151
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Shimizu T, Ding W, Kameta N. Soft-Matter Nanotubes: A Platform for Diverse Functions and Applications. Chem Rev 2020; 120:2347-2407. [PMID: 32013405 DOI: 10.1021/acs.chemrev.9b00509] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Self-assembled organic nanotubes made of single or multiple molecular components can be classified into soft-matter nanotubes (SMNTs) by contrast with hard-matter nanotubes, such as carbon and other inorganic nanotubes. To date, diverse self-assembly processes and elaborate template procedures using rationally designed organic molecules have produced suitable tubular architectures with definite dimensions, structural complexity, and hierarchy for expected functions and applications. Herein, we comprehensively discuss every functions and possible applications of a wide range of SMNTs as bulk materials or single components. This Review highlights valuable contributions mainly in the past decade. Fifteen different families of SMNTs are discussed from the viewpoints of chemical, physical, biological, and medical applications, as well as action fields (e.g., interior, wall, exterior, whole structure, and ensemble of nanotubes). Chemical applications of the SMNTs are associated with encapsulating materials and sensors. SMNTs also behave, while sometimes undergoing morphological transformation, as a catalyst, template, liquid crystal, hydro-/organogel, superhydrophobic surface, and micron size engine. Physical functions pertain to ferro-/piezoelectricity and energy migration/storage, leading to the applications to electrodes or supercapacitors, and mechanical reinforcement. Biological functions involve artificial chaperone, transmembrane transport, nanochannels, and channel reactors. Finally, medical functions range over drug delivery, nonviral gene transfer vector, and virus trap.
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Affiliation(s)
- Toshimi Shimizu
- Nanomaterials Research Institute, Department of Materials and Chemistry , National Institute of Advanced Industrial Science and Technology , Tsukuba Central 5, 1-1-1 Higashi , Tsukuba , Ibaraki 305-8565 , Japan
| | - Wuxiao Ding
- Nanomaterials Research Institute, Department of Materials and Chemistry , National Institute of Advanced Industrial Science and Technology , Tsukuba Central 5, 1-1-1 Higashi , Tsukuba , Ibaraki 305-8565 , Japan
| | - Naohiro Kameta
- Nanomaterials Research Institute, Department of Materials and Chemistry , National Institute of Advanced Industrial Science and Technology , Tsukuba Central 5, 1-1-1 Higashi , Tsukuba , Ibaraki 305-8565 , Japan
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152
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Hansen TH, Yan Y, Ahlberg G, Vad OB, Refsgaard L, Dos Santos JL, Mutsaers N, Svendsen JH, Olesen MS, Bentzen BH, Schmitt N. A Novel Loss-of-Function Variant in the Chloride Ion Channel Gene Clcn2 Associates with Atrial Fibrillation. Sci Rep 2020; 10:1453. [PMID: 31996765 PMCID: PMC6989500 DOI: 10.1038/s41598-020-58475-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 01/15/2020] [Indexed: 11/09/2022] Open
Abstract
Atrial Fibrillation (AF) is the most common cardiac arrhythmia. Its pathogenesis is complex and poorly understood. Whole exome sequencing of Danish families with AF revealed a novel four nucleotide deletion c.1041_1044del in CLCN2 shared by affected individuals. We aimed to investigate the role of genetic variation of CLCN2 encoding the inwardly rectifying chloride channel ClC-2 as a risk factor for the development of familiar AF. The effect of the CLCN2 variant was evaluated by electrophysiological recordings on transiently transfected cells. We used quantitative PCR to assess CLCN2 mRNA expression levels in human atrial and ventricular tissue samples. The nucleotide deletion CLCN2 c.1041_1044del results in a frame-shift and premature stop codon. The truncated ClC-2 p.V347fs channel does not conduct current. Co-expression with wild-type ClC-2, imitating the heterozygote state of the patients, resulted in a 50% reduction in macroscopic current, suggesting an inability of truncated ClC-2 protein to form channel complexes with wild type channel subunits. Quantitative PCR experiments using human heart tissue from healthy donors demonstrated that CLCN2 is expressed across all four heart chambers. Our genetic and functional data points to a possible link between loss of ClC-2 function and an increased risk of developing AF.
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Affiliation(s)
- Thea Hyttel Hansen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,ALK-Abelló A/S, 2970, Hørsholm, Denmark
| | - Yannan Yan
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gustav Ahlberg
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Oliver Bundgaard Vad
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Lena Refsgaard
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Joana Larupa Dos Santos
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nancy Mutsaers
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Hastrup Svendsen
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Salling Olesen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Righospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Bo Hjorth Bentzen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicole Schmitt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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153
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Lee D, Hong JH. The Fundamental Role of Bicarbonate Transporters and Associated Carbonic Anhydrase Enzymes in Maintaining Ion and pH Homeostasis in Non-Secretory Organs. Int J Mol Sci 2020; 21:ijms21010339. [PMID: 31947992 PMCID: PMC6981687 DOI: 10.3390/ijms21010339] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 12/18/2022] Open
Abstract
The bicarbonate ion has a fundamental role in vital systems. Impaired bicarbonate transport leads to various diseases, including immune disorders, cystic fibrosis, tumorigenesis, kidney diseases, brain dysfunction, tooth fracture, ischemic reperfusion injury, hypertension, impaired reproductive system, and systemic acidosis. Carbonic anhydrases are involved in the mechanism of bicarbonate movement and consist of complex of bicarbonate transport systems including bicarbonate transporters. This review focused on the convergent regulation of ion homeostasis through various ion transporters including bicarbonate transporters, their regulatory enzymes, such as carbonic anhydrases, pH regulatory role, and the expression pattern of ion transporters in non-secretory systems throughout the body. Understanding the correlation between these systems will be helpful in order to obtain new insights and design potential therapeutic strategies for the treatment of pH-related disorders. In this review, we have discussed the broad prospects and challenges that remain in elucidation of bicarbonate-transport-related biological and developmental systems.
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Affiliation(s)
| | - Jeong Hee Hong
- Correspondence: ; Tel.: +82-32-899-6682; Fax: +82-32-899-6039
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154
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Bignon Y, Sakhi I, Bitam S, Bakouh N, Keck M, Frachon N, Paulais M, Planelles G, Teulon J, Andrini O. Analysis of CLCNKB mutations at dimer-interface, calcium-binding site, and pore reveals a variety of functional alterations in ClC-Kb channel leading to Bartter syndrome. Hum Mutat 2019; 41:774-785. [PMID: 31803959 DOI: 10.1002/humu.23962] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 11/14/2019] [Accepted: 11/29/2019] [Indexed: 12/12/2022]
Abstract
Pathological missense mutations in CLCNKB gene give a wide spectrum of clinical phenotypes in Bartter syndrome type III patients. Molecular analysis of the mutated ClC-Kb channels can be helpful to classify the mutations according to their functional alteration. We investigated the functional consequences of nine mutations in the CLCNKB gene causing Bartter syndrome. We first established that all tested mutations lead to decreased ClC-Kb currents. Combining electrophysiological and biochemical methods in Xenopus laevis oocytes and in MDCKII cells, we identified three classes of mutations. One class is characterized by altered channel trafficking. p.A210V, p.P216L, p.G424R, and p.G437R are totally or partially retained in the endoplasmic reticulum. p.S218N is characterized by reduced channel insertion at the plasma membrane and altered pH-sensitivity; thus, it falls in the second class of mutations. Finally, we found a novel class of functionally inactivated mutants normally present at the plasma membrane. Indeed, we found that p.A204T alters the pH-sensitivity, p.A254V abolishes the calcium-sensitivity. p.G219C and p.G465R are probably partially inactive at the plasma membrane. In conclusion, most pathogenic mutants accumulate partly or totally in intracellular compartments, but some mutants are normally present at the membrane surface and simultaneously show a large range of altered channel gating properties.
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Affiliation(s)
- Yohan Bignon
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Imene Sakhi
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Sara Bitam
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Naziha Bakouh
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Mathilde Keck
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | | | - Marc Paulais
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Gabrielle Planelles
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Jacques Teulon
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Laboratoire Physiologie Rénale et Tubulopathies, Paris, France.,CNRS ERL8228, Paris, France
| | - Olga Andrini
- Institut NeuroMyoGène, Univ Lyon, Université Claude Bernard Lyon 1, Lyon, France
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155
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Revealing the ultrastructure of the membrane pores of intact Serratia marcescens cells by atomic force microscopy. Heliyon 2019; 5:e02636. [PMID: 31692582 PMCID: PMC6806401 DOI: 10.1016/j.heliyon.2019.e02636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/19/2019] [Accepted: 10/08/2019] [Indexed: 11/24/2022] Open
Abstract
This study aimed to characterize the surface ultrastructure of intact Serratia marcescens cells under physiological conditions. Topographic information of membrane pores of the cells was obtained by atomic force microscope (AFM). Three types of membrane pores (CH-1-Pore A, CH-1-Pore B and CH-1-Pore C) were observed and the spatial arrangements of membrane-spanning subunits in membranes were defined. High-resolution images revealed that the doughnut-shaped structures of CH-1-Pore A and CH-1-Pore B were composed of six-to-eight and four transmembrane subunits. The inverted teepee-shaped structure of CH-1-Pore C was segmented into two transmembrane subunits straddling a single funnel-like pore. This study, to the best of authors' knowledge, represents the first direct characterization of the surface ultrastructure of the membrane pores of Serratia marcescens CH-1 cells at the nanometer scale and offers new prospects of mapping membrane pores on intact prokaryotic cells.
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156
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Abstract
Cl- is the major extracellular (Cl-out) and intracellular (Cl-in) anion whose concentration is actively regulated by multiple transporters. These transporters generate Cl- gradients across the plasma membrane and between the cytoplasm and intracellular organelles. [Cl-]in changes rapidly in response to cell stimulation and influences many physiological functions, as well as cellular and systemic homeostasis. However, less appreciated is the signaling function of Cl-. Cl- interacts with multiple proteins to directly modify their activity. This review highlights the signaling function of Cl- and argues that Cl- is a bona fide signaling ion, a function deserving extensive exploration.
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Affiliation(s)
- Benjamin P Lüscher
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Laura Vachel
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Ehud Ohana
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
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157
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Araújo CET, Oliveira CMC, Barbosa JD, Oliveira-Filho JP, Resende LAL, Badial PR, Araujo-Junior JP, McCue ME, Borges AS. A large intragenic deletion in the CLCN1 gene causes Hereditary Myotonia in pigs. Sci Rep 2019; 9:15632. [PMID: 31666547 PMCID: PMC6821760 DOI: 10.1038/s41598-019-51286-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/11/2019] [Indexed: 12/14/2022] Open
Abstract
Mutations in the CLCN1 gene are the primary cause of non-dystrophic Hereditary Myotonia in several animal species. However, there are no reports of Hereditary Myotonia in pigs to date. Therefore, the objective of the present study was to characterize the clinical and molecular findings of Hereditary Myotonia in an inbred pedigree. The clinical, electromyographic, histopathological, and molecular findings were evaluated. Clinically affected pigs presented non-dystrophic recessive Hereditary Myotonia. Nucleotide sequence analysis of the entire coding region of the CLCN1 gene revealed the absence of the exons 15 and 16 in myotonic animals. Analysis of the genomic region flanking the deletion unveiled a large intragenic deletion of 4,165 nucleotides. Interestingly, non-related, non-myotonic pigs expressed transcriptional levels of an alternate transcript (i.e., X2) that was identical to the deleted X1 transcript of myotonic pigs. All myotonic pigs and their progenitors were homozygous recessive and heterozygous, respectively, for the 4,165-nucleotide deletion. This is the first study reporting Hereditary Myotonia in pigs and characterizing its clinical and molecular findings. Moreover, to the best of our knowledge, Hereditary Myotonia has never been associated with a genomic deletion in the CLCN1 gene in any other species.
