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Hershfinkel M. Cross-talk between zinc and calcium regulates ion transport: A role for the zinc receptor, ZnR/GPR39. J Physiol 2024; 602:1579-1594. [PMID: 37462604 DOI: 10.1113/jp283834] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 06/26/2023] [Indexed: 04/21/2024] Open
Abstract
Zinc is essential for many physiological functions, with a major role in digestive system, skin health, and learning and memory. On the cellular level, zinc is involved in cell proliferation and cell death. A selective zinc sensing receptor, ZnR/GPR39 is a Gq-coupled receptor that acts via the inositol trisphosphate pathway to release intracellular Ca2+. The ZnR/GPR39 serves as a mediator between extracellular changes in Zn2+ concentration and cellular Ca2+ signalling. This signalling pathway regulates ion transporters activity and thereby controls the formation of transepithelial gradients or neuronal membrane potential, which play a fundamental role in the physiological function of these tissues. This review focuses on the role of Ca2+ signalling, and specifically ZnR/GPR39, with respect to the regulation of the Na+/H+ exchanger, NHE1, and of the K+/Cl- cotransporters, KCC1-3, and also describes the physiological implications of this regulation.
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Affiliation(s)
- Michal Hershfinkel
- Department of Physiology and Cell Biology and the School of Brain Sciences and Cognition, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Alexander SPH, Fabbro D, Kelly E, Mathie AA, Peters JA, Veale EL, Armstrong JF, Faccenda E, Harding SD, Davies JA, Amarosi L, Anderson CMH, Beart PM, Broer S, Dawson PA, Gyimesi G, Hagenbuch B, Hammond JR, Hancox JC, Hershfinkel M, Inui KI, Kanai Y, Kemp S, Kunji ERS, Stewart G, Tavoulari S, Thwaites DT, Verri T. The Concise Guide to PHARMACOLOGY 2023/24: Transporters. Br J Pharmacol 2023; 180 Suppl 2:S374-S469. [PMID: 38123156 DOI: 10.1111/bph.16182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and over 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (https://www.guidetopharmacology.org/), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.16182. Transporters are one of the six major pharmacological targets into which the Guide is divided, with the others being: G protein-coupled receptors, ion channels, nuclear hormone receptors, catalytic receptors and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2023, and supersedes data presented in the 2021/22, 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.
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Affiliation(s)
- Stephen P H Alexander
- School of Life Sciences, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
| | | | - Eamonn Kelly
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Alistair A Mathie
- School of Allied Health Sciences, University of Suffolk, Ipswich, IP4 1QJ, UK
| | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - Emma L Veale
- School of Allied Health Sciences, University of Suffolk, Ipswich, IP4 1QJ, UK
| | - Jane F Armstrong
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Elena Faccenda
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Simon D Harding
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Jamie A Davies
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | | | | | - Philip M Beart
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
| | - Stefan Broer
- Australian National University, Canberra, Australia
| | | | | | | | | | | | | | | | | | - Stephan Kemp
- Amsterdam University, Amsterdam, The Netherlands
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Rozenfeld M, Azoulay IS, Ben Kasus Nissim T, Stavsky A, Melamed M, Stutzmann G, Hershfinkel M, Kofman O, Sekler I. Essential role of the mitochondrial Na +/Ca 2+ exchanger NCLX in mediating PDE2-dependent neuronal survival and learning. Cell Rep 2022; 41:111772. [PMID: 36476859 PMCID: PMC10521900 DOI: 10.1016/j.celrep.2022.111772] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 07/06/2022] [Accepted: 11/10/2022] [Indexed: 12/12/2022] Open
Abstract
Impaired phosphodiesterase (PDE) function and mitochondrial Ca2+ (i.e., [Ca2+]m) lead to multiple health syndromes by an unknown pathway. Here, we fluorescently monitor robust [Ca2+]m efflux mediated by the mitochondrial Na+/Ca2+ exchanger NCLX in hippocampal neurons sequentially evoked by caffeine and depolarization. Surprisingly, neuronal depolarization-induced Ca2+ transients alone fail to evoke strong [Ca2+]m efflux in wild-type (WT) neurons. However, pre-treatment with the selective PDE2 inhibitor Bay 60-7550 effectively rescues [Ca2+]m efflux similarly to caffeine. Moreover, PDE2 acts by diminishing mitochondrial cAMP, thus promoting NCLX phosphorylation at its PKA site. We find that the protection of neurons against excitotoxic insults, conferred by PDE2 inhibition in WT neurons, is NCLX dependent. Finally, the administration of Bay 60-7550 enhances new object recognition in WT, but not in NCLX knockout (KO), mice. Our results identify a link between PDE and [Ca2+]m signaling that may provide effective therapy for cognitive and ischemic syndromes.
