case was found to be totally inhibited at ATP concentration 2.5 mM, glibenclamide 100 µM and tolbutamide 400 µM. Existing evidence indicates an impairment of endoplasmic reticulum functions in ER stress condition. Because ER potassium channels have been involved in several ER functions including cytoprotection, apoptosis and calcium homeostasis, a study was carried out to consider whether the ER potassium channel function is altered in a high fat diet model of ER stress. Male Wistar rats were made ER stress for 2 weeks with a high fat diet. Ion channel incorporation of ER stress model into the bilayer lipid membrane allowed the characterization of K(+) channel. Our results indicate that the channel Po was significantly increased at voltages above +30 mV. Interestingly, addition of ATP 7.5 mM, glibenclamide 400 µM and tolbutamide 2400 µM totally inhibited the channel activities, 3-fold, 4-fold and 6-fold higher than that in the control groups, respectively. Our results thus demonstrate a modification in the ER K(+) channel gating properties and decreased sensitivity to drugs in membrane preparations coming from ER high fat model of ER stress, an effect potentially linked to a change in ER K(+) channel subunits in ER stress condition. Our results may provide new insights into the cellular mechanisms underlying ER dysfunctions in ER stress.
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Affiliation(s)
- Naser Khodaee
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Evin, Tehran 19857, Iran,Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Evin, Tehran 19857, Iran
| | - Maedeh Ghasemi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Evin, Tehran 19857, Iran,Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Evin, Tehran 19857, Iran
| | - Reza Saghiri
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Afsaneh Eliassi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Evin, Tehran 19857, Iran,Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Evin, Tehran 19857, Iran,*To whom correspondence should be addressed: Afsaneh Eliassi, Neurophysiology Research Center and Department of Physiology, Shahid Beheshti University of Medical Sciences, Evin, Tehran 19857, Iran. Tel-Fax: 9821-22439971, E-mail: ;
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26
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Chen M, Križaj D, Thoreson WB. Intracellular calcium stores drive slow non-ribbon vesicle release from rod photoreceptors. Front Cell Neurosci 2014; 8:20. [PMID: 24550779 PMCID: PMC3910126 DOI: 10.3389/fncel.2014.00020] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 01/13/2014] [Indexed: 01/26/2023] Open
Abstract
Rods are capable of greater slow release than cones contributing to overall slower release kinetics. Slow release in rods involves Ca2+-induced Ca2+ release (CICR). By impairing release from ribbons, we found that unlike cones where release occurs entirely at ribbon-style active zones, slow release from rods occurs mostly at ectopic, non-ribbon sites. To investigate the role of CICR in ribbon and non-ribbon release from rods, we used total internal reflection fluorescence microscopy as a tool for visualizing terminals of isolated rods loaded with fluorescent Ca2+ indicator dyes and synaptic vesicles loaded with dextran-conjugated pH-sensitive rhodamine. We found that rather than simply facilitating release, activation of CICR by ryanodine triggered release directly in rods, independent of plasma membrane Ca2+ channel activation. Ryanodine-evoked release occurred mostly at non-ribbon sites and release evoked by sustained depolarization at non-ribbon sites was mostly due to CICR. Unlike release at ribbon-style active zones, non-ribbon release did not occur at fixed locations. Fluorescence recovery after photobleaching of endoplasmic reticulum (ER)-tracker dye in rod terminals showed that ER extends continuously from synapse to soma. Release of Ca2+ from terminal ER by lengthy depolarization did not significantly deplete Ca2+ from ER in the perikaryon. Collectively, these results indicate that CICR-triggered release at non-ribbon sites is a major mechanism for maintaining vesicle release from rods and that CICR in terminals may be sustained by diffusion of Ca2+ through ER from other parts of the cell.
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Affiliation(s)
- Minghui Chen
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center Omaha, NE, USA ; Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center Omaha, NE, USA
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine Salt Lake City, UT, USA
| | - Wallace B Thoreson
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center Omaha, NE, USA ; Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center Omaha, NE, USA
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27
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Hyaluronan synthase 1 (HAS1) produces a cytokine-and glucose-inducible, CD44-dependent cell surface coat. Exp Cell Res 2014; 320:153-63. [DOI: 10.1016/j.yexcr.2013.09.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/23/2013] [Accepted: 09/28/2013] [Indexed: 02/04/2023]
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28
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Proks P, de Wet H, Ashcroft FM. Molecular mechanism of sulphonylurea block of K(ATP) channels carrying mutations that impair ATP inhibition and cause neonatal diabetes. Diabetes 2013; 62:3909-19. [PMID: 23835339 PMCID: PMC3806600 DOI: 10.2337/db13-0531] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 06/20/2013] [Indexed: 12/25/2022]
Abstract
Sulphonylurea drugs are the therapy of choice for treating neonatal diabetes (ND) caused by mutations in the ATP-sensitive K(+) channel (KATP channel). We investigated the interactions between MgATP, MgADP, and the sulphonylurea gliclazide with KATP channels expressed in Xenopus oocytes. In the absence of MgATP, gliclazide block was similar for wild-type channels and those carrying the Kir6.2 ND mutations R210C, G334D, I296L, and V59M. Gliclazide abolished the stimulatory effect of MgATP on all channels. Conversely, high MgATP concentrations reduced the gliclazide concentration, producing a half-maximal block of G334D and R201C channels and suggesting a mutual antagonism between nucleotide and gliclazide binding. The maximal extent of high-affinity gliclazide block of wild-type channels was increased by MgATP, but this effect was smaller for ND channels; channels that were least sensitive to ATP inhibition showed the smallest increase in sulphonylurea block. Consequently, G334D and I296L channels were not fully blocked, even at physiological MgATP concentrations (1 mmol/L). Glibenclamide block was also reduced in β-cells expressing Kir6.2-V59M channels. These data help to explain why patients with some mutations (e.g., G334D, I296L) are insensitive to sulphonylurea therapy, why higher drug concentrations are needed to treat ND than type 2 diabetes, and why patients with severe ND mutations are less prone to drug-induced hypoglycemia.