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Affiliation(s)
- C E T Araújo
- São Paulo State University (UNESP), School of Veterinary Medicine and Animal Science, Botucatu, São Paulo, Brazil
| | - C M C Oliveira
- Instituto de Medicina Veterinária, Universidade Federal do Pará, Campus Castanhal, PA, Brazil
| | - J D Barbosa
- Instituto de Medicina Veterinária, Universidade Federal do Pará, Campus Castanhal, PA, Brazil
| | - J P Oliveira-Filho
- São Paulo State University (UNESP), School of Veterinary Medicine and Animal Science, Botucatu, São Paulo, Brazil
| | - L A L Resende
- São Paulo State University (UNESP), Medical School, Botucatu, Brazil
| | - P R Badial
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Starkville, MS, USA
| | - J P Araujo-Junior
- São Paulo State University (UNESP), Institute of Bioscience, Botucatu, Brazil
| | - M E McCue
- College of Veterinary Medicine, University of Minnesota, St Paul, Minnesota, 55108, USA
| | - A S Borges
- São Paulo State University (UNESP), School of Veterinary Medicine and Animal Science, Botucatu, São Paulo, Brazil.
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158
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Pedersen SF, Counillon L. The SLC9A-C Mammalian Na +/H + Exchanger Family: Molecules, Mechanisms, and Physiology. Physiol Rev 2019; 99:2015-2113. [PMID: 31507243 DOI: 10.1152/physrev.00028.2018] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+ and H+ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.
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Affiliation(s)
- S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - L Counillon
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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159
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Liu S, Chang S, Han B, Xu L, Zhang M, Zhao C, Yang W, Wang F, Li J, Delpire E, Ye S, Bai XC, Guo J. Cryo-EM structures of the human cation-chloride cotransporter KCC1. Science 2019; 366:505-508. [PMID: 31649201 DOI: 10.1126/science.aay3129] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/26/2019] [Indexed: 11/02/2022]
Abstract
Cation-chloride cotransporters (CCCs) mediate the coupled, electroneutral symport of cations with chloride across the plasma membrane and are vital for cell volume regulation, salt reabsorption in the kidney, and γ-aminobutyric acid (GABA)-mediated modulation in neurons. Here we present cryo-electron microscopy (cryo-EM) structures of human potassium-chloride cotransporter KCC1 in potassium chloride or sodium chloride at 2.9- to 3.5-angstrom resolution. KCC1 exists as a dimer, with both extracellular and transmembrane domains involved in dimerization. The structural and functional analyses, along with computational studies, reveal one potassium site and two chloride sites in KCC1, which are all required for the ion transport activity. KCC1 adopts an inward-facing conformation, with the extracellular gate occluded. The KCC1 structures allow us to model a potential ion transport mechanism in KCCs and provide a blueprint for drug design.
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Affiliation(s)
- Si Liu
- Department of Biophysics, Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Shenghai Chang
- Department of Biophysics, Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Center of Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Binming Han
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Institute of Quantitative Biology, Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Lingyi Xu
- Department of Biophysics, Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Mingfeng Zhang
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Cheng Zhao
- Department of Biophysics, Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Wei Yang
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Feng Wang
- Wuxi Biortus Biosciences Co. Ltd., 6 Dongsheng West Road, Jiangyin 214437, China
| | - Jingyuan Li
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Institute of Quantitative Biology, Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China.
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Sheng Ye
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China.
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiao-Chen Bai
- Departments of Biophysics and Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Jiangtao Guo
- Department of Biophysics, Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
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160
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Göppner C, Orozco IJ, Hoegg-Beiler MB, Soria AH, Hübner CA, Fernandes-Rosa FL, Boulkroun S, Zennaro MC, Jentsch TJ. Pathogenesis of hypertension in a mouse model for human CLCN2 related hyperaldosteronism. Nat Commun 2019; 10:4678. [PMID: 31615979 PMCID: PMC6794291 DOI: 10.1038/s41467-019-12113-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 08/21/2019] [Indexed: 12/31/2022] Open
Abstract
Human primary aldosteronism (PA) can be caused by mutations in several ion channel genes but mouse models replicating this condition are lacking. We now show that almost all known PA-associated CLCN2 mutations markedly increase ClC-2 chloride currents and generate knock-in mice expressing a constitutively open ClC-2 Cl− channel as mouse model for PA. The Clcn2op allele strongly increases the chloride conductance of zona glomerulosa cells, provoking a strong depolarization and increasing cytoplasmic Ca2+ concentration. Clcn2op mice display typical features of human PA, including high serum aldosterone in the presence of low renin activity, marked hypertension and hypokalemia. These symptoms are more pronounced in homozygous Clcn2op/op than in heterozygous Clcn2+/op mice. This difference is attributed to the unexpected finding that only ~50 % of Clcn2+/op zona glomerulosa cells are depolarized. By reproducing essential features of human PA, Clcn2op mice are a valuable model to study the pathological mechanisms underlying this disease. Mutations in the chloride channel ClC-2 have been found in primary aldosteronism (PA). Here, Göppner et al. generate transgenic mice expressing a mutant form of ClC-2 that displays increased chloride currents like patient mutations, and find it recapitulates the key pathological features of PA.
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Affiliation(s)
- Corinna Göppner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Ian J Orozco
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Maja B Hoegg-Beiler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Audrey H Soria
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | | | - Fabio L Fernandes-Rosa
- INSERM, UMRS_970, Paris Cardiovascular Research Center, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sheerazed Boulkroun
- INSERM, UMRS_970, Paris Cardiovascular Research Center, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Maria-Christina Zennaro
- INSERM, UMRS_970, Paris Cardiovascular Research Center, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service de Génétique, Paris, France
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany. .,Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany. .,NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany.
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161
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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162
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Bolnykh V, Olsen JMH, Meloni S, Bircher MP, Ippoliti E, Carloni P, Rothlisberger U. Extreme Scalability of DFT-Based QM/MM MD Simulations Using MiMiC. J Chem Theory Comput 2019; 15:5601-5613. [PMID: 31498615 DOI: 10.1021/acs.jctc.9b00424] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a highly scalable DFT-based QM/MM implementation developed within MiMiC, a recently introduced multiscale modeling framework that uses a loose-coupling strategy in conjunction with a multiple-program multiple-data (MPMD) approach. The computation of electrostatic QM/MM interactions is parallelized exploiting both distributed- and shared-memory strategies. Here, we use the efficient CPMD and GROMACS programs as QM and MM engines, respectively. The scalability is demonstrated through large-scale benchmark simulations of realistic biomolecular systems employing non-hybrid and hybrid GGA exchange-correlation functionals. We show that the loose-coupling strategy adopted in MiMiC, with its inherent high flexibility, does not carry any significant computational overhead compared to a tight-coupling scheme. Furthermore, we demonstrate that the adopted parallelization strategy enables scaling up to 13,000 CPU cores with efficiency above 70%, thus making DFT-based QM/MM MD simulations using hybrid functionals at the nanosecond scale accessible.
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Affiliation(s)
- Viacheslav Bolnykh
- Department of Physics , RWTH Aachen University , 52056 Aachen , Germany.,CaSToRC , The Cyprus Institute , 2121 Aglantzia, Nicosia , Cyprus.,Institute for Advanced Simulation (IAS-5) and Institute of Neuroscience and Medicine (INM-9) , Forschungszentrum Jülich , 52425 Jülich , Germany
| | - Jógvan Magnus Haugaard Olsen
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry , UiT The Arctic University of Norway , N-9037 Tromsø , Norway
| | - Simone Meloni
- Dipartimento di Scienze Chimiche e Farmaceutiche (DipSCF) , Università degli Studi di Ferrara (Unife) , Via Luigi Borsari 46 , I-44121 Ferrara , Italy
| | - Martin P Bircher
- Laboratory of Computational Chemistry and Biochemistry , École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland
| | - Emiliano Ippoliti
- Institute for Advanced Simulation (IAS-5) and Institute of Neuroscience and Medicine (INM-9) , Forschungszentrum Jülich , 52425 Jülich , Germany
| | - Paolo Carloni
- Department of Physics , RWTH Aachen University , 52056 Aachen , Germany.,Institute for Advanced Simulation (IAS-5) and Institute of Neuroscience and Medicine (INM-9) , Forschungszentrum Jülich , 52425 Jülich , Germany.,Institute for Neuroscience and Medicine (INM-11) , Forschungszentrum Jülich , 52425 Jülich , Germany
| | - Ursula Rothlisberger
- Laboratory of Computational Chemistry and Biochemistry , École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland
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163
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Vázquez-González V, Mayoral MJ, Chamorro R, Hendrix MMRM, Voets IK, González-Rodríguez D. Noncovalent Synthesis of Self-Assembled Nanotubes through Decoupled Hierarchical Cooperative Processes. J Am Chem Soc 2019; 141:16432-16438. [DOI: 10.1021/jacs.9b07868] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Violeta Vázquez-González
- Nanostructured Molecular Systems and Materials Group, Organic Chemistry Department, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Maria J. Mayoral
- Nanostructured Molecular Systems and Materials Group, Organic Chemistry Department, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Raquel Chamorro
- Nanostructured Molecular Systems and Materials Group, Organic Chemistry Department, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Marco M. R. M. Hendrix
- Laboratory of Self-Organizing Soft Matter, Laboratory of Macro-Organic Chemistry, Chemical Engineering and Chemistry & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
| | - Ilja K. Voets
- Laboratory of Self-Organizing Soft Matter, Laboratory of Macro-Organic Chemistry, Chemical Engineering and Chemistry & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
| | - David González-Rodríguez
- Nanostructured Molecular Systems and Materials Group, Organic Chemistry Department, Universidad Autónoma de Madrid, Madrid 28049, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Campus de Cantoblanco, Madrid 28049, Spain
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164
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Okamoto Y, Nagasawa Y, Obara Y, Ishii K, Takagi D, Ono K. Molecular identification of HSPA8 as an accessory protein of a hyperpolarization-activated chloride channel from rat pulmonary vein cardiomyocytes. J Biol Chem 2019; 294:16049-16061. [PMID: 31506297 DOI: 10.1074/jbc.ra119.007416] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 08/28/2019] [Indexed: 12/26/2022] Open
Abstract
Pulmonary veins (PVs) are the major origin of atrial fibrillation. Recently, we recorded hyperpolarization-activated Cl- current (I Cl, h) in rat PV cardiomyocytes. Unlike the well-known chloride channel protein 2 (CLCN2) current, the activation curve of I Cl, h was hyperpolarized as the Cl- ion concentration ([Cl-] i ) increased. This current could account for spontaneous activity in PV cardiomyocytes linked to atrial fibrillation. In this study, we aimed to identify the channel underlying I Cl, h Using RT-PCR amplification specific for Clcn2 or its homologs, a chloride channel was cloned from rat PV and detected in rat PV cardiomyocytes using immunocytochemistry. The gene sequence and electrophysiological functions of the protein were identical to those previously reported for Clcn2, with protein activity observed as a hyperpolarization-activated current by the patch-clamp method. However, the [Cl-] i dependence of activation was entirely different from the observed I Cl, h of PV cardiomyocytes; the activation curve of the Clcn2-transfected cells shifted toward positive potential with increased [Cl-] i , whereas the I Cl, h of PV and left ventricular cardiomyocytes showed a leftward shift. Therefore, we used MS to explore the possibility of additional proteins interacting with CLCN2 and identified an individual 71-kDa protein, HSPA8, that was strongly expressed in rat PV cardiomyocytes. With co-expression of HSPA8 in HEK293 and PC12 cells, the CLCN2 current showed voltage-dependent activation and shifted to negative potential with increasing [Cl-] i Molecular docking simulations further support an interaction between CLCN2 and HSPA8. These findings suggest that CLCN2 in rat heart contains HSPA8 as a unique accessory protein.
