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Kunzelmann K, Centeio R, Ousingsawat J, Talbi K, Seidler U, Schreiber R. SLC26A9 in airways and intestine: secretion or absorption? Channels (Austin) 2023; 17:2186434. [PMID: 36866602 PMCID: PMC9988340 DOI: 10.1080/19336950.2023.2186434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
SLC26A9 is one out of 11 proteins that belong to the SLC26A family of anion transporters. Apart from expression in the gastrointestinal tract, SLC26A9 is also found in the respiratory system, in male tissues and in the skin. SLC26A9 has gained attention because of its modifier role in the gastrointestinal manifestation of cystic fibrosis (CF). SLC26A9 appears to have an impact on the extent of intestinal obstruction caused by meconium ileus. SLC26A9 supports duodenal bicarbonate secretion, but was assumed to provide a basal Cl- secretory pathway in airways. However, recent results show that basal airway Cl- secretion is due to cystic fibrosis conductance regulator (CFTR), while SLC26A9 may rather secrete HCO3-, thereby maintaining proper airway surface liquid (ASL) pH. Moreover, SLC26A9 does not secrete but probably supports reabsorption of fluid particularly in the alveolar space, which explains early death by neonatal distress in Slc26a9-knockout animals. While the novel SLC26A9 inhibitor S9-A13 helped to unmask the role of SLC26A9 in the airways, it also provided evidence for an additional role in acid secretion by gastric parietal cells. Here we discuss recent data on the function of SLC26A9 in airways and gut, and how S9-A13 may be useful in unraveling the physiological role of SLC26A9.
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Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
- CONTACT Karl Kunzelmann
| | - Raquel Centeio
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
| | - Jiraporn Ousingsawat
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
| | - Khaoula Talbi
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hannover Medical School, Hannover, Germany
| | - Rainer Schreiber
- Institut für Physiologie, Universität, Universitätsstraße 31, Regensburg, Germany
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Benko F, Urminská D, Ďuračka M, Tvrdá E. Signaling Roleplay between Ion Channels during Mammalian Sperm Capacitation. Biomedicines 2023; 11:2519. [PMID: 37760960 PMCID: PMC10525812 DOI: 10.3390/biomedicines11092519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
In order to accomplish their primary goal, mammalian spermatozoa must undergo a series of physiological, biochemical, and functional changes crucial for the acquisition of fertilization ability. Spermatozoa are highly polarized cells, which must swiftly respond to ionic changes on their passage through the female reproductive tract, and which are necessary for male gametes to acquire their functional competence. This review summarizes the current knowledge about specific ion channels and transporters located in the mammalian sperm plasma membrane, which are intricately involved in the initiation of changes within the ionic milieu of the sperm cell, leading to variations in the sperm membrane potential, membrane depolarization and hyperpolarization, changes in sperm motility and capacitation to further lead to the acrosome reaction and sperm-egg fusion. We also discuss the functionality of selected ion channels in male reproductive health and/or disease since these may become promising targets for clinical management of infertility in the future.
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Affiliation(s)
- Filip Benko
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
| | - Dana Urminská
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
| | - Michal Ďuračka
- AgroBioTech Research Centre, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia;
| | - Eva Tvrdá
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
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3
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Liu Q, Zhang X, Huang H, Chen Y, Wang F, Hao A, Zhan W, Mao Q, Hu Y, Han L, Sun Y, Zhang M, Liu Z, Li GL, Zhang W, Shu Y, Sun L, Chen Z. Asymmetric pendrin homodimer reveals its molecular mechanism as anion exchanger. Nat Commun 2023; 14:3012. [PMID: 37230976 DOI: 10.1038/s41467-023-38303-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 04/23/2023] [Indexed: 05/27/2023] Open
Abstract
Pendrin (SLC26A4) is an anion exchanger expressed in the apical membranes of selected epithelia. Pendrin ablation causes Pendred syndrome, a genetic disorder associated with sensorineural hearing loss, hypothyroid goiter, and reduced blood pressure. However its molecular structure has remained unknown, limiting our understanding of the structural basis of transport. Here, we determine the cryo-electron microscopy structures of mouse pendrin with symmetric and asymmetric homodimer conformations. The asymmetric homodimer consists of one inward-facing protomer and the other outward-facing protomer, representing coincident uptake and secretion- a unique state of pendrin as an electroneutral exchanger. The multiple conformations presented here provide an inverted alternate-access mechanism for anion exchange. The structural and functional data presented here disclose the properties of an anion exchange cleft and help understand the importance of disease-associated variants, which will shed light on the pendrin exchange mechanism.