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Affiliation(s)
- Peter Proks
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, U.K
| | - Heidi de Wet
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, U.K
| | - Frances M. Ashcroft
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, U.K
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Kilgore JA, Dolman NJ, Davidson MW. A review of reagents for fluorescence microscopy of cellular compartments and structures, Part II: reagents for non-vesicular organelles. ACTA ACUST UNITED AC 2013; 66:12.31.1-12.31.24. [PMID: 24510724 DOI: 10.1002/0471142956.cy1231s66] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A wide range of fluorescent dyes and reagents exist for labeling organelles in live and fixed cells. Choosing between them can sometimes be confusing, and optimization for many of them can be challenging. Presented here is a discussion on the commercially-available reagents that have shown the most promise for each organelle of interest, including endoplasmic reticulum/nuclear membrane, Golgi apparatus, mitochondria, nucleoli, and nuclei, with an emphasis on localization of these structures for microscopy. Included is a featured reagent for each structure with a recommended protocol, troubleshooting guide, and example image.
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Affiliation(s)
- Jason A Kilgore
- Molecular Probes Labeling and Detection, Life Technologies, Eugene, Oregon
| | - Nick J Dolman
- Molecular Probes Labeling and Detection, Life Technologies, Eugene, Oregon
| | - Michael W Davidson
- National High Magnetic Field Laboratory and Department of Biological Science, Florida State University, Tallahassee, Florida
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Meyer F, Flötenmeyer M, Moussian B. The sulfonylurea receptor Sur is dispensable for chitin synthesis in Drosophila melanogaster embryos. PEST MANAGEMENT SCIENCE 2013; 69:1136-1140. [PMID: 23441090 DOI: 10.1002/ps.3476] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 11/05/2012] [Accepted: 01/03/2013] [Indexed: 06/01/2023]
Abstract
BACKGROUND Chitin produced by membrane-inserted chitin synthases is an important constituent of the arthropod cuticle and midgut peritrophic matrix. Chitin synthesis inhibitors are common insecticides in pest control. As the target of sulfonylurea-derived insecticides such as diflubenzuron, the ABC transporter sulfonylurea receptor (Sur) has been postulated to be an essential cofactor of chitin synthesis. However, direct evidence for this assumption is missing. RESULTS Here, a study has been made of the phenotype of Drosophila melanogaster larvae suffering completely eliminated Sur function. Taken together, it is found that cuticle architecture is normal and chitin amounts are not diminished in the cuticle of these animals, indicating that Sur is dispensable for chitin synthesis. CONCLUSION The data obtained suggest that there must exist another sulfonylurea-sensitive ABC transporter that either instead of Sur is the true sulfonylurea-sensitive transporter involved in chitin synthesis or is able to substitute Sur function during cuticle formation. Identification and characterisation of this factor is pivotal for understanding the mode of action of sulfonylurea as insecticide.
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Affiliation(s)
- Frauke Meyer
- Animal Genetics, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
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Sultana N, Arayne MS, Iftikhar B. Simultaneous Determination of Atenolol, Rosuvastatin, Spironolactone, Glibenclamide and Naproxen Sodium in Pharmaceutical Formulations and Human Plasma by RP-HPLC. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200800149] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels in pancreatic β-cells play a crucial role in insulin secretion and glucose homeostasis. These channels are composed of two subunits: a pore-forming subunit (Kir6.2) and a regulatory subunit (sulphonylurea receptor-1). Recent studies identified large number of gain of function mutations in the regulatory subunit of the channel which cause neonatal diabetes. Majority of mutations cause neonatal diabetes alone, however some lead to a severe form of neonatal diabetes with associated neurological complications. This review focuses on the functional effects of these mutations as well as the implications for treatment.
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Affiliation(s)
- Peter Proks
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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Viroporin activity and membrane topology of classic swine fever virus p7 protein. Int J Biochem Cell Biol 2013; 45:1186-94. [PMID: 23583663 DOI: 10.1016/j.biocel.2013.03.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 02/28/2013] [Accepted: 03/17/2013] [Indexed: 11/23/2022]
Abstract
Viroporins are a group of viral proteins that participate in viral replication cycles, including modification of membrane permeability and promotion of viral release. Although biological data have been accumulated on viroporion-like proteins of other viruses belonging to family Flaviviridae, the viroporin activity and membrane topology of p7 protein from classical swine fever virus (CSFV), a member of the genus Pestivirus of the family Flaviviridae, are largely unknown. In this study, sequence analysis of the primary structure of p7 polypeptide demonstrates that p7 contains two putative transmembrane regions connected by a short hydrophilic segment. Expression of p7 protein in Escherichia coli leads to the permeabilization of bacterial cells to small molecules. The p7 protein also enhances the permeability of mammalian cells, increasing the intracellular Ca(2+) concentration and the permeability of cells to the translation inhibitor Hygromycin B. This protein is an integral membrane protein and can form homo-oligomers. It mainly localizes to the ER at the early stage of the expression and can be transferred to the plasma membrane at the late stage of the expression. Detergent permeabilization assays confirmed that the p7 protein is a 2-pass transmembrane protein and its N and C termini are exposed to the ER lumen. Deletion analysis showed that amino acid residues 41-63 may be essential for the viroporin activity of the protein. Our studies demonstrate that CSFV p7 possesses properties commonly associated with viroporins, which could be a potential target for the development of a therapeutic intervention for classic swine fever virus infection.