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Affiliation(s)
- Yosuke Okamoto
- Department of Cell Physiology, Akita Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Yoshinobu Nagasawa
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Chiba 274-8510, Japan
| | - Yutaro Obara
- Department of Pharmacology, Yamagata University Faculty of Medicine, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Kuniaki Ishii
- Department of Pharmacology, Yamagata University Faculty of Medicine, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Daichi Takagi
- Department of Cell Physiology, Akita Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Kyoichi Ono
- Department of Cell Physiology, Akita Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
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165
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Mutation of external glutamate residue reveals a new intermediate transport state and anion binding site in a CLC Cl -/H + antiporter. Proc Natl Acad Sci U S A 2019; 116:17345-17354. [PMID: 31409705 DOI: 10.1073/pnas.1901822116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The CLC family of proteins are involved in a variety of physiological processes to control cellular chloride concentration. Two distinct classes of CLC proteins, Cl- channels and Cl-/H+ antiporters, have been functionally and structurally investigated over the last several decades. Previous studies have suggested that the conformational heterogeneity of the critical glutamate residue, Gluex, could explain the transport cycle of CLC-type Cl-/H+ antiporters. However, the presence of multiple conformations (Up, Middle, and Down) of the Gluex has been suggested from combined structural snapshots of 2 different CLC antiporters: CLC-ec1 from Escherichia coli and cmCLC from a thermophilic red alga, Cyanidioschyzon merolae Thus, we aimed to investigate further the heterogeneity of Gluex-conformations in CLC-ec1, the most deeply studied CLC antiporter, at both functional and structural levels. Here, we show that the crystal structures of the Gluex mutant E148D and wild-type CLC-ec1 with varying anion concentrations suggest a structural intermediate, the "Midlow" conformation. We also found that an extra anion can be located above the external Cl--binding site in the E148D mutant when the anion concentration is high. Moreover, we observed that a carboxylate in solution can occupy either the external or central Cl--binding site in the ungated E148A mutant using an anomalously detectable short carboxylic acid, bromoacetate. These results lend credibility to the idea that the Gluex can take at least 3 distinct conformational states during the transport cycle of a single CLC antiporter.
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166
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Walter JD, Sawicka M, Dutzler R. Cryo-EM structures and functional characterization of murine Slc26a9 reveal mechanism of uncoupled chloride transport. eLife 2019; 8:46986. [PMID: 31339488 PMCID: PMC6656431 DOI: 10.7554/elife.46986] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 06/21/2019] [Indexed: 12/14/2022] Open
Abstract
The epithelial anion transporter SLC26A9 contributes to airway surface hydration and gastric acid production. Colocalizing with CFTR, SLC26A9 has been proposed as a target for the treatment of cystic fibrosis. To provide molecular details of its transport mechanism, we present cryo-EM structures and a functional characterization of murine Slc26a9. These structures define the general architecture of eukaryotic SLC26 family members and reveal an unusual mode of oligomerization which relies predominantly on the cytosolic STAS domain. Our data illustrates conformational transitions of Slc26a9, supporting a rapid alternate-access mechanism which mediates uncoupled chloride transport with negligible bicarbonate or sulfate permeability. The characterization of structure-guided mutants illuminates the properties of the ion transport path, including a selective anion binding site located in the center of a mobile module within the transmembrane domain. This study thus provides a structural foundation for the understanding of the entire SLC26 family and potentially facilitates their therapeutic exploitation. Many processes in the human body are regulated by chloride and other charged particles (known as ions) moving in and out of cells. Each cell is surrounded by a membrane barrier, which prevents ions from entering or exiting. Therefore, to control the levels of ions inside the cell, specific proteins in the membrane act as channels or transporters to provide routes for the ions to pass through the membrane. Channel proteins form pores that, when open, allow a steady stream of ions to pass through the membrane. Transporter proteins, on the other hand, generally contain a pocket that is only accessible from one side of the membrane. When individual ions enter this pocket the transporter changes shape. This causes the entrance of the pocket to close and then re-open on the other side of the membrane. Inside the lung, an ion channel known as CFTR provides a route for chloride ions to move out of cells, which helps clear harmful material from the airways. Mutations affecting this protein cause the mucus lining the airways to become very sticky, leading to a severe disease known as cystic fibrosis. CFTR works together with another protein that is also found in the membrane, called SLC26A9. Previous studies have suggested that SLC26A9 also allows chloride ions to pass through the membrane. It was not clear, however, if SLC26A9 operates as an ion channel or a transporter protein, or how the protein is arranged in the membrane. Now, Walter, Sawicka and Dutzler combined two techniques known as cryo-electron microscopy and patch-clamp electrophysiology to reveal the detailed three-dimensional structure of the mouse version of SLC26A9, which is highly similar to the human form. The experiments found that mouse SLC26A9 proteins form pairs in the membrane referred to as homodimers, which arranged themselves in an unexpected way. Further investigation into the structure of these homodimers suggests that despite having many channel-like properties, SLC26A9 operates as a fast transporter, rather than a true channel. These findings help us understand the role of SLC26A9 and other similar proteins in the lung and other parts of the body. In the future it may be possible to develop drugs that target SLC26A9 to treat cystic fibrosis and other severe lung diseases.
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Affiliation(s)
- Justin D Walter
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Marta Sawicka
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Raimund Dutzler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
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167
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Flood E, Boiteux C, Lev B, Vorobyov I, Allen TW. Atomistic Simulations of Membrane Ion Channel Conduction, Gating, and Modulation. Chem Rev 2019; 119:7737-7832. [DOI: 10.1021/acs.chemrev.8b00630] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Emelie Flood
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Céline Boiteux
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Bogdan Lev
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Igor Vorobyov
- Department of Physiology & Membrane Biology/Department of Pharmacology, University of California, Davis, 95616, United States
| | - Toby W. Allen
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
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168
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Möller IR, Slivacka M, Hausner J, Nielsen AK, Pospíšilová E, Merkle PS, Lišková R, Polák M, Loland CJ, Kádek A, Man P, Rand KD. Improving the Sequence Coverage of Integral Membrane Proteins during Hydrogen/Deuterium Exchange Mass Spectrometry Experiments. Anal Chem 2019; 91:10970-10978. [DOI: 10.1021/acs.analchem.9b00973] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Ingvar R. Möller
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Marika Slivacka
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Jiří Hausner
- BioCeV - Institute of Microbiology of the CAS, Prumyslova 595, CZ-252 50 Vestec, Czech Republic
- Faculty of Science, Charles University, Hlavova 8, CZ-128 20 Prague, Czech Republic
| | - Anne Kathrine Nielsen
- Laboratory for Membrane Protein Dynamics, Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, Copenhagen N DK-2200, Denmark
| | - Eliška Pospíšilová
- BioCeV - Institute of Microbiology of the CAS, Prumyslova 595, CZ-252 50 Vestec, Czech Republic
- Faculty of Science, Charles University, Hlavova 8, CZ-128 20 Prague, Czech Republic
| | - Patrick S. Merkle
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen E DK-2100, Denmark
| | - Růžena Lišková
- BioCeV - Institute of Microbiology of the CAS, Prumyslova 595, CZ-252 50 Vestec, Czech Republic
- Faculty of Science, Charles University, Hlavova 8, CZ-128 20 Prague, Czech Republic
| | - Marek Polák
- BioCeV - Institute of Microbiology of the CAS, Prumyslova 595, CZ-252 50 Vestec, Czech Republic
- Faculty of Science, Charles University, Hlavova 8, CZ-128 20 Prague, Czech Republic
| | - Claus J. Loland
- Laboratory for Membrane Protein Dynamics, Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, Copenhagen N DK-2200, Denmark
| | - Alan Kádek
- BioCeV - Institute of Microbiology of the CAS, Prumyslova 595, CZ-252 50 Vestec, Czech Republic
- Faculty of Science, Charles University, Hlavova 8, CZ-128 20 Prague, Czech Republic
| | - Petr Man
- BioCeV - Institute of Microbiology of the CAS, Prumyslova 595, CZ-252 50 Vestec, Czech Republic
- Faculty of Science, Charles University, Hlavova 8, CZ-128 20 Prague, Czech Republic
| | - Kasper D. Rand
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen E DK-2100, Denmark
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169
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Boer SA, Foyle EM, Thomas CM, White NG. Anion coordination chemistry using O-H groups. Chem Soc Rev 2019; 48:2596-2614. [PMID: 30860210 DOI: 10.1039/c8cs00828k] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review covers significant advances in the use of O-H groups in anion coordination chemistry. The review focuses on the use of these groups in synthetic anion receptors, as well as more recent developments in transport, self-assembly and catalysis.
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Affiliation(s)
- Stephanie A Boer
- Research School of Chemistry, The Australian National University, Canberra, Australia.
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170
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Wang W, Xu Y, Chen T, Xing L, Xu K, Xu Y, Ji D, Chen C, Xie C. Regulatory mechanisms underlying the maintenance of homeostasis in Pyropia haitanensis under hypersaline stress conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 662:168-179. [PMID: 30690352 DOI: 10.1016/j.scitotenv.2019.01.214] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/04/2019] [Accepted: 01/18/2019] [Indexed: 05/10/2023]
Abstract
Intertidal macroalgae are highly resistant to hypersaline stress conditions. However, the underlying mechanism remains unknown. In the present study, the mechanism behind Pyropia haitanensis responses to two hypersaline stress conditions [100‰ (HSS_100) and 110‰ (HSS_110)] was investigated via analyses of physiological and transcriptomic changes. We observed that the differences between the responses of Py. haitanensis to HSS_100 and HSS_110 conditions involved the following three aspects: osmotic regulation, ionic homeostasis, and adjustment to secondary stresses. First, the water retention of Py. haitanensis was maintained through increased expansin production under HSS_100 conditions, while cell wall pectin needed to be protected from hydrolysis via the increased abundance of a pectin methylesterase inhibitor under HSS_110 conditions. Meanwhile, Py. haitanensis achieved stable and rapid osmotic adjustments because of the coordinated accumulation of inorganic ions (K+, Na+, and Cl-) and organic osmolytes (glycine betaine and trehalose) under HSS_100 conditions, but not under HSS_110 conditions. Second, Py. haitanensis maintained a higher K+/Na+ ratio under HSS_100 conditions than under HSS_110 conditions, mainly via the export of Na+ into the apoplast rather than compartmentalizing it into the vacuoles, and the enhanced uptake and retention of K+. However, K+/Na+ homeostasis was not completely disrupted during a short-term exposure to HSS_110 conditions. Finally, the Py. haitanensis antioxidant system scavenged more ROS and synthesized more heat shock proteins under HSS_100 conditions than under HSS_110 conditions, although thalli may have been able to maintain a certain redox balance during a short-term exposure to HSS_110 conditions. These differences may explain why Py. haitanensis can adapt to HSS_100 conditions rather than HSS_110 conditions, and also why the thalli exposed to HSS_110 conditions can recover after being transferred to normal seawater. Thus, the data presented herein may elucidate the mechanisms enabling Pyropia species to tolerate the sudden and periodic changes in salinity typical of intertidal systems.