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Affiliation(s)
- Maya Rozenfeld
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ivana Savic Azoulay
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Tsipi Ben Kasus Nissim
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Alexandra Stavsky
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Moran Melamed
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Grace Stutzmann
- Rosalind Franklin University of Medicine and Science, Chicago Medical School, Center for Neurodegenerative Disease and Therapeutics, Chicago, IL, USA
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ora Kofman
- Department of Psychology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Asraf H, Bogdanovic M, Gottesman N, Sekler I, Aizenman E, Hershfinkel M. SNAP23 regulates KCC2 membrane insertion and activity following mZnR/GPR39 activation in hippocampal neurons. iScience 2022; 25:103751. [PMID: 35118363 PMCID: PMC8800107 DOI: 10.1016/j.isci.2022.103751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/25/2021] [Accepted: 01/06/2022] [Indexed: 11/23/2022] Open
Abstract
Modulation of the neuronal K+/Cl− cotransporter 2 (KCC2) activity, which mediates Cl− export, is critical to neuronal function. Here, we demonstrate that KCC2 interacts with the SNARE protein synaptosome-associated protein 23, SNAP23, an essential component of membrane insertion machinery. Using KCC2 truncated mutants, we show that KCC2 C-terminal domain is essential for membrane targeting and SNAP23-dependent upregulation of KCC2 activity triggered by activation of the Zn2+-sensitive receptor mZnR/GPR39 in HEK293 cells. Expression of SNAP23 phosphorylation-insensitive mutants or inhibition of its upstream activator IκB kinase (IKK) prevents mZnR/GPR39 upregulation of KCC2 activity in mouse hippocampal neurons. We further find that SNAP23 interacts with Syntaxin 1A and KCC2, and that all three proteins exhibit increased membrane insertion following mZnR/GPR39 activation in neurons. Our results elucidate a G-protein-coupled receptor-dependent pathway for regulation of KCC activity, mediated via interaction with SNARE proteins. Neuronal K+/Cl− cotransporter 2 (KCC2) is regulated via interaction with SNAP23 Zn2+ enhances interaction and membrane insertion of SNAP23, Syntaxin 1A, and KCC2 Zn2+-dependent mZnR/GPR39 regulation of KCC2 requires SNAP23 phosphorylation Epithelial KCC3 regulation by ZnR/GPR39 also requires SNAP23
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Chakraborty M, Asraf H, Sekler I, Hershfinkel M. ZnR/GPR39 controls cell migration by orchestrating recruitment of KCC3 into protrusions, re-organization of actin and activation of MMP. Cell Calcium 2021; 94:102330. [PMID: 33465674 DOI: 10.1016/j.ceca.2020.102330] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/16/2020] [Accepted: 11/30/2020] [Indexed: 12/23/2022]
Abstract
Actin re-organization and degradation of extracellular matrix by metalloproteases (MMPs) facilitate formation of cellular protrusions that are required for cell proliferation and migration. We find that Zn2+ activation of the Gq-coupled receptor ZnR/GPR39 controls these processes by regulating K+/Cl- co-transporter KCC3, which modulates cell volume. Silencing of KCC3 expression or activity reverses ZnR/GPR39 enhancement of cell proliferation, migration and invasion through Matrigel. Activation of ZnR/GPR39 recruits KCC3 into F-actin rich membrane protrusions, suggesting that it can locally control volume changes. Immunofluorescence analysis indicates that Zn2+ activation of ZnR/GPR39 and KCC3 are required to enhance formation of F-actin stress fibers and cellular protrusions. In addition, ZnR/GPR39 upregulation of KCC3-dependent transport increases the activity of matrix metalloproteases MMP2 and MMP9. Our study establishes a mechanism in which ZnR/GPR39 orchestrates localization and activation of KCC3, formation of F-actin rich cell protrusions and activation of MMPs, and thereby controls cell proliferation and migration.