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Teng CY, Chang SL, Tsai MF, Wu TY. Α-synuclein and β-synuclein enhance secretion protein production in baculovirus expression vector system. Appl Microbiol Biotechnol 2013; 97:3875-84. [PMID: 23314197 DOI: 10.1007/s00253-012-4679-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 12/20/2012] [Accepted: 12/22/2012] [Indexed: 11/26/2022]
Abstract
The baculovirus expression vector system (BEVS) is widely used as a tool for expressing of recombinant proteins in insect cells or larvae. However, the expression level of secretion pathway proteins is often lower than that of cytosolic and nucleus proteins. Thus, we attempted to improve production of secreted proteins by using a secretory alkaline phosphatase-EGFP fusion protein (SEFP)-based bi-cistronic baculovirus vector to identify chaperones that have potential on boosting secreted protein production. As co-expressed SEFP with a chaperone, calreticulin (CALR), it was found that the secreted SEFP enzyme activity can be boosted up to twofold. This result demonstrated the SEFP-based bi-cistronic approach can be used to identify the genes that can enhance secretion protein production in BEVS. Thus, the chaperone activity of α-synuclein (α-syn) and β-synuclein (β-syn) was evaluated in cells co-expressed with SEFP and compared that with CALR by analyzing localization, alkaline phosphatase enzyme activity, and mRNA expression levels of SEFP. Our results showed that SEFP enzyme activity from cells co-expressed with both synuclein proteins can be enhanced up to 2.3-fold and this increment was better than that caused by CALR. Moreover, this enhancement might arise from the transcription enhancement or higher RNA stability. By this novel approach, we provided evidences that α- and β-syn can enhance secretion proteins production in BEVS.
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Affiliation(s)
- Chao-Yi Teng
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
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Di Gialleonardo V, de Vries EFJ, Di Girolamo M, Quintero AM, Dierckx RAJO, Signore A. Imaging of β-cell mass and insulitis in insulin-dependent (Type 1) diabetes mellitus. Endocr Rev 2012; 33:892-919. [PMID: 22889646 DOI: 10.1210/er.2011-1041] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Insulin-dependent (type 1) diabetes mellitus is a metabolic disease with a complex multifactorial etiology and a poorly understood pathogenesis. Genetic and environmental factors cause an autoimmune reaction against pancreatic β-cells, called insulitis, confirmed in pancreatic samples obtained at autopsy. The possibility to noninvasively quantify β-cell mass in vivo would provide important biological insights and facilitate aspects of diagnosis and therapy, including follow-up of islet cell transplantation. Moreover, the availability of a noninvasive tool to quantify the extent and severity of pancreatic insulitis could be useful for understanding the natural history of human insulin-dependent (type 1) diabetes mellitus, to early diagnose children at risk to develop overt diabetes, and to select patients to be treated with immunotherapies aimed at blocking the insulitis and monitoring the efficacy of these therapies. In this review, we outline the imaging techniques currently available for in vivo, noninvasive detection of β-cell mass and insulitis. These imaging techniques include magnetic resonance imaging, ultrasound, computed tomography, bioluminescence and fluorescence imaging, and the nuclear medicine techniques positron emission tomography and single-photon emission computed tomography. Several approaches and radiopharmaceuticals for imaging β-cells and lymphocytic insulitis are reviewed in detail.
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Affiliation(s)
- Valentina Di Gialleonardo
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, 9700 AB, Groningen, The Netherlands
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Abstract
A major multidrug transporter, MDR1 (multidrug resistance 1), a member of the MFS (major facilitator superfamily), invariably contributes to an increased efflux of commonly used azoles and thus corroborates their direct involvement in MDR in Candida albicans. The Mdr1 protein has two transmembrane domains, each comprising six transmembrane helices, interconnected with extracellular loops and ICLs (intracellular loops). The introduction of deletions and insertions through mutagenesis was used to address the role of the largest interdomain ICL3 of the MDR1 protein. Most of the progressive deletants, when overexpressed, eliminated the drug resistance. Notably, restoration of the length of the ICL3 by insertional mutagenesis did not restore the functionality of the protein. Interestingly, most of the insertion and deletion variants of ICL3 became amenable to trypsinization, yielding peptide fragments. The homology model of the Mdr1 protein showed that the molecular surface-charge distribution was perturbed in most of the ICL3 mutant variants. Taken together, these results provide the first evidence that the CCL (central cytoplasmic loop) of the fungal MFS transporter of the DHA1 (drug/proton antiporter) family is critical for the function of MDR. Unlike other homologous proteins, ICL3 has no apparent role in imparting substrate specificity or in the recruitment of the transporter protein.