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Affiliation(s)
- Wenlei Wang
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China
| | - Yan Xu
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China
| | - TianXiang Chen
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China
| | - Lei Xing
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China
| | - Kai Xu
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China
| | - Yan Xu
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China
| | - Dehua Ji
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China
| | - Changsheng Chen
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China
| | - Chaotian Xie
- Fisheries College, Jimei University, Xiamen 361021, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Xiamen 361021, China.
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171
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Morshedi M, Boer SA, Thomas M, White NG. Easily-prepared Hydroxy-containing Receptors Recognize Anions in Aqueous Media. Chem Asian J 2019; 14:1271-1277. [PMID: 30747486 DOI: 10.1002/asia.201900033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Indexed: 12/20/2022]
Abstract
Despite their ready availability, O-H groups have received relatively little attention as anion recognition motifs. Here, we report two simple hydroxy-containing anion receptors that are prepared in two facile steps followed by anion exchange, without the need for chromatographic purification at any stage. These receptors contain a pyridinium bis(amide) motif as well as hydroxyphenyl groups, and bind mono- and divalent anions in 9:1 CD3 CN:D2 O, showing a selectivity preference for sulfate. Notably, a "model" receptor that does not contain hydroxy groups shows only very weak sulfate binding in this competitive solvent mixture. In the solid state, X-ray crystallographic studies show that the receptors tend to form extended assemblies with anions; however, 1 H and DOSY NMR studies as well as molecular dynamics simulations show that only 1:1 complexes are present in solution. Molecular dynamics simulations suggest that one of the receptors suffers from competing intramolecular hydrogen bonding, while another binds partially-hydrated anions, with the receptor's O-H groups forming hydrogen bonds to water molecules within the anion's coordination sphere.
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Affiliation(s)
- Mahbod Morshedi
- Research School of Chemistry, The Australian National University, Canberra, ACT, Australia
| | - Stephanie A Boer
- Research School of Chemistry, The Australian National University, Canberra, ACT, Australia
| | - Michael Thomas
- Research School of Chemistry, The Australian National University, Canberra, ACT, Australia
| | - Nicholas G White
- Research School of Chemistry, The Australian National University, Canberra, ACT, Australia
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172
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Wang K, Preisler SS, Zhang L, Cui Y, Missel JW, Grønberg C, Gotfryd K, Lindahl E, Andersson M, Calloe K, Egea PF, Klaerke DA, Pusch M, Pedersen PA, Zhou ZH, Gourdon P. Structure of the human ClC-1 chloride channel. PLoS Biol 2019; 17:e3000218. [PMID: 31022181 PMCID: PMC6483157 DOI: 10.1371/journal.pbio.3000218] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 03/22/2019] [Indexed: 11/18/2022] Open
Abstract
ClC-1 protein channels facilitate rapid passage of chloride ions across cellular membranes, thereby orchestrating skeletal muscle excitability. Malfunction of ClC-1 is associated with myotonia congenita, a disease impairing muscle relaxation. Here, we present the cryo-electron microscopy (cryo-EM) structure of human ClC-1, uncovering an architecture reminiscent of that of bovine ClC-K and CLC transporters. The chloride conducting pathway exhibits distinct features, including a central glutamate residue ("fast gate") known to confer voltage-dependence (a mechanistic feature not present in ClC-K), linked to a somewhat rearranged central tyrosine and a narrower aperture of the pore toward the extracellular vestibule. These characteristics agree with the lower chloride flux of ClC-1 compared with ClC-K and enable us to propose a model for chloride passage in voltage-dependent CLC channels. Comparison of structures derived from protein studied in different experimental conditions supports the notion that pH and adenine nucleotides regulate ClC-1 through interactions between the so-called cystathionine-β-synthase (CBS) domains and the intracellular vestibule ("slow gating"). The structure also provides a framework for analysis of mutations causing myotonia congenita and reveals a striking correlation between mutated residues and the phenotypic effect on voltage gating, opening avenues for rational design of therapies against ClC-1-related diseases.
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Affiliation(s)
- Kaituo Wang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Microbiology, Immunology & Molecular Genetics, University of California at Los Angeles, Los Angeles, California
- California NanoSystems Institute, University of California at Los Angeles, Los Angeles, California
| | | | - Liying Zhang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yanxiang Cui
- Department of Microbiology, Immunology & Molecular Genetics, University of California at Los Angeles, Los Angeles, California
- California NanoSystems Institute, University of California at Los Angeles, Los Angeles, California
| | - Julie Winkel Missel
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christina Grønberg
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kamil Gotfryd
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Erik Lindahl
- Department of Biochemistry & Biophysics, Stockholm University, Stockholm, Sweden
| | | | - Kirstine Calloe
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Pascal F. Egea
- Department of Biological Chemistry, University of California at Los Angeles, Los Angeles, California
| | - Dan Arne Klaerke
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Michael Pusch
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
| | | | - Z. Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California at Los Angeles, Los Angeles, California
- California NanoSystems Institute, University of California at Los Angeles, Los Angeles, California
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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173
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Abstract
Of all the macromolecular assemblies of life, the least understood is the biomembrane. This is especially true in regard to its atomic structure. Ideas on biomembranes, developed in the last 200 years, culminated in the fluid mosaic model of the membrane. In this essay, I provide a historical outline of how we arrived at our current understanding of biomembranes and the models we use to describe them. A selection of direct experimental findings on the nano-scale structure of biomembranes is taken up to discuss their physical nature, and special emphasis is put on the surprising insights that arise from atomic scale descriptions.
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174
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Strickland M, Yacoubi-Loueslati B, Bouhaouala-Zahar B, Pender SLF, Larbi A. Relationships Between Ion Channels, Mitochondrial Functions and Inflammation in Human Aging. Front Physiol 2019; 10:158. [PMID: 30881309 PMCID: PMC6405477 DOI: 10.3389/fphys.2019.00158] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/08/2019] [Indexed: 12/19/2022] Open
Abstract
Aging is often associated with a loss of function. We believe aging to be more an adaptation to the various, and often continuous, stressors encountered during life in order to maintain overall functionality of the systems. The maladaptation of a system during aging may increase the susceptibility to diseases. There are basic cellular functions that may influence and/or are influenced by aging. Mitochondrial function is amongst these. Their presence in almost all cell types makes of these valuable targets for interventions to slow down or even reserve signs of aging. In this review, the role of mitochondria and essential physiological regulators of mitochondria and cellular functions, ion channels, will be discussed in the context of human aging. The origins of inflamm-aging, associated with poor clinical outcomes, will be linked to mitochondria and ion channel biology.
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Affiliation(s)
- Marie Strickland
- Singapore Immunology Network, Agency for Science Technology and Research, Singapore, Singapore
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Besma Yacoubi-Loueslati
- Laboratory of Mycology, Pathologies and Biomarkers, Department of Biology, Faculty of Sciences, University Tunis El Manar, Tunis, Tunisia
| | - Balkiss Bouhaouala-Zahar
- Laboratory of Venoms and Therapeutic Molecules, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
- Medical School of Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Sylvia L. F. Pender
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- Chinese University of Hong Kong – University of Southampton Joint Lab for Stem Cell and Regenerative Medicine, Hong Kong, China
| | - Anis Larbi
- Singapore Immunology Network, Agency for Science Technology and Research, Singapore, Singapore
- Department of Biology, Faculty of Sciences, University Tunis El Manar, Tunis, Tunisia
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Geriatrics Division, Department of Medicine, Research Center on Aging, University of Sherbrooke, Sherbrooke, QC, Canada
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175
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Elorza-Vidal X, Gaitán-Peñas H, Estévez R. Chloride Channels in Astrocytes: Structure, Roles in Brain Homeostasis and Implications in Disease. Int J Mol Sci 2019; 20:ijms20051034. [PMID: 30818802 PMCID: PMC6429410 DOI: 10.3390/ijms20051034] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/15/2019] [Accepted: 02/17/2019] [Indexed: 12/29/2022] Open
Abstract
Astrocytes are the most abundant cell type in the CNS (central nervous system). They exert multiple functions during development and in the adult CNS that are essential for brain homeostasis. Both cation and anion channel activities have been identified in astrocytes and it is believed that they play key roles in astrocyte function. Whereas the proteins and the physiological roles assigned to cation channels are becoming very clear, the study of astrocytic chloride channels is in its early stages. In recent years, we have moved from the identification of chloride channel activities present in astrocyte primary culture to the identification of the proteins involved in these activities, the determination of their 3D structure and attempts to gain insights about their physiological role. Here, we review the recent findings related to the main chloride channels identified in astrocytes: the voltage-dependent ClC-2, the calcium-activated bestrophin, the volume-activated VRAC (volume-regulated anion channel) and the stress-activated Maxi-Cl−. We discuss key aspects of channel biophysics and structure with a focus on their role in glial physiology and human disease.
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Affiliation(s)
- Xabier Elorza-Vidal
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
- Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII, 08907 Barcelona, Spain.
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176
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Abstract
Most proteins associate with other proteins to function, forming complexes that are central to almost all physiological processes. Determining the structures of these complexes and understanding how they associate are problems of fundamental importance. Using long-timescale molecular dynamics simulations, some performed using a new enhanced sampling method, we observed spontaneous association and dissociation of five protein–protein systems to and from their experimentally determined native complexes. By analyzing the simulations of these five systems, which include members of diverse structural and functional classes, we are able to draw general mechanistic conclusions about protein association. Despite the biological importance of protein–protein complexes, determining their structures and association mechanisms remains an outstanding challenge. Here, we report the results of atomic-level simulations in which we observed five protein–protein pairs repeatedly associate to, and dissociate from, their experimentally determined native complexes using a molecular dynamics (MD)–based sampling approach that does not make use of any prior structural information about the complexes. To study association mechanisms, we performed additional, conventional MD simulations, in which we observed numerous spontaneous association events. A shared feature of native association for these five structurally and functionally diverse protein systems was that if the proteins made contact far from the native interface, the native state was reached by dissociation and eventual reassociation near the native interface, rather than by extensive interfacial exploration while the proteins remained in contact. At the transition state (the conformational ensemble from which association to the native complex and dissociation are equally likely), the protein–protein interfaces were still highly hydrated, and no more than 20% of native contacts had formed.