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Affiliation(s)
- Qianying Liu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Xiang Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Hui Huang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuxin Chen
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Fang Wang
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Aihua Hao
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Wuqiang Zhan
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Qiyu Mao
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuxia Hu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Lin Han
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yifang Sun
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Meng Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Zhimin Liu
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Geng-Lin Li
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Weijia Zhang
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yilai Shu
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China.
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031, China.
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China.
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
| | - Lei Sun
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai, 200032, China.
- Shanghai Key Laboratory of Medical Epigenetics, Shanghai, 200032, China.
| | - Zhenguo Chen
- The Fifth People's Hospital of Shanghai and Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
- Shanghai Institute of Infectious Disease and Biosecurity, Shanghai, 200032, China.
- Shanghai Key Laboratory of Medical Epigenetics, Shanghai, 200032, China.
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Silveira C, da Costa Silveira K, Lacarrubba-Flores MD, Sakata MT, Carbognani SN, Llerena Jr. J, Moreno CA, Cavalcanti DP. SLC26A2/DTDST Spectrum: A Cohort of 12 Patients Associated with a Comprehensive Review of the Genotype-Phenotype Correlation. Mol Syndromol 2023; 13:485-495. [PMID: 36660027 PMCID: PMC9843583 DOI: 10.1159/000525020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 05/10/2022] [Indexed: 01/22/2023] Open
Abstract
Introduction Pathogenic variants in the SLC26A2/DTDST gene cause the following spectrum of phenotypes: achondrogenesis 1B (ACG1B), atelosteogenesis 2 (AO2), diastrophic dysplasia (DTD), and recessive-multiple epiphyseal dysplasia (rMED), the first 2 being lethal. Here, we report a cohort and a comprehensive literature review on a genotype-phenotype correlation of SLC26A2/DTDST-related disorders. Methods The local patients were genotyped by Sanger sequencing or next-generation sequencing (NGS). We reviewed data from the literature regarding phenotype, zygosity, and genotype in parallel. Results The local cohort enrolled 12 patients, including one with a Desbuquois-like phenotype. All but one showed biallelic mutations, however, only one allele mutated in a fetus presenting ACG1B was identified. The literature review identified 42 articles and the analyses of genotype and zygosity included the 12 local patients. Discussion The R279W variant was the most prevalent among the local patients. It was in homozygosity (hmz) in 2 patients with rMED and in compound heterozygosity (chtz) in 9 patients. The genotype and zygosity review of all patients led to the following conclusions: DTD is the most common phenotype in Finland due to a Finnish mutation (c.727-1G>C). Outside of Finland, rMED is the most prevalent phenotype, usually associated with R279W in hmz. In contrast, DTD's genotype is usually in chtz. Despite a large number of variants (38), just 8 are recurrent (R279W, C653S, c.-26+2T>C, R178*, K575Sfs*10, V340del, G663R, T512K). The last 3 in hmz lead to lethal phenotypes. The Finnish mutation is found only in chtz outside of Finland, being associated with all 4 classical phenotypes. The p.R178* and p.K575Sfs*10 variants should be viewed as lethal mutations since both were mainly described with lethal phenotypes and were never reported in hmz. The existence of 9 patients with only one mutated allele suggests that other mutations in the other allele of these patients still need to be unveiled.
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Affiliation(s)
- Cynthia Silveira
- Skeletal Dysplasia Group, Department of Translational Medicine, Faculty of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Karina da Costa Silveira
- Skeletal Dysplasia Group, Department of Translational Medicine, Faculty of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Maria D. Lacarrubba-Flores
- Skeletal Dysplasia Group, Department of Translational Medicine, Faculty of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Maurício T. Sakata
- Skeletal Dysplasia Group, Department of Translational Medicine, Faculty of Medical Sciences, University of Campinas, Campinas, Brazil
| | | | - Juan Llerena Jr.