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Ortiz D, Voyvodic P, Gossack L, Quast U, Bryan J. Two neonatal diabetes mutations on transmembrane helix 15 of SUR1 increase affinity for ATP and ADP at nucleotide binding domain 2. J Biol Chem 2012; 287:17985-95. [PMID: 22451668 DOI: 10.1074/jbc.m112.349019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
K(ATP) channels, (SUR1/Kir6.2)(4) (sulfonylurea receptor type 1/potassium inward rectifier type 6.2) respond to the metabolic state of pancreatic β-cells, modulating membrane potential and insulin exocytosis. Mutations in both subunits cause neonatal diabetes by overactivating the pore. Hyperactive channels fail to close appropriately with increased glucose metabolism; thus, β-cell hyperpolarization limits insulin release. K(ATP) channels are inhibited by ATP binding to the Kir6.2 pore and stimulated, via an uncertain mechanism, by magnesium nucleotides at SUR1. Glibenclamide (GBC), a sulfonylurea, was used as a conformational probe to compare nucleotide action on wild type versus Q1178R and R1182Q SUR1 mutants. GBC binds with high affinity to aporeceptors, presumably in the inward facing ATP-binding cassette configuration; MgATP reduces binding affinity via a shift to the outward facing conformation. To determine nucleotide affinities under equilibrium, non-hydrolytic conditions, Mg(2+) was eliminated. A four-state equilibrium model describes the allosteric linkage. The K(D) for ATP(4-) is ~1 versus 12 mM, Q1178R versus wild type, respectively. The linkage constant is ~10, implying that outward facing conformations bind GBC with a lower affinity, 9-10 nM for Q1178R. Thus, nucleotides cannot completely inhibit GBC binding. Binding of channel openers is reported to require ATP hydrolysis, but diazoxide, a SUR1-selective agonist, concentration-dependently augments ATP(4-) action. An eight-state model describes linkage between diazoxide and ATP(4-) binding; diazoxide markedly increases the affinity of Q1178R for ATP(4-) and ATP(4-) augments diazoxide binding. NBD2, but not NBD1, has a higher affinity for ATP (and ADP) in mutant versus wild type (with or without Mg(2+)). Thus, the mutants spend more time in nucleotide-bound conformations, with reduced affinity for GBC, that activate the pore.
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Affiliation(s)
- David Ortiz
- Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA
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38
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Winkler M, Kühner P, Russ U, Ortiz D, Bryan J, Quast U. Role of the amino-terminal transmembrane domain of sulfonylurea receptor SUR2B for coupling to KIR6.2, ligand binding, and oligomerization. Naunyn Schmiedebergs Arch Pharmacol 2011; 385:287-98. [DOI: 10.1007/s00210-011-0708-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 10/24/2011] [Indexed: 01/11/2023]
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39
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Amann T, Schell S, Kühner P, Winkler M, Schwanstecher M, Russ U, Quast U. Substitution of the Walker A lysine by arginine in the nucleotide-binding domains of sulphonylurea receptor SUR2B: effects on ligand binding and channel activity. Naunyn Schmiedebergs Arch Pharmacol 2010; 381:507-16. [PMID: 20352196 DOI: 10.1007/s00210-010-0510-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 02/28/2010] [Indexed: 10/19/2022]
Abstract
Sulphonylurea receptors (SURs) serve as regulatory subunits of ATP-sensitive K(+) channels. SURs are members of the ATP-binding cassette (ABC) protein superfamily and contain two conserved nucleotide-binding domains (NBDs) which bind and hydrolyse MgATP; in addition, they carry the binding sites for the sulphonylureas like glibenclamide (GBC) which close the channel and for the K(ATP) channel openers such as P1075. Here we have exchanged the conserved Lys in the Walker A motif by Arg in both NBDs of SUR2B, the regulatory subunit of the vascular K(ATP) channel. Then the effect of the mutation on the ATPase-dependent binding of GBC and P1075 to SUR2B and on the activity of the recombinant vascular (Kir6.1/SUR2B) channel was assessed. Surprisingly, in the absence of MgATP, the mutation weakened binding of P1075 and the extent of allosteric inhibition of GBC binding by P1075. The mutation abolished most, but not all, of the MgATP effects on the binding of GBC and P1075 and prevented nucleotide-induced activation of the channel which relies on SUR reaching the posthydrolytic (MgADP-bound) state; the mutant channel was, however, opened by P1075 at higher concentrations. The data provide evidence that mutant SUR2B binds MgATP but that the posthydrolytic state is insufficiently populated. This suggests that the mutation locks SUR2B in an MgATP-binding prehydrolytic-like state; binding of P1075 may induce a posthydrolytic-like conformation to open the channel.
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Affiliation(s)
- Tobias Amann
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard-Karls-University Hospitals and Clinics, University of Tübingen, Wilhelmstr. 56, 72074, Tübingen, Germany
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Hibino H, Inanobe A, Furutani K, Murakami S, Findlay I, Kurachi Y. Inwardly rectifying potassium channels: their structure, function, and physiological roles. Physiol Rev 2010; 90:291-366. [PMID: 20086079 DOI: 10.1152/physrev.00021.2009] [Citation(s) in RCA: 1081] [Impact Index Per Article: 77.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Inwardly rectifying K(+) (Kir) channels allow K(+) to move more easily into rather than out of the cell. They have diverse physiological functions depending on their type and their location. There are seven Kir channel subfamilies that can be classified into four functional groups: classical Kir channels (Kir2.x) are constitutively active, G protein-gated Kir channels (Kir3.x) are regulated by G protein-coupled receptors, ATP-sensitive K(+) channels (Kir6.x) are tightly linked to cellular metabolism, and K(+) transport channels (Kir1.x, Kir4.x, Kir5.x, and Kir7.x). Inward rectification results from pore block by intracellular substances such as Mg(2+) and polyamines. Kir channel activity can be modulated by ions, phospholipids, and binding proteins. The basic building block of a Kir channel is made up of two transmembrane helices with cytoplasmic NH(2) and COOH termini and an extracellular loop which folds back to form the pore-lining ion selectivity filter. In vivo, functional Kir channels are composed of four such subunits which are either homo- or heterotetramers. Gene targeting and genetic analysis have linked Kir channel dysfunction to diverse pathologies. The crystal structure of different Kir channels is opening the way to understanding the structure-function relationships of this simple but diverse ion channel family.