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177
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Structure and Mechanism of the Divalent Anion/Na⁺ Symporter. Int J Mol Sci 2019; 20:ijms20020440. [PMID: 30669552 PMCID: PMC6359215 DOI: 10.3390/ijms20020440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/14/2019] [Accepted: 01/18/2019] [Indexed: 12/22/2022] Open
Abstract
Integral membrane proteins of the divalent anion/Na⁺ symporter (DASS) family are conserved from bacteria to humans. DASS proteins typically mediate the coupled uptake of Na⁺ ions and dicarboxylate, tricarboxylate, or sulfate. Since the substrates for DASS include key intermediates and regulators of energy metabolism, alterations of DASS function profoundly affect fat storage, energy expenditure and life span. Furthermore, loss-of-function mutations in a human DASS have been associated with neonatal epileptic encephalopathy. More recently, human DASS has also been implicated in the development of liver cancers. Therefore, human DASS proteins are potentially promising pharmacological targets for battling obesity, diabetes, kidney stone, fatty liver, as well as other metabolic and neurological disorders. Despite its clinical relevance, the mechanism by which DASS proteins recognize and transport anionic substrates remains unclear. Recently, the crystal structures of a bacterial DASS and its humanized variant have been published. This article reviews the mechanistic implications of these structures and suggests future work to better understand how the function of DASS can be modulated for potential therapeutic benefit.
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178
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Duster AW, Garza CM, Aydintug BO, Negussie MB, Lin H. Adaptive Partitioning QM/MM for Molecular Dynamics Simulations: 6. Proton Transport through a Biological Channel. J Chem Theory Comput 2019; 15:892-905. [DOI: 10.1021/acs.jctc.8b01128] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adam W. Duster
- Chemistry Department, CB 194, University of Colorado, Denver, Colorado 80217, United States
| | - Christina M. Garza
- Chemistry Department, CB 194, University of Colorado, Denver, Colorado 80217, United States
| | - Baris O. Aydintug
- Chemistry Department, CB 194, University of Colorado, Denver, Colorado 80217, United States
| | - Mikias B. Negussie
- Chemistry Department, CB 194, University of Colorado, Denver, Colorado 80217, United States
| | - Hai Lin
- Chemistry Department, CB 194, University of Colorado, Denver, Colorado 80217, United States
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179
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Lagostena L, Zifarelli G, Picollo A. New Insights into the Mechanism of NO 3 - Selectivity in the Human Kidney Chloride Channel ClC-Ka and the CLC Protein Family. J Am Soc Nephrol 2019; 30:293-302. [PMID: 30635372 DOI: 10.1681/asn.2018060593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 12/01/2018] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND The mechanism of anion selectivity in the human kidney chloride channels ClC-Ka and ClC-Kb is unknown. However, it has been thought to be very similar to that of other channels and antiporters of the CLC protein family, and to rely on anions interacting with a conserved Ser residue (Sercen) at the center of three anion binding sites in the permeation pathway Scen. In both CLC channels and antiporters, mutations of Sercen alter the anion selectivity. Structurally, the side chain of Sercen of CLC channels and antiporters typically projects into the pore and coordinates the anion bound at Scen. METHODS To investigate the role of several residues in anion selectivity of ClC-Ka, we created mutations that resulted in amino acid substitutions in these residues. We also used electrophysiologic techniques to assess the properties of the mutants. RESULTS Mutations in ClC-Ka that change Sercen to Gly, Pro, or Thr have only minor effects on anion selectivity, whereas the mutations in residues Y425A, F519A, and Y520A increase the NO3 -/Cl- permeability ratio, with Y425A having a particularly strong effect. CONCLUSION s ClC-Ka's mechanism of anion selectivity is largely independent of Sercen, and it is therefore unique in the CLC protein family. We identified the residue Y425 in ClC-Ka-and the corresponding residue (A417) in the chloride channel ClC-0-as residues that contribute to NO3 - discrimination in these channels. This work provides important and timely insight into the relationship between structure and function for the kidney chloride channels ClC-Ka and ClC-Kb, and for CLC proteins in general.
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Affiliation(s)
- Laura Lagostena
- Dulbecco Telethon Laboratory, Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy; and
| | - Giovanni Zifarelli
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Alessandra Picollo
- Dulbecco Telethon Laboratory, Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy; and
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180
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Dayal A, Ng SFJ, Grabner M. Ca 2+-activated Cl - channel TMEM16A/ANO1 identified in zebrafish skeletal muscle is crucial for action potential acceleration. Nat Commun 2019; 10:115. [PMID: 30631052 PMCID: PMC6328546 DOI: 10.1038/s41467-018-07918-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 12/03/2018] [Indexed: 01/16/2023] Open
Abstract
The Ca2+-activated Cl− channel (CaCC) TMEM16A/Anoctamin 1 (ANO1) is expressed in gastrointestinal epithelia and smooth muscle cells where it mediates secretion and intestinal motility. However, ANO1 Cl− conductance has never been reported to play a role in skeletal muscle. Here we show that ANO1 is robustly expressed in the highly evolved skeletal musculature of the euteleost species zebrafish. We characterised ANO1 as bonafide CaCC which is activated close to maximum by Ca2+ ions released from the SR during excitation-contraction (EC) coupling. Consequently, our study addressed the question about the physiological advantage of implementation of ANO1 into the euteleost skeletal-muscle EC coupling machinery. Our results reveal that Cl− influx through ANO1 plays an essential role in restricting the width of skeletal-muscle action potentials (APs) by accelerating the repolarisation phase. Resulting slimmer APs enable higher AP-frequencies and apparently tighter controlled, faster and stronger muscle contractions, crucial for high speed movements. The Ca2+-activated Cl- channel TMEM16A/Anoctamin 1 (ANO1) mediates secretion and intestinal motility in gastrointestinal epithelia and smooth muscle cells. Here, the authors show a role for ANO1 in zebrafish skeletal muscle which is activated by SR Ca2+ release during excitation-contraction coupling.
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Affiliation(s)
- Anamika Dayal
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria.
| | - Shu Fun J Ng
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria
| | - Manfred Grabner
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division of Biochemical Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1, A-6020, Innsbruck, Austria.
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181
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Ju C, Park C, Kim T, Kang S, Kang H. Thermo-responsive draw solute for forward osmosis process; poly(ionic liquid) having lower critical solution temperature characteristics. RSC Adv 2019; 9:29493-29501. [PMID: 35531499 PMCID: PMC9072005 DOI: 10.1039/c9ra04020j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/30/2019] [Indexed: 12/31/2022] Open
Abstract
A poly(ionic liquid) having lower critical solution temperature characteristics was synthesized to investigate its suitability as a draw solute for forward osmosis.
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Affiliation(s)
- Changha Ju
- Department of Chemical Engineering
- Dong-A University
- Busan 49315
- Republic of Korea
| | - Chanhyuk Park
- Department of Chemical Engineering
- Dong-A University
- Busan 49315
- Republic of Korea
| | - Taehyung Kim
- Department of Chemical Engineering
- Dong-A University
- Busan 49315
- Republic of Korea
| | - Shinwoo Kang
- Department of Chemical Engineering
- Dong-A University
- Busan 49315
- Republic of Korea
| | - Hyo Kang
- Department of Chemical Engineering
- Dong-A University
- Busan 49315
- Republic of Korea
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182
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Teulon J, Planelles G, Sepúlveda FV, Andrini O, Lourdel S, Paulais M. Renal Chloride Channels in Relation to Sodium Chloride Transport. Compr Physiol 2018; 9:301-342. [DOI: 10.1002/cphy.c180024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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183
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Wang Z, Swanson JMJ, Voth GA. Modulating the Chemical Transport Properties of a Transmembrane Antiporter via Alternative Anion Flux. J Am Chem Soc 2018; 140:16535-16543. [PMID: 30421606 PMCID: PMC6379079 DOI: 10.1021/jacs.8b07614] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
![]()
ClC-ec1 is a prototype of the ClC
antiporters, proteins that stoichiometrically
exchange Cl– and H+ ions in opposite
directions across a membrane. It has been shown that other polyatomic
anions, such as NO3– and SCN–, can also be transported by ClC-ec1, but with partially or completely
uncoupled proton flux. Herein, with the help of multiscale computer
simulations in which the Grotthuss mechanism of proton transport (PT)
is treated explicitly, we demonstrate how the chemical nature of these
anions alters the coupling mechanism and qualitatively explain the
shifts in the ion stoichiometry. Multidimensional free energy profiles
for PT and the coupled changes in hydration are presented for NO3– and SCN–. The calculated
proton conductances agree with experiment, showing reduced or abolished
proton flux. Surprisingly, the proton affinity of the anion is less
influential on the PT, while its size and interactions with the protein
significantly alter hydration and shift its influence on PT from facilitating
to inhibiting. We find that the hydration of the cavity below the
anion is relatively fast, but connecting the water network past the
steric hindrance of these polyatomic anions is quite slow. Hence,
the most relevant coordinate to the PT free energy barrier is the
water connectivity along the PT pathway, but importantly only in the
presence of the excess proton, and this coordinate is significantly
affected by the nature of the bound anion. This work again demonstrates
how PT is intrinsically coupled with protein cavity hydration changes
as well as influenced by the protein environment. It additionally
suggests ways in which ion exchange can be modulated and exchange
stoichiometries altered.
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Affiliation(s)
- Zhi Wang
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Jessica M J Swanson
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Gregory A Voth
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics , The University of Chicago , Chicago , Illinois 60637 , United States
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184
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Rapp CL, Li J, Badior KE, Williams DB, Casey JR, Reithmeier RAF. Role of N-glycosylation in the expression of human SLC26A2 and A3 anion transport membrane glycoproteins 1. Biochem Cell Biol 2018; 97:290-306. [PMID: 30462520 DOI: 10.1139/bcb-2018-0139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The human solute carrier 26 (SLC26) gene family of anion transporters consists of 10 members (SLC26A1-A11, A10 being a pseudogene) that encode membrane glycoproteins with 14 transmembrane segments and a C-terminal cytoplasmic sulfate transporter anti-sigma antagonist domain. Thus far, mutations in eight members of the SLC26 family (A1-A6, A8, and A9) have been linked to diseases in humans. Our goal is to characterize the role of N-glycosylation and the effect of mutations in SLC26A2 and A3 proteins on their functional expression in transfected HEK-293 cells. We found that certain mutants were retained in the endoplamic reticulum via an interaction with the lectin chaperone calnexin. Some could escape protein quality control and traffic to the cell surface upon removal of the N-glycosylation sites. Furthermore, we found that loss of N-glycosylation reduced expression of SLC26A2 at the cell surface. Loss of N-glycosylation had no effect on the stability of SLC26A3, yet resulted in a profound decrease in transport activity. Thus, N-glycosylation plays three roles in the functional expression of SLC26 proteins: (1) to retain misfolded proteins in the endoplamic reticulum, (2) to stabilize the protein at the cell surface, and (3) to maintain the transport protein in a functional state.