- Centro de Genética Médica & Centro de Referência para Doenças Raras, IFF/Fiocruz, Rio de Janeiro, Brazil,INAGEMP, Porto Alegre, Brazil
| | - Carolina A. Moreno
- Perinatal Genetic Program, Department of Translational Medicine, University of Campinas, Campinas, Brazil
| | - Denise P. Cavalcanti
- Skeletal Dysplasia Group, Department of Translational Medicine, Faculty of Medical Sciences, University of Campinas, Campinas, Brazil,Perinatal Genetic Program, Department of Translational Medicine, University of Campinas, Campinas, Brazil,*Denise Pontes Cavalcanti,
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Danilchenko VY, Zytsar MV, Maslova EA, Posukh OL. Selection of Diagnostically Significant Regions of the SLC26A4 Gene Involved in Hearing Loss. Int J Mol Sci 2022; 23:ijms232113453. [PMID: 36362242 PMCID: PMC9655724 DOI: 10.3390/ijms232113453] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/23/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
Screening pathogenic variants in the SLC26A4 gene is an important part of molecular genetic testing for hearing loss (HL) since they are one of the common causes of hereditary HL in many populations. However, a large size of the SLC26A4 gene (20 coding exons) predetermines the difficulties of its complete mutational analysis, especially in large samples of patients. In addition, the regional or ethno-specific prevalence of SLC26A4 pathogenic variants has not yet been fully elucidated, except variants c.919-2A>G and c.2168A>G (p.His723Arg), which have been proven to be most common in Asian populations. We explored the distribution of currently known pathogenic and likely pathogenic (PLP) variants across the SLC26A4 gene sequence presented in the Deafness Variation Database for the selection of potential diagnostically important parts of this gene. As a result of this bioinformatic analysis, we found that molecular testing ten SLC26A4 exons (4, 6, 10, 11, 13−17 and 19) with flanking intronic regions can provide a diagnostic rate of 61.9% for all PLP variants in the SLC26A4 gene. The primary sequencing of these SLC26A4 regions may be applied as an initial effective diagnostic testing in samples of patients of unknown ethnicity or as a subsequent step after the targeted testing of already-known ethno- or region-specific pathogenic SLC26A4 variants.
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Affiliation(s)
- Valeriia Yu. Danilchenko
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Marina V. Zytsar
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Ekaterina A. Maslova
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Olga L. Posukh
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Novosibirsk State University, 630090 Novosibirsk, Russia
- Correspondence:
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Futamata H, Fukuda M, Umeda R, Yamashita K, Tomita A, Takahashi S, Shikakura T, Hayashi S, Kusakizako T, Nishizawa T, Homma K, Nureki O. Cryo-EM structures of thermostabilized prestin provide mechanistic insights underlying outer hair cell electromotility. Nat Commun 2022; 13:6208. [PMID: 36266333 PMCID: PMC9584906 DOI: 10.1038/s41467-022-34017-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 10/11/2022] [Indexed: 01/11/2023] Open
Abstract
Outer hair cell elecromotility, driven by prestin, is essential for mammalian cochlear amplification. Here, we report the cryo-EM structures of thermostabilized prestin (PresTS), complexed with chloride, sulfate, or salicylate at 3.52-3.63 Å resolutions. The central positively-charged cavity allows flexible binding of various anion species, which likely accounts for the known distinct modulations of nonlinear capacitance (NLC) by different anions. Comparisons of these PresTS structures with recent prestin structures suggest rigid-body movement between the core and gate domains, and provide mechanistic insights into prestin inhibition by salicylate. Mutations at the dimeric interface severely diminished NLC, suggesting that stabilization of the gate domain facilitates core domain movement, thereby contributing to the expression of NLC. These findings advance our understanding of the molecular mechanism underlying mammalian cochlear amplification.