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Affiliation(s)
- Hiroshi Hibino
- Department of Pharmacology, Graduate School of Medicine and The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka 565-0871, Japan
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5-Hydroxydecanoate and coenzyme A are inhibitors of native sarcolemmal KATP channels in inside-out patches. Biochim Biophys Acta Gen Subj 2009; 1800:385-91. [PMID: 19931596 DOI: 10.1016/j.bbagen.2009.11.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 11/11/2009] [Accepted: 11/12/2009] [Indexed: 11/23/2022]
Abstract
BACKGROUND 5-Hydroxydecanoate (5-HD) inhibits preconditioning, and it is assumed to be a selective inhibitor of mitochondrial ATP-sensitive K(+) (mitoK(ATP)) channels. However, 5-HD is a substrate for mitochondrial outer membrane acyl-CoA synthetase, which catalyzes the reaction: 5HD + CoA + ATP --> 5-HD-CoA (5-hydroxydecanoyl-CoA) + AMP + pyrophosphate. We aimed to determine whether the reactants or principal product of this reaction modulate sarcolemmal K(ATP) (sarcK(ATP)) channel activity. METHODS Single sarcK(ATP) channel currents were measured in inside-out patches excised from rat ventricular myocytes. In addition, sarcK(ATP) channel activity was recorded in whole-cell configuration or in giant inside-out patches excised from oocytes expressing Kir6.2/SUR2A. RESULTS 5-HD inhibited (IC(50) approximately 30 microM) K(ATP) channel activity, albeit only in the presence of (non-inhibitory) concentrations of ATP. Similarly, when the inhibitory effect of 0.2 mM ATP was reversed by 1 microM oleoyl-CoA, subsequent application of 5-HD blocked channel activity, but no effect was seen in the absence of ATP. Furthermore, we found that 1 microM coenzyme A (CoA) inhibited sarcK(ATP) channels. Using giant inside-out patches, which are weakly sensitive to "contaminating" CoA, we found that Kir6.2/SUR2A channels were insensitive to 5-HD-CoA. In intact myocytes, 5-HD failed to reverse sarcK(ATP) channel activation by either metabolic inhibition or rilmakalim. GENERAL SIGNIFICANCE SarcK(ATP) channels are inhibited by 5-HD (provided that ATP is present) and CoA but insensitive to 5-HD-CoA. 5-HD is equally potent at "directly" inhibiting sarcK(ATP) and mitoK(ATP) channels. However, in intact cells, 5-HD fails to inhibit sarcK(ATP) channels, suggesting that mitochondria are the preconditioning-relevant targets of 5-HD.
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Galanou MC, Theodossiou TA, Tsiourvas D, Sideratou Z, Paleos CM. Interactive transport, subcellular relocation and enhanced phototoxicity of hypericin encapsulated in guanidinylated liposomes via molecular recognition. Photochem Photobiol 2009; 84:1073-83. [PMID: 18627515 DOI: 10.1111/j.1751-1097.2008.00392.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Hypericin (HYP), a photocytotoxic phenanthroperylenquinone was encapsulated in liposomes outfitted with guanidinium-bearing lipids to ensure efficient cell binding through molecular recognition with anionic groups resident on the plasma membrane. The uptake of HYP encapsulated in these liposomes by DU145 human prostate cancer cells, was studied employing fluorescence, versus nonguadinylated liposomes and free HYP. The subcellular localization was in all cases studied by confocal microscopy employing specific subcellular organelle probes. The photocytotoxicity of HYP was assessed, 24 h following irradiation with 15 mWcm(-2) light through a GG 495 Schott filter, by a standard tetrazolium to formazan assay (XTT). HYP uptake by DU145 cells was found to be profoundly enhanced by using guanidinylated liposomes. Also the distance of the guanidinium group from the liposomal surface was found to significantly affect HYP loading, subcellular localization and phototoxicity. The two different modes of liposome cell internalization observed, i.e. plasma membrane fusion and endocytosis, were found to greatly affect the phototoxicity of HYP. Molecular recognition was overall appraised as a promising, novel route for photodynamic therapy, profoundly enhancing its efficacy. HYP encapsulated in liposomes-bearing guanidinium groups was more efficiently taken up by cells, leading to enhanced phototoxicity, in contrast to HYP encapsulated in their nonguanidinylated counterparts.
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Affiliation(s)
- Maria C Galanou
- Institute of Physical Chemistry, NCSR "DEMOKRITOS," Aghia Paraskevi, Attiki, Greece
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43
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Ploug KB, Sørensen MA, Strøbech L, Klaerke DA, Hay-Schmidt A, Sheykhzade M, Olesen J, Jansen-Olesen I. K ATP channels in pig and human intracranial arteries. Eur J Pharmacol 2008; 601:43-9. [PMID: 18996111 DOI: 10.1016/j.ejphar.2008.10.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 10/02/2008] [Accepted: 10/20/2008] [Indexed: 11/29/2022]
Abstract
Clinical trials suggest that synthetic ATP-sensitive K(+) (K(ATP)) channel openers may cause headache and migraine by dilating cerebral and meningeal arteries. We studied the mRNA expression profile of K(ATP) channel subunits in the pig and human middle meningeal artery (MMA) and in the pig middle cerebral artery (MCA). We determined the order of potency of four K(ATP) channel openers when applied to isolated pig MMA and MCA, and we examined the potential inhibitory effects of the Kir6.1 subunit specific K(ATP) channel blocker PNU-37883A on K(ATP) channel opener-induced relaxation of the isolated pig MMA and MCA. Using conventional RT-PCR, we detected the mRNA transcripts of the K(ATP) channel subunits Kir6.1 and SUR2B in all the examined pig and human intracranial arteries. Application of K(ATP) channel openers to isolated pig MMA and MCA in myographs caused a concentration-dependent vasodilatation with an order of potency that supports the presence of functional SUR2B K(ATP) channel subunits. 10(-7) M PNU-37883A significantly inhibited the in vitro dilatory responses of the potent K(ATP) channel opener P-1075 in both pig MMA and MCA. In conclusion, our combined mRNA expression and pharmacological studies indicate that Kir6.1/SUR2B is the major functional K(ATP) channel complex in the pig MMA and MCA, and mRNA expression studies suggest that the human MMA shares this K(ATP) channel subunit profile. Specific blocking of Kir6.1 or SUR2B K(ATP) channel subunits in large cerebral and meningeal arteries may be a future anti-migraine strategy.