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Affiliation(s)
- Chloe L Rapp
- a Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Jing Li
- a Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Katherine E Badior
- b Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - David B Williams
- a Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Joseph R Casey
- b Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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185
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Zhang H, Jin J, Jin L, Li Z, Xu G, Wang R, Zhang J, Zhai N, Chen Q, Liu P, Chen X, Zheng Q, Zhou H. Identification and analysis of the chloride channel gene family members in tobacco (Nicotiana tabacum). Gene 2018; 676:56-64. [PMID: 29958955 DOI: 10.1016/j.gene.2018.06.073] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/12/2018] [Accepted: 06/22/2018] [Indexed: 11/30/2022]
Abstract
The chloride channel (CLC) protein family, which includes both chloride (Cl-) channels and chloride/proton (Cl-/H+) antiporters, is present in all domains of life, from prokaryotes to eukaryotes. However, there are no reported studies about this gene family in tobacco, an economically important global crop plant. In this study, we identified seventeen CLC genes in the genome of Nicotiana tabacum. A multiple sequence alignment showed that all of the predicted proteins shared a high sequence similarity and had a highly conserved GKxGPxxH motif. A gene structure analysis revealed that the NtCLC genes had highly divergent intron-exon patterns. A phylogenetic and conserved motif analysis revealed that the NtCLC family was divided into two clades, in a manner similar to other plants. We also evaluated the expression patterns of these NtCLC genes in different tissues and in plants treated with salt stress. The NtCLC genes had highly variable expression patterns, for example, the largely stem- and bud-specific expression patterns of NtCLC6 and NtCLC8, respectively. Salt stress treatment (300 mM NaCl) induced the expression of NtCLC2, NtCLC3, and NtCLC12, suggesting that these genes might play a role in tobacco responses to salt stress. Furthermore, the concentration of Cl- in the NtCLC2- and NtCLC13-silenced plants showed an obvious lower and higher level, respectively, than the control plants. Thus, we indicated that NtCLC2 or NtCLC13 might play an important role in chloride transport or metabolism in tobacco. Together, these findings establish an empirical foundation for the further functional characterization of the NtCLC genes in tobacco.
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Affiliation(s)
- Hui Zhang
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Jingjing Jin
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Lifeng Jin
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Zefeng Li
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Guoyun Xu
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Ran Wang
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Jianfeng Zhang
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Niu Zhai
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Qiansi Chen
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Pingping Liu
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Xia Chen
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Qingxia Zheng
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China
| | - Huina Zhou
- China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450000, China.
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186
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Espinoza EM, Clark JA, Derr JB, Bao D, Georgieva B, Quina FH, Vullev VI. How Do Amides Affect the Electronic Properties of Pyrene? ACS OMEGA 2018; 3:12857-12867. [PMID: 31458010 PMCID: PMC6644773 DOI: 10.1021/acsomega.8b01581] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/24/2018] [Indexed: 05/12/2023]
Abstract
The electronic properties of amide linkers, which are intricate components of biomolecules, offer a wealth of unexplored possibilities. Herein, we demonstrate how the different modes of attaching an amide to a pyrene chromophore affect the electrochemical and optical properties of the chromophore. Thus, although they cause minimal spectral shifts, amide substituents can improve either the electron-accepting or electron-donating capabilities of pyrene. Specifically, inversion of the amide orientation shifts the reduction potentials by 200 mV. These trends indicate that, although amides affect to a similar extent the energies of the ground and singlet excited states of pyrene, the effects on the doublet states of its radical ions are distinctly different. This behavior reflects the unusually strong orientation dependence of the resonance effects of amide substituents, which should extend to amide substituents on other types of chromophores in general. These results represent an example where the Hammett sigma constants fail to predict substituent effects on electrochemical properties. On the other hand, Swain-Lupton parameters are found to be in good agreement with the observed trends. Examination of the frontier orbitals of the pyrene derivatives and their components reveals the underlying reason for the observed amide effects on the electronic properties of this polycyclic aromatic hydrocarbon and points to key molecular-design strategies for electronic and energy-conversion systems.
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Affiliation(s)
- Eli M. Espinoza
- Department
of Chemistry, Department of Bioengineering, Department of Biochemistry, and Materials Science
and Engineering Program, University of California, Riverside, California 92521, United States
- Instituto
de Química, Universidade de São
Paulo, Avenida Lineu
Prestes 748, Cidade Universitária, São
Paulo 05508-000, Brazil
| | - John A. Clark
- Department
of Chemistry, Department of Bioengineering, Department of Biochemistry, and Materials Science
and Engineering Program, University of California, Riverside, California 92521, United States
| | - James B. Derr
- Department
of Chemistry, Department of Bioengineering, Department of Biochemistry, and Materials Science
and Engineering Program, University of California, Riverside, California 92521, United States
| | - Duoduo Bao
- Department
of Chemistry, Department of Bioengineering, Department of Biochemistry, and Materials Science
and Engineering Program, University of California, Riverside, California 92521, United States
| | - Boriana Georgieva
- Department
of Chemistry, Department of Bioengineering, Department of Biochemistry, and Materials Science
and Engineering Program, University of California, Riverside, California 92521, United States
| | - Frank H. Quina
- Instituto
de Química, Universidade de São
Paulo, Avenida Lineu
Prestes 748, Cidade Universitária, São
Paulo 05508-000, Brazil
- E-mail: (F.H.Q.)
| | - Valentine I. Vullev
- Department
of Chemistry, Department of Bioengineering, Department of Biochemistry, and Materials Science
and Engineering Program, University of California, Riverside, California 92521, United States
- E-mail: (V.I.V.)
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187
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Vachel L, Shcheynikov N, Yamazaki O, Fremder M, Ohana E, Son A, Shin DM, Yamazaki-Nakazawa A, Yang CR, Knepper MA, Muallem S. Modulation of Cl - signaling and ion transport by recruitment of kinases and phosphatases mediated by the regulatory protein IRBIT. Sci Signal 2018; 11:11/554/eaat5018. [PMID: 30377224 DOI: 10.1126/scisignal.aat5018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
IRBIT is a multifunctional protein that controls the activity of various epithelial ion transporters including NBCe1-B. Interaction with IRBIT increases NBCe1-B activity and exposes two cryptic Cl--sensing GXXXP sites that enable regulation of NBCe1-B by intracellular Cl- (Cl- in). Here, phosphoproteomic analysis revealed that IRBIT controlled five phosphorylation sites in NBCe1-B that determined both the active conformation of the transporter and its regulation by Cl- in Mutational analysis suggested that the phosphorylation status of Ser232, Ser233, and Ser235 was regulated by IRBIT and determined whether NBCe1 transporters are in active or inactive conformations. The absence of phosphorylation at Ser232, Ser233, or Ser235 produced NBCe1-B in the conformations pSer233/pSer235, pSer232/pSer235, or pSer232/pSer233, respectively. The activity of the pSer233/pSer235 form was similar to that of IRBIT-activated NBCe1-B, but it was insensitive to inhibition by Cl- in The properties of the pSer232/pSer235 form were similar to those of wild-type NBCe1-B, whereas the pSer232/pSer233 form was partially active, further activated by IRBIT, but retained inhibition by Cl- in Furthermore, IRBIT recruited the phosphatase PP1 and the kinase SPAK to control phosphorylation of Ser65, which affected Cl- in sensing by the 32GXXXP36 motif. IRBIT also recruited the phosphatase calcineurin and the kinase CaMKII to control phosphorylation of Ser12, which affected Cl- in sensing by the 194GXXXP198 motif. Ser232, Ser233, and Ser235 are conserved in all NBCe1 variants and affect their activity. These findings reveal how multiple kinase and phosphatase pathways use phosphorylation sites to fine-tune a transporter, which have important implications for epithelial fluid and HCO3 - secretion.
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Affiliation(s)
- Laura Vachel
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nikolay Shcheynikov
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Osamu Yamazaki
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.,Apheresis and Dialysis Center/General Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-0016, Japan
| | - Moran Fremder
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Ehud Ohana
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Aran Son
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul 120-752, Korea
| | - Ai Yamazaki-Nakazawa
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chin-Rang Yang
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
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188
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The extracellular loop of Man-PTS subunit IID is responsible for the sensitivity of Lactococcus garvieae to garvicins A, B and C. Sci Rep 2018; 8:15790. [PMID: 30361679 PMCID: PMC6202411 DOI: 10.1038/s41598-018-34087-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/07/2018] [Indexed: 11/23/2022] Open
Abstract
Mannose phosphotransferase system (Man-PTS) serves as a receptor for several bacteriocins in sensitive bacterial cells, namely subclass IIa bacteriocins (pediocin-like; pediocins) and subclass IId ones - lactococcin A (LcnA), lactococcin B (LcnB) and garvicin Q (GarQ). Here, to identify the receptor for three other narrow-spectrum subclass IId bacteriocins - garvicins A, B and C (GarA-C) Lactococcus garvieae mutants resistant to bacteriocins were generated and sequenced to look for mutations responsible for resistance. Spontaneous mutants had their whole genome sequenced while in mutants obtained by integration of pGhost9::ISS1 regions flanking the integration site were sequenced. For both types of mutants mutations were found in genes encoding Man-PTS components IIC and IID indicating that Man-PTS likely serves as the receptor for these bacteriocins as well. This was subsequently confirmed by deletion of the man-PTS operon in the bacteriocin-sensitive L. garvieae IBB3403, which resulted in resistant cells, and by heterologous expression of appropriate man-PTS genes in the resistant Lactococcus lactis strains, which resulted in sensitive cells. GarA, GarB, GarC and other Man-PTS-targeting bacteriocins differ in the amino acid sequence and activity spectrum, suggesting that they interact with the receptor through distinct binding patterns. Comparative analyses and genetic studies identified a previously unrecognized extracellular loop of Man-PTS subunit IID (γ+) implicated in the L. garvieae sensitivity to the bacteriocins studied here. Additionally, individual amino acids localized mostly in the sugar channel-forming transmembrane parts of subunit IIC or in the extracellular parts of IID likely involved in the interaction with each bacteriocin were specified. Finally, template-based 3D models of Man-PTS subunits IIC and IID were built to allow a deeper insight into the Man-PTS structure and functioning.
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189
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Böhm J, Messerer M, Müller HM, Scholz-Starke J, Gradogna A, Scherzer S, Maierhofer T, Bazihizina N, Zhang H, Stigloher C, Ache P, Al-Rasheid KAS, Mayer KFX, Shabala S, Carpaneto A, Haberer G, Zhu JK, Hedrich R. Understanding the Molecular Basis of Salt Sequestration in Epidermal Bladder Cells of Chenopodium quinoa. Curr Biol 2018; 28:3075-3085.e7. [PMID: 30245105 DOI: 10.1016/j.cub.2018.08.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/20/2018] [Accepted: 08/01/2018] [Indexed: 02/03/2023]
Abstract
Soil salinity is destroying arable land and is considered to be one of the major threats to global food security in the 21st century. Therefore, the ability of naturally salt-tolerant halophyte plants to sequester large quantities of salt in external structures, such as epidermal bladder cells (EBCs), is of great interest. Using Chenopodium quinoa, a pseudo-cereal halophyte of great economic potential, we have shown previously that, upon removal of salt bladders, quinoa becomes salt sensitive. In this work, we analyzed the molecular mechanism underlying the unique salt dumping capabilities of bladder cells in quinoa. The transporters differentially expressed in the EBC transcriptome and functional electrophysiological testing of key EBC transporters in Xenopus oocytes revealed that loading of Na+ and Cl- into EBCs is mediated by a set of tailored plasma and vacuole membrane-based sodium-selective channel and chloride-permeable transporter.