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Affiliation(s)
- Haon Futamata
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masahiro Fukuda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo; Meguro-ku, Tokyo, 153-8503, Japan
| | - Rie Umeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Keitaro Yamashita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Atsuhiro Tomita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Satoe Takahashi
- Department of Otolaryngology-Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Takafumi Shikakura
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Shigehiko Hayashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Tomohiro Nishizawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan.
| | - Kazuaki Homma
- Department of Otolaryngology-Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
- The Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University, Evanston, IL, 60608, USA.
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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Delgado-Bermúdez A, Yeste M, Bonet S, Pinart E. A Review on the Role of Bicarbonate and Proton Transporters during Sperm Capacitation in Mammals. Int J Mol Sci 2022; 23:ijms23116333. [PMID: 35683013 PMCID: PMC9180951 DOI: 10.3390/ijms23116333] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/01/2022] [Accepted: 06/05/2022] [Indexed: 12/14/2022] Open
Abstract
Alkalinization of sperm cytosol is essential for plasma membrane hyperpolarization, hyperactivation of motility, and acrosomal exocytosis during sperm capacitation in mammals. The plasma membrane of sperm cells contains different ion channels implicated in the increase of internal pH (pHi) by favoring either bicarbonate entrance or proton efflux. Bicarbonate transporters belong to the solute carrier families 4 (SLC4) and 26 (SLC26) and are currently grouped into Na+/HCO3− transporters and Cl−/HCO3− exchangers. Na+/HCO3− transporters are reported to be essential for the initial and fast entrance of HCO3− that triggers sperm capacitation, whereas Cl−/HCO3− exchangers are responsible for the sustained HCO3− entrance which orchestrates the sequence of changes associated with sperm capacitation. Proton efflux is required for the fast alkalinization of capacitated sperm cells and the activation of pH-dependent proteins; according to the species, this transport can be mediated by Na+/H+ exchangers (NHE) belonging to the SLC9 family and/or voltage-gated proton channels (HVCN1). Herein, we discuss the involvement of each of these channels in sperm capacitation and the acrosome reaction.
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Affiliation(s)
- Ariadna Delgado-Bermúdez
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
| | - Marc Yeste
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), ES-08010 Barcelona, Spain
| | - Sergi Bonet
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
| | - Elisabeth Pinart
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
- Correspondence: ; Tel.: +34-972-419-514
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Albader N, Zou M, BinEssa HA, Abdi S, Al-Enezi AF, Meyer BF, Alzahrani AS, Shi Y. Insights of Noncanonical Splice-site Variants on RNA Splicing in Patients With Congenital Hypothyroidism. J Clin Endocrinol Metab 2022; 107:e1263-e1276. [PMID: 34632506 DOI: 10.1210/clinem/dgab737] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Congenital hypothyroidism (CH) is caused by mutations in the genes for thyroid hormone synthesis. In our previous investigation of CH patients, approximately 53% of patients had mutations in either coding exons or canonical splice sites of causative genes. Noncanonical splice-site variants in the intron were detected but their pathogenic significance was not known. OBJECTIVE This work aims to evaluate noncanonical splice-site variants on pre-messenger RNA (pre-mRNA) splicing of CH-causing genes. METHODS Next-generation sequencing data of 55 CH cases in 47 families were analyzed to identify rare intron variants. The effects of variants on pre-mRNA splicing were investigated by minigene RNA-splicing assay. RESULTS Four intron variants were found in 3 patients: solute carrier family 26 member 4 (SLC26A4) c.1544+9C>T and c.1707+94C>T in one patient, and solute carrier family 5 member 5 (SLC5A5) c.970-48G>C and c.1652-97A>C in 2 other patients. The c.1707+94C>T and c.970-48G>C caused exons 15 and 16 skipping, and exon 8 skipping, respectively. The remaining variants had no effect on RNA splicing. Furthermore, we analyzed 28 previously reported noncanonical splice-site variants (4 in TG and 24 in SLC26A4). Among them, 15 variants (~ 54%) resulted in aberrant splicing and 13 variants had no effect on RNA splicing. These data were compared with 3 variant-prediction programs (FATHMM-XF, FATHMM-MKL, and CADD). Among 32 variants, FATHMM-XF, FATHMM-MKL, and CADD correctly predicted 20 (63%), 17 (53%), and 26 (81%) variants, respectively. CONCLUSION Two novel deep intron mutations have been identified in SLC26A4 and SLC5A5, bringing the total number of solved families with disease-causing mutations to approximately 45% in our cohort. Approximately 46% (13/28) of reported noncanonical splice-site mutations do not disrupt pre-mRNA splicing. CADD provides highest prediction accuracy of noncanonical splice-site variants.