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Affiliation(s)
- Kenneth Beri Ploug
- Department of Neurology and Danish Headache Center, Glostrup Research Institute, Glostrup Hospital, Faculty of Health Sciences, University of Copenhagen, Denmark.
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Merianda TT, Lin AC, Lam JSY, Vuppalanchi D, Willis DE, Karin N, Holt CE, Twiss JL. A functional equivalent of endoplasmic reticulum and Golgi in axons for secretion of locally synthesized proteins. Mol Cell Neurosci 2008; 40:128-42. [PMID: 19022387 DOI: 10.1016/j.mcn.2008.09.008] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 09/26/2008] [Indexed: 12/27/2022] Open
Abstract
Subcellular localization of protein synthesis provides a means to regulate the protein composition in far reaches of a cell. This localized protein synthesis gives neuronal processes autonomy to rapidly respond to extracellular stimuli. Locally synthesized axonal proteins enable neurons to respond to guidance cues and can help to initiate regeneration after injury. Most studies of axonal mRNA translation have concentrated on cytoplasmic proteins. While ultrastructural studies suggest that axons do not have rough endoplasmic reticulum or Golgi apparatus, mRNAs for transmembrane and secreted proteins localize to axons. Here, we show that growing axons with protein synthetic activity contain ER and Golgi components needed for classical protein synthesis and secretion. Isolated axons have the capacity to traffic locally synthesized proteins into secretory pathways and inhibition of Golgi function attenuates translation-dependent axonal growth responses. Finally, the capacity for secreting locally synthesized proteins in axons appears to be increased by injury.
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Affiliation(s)
- Tanuja T Merianda
- Nemours Biomedical Research, Alfred I duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE 19803, USA
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Johnson J, Goulding R, Ding Z, Partovi A, Anthony K, Beaulieu N, Tazmini G, Cornell R, Kay R. Differential membrane binding and diacylglycerol recognition by C1 domains of RasGRPs. Biochem J 2007; 406:223-36. [PMID: 17523924 PMCID: PMC1948961 DOI: 10.1042/bj20070294] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
RasGRPs (guanine-nucleotide-releasing proteins) are exchange factors for membrane-bound GTPases. All RasGRP family members contain C1 domains which, in other proteins, bind DAG (diacylglycerol) and thus mediate the proximal signal-transduction events induced by this lipid second messenger. The presence of C1 domains suggests that all RasGRPs could be regulated by membrane translocation driven by C1-DAG interactions. This has been demonstrated for RasGRP1 and RasGRP3, but has not been tested directly for RasGRP2, RasGRP4alpha and RasGRP4beta. Sequence alignments indicate that all RasGRP C1 domains have the potential to bind DAG. In cells, the isolated C1 domains of RasGRP1, RasGRP3 and RasGRP4alpha co-localize with membranes and relocalize in response to DAG, whereas the C1 domains of RasGRP2 and RasGRP4beta do not. Only the C1 domains of RasGRP1, RasGRP3 and RasGRP4alpha recognize DAG as a ligand within phospholipid vesicles and do so with differential affinities. Other lipid second messengers were screened as ligands for RasGRP C1 domains, but none was found to serve as an alternative to DAG. All of the RasGRP C1 domains bound to vesicles which contained a high concentration of anionic phospholipids, indicating that this could provide a DAG-independent mechanism for membrane binding by C1 domains. This concept was supported by demonstrating that the C1 domain of RasGRP2 could functionally replace the membrane-binding role of the C1 domain within RasGRP1, despite the inability of the RasGRP2 C1 domain to bind DAG. The RasGRP4beta C1 domain was non-functional when inserted into either RasGRP1 or RasGRP4, implying that the alternative splicing which produces this C1 domain eliminates its contribution to membrane binding.