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Affiliation(s)
- Moumita Chakraborty
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Krall RF, Moutal A, Phillips MB, Asraf H, Johnson JW, Khanna R, Hershfinkel M, Aizenman E, Tzounopoulos T. Synaptic zinc inhibition of NMDA receptors depends on the association of GluN2A with the zinc transporter ZnT1. Sci Adv 2020; 6:eabb1515. [PMID: 32937457 PMCID: PMC7458442 DOI: 10.1126/sciadv.abb1515] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 05/20/2020] [Indexed: 05/08/2023]
Abstract
The NMDA receptor (NMDAR) is inhibited by synaptically released zinc. This inhibition is thought to be the result of zinc diffusion across the synaptic cleft and subsequent binding to the extracellular domain of the NMDAR. However, this model fails to incorporate the observed association of the highly zinc-sensitive NMDAR subunit GluN2A with the postsynaptic zinc transporter ZnT1, which moves intracellular zinc to the extracellular space. Here, we report that disruption of ZnT1-GluN2A association by a cell-permeant peptide strongly reduced NMDAR inhibition by synaptic zinc in mouse dorsal cochlear nucleus synapses. Moreover, synaptic zinc inhibition of NMDARs required postsynaptic intracellular zinc, suggesting that cytoplasmic zinc is transported by ZnT1 to the extracellular space in close proximity to the NMDAR. These results challenge a decades-old dogma on how zinc inhibits synaptic NMDARs and demonstrate that presynaptic release and a postsynaptic transporter organize zinc into distinct microdomains to modulate NMDAR neurotransmission.
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Affiliation(s)
- Rebecca F Krall
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Aubin Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Matthew B Phillips
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Hila Asraf
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Jon W Johnson
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Rajesh Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Elias Aizenman
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Thanos Tzounopoulos
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Dershem R, Metpally RPR, Jeffreys K, Krishnamurthy S, Smelser DT, Hershfinkel M, Carey DJ, Robishaw JD, Breitwieser GE. Rare-variant pathogenicity triage and inclusion of synonymous variants improves analysis of disease associations of orphan G protein-coupled receptors. J Biol Chem 2019; 294:18109-18121. [PMID: 31628190 DOI: 10.1074/jbc.ra119.009253] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 10/08/2019] [Indexed: 02/02/2023] Open
Abstract
The pace of deorphanization of G protein-coupled receptors (GPCRs) has slowed, and new approaches are required. Small molecule targeting of orphan GPCRs can potentially be of clinical benefit even if the endogenous receptor ligand has not been identified. Many GPCRs lack common variants that lead to reproducible genome-wide disease associations, and rare-variant approaches have emerged as a viable alternative to identify disease associations for such genes. Therefore, our goal was to prioritize orphan GPCRs by determining their associations with human diseases in a large clinical population. We used sequence kernel association tests to assess the disease associations of 85 orphan or understudied GPCRs in an unselected cohort of 51,289 individuals. Using rare loss-of-function variants, missense variants predicted to be pathogenic or likely pathogenic, and a subset of rare synonymous variants that cause large changes in local codon bias as independent data sets, we found strong, phenome-wide disease associations shared by two or more variant categories for 39% of the GPCRs. To validate the bioinformatics and sequence kernel association test analyses, we functionally characterized rare missense and synonymous variants of GPR39, a family A GPCR, revealing altered expression or Zn2+-mediated signaling for members of both variant classes. These results support the utility of rare variant analyses for identifying disease associations for GPCRs that lack impactful common variants. We highlight the importance of rare synonymous variants in human physiology and argue for their routine inclusion in any comprehensive analysis of genomic variants as potential causes of disease.