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Affiliation(s)
- Najla Albader
- Department of Biochemistry, College of Science, King Saud University, Riyadh 11495, Saudi Arabia
| | - Minjing Zou
- Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Huda A BinEssa
- Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Saba Abdi
- Department of Biochemistry, College of Science, King Saud University, Riyadh 11495, Saudi Arabia
| | - Anwar F Al-Enezi
- Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Brian F Meyer
- Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Ali S Alzahrani
- Department of Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Yufei Shi
- Centre for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
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9
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SLC26A9 is selected for endoplasmic reticulum associated degradation (ERAD) via Hsp70-dependent targeting of the soluble STAS domain. Biochem J 2021; 478:4203-4220. [PMID: 34821356 PMCID: PMC8826537 DOI: 10.1042/bcj20210644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 12/24/2022]
Abstract
SLC26A9, a member of the solute carrier protein family, transports chloride ions across various epithelia. SLC26A9 also associates with other ion channels and transporters linked to human health, and in some cases these heterotypic interactions are essential to support the biogenesis of both proteins. Therefore, understanding how this complex membrane protein is initially folded might provide new therapeutic strategies to overcome deficits in the function of SLC26A9 partners, one of which is associated with Cystic Fibrosis. To this end, we developed a novel yeast expression system for SLC26A9. This facile system has been used extensively with other ion channels and transporters to screen for factors that oversee protein folding checkpoints. As commonly observed for other channels and transporters, we first noted that a substantial fraction of SLC26A9 is targeted for endoplasmic reticulum associated degradation (ERAD), which destroys folding-compromised proteins in the early secretory pathway. We next discovered that ERAD selection requires the Hsp70 chaperone, which can play a vital role in ERAD substrate selection. We then created SLC26A9 mutants and found that the transmembrane-rich domain of SLC26A9 was quite stable, whereas the soluble cytosolic STAS domain was responsible for Hsp70-dependent ERAD. To support data obtained in the yeast model, we were able to recapitulate Hsp70-facilitated ERAD of the STAS domain in human tissue culture cells. These results indicate that a critical barrier to nascent membrane protein folding can reside within a specific soluble domain, one that is monitored by components associated with the ERAD machinery.
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10
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Hu CJ, Lu YC, Tsai CY, Chan YH, Lin PH, Lee YS, Yu IS, Lin SW, Liu TC, Hsu CJ, Yang TH, Cheng YF, Wu CC. Insights into phenotypic differences between humans and mice with p.T721M and other C-terminal variants of the SLC26A4 gene. Sci Rep 2021; 11:20983. [PMID: 34697379 PMCID: PMC8545921 DOI: 10.1038/s41598-021-00448-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/22/2021] [Indexed: 11/17/2022] Open
Abstract
Recessive variants of the SLC26A4 gene are an important cause of hereditary hearing impairment. Several transgenic mice with different Slc26a4 variants have been generated. However, none have recapitulated the auditory phenotypes in humans. Of the SLC26A4 variants identified thus far, the p.T721M variant is of interest, as it appears to confer a more severe pathogenicity than most of the other missense variants, but milder pathogenicity than non-sense and frameshift variants. Using a genotype-driven approach, we established a knock-in mouse model homozygous for p.T721M. To verify the pathogenicity of p.T721M, we generated mice with compound heterozygous variants by intercrossing Slc26a4+/T721M mice with Slc26a4919-2A>G/919-2A>G mice, which segregated the c.919-2A > G variant with abolished Slc26a4 function. We then performed serial audiological assessments, vestibular evaluations, and inner ear morphological studies. Surprisingly, both Slc26a4T721M/T721M and Slc26a4919-2A>G/T721M showed normal audiovestibular functions and inner ear morphology, indicating that p.T721M is non-pathogenic in mice and a single p.T721M allele is sufficient to maintain normal inner ear physiology. The evidence together with previous reports on mouse models with Slc26a4 p.C565Y and p.H723R variants, support our speculation that the absence of audiovestibular phenotypes in these mouse models could be attributed to different protein structures at the C-terminus of human and mouse pendrin.