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Affiliation(s)
- Joanne E. Johnson
- *Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada, V5A 1S6
| | - Rebecca E. Goulding
- †Terry Fox Laboratory, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada, V5Z 1L3
| | - Ziwei Ding
- *Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada, V5A 1S6
| | - Amir Partovi
- *Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada, V5A 1S6
| | - Kira V. Anthony
- †Terry Fox Laboratory, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada, V5Z 1L3
| | - Nadine Beaulieu
- †Terry Fox Laboratory, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada, V5Z 1L3
| | - Ghazaleh Tazmini
- †Terry Fox Laboratory, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada, V5Z 1L3
| | - Rosemary B. Cornell
- *Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada, V5A 1S6
- Correspondence may be addressed to either of these authors (email or )
| | - Robert J. Kay
- †Terry Fox Laboratory, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, Canada, V5Z 1L3
- Correspondence may be addressed to either of these authors (email or )
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Winkler M, Stephan D, Bieger S, Kühner P, Wolff F, Quast U. Testing the bipartite model of the sulfonylurea receptor binding site: binding of A-, B-, and A + B-site ligands. J Pharmacol Exp Ther 2007; 322:701-8. [PMID: 17495126 DOI: 10.1124/jpet.107.123224] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive K(+) (K(ATP)) channels are composed of pore-forming subunits (Kir6.x) and of regulatory subunits, the sulfonylurea receptors (SURx). Subtypes of K(ATP) channels are expressed in different organs. The sulfonylureas and glinides (insulinotropes) close the K(ATP) channel in pancreatic beta-cells and stimulate insulin secretion. The insulinotrope binding site of the pancreatic channel (Kir6.2/SUR1) consists of two overlapping (sub)-sites, site A, located on SUR1 and containing Ser1237 (which in SUR2 is replaced by Tyr1206), and site B, formed by SUR1 and Kir6.2. Insulinotropes bind to the A-, B-, or A + B-site(s) and are grouped accordingly. A-ligands are highly selective in closing the pancreatic channel, whereas B-ligands are nonselective and insensitive to the mutation S1237Y. We have examined the binding of insulinotropes representative of the three groups in [(3)H]glibenclamide competition experiments to determine the contribution of Kir6.x to binding affinity, the effect of the mutation Y1206S in site A of SUR2, and the subtype selectivity of the compounds. The results show that the bipartite nature of the SUR1 binding site applies also to SUR2. Kir6.2 as part of the B-site may interact directly or allosterically with structural elements common to all insulinotropes, i.e., the negative charge and/or the adjacent phenyl ring. The B-site confers a moderate subtype selectivity on B-ligands. The affinity of B-ligands is altered by the mutation SUR2(Y1206S), suggesting that the mutation affects the binding chamber of SUR2 as a whole or subsite A, including the region where the subsites overlap.
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Affiliation(s)
- Marcus Winkler
- Department of Pharmacology and Toxicology, Medical Faculty, University of Tübingen, Wilhelmstrasse 56, D-72074 Tübingen, Germany
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Vila-Carriles WH, Zhao G, Bryan J. Defining a binding pocket for sulfonylureas in ATP-sensitive potassium channels. FASEB J 2006; 21:18-25. [PMID: 17110465 DOI: 10.1096/fj.06-6730hyp] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sulfonylurea receptors SUR1 and SUR2 are the regulatory subunits of K(ATP) channels. Their differential affinity for hypoglycemic sulfonylureas provides a basis for the selectivity of these compounds for different K(ATP) channel isoforms. Sulfonylureas have a 100- to 1000-fold greater affinity for SUR1 vs. SUR2. Structure-activity studies suggested a bipartite binding pocket. Chimeric SUR1 approximately SUR2 receptors have shown TMD2, the third bundle of transmembrane helices, to be part of an "A" site that confers SUR1 selectivity for sulfonylureas. The purpose of this study is to determine the position of the "B" site. Previous photoaffinity labeling studies have placed the B site on the amino-terminal third of SUR and colabeled the associated K(IR). In our study, deletion of TMD0, the first bundle of transmembrane helices, did not compromise labeling. Further deletions into the cytoplasmic linker, L0, eliminated binding and labeling. Alanine substitutions in L0 identified a limited number of conserved residues, Y230 and W232, important for affinity labeling. A fragment of K(IR)6.2, missing M2 and the entire carboxyl terminal, assembles with SUR1 and is affinity labeled, while deletion of 10 or more amino-terminal residues compromises labeling. These studies indicate that the B site involves L0 and the K(IR) amino terminus, elements that are critical for control of channel gating.
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Affiliation(s)
- Wanda H Vila-Carriles
- Department of Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA.
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Frelet A, Klein M. Insight in eukaryotic ABC transporter function by mutation analysis. FEBS Lett 2006; 580:1064-84. [PMID: 16442101 DOI: 10.1016/j.febslet.2006.01.024] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 01/10/2006] [Accepted: 01/10/2006] [Indexed: 11/21/2022]
Abstract
With regard to structure-function relations of ATP-binding cassette (ABC) transporters several intriguing questions are in the spotlight of active research: Why do functional ABC transporters possess two ATP binding and hydrolysis domains together with two ABC signatures and to what extent are the individual nucleotide-binding domains independent or interacting? Where is the substrate-binding site and how is ATP hydrolysis functionally coupled to the transport process itself? Although much progress has been made in the elucidation of the three-dimensional structures of ABC transporters in the last years by several crystallographic studies including novel models for the nucleotide hydrolysis and translocation catalysis, site-directed mutagenesis as well as the identification of natural mutations is still a major tool to evaluate effects of individual amino acids on the overall function of ABC transporters. Apart from alterations in characteristic sequence such as Walker A, Walker B and the ABC signature other parts of ABC proteins were subject to detailed mutagenesis studies including the substrate-binding site or the regulatory domain of CFTR. In this review, we will give a detailed overview of the mutation analysis reported for selected ABC transporters of the ABCB and ABCC subfamilies, namely HsCFTR/ABCC7, HsSUR/ABCC8,9, HsMRP1/ABCC1, HsMRP2/ABCC2, ScYCF1 and P-glycoprotein (Pgp)/MDR1/ABCB1 and their effects on the function of each protein.