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Affiliation(s)
- Ridge Dershem
- Department of Molecular and Functional Genomics, Geisinger, Weis Center for Research, Danville, Pennsylvania 17822
| | - Raghu P R Metpally
- Department of Molecular and Functional Genomics, Geisinger, Weis Center for Research, Danville, Pennsylvania 17822
| | - Kirk Jeffreys
- Department of Molecular and Functional Genomics, Geisinger, Weis Center for Research, Danville, Pennsylvania 17822
| | - Sarathbabu Krishnamurthy
- Department of Molecular and Functional Genomics, Geisinger, Weis Center for Research, Danville, Pennsylvania 17822
| | - Diane T Smelser
- Department of Molecular and Functional Genomics, Geisinger, Weis Center for Research, Danville, Pennsylvania 17822
| | - Michal Hershfinkel
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 8410501 Israel
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- Regeneron Pharmaceuticals, Inc., Tarrytown, New York 10591
| | - David J Carey
- Department of Molecular and Functional Genomics, Geisinger, Weis Center for Research, Danville, Pennsylvania 17822
| | - Janet D Robishaw
- Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida 33431
| | - Gerda E Breitwieser
- Department of Molecular and Functional Genomics, Geisinger, Weis Center for Research, Danville, Pennsylvania 17822.
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Mero M, Asraf H, Sekler I, Taylor KM, Hershfinkel M. Corrigendum to "ZnR/GPR39 upregulation of K +/Cl --cotransporter 3 in tamoxifen resistant breast cancer cells" [Cell Calcium 81 (2019) 12-20]. Cell Calcium 2019; 83:102077. [PMID: 31519404 DOI: 10.1016/j.ceca.2019.102077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- M Mero
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - H Asraf
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - I Sekler
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - K M Taylor
- Breast Cancer Molecular Pharmacology Group, School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB, UK
| | - M Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Mero M, Asraf H, Sekler I, Taylor KM, Hershfinkel M. ZnR/GPR39 upregulation of K +/Cl --cotransporter 3 in tamoxifen resistant breast cancer cells. Cell Calcium 2019; 81:12-20. [PMID: 31146164 DOI: 10.1016/j.ceca.2019.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/20/2019] [Accepted: 05/20/2019] [Indexed: 01/01/2023]
Abstract
Expression of the zinc receptor, ZnR/GPR39, is increased in higher grade breast cancer tumors and cells. Zinc, its ligand, is accumulated at larger concentrations in the tumor tissue and can therefore activate ZnR/GPR39-dependent Ca2+ signaling leading to tumor progression. The K+/Cl- co-transporters (KCC), activated by intracellular signaling, enhance breast cancer cell migration and invasion. We asked if ZnR/GPR39 enhances breast cancer cell malignancy by activating KCC. Activation of ZnR/GPR39 by Zn2+ upregulated K+/Cl- co-transport activity, measured using NH4+ as a surrogate to K+ while monitoring intracellular pH. Upregulation of NH4+ transport was monitored in tamoxifen resistant cells with functional ZnR/GPR39-dependent Ca2+ signaling but not in MCF-7 cells lacking this response. The NH4+ transport was Na+-independent, and we therefore focused on KCC family members. Silencing of KCC3, but not KCC4, expression abolished Zn2+-dependent K+/Cl- co-transport, suggesting that KCC3 is mediating upregulated NH4+ transport. The ZnR/GPR39-dependent KCC3 activation accelerated scratch closure rate, which was abolished by inhibiting KCC transport with [(DihydroIndenyl) Oxy] Alkanoic acid (DIOA). Importantly, silencing of either ZnR/GPR39 or KCC3 attenuated Zn2+-dependent scratch closure. Thus, a novel link between KCC3 and Zn2+, via ZnR/GPR39, promotes breast cancer cell migration and proliferation.