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Affiliation(s)
- Chin-Ju Hu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, 02115, USA
| | - Ying-Chang Lu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Cheng-Yu Tsai
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Yen-Hui Chan
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, 427, Taiwan
| | - Pei-Hsuan Lin
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - Yi-Shan Lee
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan
| | - I-Shing Yu
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei, 100, Taiwan
| | - Shu-Wha Lin
- Transgenic Mouse Models Core (TMMC), Division of Genomic Medicine, Research Center for Medical Excellence, National Taiwan University, Taipei, 100, Taiwan
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.,Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, 427, Taiwan
| | - Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan.
| | - Yen-Fu Cheng
- Department of Medical Research, Taipei Veteran General Hospital, 201, Sec.2, Shi-Pai Rd, Taipei, 112, Taiwan. .,Department of Otolaryngology-Head and Neck Surgery, Taipei Veteran General Hospital, Taipei, 112, Taiwan. .,School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112, Taiwan.
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, 7 Chung-Shan S. Rd., Taipei, 100, Taiwan. .,Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan. .,Department of Medical Research, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, 302, Taiwan.
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11
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Wang W, Tsirulnikov K, Zhekova HR, Kayık G, Khan HM, Azimov R, Abuladze N, Kao L, Newman D, Noskov SY, Zhou ZH, Pushkin A, Kurtz I. Cryo-EM structure of the sodium-driven chloride/bicarbonate exchanger NDCBE. Nat Commun 2021; 12:5690. [PMID: 34584093 PMCID: PMC8478935 DOI: 10.1038/s41467-021-25998-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 09/08/2021] [Indexed: 02/08/2023] Open
Abstract
SLC4 transporters play significant roles in pH regulation and cellular sodium transport. The previously solved structures of the outward facing (OF) conformation for AE1 (SLC4A1) and NBCe1 (SLC4A4) transporters revealed an identical overall fold despite their different transport modes (chloride/bicarbonate exchange versus sodium-carbonate cotransport). However, the exact mechanism determining the different transport modes in the SLC4 family remains unknown. In this work, we report the cryo-EM 3.4 Å structure of the OF conformation of NDCBE (SLC4A8), which shares transport properties with both AE1 and NBCe1 by mediating the electroneutral exchange of sodium-carbonate with chloride. This structure features a fully resolved extracellular loop 3 and well-defined densities corresponding to sodium and carbonate ions in the tentative substrate binding pocket. Further, we combine computational modeling with functional studies to unravel the molecular determinants involved in NDCBE and SLC4 transport.
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Affiliation(s)
- Weiguang Wang
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA ,grid.509979.b0000 0004 7666 6191Electron Imaging Center for Nanomachines, California NanoSystems Institute, University of California, Los Angeles, CA USA
| | - Kirill Tsirulnikov
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Hristina R. Zhekova
- grid.22072.350000 0004 1936 7697Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Gülru Kayık
- grid.22072.350000 0004 1936 7697Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Hanif Muhammad Khan
- grid.22072.350000 0004 1936 7697Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Rustam Azimov
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Natalia Abuladze
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Liyo Kao
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Debbie Newman
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Sergei Yu. Noskov
- grid.22072.350000 0004 1936 7697Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Canada
| | - Z. Hong Zhou
- grid.509979.b0000 0004 7666 6191Electron Imaging Center for Nanomachines, California NanoSystems Institute, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA USA
| | - Alexander Pushkin
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Ira Kurtz
- grid.19006.3e0000 0000 9632 6718Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Brain Research Institute, University of California, Los Angeles, CA USA
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12
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Comparative Molecular Dynamics Investigation of the Electromotile Hearing Protein Prestin. Int J Mol Sci 2021; 22:ijms22158318. [PMID: 34361083 PMCID: PMC8347359 DOI: 10.3390/ijms22158318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 01/05/2023] Open
Abstract