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Affiliation(s)
- Annie Frelet
- Zurich Basel Plant Science Center, University of Zurich, Plant Biology, Zollikerstrasse 107, CH-8008 Zurich, Switzerland
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Klein A, Lichtenberg J, Stephan D, Quast U. Lipids modulate ligand binding to sulphonylurea receptors. Br J Pharmacol 2006; 145:907-15. [PMID: 15895108 PMCID: PMC1576209 DOI: 10.1038/sj.bjp.0706252] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
ATP-sensitive K(+) channels (K(ATP) channels) are complexes of inwardly rectifying K(+) channels (Kir6.x) and sulphonylurea receptors (SURs). Kir6.2-containing channels are closed by ATP binding to Kir6.2, and opened by MgADP binding to SUR. Channel activity is modulated by synthetic compounds such as the channel-blocking sulphonylureas and the K(ATP) channel openers, which both act by binding to SUR. By interacting with Kir6.2, phosphatidylinositol-4,5-bisphosphate (PIP(2)) and oleoyl-coenzyme A (OCoA) decrease the ATP-sensitivity of the channel and abolish the effect of the synthetic channel modulators. Here, we have investigated whether lipids and related compounds interfered with the binding of the sulphonylurea, glibenclamide (GBC) and of the opener, N-cyano-N'-(1,1-dimethylpropyl)-N''-3-pyridylguanidine (P1075), to the SUR subtypes. Lipids (100-300 microM) inhibited binding of [(3)H]GBC and [(3)H]P1075 to SUR subtypes in the rank order OCoA>dioleylglycerol-succinyl-nitriloacetic acid (DOGS-NTA)>oleate>malonyl-CoA>PIP(2.)OCoA inhibited radioligand binding to SUR completely, with IC(50) values ranging from 6 to 44 microM. Inhibition was reversed by increasing the concentration of the radioligands in agreement with an essentially competitive mechanism. MgATP and coexpression with Kir6.2 decreased the potency of OCoA. DOGS-NTA inhibited radioligand binding to SUR by 40-88%, with IC(50) values ranging from 38 to 120 microM. Poly-lysine increased radioligand binding to SUR by up to 30% but did not affect much the inhibition of ligand binding by OCoA and DOGS-NTA. Radioligand binding to SUR2A but not to the other SUR subtypes was slightly (10-20%) stimulated by lipids at concentrations approximately 10 x lower than required for inhibition. The data show that certain lipids, at high concentrations, interact with SUR and inhibit the binding of GBC and P1075; with SUR2A, a modest stimulation of ligand binding precedes inhibition. Regarding K(ATP) channel activity, these effects will be overruled by the interaction of the lipids with Kir6.2 at lower (physiological) concentrations. They are, however, of pharmacological importance and must be taken into account if high concentrations of these compounds (e.g. OCoA>10 microM) are used to interfere with the action of sulphonylureas and openers on K(ATP) channel activity.
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Affiliation(s)
- Alexander Klein
- Department of Pharmacology and Toxicology, Medical Faculty, University of Tübingen, Wilhelmstr. 56, D-72074 Tübingen, Germany
| | - Jochen Lichtenberg
- Department of Pharmacology and Toxicology, Medical Faculty, University of Tübingen, Wilhelmstr. 56, D-72074 Tübingen, Germany
| | - Damian Stephan
- Department of Pharmacology and Toxicology, Medical Faculty, University of Tübingen, Wilhelmstr. 56, D-72074 Tübingen, Germany
| | - Ulrich Quast
- Department of Pharmacology and Toxicology, Medical Faculty, University of Tübingen, Wilhelmstr. 56, D-72074 Tübingen, Germany
- Author for correspondence:
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50
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Hambrock A, de Oliveira Franz CB, Hiller S, Osswald H. Glibenclamide-induced apoptosis is specifically enhanced by expression of the sulfonylurea receptor isoform SUR1 but not by expression of SUR2B or the mutant SUR1(M1289T). J Pharmacol Exp Ther 2005; 316:1031-7. [PMID: 16306272 DOI: 10.1124/jpet.105.097501] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Sulfonylurea receptor 1 (SUR1) is the regulatory subunit of the pancreatic ATP-sensitive K+ channel (K(ATP) channel), which is essential for triggering insulin secretion via membrane depolarization. Sulfonylureas, such as glibenclamide and tolbutamide, act as K(ATP) channel blockers and are widely used in diabetes treatment. These antidiabetic substances are known to induce apoptosis in pancreatic beta-cells or beta-cell lines under certain conditions. However, the precise molecular mechanisms of this sulfonylurea-induced apoptosis are still unidentified. To investigate the role of SUR in apoptosis induction, we tested the effect of glibenclamide on recombinant human embryonic kidney 293 cells expressing either SUR1, the smooth muscular isoform SUR2B, or the mutant SUR1(M1289T) at which a single amino acid in transmembrane helix 17 (TM17) was exchanged by the corresponding amino acid of SUR2. By analyzing cell detachment, nuclear condensation, DNA fragmentation, and caspase-3-like activity, we observed a SUR1-specific enhancement of glibenclamide-induced apoptosis that was not seen in SUR2B, SUR1(M1289T), or control cells. Coexpression with the pore-forming Kir6.2 subunit did not significantly alter the apoptotic effect of glibenclamide on SUR1 cells. In conclusion, expression of SUR1, but not of SUR2B or SUR1(M1289T), renders cells more susceptible to glibenclamide-induced apoptosis. Therefore, SUR1 as a pancreatic protein could be involved in specific variation of beta-cell mass and might also contribute to the regulation of insulin secretion at this level. According to our results, TM17 is essentially involved in SUR1-mediated apoptosis. This effect does not require the presence of functional Kir6.2-containing K(ATP) channels, which points to additional, so far unknown functions of SUR.
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Affiliation(s)
- Annette Hambrock
- Department of Pharmacology and Toxicology, Medical Faculty, University of Tübingen, Tübingen, Germany.
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