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Affiliation(s)
- Maayan Mero
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Kathryn M Taylor
- Breast Cancer Molecular Pharmacology Group, School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB, UK
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Levy M, Elkoshi N, Barber-Zucker S, Hoch E, Zarivach R, Hershfinkel M, Sekler I. Zinc transporter 10 (ZnT10)-dependent extrusion of cellular Mn 2+ is driven by an active Ca 2+-coupled exchange. J Biol Chem 2019; 294:5879-5889. [PMID: 30755481 DOI: 10.1074/jbc.ra118.006816] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/30/2019] [Indexed: 01/11/2023] Open
Abstract
Manganese (Mn2+) is extruded from the cell by the zinc transporter 10 (ZnT10). Loss of ZnT10 expression caused by autosomal mutations in the ZnT10 gene leads to hypermanganesemia in multiple organs. Here, combining fluorescent monitoring of cation influx in HEK293-T cells expressing human ZnT10 with molecular modeling of ZnT10 cation selectivity, we show that ZnT10 is exploiting the transmembrane Ca2+ inward gradient for active cellular exchange of Mn2+ In analyzing ZnT10 activity we used the ability of Fura-2 to spectrally distinguish between Mn2+ and Ca2+ fluxes. We found that (a) application of Mn2+-containing Ca2+-free solution to ZnT10-expressing cells triggers an influx of Mn2+, (b) reintroduction of Ca2+ leads to cellular Mn2+ extrusion against an inward Mn2+ gradient, and (c) the cellular transport of Mn2+ by ZnT10 is coupled to a reciprocal movement of Ca2+ Remarkably, replacing a single asparagine residue in ZnT10 (Asp-43) with threonine (ZnT10 N43T) converted the Mn2+/Ca2+ exchange to an uncoupled channel mode, permeable to both Ca2+ and Mn2+ The findings in our study identify the first ion transporter that uses the Ca2+ gradient for active counter-ion exchange. They highlight a remarkable versatility in metal selectivity and mode of transport controlled by the tetrahedral metal transport site of ZnT proteins.
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Affiliation(s)
- Moshe Levy
- From the Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Nadav Elkoshi
- From the Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Shiran Barber-Zucker
- Department of Life Sciences and The National Institute for Biotechnology in the Negev and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Eitan Hoch
- Program in Medical and Population Genetics and Metabolism Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Raz Zarivach
- Department of Life Sciences and The National Institute for Biotechnology in the Negev and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Michal Hershfinkel
- From the Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Israel Sekler
- From the Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel.
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Ventura-Bixenshpaner H, Asraf H, Chakraborty M, Elkabets M, Sekler I, Taylor KM, Hershfinkel M. Enhanced ZnR/GPR39 Activity in Breast Cancer, an Alternative Trigger of Signaling Leading to Cell Growth. Sci Rep 2018; 8:8119. [PMID: 29802348 PMCID: PMC5970167 DOI: 10.1038/s41598-018-26459-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 04/20/2018] [Indexed: 12/14/2022] Open
Abstract
Acquired resistance to the estrogen receptor (ER) antagonist tamoxifen, is a major obstacle in treatment of breast cancer. Changes in Zn2+ accumulation and distribution are associated with tamoxifen-resistance and breast cancer progression. The Zn2+-sensing G-protein coupled receptor, ZnR/GPR39, triggers signaling leading to cell growth, but a role for this receptor in breast cancer in unknown. Using fluorescence imaging, we found Zn2+-dependent Ca2+ release, mediated by ZnR/GPR39 activity, in TAMR tamoxifen-resistant cells derived from MCF-7 cells, but not in ER-expressing MCF-7 or T47D cells. Furthermore, ZnR/GPR39 signaling was monitored in ER negative BT20, MDA-MB-453 and JIMT-1 cells. Expression of ZnR/GPR39 was increased in grade 3 human breast cancer biopsies compared to grade 2. Consistently, analysis of two breast cancer patient cohorts, GDS4057 and TCGA, indicated that in ER-negative tumors higher ZnR/GPR39 mRNA levels are associated with more aggressive tumors. Activation of ZnR/GPR39 in TAMR cells triggered MAPK, mTOR and PI3K signaling. Importantly, enhanced cell growth and invasiveness was observed in the ER negative breast cancer cells, TAMR, MDA-MB-453 and BT20 cells but not in the ER expressing MCF-7 cells. Thus, we suggest ZnR/GPR39 as a potential therapeutic target for combination treatment in breast cancer, particularly relevant in ER negative tumors.