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Affiliation(s)
- Jennifer Böhm
- Tasmanian Institute for Agriculture, College of Science and Engineering, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia
| | - Maxim Messerer
- Plant Genome and Systems Biology, Helmholtz Center Munich, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Heike M Müller
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius-von-Sachs Platz 2, 97082 Wuerzburg, Germany
| | - Joachim Scholz-Starke
- Institute of Biophysics, National Research Council (CNR), Via De Marini 6, 16149 Genova, Italy
| | - Antonella Gradogna
- Institute of Biophysics, National Research Council (CNR), Via De Marini 6, 16149 Genova, Italy
| | - Sönke Scherzer
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius-von-Sachs Platz 2, 97082 Wuerzburg, Germany
| | - Tobias Maierhofer
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius-von-Sachs Platz 2, 97082 Wuerzburg, Germany
| | - Nadia Bazihizina
- Tasmanian Institute for Agriculture, College of Science and Engineering, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia; Department of Agrifood Production and Environmental Sciences, Università degli Studi di Firenze, Viale delle Idee 30, 50019 Sesto Fiorentino, Florence, Italy
| | - Heng Zhang
- Shanghai Center for Plant Stress Biology, and CAS Center for Excellence in Molecular Plant Sciences, 3888 Chenhua Road, Shanghai 201602, China
| | - Christian Stigloher
- Imaging Core Facility, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
| | - Peter Ache
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius-von-Sachs Platz 2, 97082 Wuerzburg, Germany
| | - Khaled A S Al-Rasheid
- Zoology Department, College of Science, King Saud University, PO Box 2455, Riyadh 11451, Saudi Arabia
| | - Klaus F X Mayer
- Plant Genome and Systems Biology, Helmholtz Center Munich, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Sergey Shabala
- Tasmanian Institute for Agriculture, College of Science and Engineering, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia; Department of Horticulture, Foshan University, Foshan 528000, PRC
| | - Armando Carpaneto
- Institute of Biophysics, National Research Council (CNR), Via De Marini 6, 16149 Genova, Italy; Department of Earth, Environment and Life Sciences (DISTAV), University of Genoa, Viale Benedetto XV 5, 16132 Genova, Italy
| | - Georg Haberer
- Plant Genome and Systems Biology, Helmholtz Center Munich, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, and CAS Center for Excellence in Molecular Plant Sciences, 3888 Chenhua Road, Shanghai 201602, China; Department of Horticulture and Landscape Architecture, Purdue University, 625 Agriculture Mall Drive, West Lafayette, IN 47907, USA.
| | - Rainer Hedrich
- Institute for Molecular Plant Physiology and Biophysics, University of Wuerzburg, Julius-von-Sachs Platz 2, 97082 Wuerzburg, Germany.
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190
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Derr JB, Tamayo J, Espinoza EM, Clark JA, Vullev VI. Dipole-induced effects on charge transfer and charge transport. Why do molecular electrets matter? CAN J CHEM 2018. [DOI: 10.1139/cjc-2017-0389] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Charge transfer (CT) and charge transport (CTr) are at the core of life-sustaining biological processes and of processes that govern the performance of electronic and energy-conversion devices. Electric fields are invaluable for guiding charge movement. Therefore, as electrostatic analogues of magnets, electrets have unexplored potential for generating local electric fields for accelerating desired CT processes and suppressing undesired ones. The notion about dipole-generated local fields affecting CT has evolved since the middle of the 20th century. In the 1990s, the first reports demonstrating the dipole effects on the kinetics of long-range electron transfer appeared. Concurrently, the development of molecular-level designs of electric junctions has led the exploration of dipole effects on CTr. Biomimetic molecular electrets such as polypeptide helices are often the dipole sources in CT systems. Conversely, surface-charge electrets and self-assembled monolayers of small polar conjugates are the preferred sources for modifying interfacial electric fields for controlling CTr. The multifaceted complexity of such effects on CT and CTr testifies for the challenges and the wealth of this field that still remains largely unexplored. This review outlines the basic concepts about dipole effects on CT and CTr, discusses their evolution, and provides accounts for their future developments and impacts.
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Affiliation(s)
- James B. Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
| | - Jesse Tamayo
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Eli M. Espinoza
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - John A. Clark
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Valentine I. Vullev
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
- Department of Chemistry, University of California, Riverside, CA 92521, USA
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
- Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA
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191
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Jennings ML. Carriers, exchangers, and cotransporters in the first 100 years of the Journal of General Physiology. J Gen Physiol 2018; 150:1063-1080. [PMID: 30030301 PMCID: PMC6080889 DOI: 10.1085/jgp.201812078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Jennings reviews the many contributions of JGP articles to our current understanding of solute transporter mechanisms. Transporters, pumps, and channels are proteins that catalyze the movement of solutes across membranes. The single-solute carriers, coupled exchangers, and coupled cotransporters that are collectively known as transporters are distinct from conductive ion channels, water channels, and ATP-hydrolyzing pumps. The main conceptual framework for studying transporter mechanisms is the alternating access model, which comprises substrate binding and release events on each side of the permeability barrier and translocation events involving conformational changes between inward-facing and outward-facing conformational states. In 1948, the Journal of General Physiology began to publish work that focused on the erythrocyte glucose transporter—the first transporter to be characterized kinetically—followed by articles on the rates, stoichiometries, asymmetries, voltage dependences, and regulation of coupled exchangers and cotransporters beginning in the 1960s. After the dawn of cDNA cloning and sequencing in the 1980s, heterologous expression systems and site-directed mutagenesis allowed identification of the functional roles of specific amino acid residues. In the past two decades, structures of transport proteins have made it possible to propose specific models for transporter function at the molecular level. Here, we review the contribution of JGP articles to our current understanding of solute transporter mechanisms. Whether the topic has been kinetics, energetics, regulation, mutagenesis, or structure-based modeling, a common feature of these articles has been a quantitative, mechanistic approach, leading to lasting insights into the functions of transporters.
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Affiliation(s)
- Michael L Jennings
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR
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192
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Thomassen M, Hostrup M, Murphy RM, Cromer BA, Skovgaard C, Gunnarsson TP, Christensen PM, Bangsbo J. Abundance of ClC-1 chloride channel in human skeletal muscle: fiber type specific differences and effect of training. J Appl Physiol (1985) 2018; 125:470-478. [DOI: 10.1152/japplphysiol.01042.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cl− channel protein 1 (ClC-1) may be important for excitability and contractility in skeletal muscle, but ClC-1 abundance has not been examined in human muscle. The aim of the present study was to examine ClC-1 abundance in human skeletal muscle, including fiber type specific differences and the effect of exercise training. A commercially available antibody was tested with positive and negative control tissue, and it recognized specifically ClC-1 in the range from 100 to 150 kDa. Abundance of ClC-1 was 38% higher ( P < 0.01) in fast twitch Type IIa muscle fibers than in slow twitch Type I. Muscle ClC-1 abundance did not change with 4 wk of training consisting of 30 min cycling at 85% of maximal heart rate (HRmax) and 3 × 30-s all out sprints or during a 7-wk training period with 10–12 × 30 s uphill cycling and 4–5 × ~4 min cycling at 90%–95% of HRmax. ClC-1 abundance correlated negatively ( P < 0.01) with maximal oxygen consumption ( r = –0.552) and incremental exercise performance ( r = –0.546). In addition, trained cyclists had lower ( P < 0.01) ClC-1 abundance than lesser trained individuals. The present observations indicate that a low abundance of muscle ClC-1 may be beneficial for exercise performance, but the role of abundance and regulation of ClC-1 in skeletal muscle of humans with respect to exercise performance and trainability need to be elucidated. NEW & NOTEWORTHY Abundance of the Cl− channel protein 1 (ClC-1) chloride channel may be important for excitability and contractility in human skeletal muscle and may therefore have implications for fatigue development. In this study, we confirmed ClC-1 specificity for a commercially available antibody, and this study is first to our knowledge to determine ClC-1 protein abundance in human muscle by Western blotting. We observed that abundance of ClC-1 was higher in fast compared with slow twitch fibers and lower in trained individuals than in recreationally active.
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Affiliation(s)
- Martin Thomassen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Robyn M. Murphy
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Brett A. Cromer
- Department of Chemistry and Biotechnology, Swinburne University, Melbourne, Victoria, Australia
| | - Casper Skovgaard
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Thomas P. Gunnarsson
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Peter M. Christensen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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193
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Ortiz E, Possani LD. Scorpion toxins to unravel the conundrum of ion channel structure and functioning. Toxicon 2018; 150:17-27. [DOI: 10.1016/j.toxicon.2018.04.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/24/2018] [Accepted: 04/29/2018] [Indexed: 01/11/2023]
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194
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Lee SK, Boron WF. Exploring the autoinhibitory domain of the electrogenic Na + /HCO 3- transporter NBCe1-B, from residues 28 to 62. J Physiol 2018; 596:3637-3653. [PMID: 29808931 DOI: 10.1113/jp276241] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/11/2018] [Indexed: 12/30/2022] Open
Abstract
KEY POINTS Slc4a4 (mouse) encodes at least five variants of the electrogenic sodium/bicarbonate transporter NBCe1. The initial 41 cytosolic amino acids of NBCe1-A and -D are unique; NBCe1-A has high activity. The initial 85 amino acids of NBCe1-B, -C and -E are unique; NBCe1-B and -C have low activity. Previous work showed that deleting residues 1-85 or 40-62 of NBCe1-B, or 1-87 of NBCe1-C, eliminates autoinhibition. These regions also include binding determinants for IRBIT (inositol trisphosphate (IP3 )-receptor binding protein released with IP3 ), which relieves autoinhibition. Here, systematically replacing/deleting residues 28-62, we find that only the nine amino acid cationic cluster (residues 40-48) of NBCe1-B is essential for autoinhibition. IRBIT stimulates all but one low-activity construct. We suggest that electrostatic interactions - which IRBIT presumably interrupts - between the cationic cluster and the membrane or other domains of NBCe1 play a central role in tempering the activity of NBCe1-B in the pancreas, brain and other organs. ABSTRACT Variant B of the electrogenic Na+ /HCO3- cotransporter (NBCe1-B) contributes to the vectorial transport of HCO3- in epithelia (e.g. pancreatic ducts) and to the maintenance of intracellular pH in the central nervous systems (e.g. astrocytes). NBCe1-B has very low basal activity due to an autoinhibitory domain (AID) located, at least in part, in the unique portion (residues 1-85) of the cytosolic NH2 -terminus. Previous work has shown that removing 23 amino acids (residues 40-62) stimulates NBCe1-B. Here, we test the hypothesis that a cationic cluster of nine consecutive positively charged amino acids (residues 40-48) is a necessary part of the AID. Using two-electrode voltage clamping of Xenopus oocytes, we assess the activity of human NBCe1-B constructs in which we systematically replace or delete residues 28-62, which includes the cationic cluster. We find that replacing or deleting all residues within the cationic cluster markedly increases NBCe1-B activity (i.e. eliminates autoinhibition). On the background of a cationic clusterless construct, systematically restoring Arg residues restores autoinhibition in two distinct quanta, with one to three Arg residues restoring ∼50%, and four or more Arg residues restoring virtually all autoinhibition. Systematically deleting residues before the cluster reduces autoinhibition by, at most, a small amount. Replacing or deleting residues after the cluster has no effect. For constructs with low NBCe1 activity (but good surface expression, as assessed by biotinylation), co-expression with super-IRBIT (lacking PP1-binding site) restores full activity (i.e. relieves autoinhibition). In summary, the cationic cluster is a necessary component of the AID of NBCe1-B.