The mammalian protein prestin is expressed in the lateral membrane wall of the cochlear hair outer cells and is responsible for the electromotile response of the basolateral membrane, following hyperpolarisation or depolarisation of the cells. Its impairment marks the onset of severe diseases, like non-syndromic deafness. Several studies have pointed out possible key roles of residues located in the Transmembrane Domain (TMD) that differentiate mammalian prestins as incomplete transporters from the other proteins belonging to the same solute-carrier (SLC) superfamily, which are classified as complete transporters. Here, we exploit the homology of a prototypical incomplete transporter (rat prestin, rPres) and a complete transporter (zebrafish prestin, zPres) with target structures in the outward open and inward open conformations. The resulting models are then embedded in a model membrane and investigated via a rigorous molecular dynamics simulation protocol. The resulting trajectories are analyzed to obtain quantitative descriptors of the equilibration phase and to assess a structural comparison between proteins in different states, and between different proteins in the same state. Our study clearly identifies a network of key residues at the interface between the gate and the core domains of prestin that might be responsible for the conformational change observed in complete transporters and hindered in incomplete transporters. In addition, we study the pathway of Cl− ions in the presence of an applied electric field towards their putative binding site in the gate domain. Based on our simulations, we propose a tilt and shift mechanism of the helices surrounding the ion binding cavity as the working principle of the reported conformational changes in complete transporters.
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13
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Shimshilashvili L, Aharon S, Moe OW, Ohana E. Novel Human Polymorphisms Define a Key Role for the SLC26A6-STAS Domain in Protection From Ca 2+-Oxalate Lithogenesis. Front Pharmacol 2020; 11:405. [PMID: 32317970 PMCID: PMC7154107 DOI: 10.3389/fphar.2020.00405] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/17/2020] [Indexed: 12/27/2022] Open
Abstract
Impaired homeostasis of the carboxylic acids oxalate and citrate, dramatically increases the risk for the formation of Ca2+-oxalate kidney stones, which is the most common form of kidney stones in humans. Renal homeostasis of oxalate and citrate is controlled by complex mechanisms including epithelial transport proteins such as the oxalate transporter, SLC26A6, and the citrate transporters, the SLC13’s. These transporters interact via the SLC26A6-STAS domain in vitro, however, the role of the Sulfate Transporter and Anti-Sigma factor antagonist (STAS) domain in Ca2+-oxalate stone formation was not investigated in humans. Here, we report two novel human SLC26A6 polymorphisms identified in the STAS domain of SLC26A6 in two heterozygous carriers. Intriguingly, these individuals have low urinary citrate, but different clinical manifestations. Our in vitro experiments indicate that the homolog mutations of SLC26A6(D23H/D673N) and SLC26A6(D673N) alone abolished the expression and function of SLC26A6, and impaired the regulation of SLC13-mediated citrate transport by SLC26A6. On the other hand, the SLC26A6(R621G) variant showed reduced SLC26A6 protein expression and membrane trafficking, retained full transport activity, but impaired the regulation of the citrate transporter. Accordingly, the human SLC26A6(D23H/D673N) carrier showed a dramatic reduction in urinary citrate concentrations which resulted in Ca2+-oxalate stones formation, as opposed to the carrier of SLC26A6(R621G). Our findings indicate that the human SLC26A6-STAS domain mutations differentially impair SLC26A6 expression, function, and regulation of citrate transporters. This interferes with citrate and oxalate homeostasis thus potentially predisposes to Ca2+-oxalate kidney stones.
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Affiliation(s)
- Liana Shimshilashvili
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Sara Aharon
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Orson W Moe
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Ehud Ohana
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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14
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Seidler U, Nikolovska K. Slc26 Family of Anion Transporters in the Gastrointestinal Tract: Expression, Function, Regulation, and Role in Disease. Compr Physiol 2019; 9:839-872. [DOI: 10.1002/cphy.c180027] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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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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16
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Abbas YM, Toye AM, Rubinstein JL, Reithmeier RA. Band 3 function and dysfunction in a structural context. Curr Opin Hematol 2018; 25:163-170. [DOI: 10.1097/moh.0000000000000418] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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