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Affiliation(s)
- Seong-Ki Lee
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
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195
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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196
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Falzone ME, Malvezzi M, Lee BC, Accardi A. Known structures and unknown mechanisms of TMEM16 scramblases and channels. J Gen Physiol 2018; 150:933-947. [PMID: 29915161 PMCID: PMC6028493 DOI: 10.1085/jgp.201711957] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/29/2018] [Indexed: 12/25/2022] Open
Abstract
Falzone et al. interpret the mechanisms underlying the activity of TMEM16 family members from recent structural and functional work. The TMEM16 family of membrane proteins is composed of both Ca2+-gated Cl− channels and Ca2+-dependent phospholipid scramblases. The functional diversity of TMEM16s underlies their involvement in numerous signal transduction pathways that connect changes in cytosolic Ca2+ levels to cellular signaling networks. Indeed, defects in the function of several TMEM16s cause a variety of genetic disorders, highlighting their fundamental pathophysiological importance. Here, we review how our mechanistic understanding of TMEM16 function has been shaped by recent functional and structural work. Remarkably, the recent determination of near-atomic-resolution structures of TMEM16 proteins of both functional persuasions has revealed how relatively minimal rearrangements in the substrate translocation pathway are sufficient to precipitate the dramatic functional differences that characterize the family. These structures, when interpreted in the light of extensive functional analysis, point to an unusual mechanism for Ca2+-dependent activation of TMEM16 proteins in which substrate permeation is regulated by a combination of conformational rearrangements and electrostatics. These breakthroughs pave the way to elucidate the mechanistic bases of ion and lipid transport by the TMEM16 proteins and unravel the molecular links between these transport activities and their function in human pathophysiology.
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Affiliation(s)
- Maria E Falzone
- Department of Biochemistry, Weill Cornell Medical School, New York, NY
| | - Mattia Malvezzi
- Department of Anesthesiology, Weill Cornell Medical School, New York, NY
| | - Byoung-Cheol Lee
- Department of Anesthesiology, Weill Cornell Medical School, New York, NY
| | - Alessio Accardi
- Department of Biochemistry, Weill Cornell Medical School, New York, NY .,Department of Anesthesiology, Weill Cornell Medical School, New York, NY.,Department of Physiology, Biophysics and Systems Biology, Weill Cornell Medical School, New York, NY
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197
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Riederer EA, Focke PJ, Georgieva ER, Akyuz N, Matulef K, Borbat PP, Freed JH, Blanchard SC, Boudker O, Valiyaveetil FI. A facile approach for the in vitro assembly of multimeric membrane transport proteins. eLife 2018; 7:36478. [PMID: 29889023 PMCID: PMC6025958 DOI: 10.7554/elife.36478] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/08/2018] [Indexed: 11/13/2022] Open
Abstract
Membrane proteins such as ion channels and transporters are frequently homomeric. The homomeric nature raises important questions regarding coupling between subunits and complicates the application of techniques such as FRET or DEER spectroscopy. These challenges can be overcome if the subunits of a homomeric protein can be independently modified for functional or spectroscopic studies. Here, we describe a general approach for in vitro assembly that can be used for the generation of heteromeric variants of homomeric membrane proteins. We establish the approach using GltPh, a glutamate transporter homolog that is trimeric in the native state. We use heteromeric GltPh transporters to directly demonstrate the lack of coupling in substrate binding and demonstrate how heteromeric transporters considerably simplify the application of DEER spectroscopy. Further, we demonstrate the general applicability of this approach by carrying out the in vitro assembly of VcINDY, a Na+-coupled succinate transporter and CLC-ec1, a Cl-/H+ antiporter.
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Affiliation(s)
- Erika A Riederer
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, United States
| | - Paul J Focke
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, United States
| | - Elka R Georgieva
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, Unites States.,National Biomedical Center for Advanced Electron Spin Resonance Technology, Cornell University, Ithaca, United States
| | | | - Kimberly Matulef
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, United States
| | - Peter P Borbat
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, Unites States.,National Biomedical Center for Advanced Electron Spin Resonance Technology, Cornell University, Ithaca, United States
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, Unites States.,National Biomedical Center for Advanced Electron Spin Resonance Technology, Cornell University, Ithaca, United States
| | | | - Olga Boudker
- Weill Cornell Medicine, New York, United States.,Howard Hughes Medical Institute, Maryland, United States
| | - Francis I Valiyaveetil
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, United States
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198
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Bignon Y, Alekov A, Frachon N, Lahuna O, Jean-Baptiste Doh-Egueli C, Deschênes G, Vargas-Poussou R, Lourdel S. A novel CLCN5 pathogenic mutation supports Dent disease with normal endosomal acidification. Hum Mutat 2018; 39:1139-1149. [PMID: 29791050 DOI: 10.1002/humu.23556] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/23/2018] [Accepted: 05/19/2018] [Indexed: 12/13/2022]
Abstract
Dent disease is an X-linked recessive renal tubular disorder characterized by low-molecular-weight proteinuria, hypercalciuria, nephrolithiasis, nephrocalcinosis, and progressive renal failure. Inactivating mutations of CLCN5, the gene encoding the 2Cl- /H+ exchanger ClC-5, have been reported in patients with Dent disease 1. In vivo studies in mice harboring an artificial mutation in the "gating glutamate" of ClC-5 (c.632A > C, p.Glu211Ala) and mathematical modeling suggest that endosomal chloride concentration could be an important parameter in endocytosis, rather than acidification as earlier hypothesized. Here, we described a novel pathogenic mutation affecting the "gating glutamate" of ClC-5 (c.632A>G, p.Glu211Gly) and investigated its molecular consequences. In HEK293T cells, the p.Glu211Gly ClC-5 mutant displayed unaltered N-glycosylation and normal plasma membrane and early endosomes localizations. In Xenopus laevis oocytes and HEK293T cells, we found that contrasting with wild-type ClC-5, the mutation abolished the outward rectification, the sensitivity to extracellular H+ and converted ClC-5 into a Cl- channel. Investigation of endosomal acidification in HEK293T cells using the pH-sensitive pHluorin2 probe showed that the luminal pH of cells expressing a wild-type or p.Glu211Gly ClC-5 was not significantly different. Our study further confirms that impaired acidification of endosomes is not the only parameter leading to defective endocytosis in Dent disease 1.
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Affiliation(s)
- Yohan Bignon
- Sorbonne Université, Université Paris-Descartes, INSERM, CNRS, Paris, France
| | - Alexi Alekov
- Institut für Neurophysiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Nadia Frachon
- Sorbonne Université, Université Paris-Descartes, INSERM, CNRS, Paris, France
| | | | | | - Georges Deschênes
- Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Service de Néphrologie Pédiatrique, Paris, France.,Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France
| | - Rosa Vargas-Poussou
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Département de génétique, Paris, France.,Université Paris-Descartes, Faculté de Médecine, Paris, France
| | - Stéphane Lourdel
- Sorbonne Université, Université Paris-Descartes, INSERM, CNRS, Paris, France
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199
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Majumdar S, Pal S. Information transmission in microbial and fungal communication: from classical to quantum. J Cell Commun Signal 2018; 12:491-502. [PMID: 29476316 PMCID: PMC5910326 DOI: 10.1007/s12079-018-0462-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 02/08/2018] [Indexed: 01/05/2023] Open
Abstract
Microbes have their own communication systems. Secretion and reception of chemical signaling molecules and ion-channels mediated electrical signaling mechanism are yet observed two special ways of information transmission in microbial community. In this article, we address the aspects of various crucial machineries which set the backbone of microbial cell-to-cell communication process such as quorum sensing mechanism (bacterial and fungal), quorum sensing regulated biofilm formation, gene expression, virulence, swarming, quorum quenching, role of noise in quorum sensing, mathematical models (therapy model, evolutionary model, molecular mechanism model and many more), synthetic bacterial communication, bacterial ion-channels, bacterial nanowires and electrical communication. In particular, we highlight bacterial collective behavior with classical and quantum mechanical approaches (including quantum information). Moreover, we shed a new light to introduce the concept of quantum synthetic biology and possible cellular quantum Turing test.
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Affiliation(s)
- Sarangam Majumdar
- Dipartimento di Ingegneria Scienze Informatiche e Matematica, Università degli Studi di L’ Aquila, Via Vetoio – Loc. Coppito, 67010 L’ Aquila, Italy
| | - Sukla Pal
- Theoretical Physics Division, Physical Research Laboratory, Navrangpura, Ahmedabad, Gujarat 380009 India
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200
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Park E, MacKinnon R. Structure of the CLC-1 chloride channel from Homo sapiens. eLife 2018; 7:36629. [PMID: 29809153 PMCID: PMC6019066 DOI: 10.7554/elife.36629] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/15/2018] [Indexed: 11/18/2022] Open
Abstract
CLC channels mediate passive Cl− conduction, while CLC transporters mediate active Cl− transport coupled to H+ transport in the opposite direction. The distinction between CLC-0/1/2 channels and CLC transporters seems undetectable by amino acid sequence. To understand why they are different functionally we determined the structure of the human CLC-1 channel. Its ‘glutamate gate’ residue, known to mediate proton transfer in CLC transporters, adopts a location in the structure that appears to preclude it from its transport function. Furthermore, smaller side chains produce a wider pore near the intracellular surface, potentially reducing a kinetic barrier for Cl− conduction. When the corresponding residues are mutated in a transporter, it is converted to a channel. Finally, Cl− at key sites in the pore appear to interact with reduced affinity compared to transporters. Thus, subtle differences in glutamate gate conformation, internal pore diameter and Cl− affinity distinguish CLC channels and transporters. Channels and transporters are two classes of proteins that transport molecules and ions – collectively referred to as “substrates” – across cell membranes. Channels form a pore in the membrane and the substrates diffuse through passively. Transporters, on the other hand, actively pump substrates across a membrane, consuming energy in the process. Thus, channels and transporters work in distinct ways. Channels and transporters most often have unrelated structures, but there are rare examples of both existing within the same family of structurally similar proteins. CLC proteins, for example, include both chloride ion channels and transporters that pump chloride ions in one direction by harnessing the energy from hydrogen ions flowing in the other direction. It remains unclear why some CLC proteins work as channels while others are transporters, especially since the two seem indistinguishable on the basis of the order of their amino acids – the building blocks of all proteins. The conservation of the amino acid sequences implies they are structurally very similar. How then can different members perform such energetically distinct processes? Park and MacKinnon now show that the answer to this question serves as a reminder of how subtle nature can be. Indeed, while the structure of a human CLC channel (called CLC-1) is indeed similar to those of CLC transporters, one amino acid adopts a unique shape that explains why the protein cannot act as a transporter. This specific amino acid, a glutamate, is central to the exchange of chloride and hydrogen ions in CLC transporters. Park and MacKinnon show that its conformation in the CLC-1 channel stops this exchange, while leaving the pore open for the passive transport of chloride ions. Also, two other amino acids along the ion diffusion pathway in the CLC channel are smaller than their counterparts in CLC transporters, and so allow chloride ions to diffuse through more quickly. Lastly, Park and MacKinnon also note that channels do not require a wide pore: instead ions can still flow rapidly through a narrow pore if the chemical environment inside permits it. CLC proteins perform a number of important roles in humans, and mutations in CLC-encoding genes underlie numerous heritable diseases. It remains too early to know how this mechanistic study may or may not impact treatments, yet the findings will likely interest scientists working on ion conduction mechanisms and the evolution of molecular function.
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Affiliation(s)
- Eunyong Park
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
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