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Affiliation(s)
- Hila Ventura-Bixenshpaner
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Moumita Chakraborty
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Moshe Elkabets
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Kathryn M Taylor
- Breast Cancer Molecular Pharmacology Group, School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3NB, UK
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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12
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Abstract
A distinct G-protein coupled receptor that senses changes in extracellular Zn2+, ZnR/GPR39, was found in cells from tissues in which Zn2+ plays a physiological role. Most prominently, ZnR/GPR39 activity was described in prostate cancer, skin keratinocytes, and colon epithelial cells, where zinc is essential for cell growth, wound closure, and barrier formation. ZnR/GPR39 activity was also described in neurons that are postsynaptic to vesicular Zn2+ release. Activation of ZnR/GPR39 triggers Gαq-dependent signaling and subsequent cellular pathways associated with cell growth and survival. Furthermore, ZnR/GPR39 was shown to regulate the activity of ion transport mechanisms that are essential for the physiological function of epithelial and neuronal cells. Thus, ZnR/GPR39 provides a unique target for therapeutically modifying the actions of zinc in a specific and selective manner.
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Affiliation(s)
- Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, POB 653, Ben-Gurion Ave. Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
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13
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Sunuwar L, Medini M, Cohen L, Sekler I, Hershfinkel M. The zinc sensing receptor, ZnR/GPR39, triggers metabotropic calcium signalling in colonocytes and regulates occludin recovery in experimental colitis. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0420. [PMID: 27377730 DOI: 10.1098/rstb.2015.0420] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2016] [Indexed: 12/22/2022] Open
Abstract
Impaired epithelial barrier function is a hallmark of inflammatory bowel diseases, such as colitis, contributing to diarrhoea and perpetuating inflammation. We show that the zinc sensing receptor, ZnR/GPR39, triggers intracellular Ca(2+) signalling in colonocytes thereby inducing occludin expression. Moreover, ZnR/GPR39 is essential for epithelial barrier recovery in the dextran sodium sulfate (DSS) ulcerative colitis model. Loss of ZnR/GPR39 results in increased susceptibility to DSS-induced inflammation, owing to low expression of the tight junction protein occludin and impaired epithelial barrier. Recovery of wild-type (WT) mice from the DSS insult was faster than that of ZnR/GPR39 knockout (KO) mice. Enhanced recovery of the epithelial layer and increased crypt regeneration were observed in WT mice compared with ZnR/GPR39 KO, suggesting that ZnR/GPR39 is promoting epithelial barrier integrity following DSS insult. Indeed, cell proliferation and apical expression of occludin, following the DSS-induced epithelial erosion, were increased in WT tissue but not in ZnR/GPR39 KO tissue. Importantly, survival following DSS treatment was higher in WT mice compared with ZnR/GPR39 KO mice. Our results support a direct role for ZnR/GPR39 in promoting epithelial renewal and barrier function following DSS treatment, thereby affecting the severity of the disease. We suggest ZnR/GPR39 as a novel therapeutic target that can improve epithelial barrier function in colitis.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.
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Affiliation(s)
- Laxmi Sunuwar
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Michal Medini
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Limor Cohen
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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14
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Sunuwar L, Asraf H, Donowitz M, Sekler I, Hershfinkel M. The Zn 2+-sensing receptor, ZnR/GPR39, upregulates colonocytic Cl - absorption, via basolateral KCC1, and reduces fluid loss. Biochim Biophys Acta Mol Basis Dis 2017; 1863:947-960. [PMID: 28093242 PMCID: PMC5557417 DOI: 10.1016/j.bbadis.2017.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 12/13/2022]
Abstract
Administration of zinc, as a complement to oral rehydration solutions, effectively diminishes duration and severity of diarrhea, but it is not known whether it merely fulfills a nutritional deficiency, or if zinc has a direct role of regulating solute absorption. We show that Zn2+ acts via a specific receptor, ZnR/GPR39, to reduce fluid loss. Intestinal fluid secretion triggered by cholera toxin (CTx) was lower in WT mice compared to ZnR/GPR39 KO. In the absence of dietary Zn2+ we observed similar fluid accumulation in WT and ZnR/GPR39 KO mice, indicating that Zn2+ and ZnR/GPR39 are both required for a beneficial effect of Zn2+ in diarrhea. In primary colonocytes and in Caco-2 colonocytic cells, activation of ZnR/GPR39 enhanced Cl- transport, a critical factor in diarrhea, by upregulating K+/Cl- cotransporter (KCC1) activity. Importantly, we show basolateral expression of KCC1 in mouse and human colonocytes, thus identifying a novel Cl- absorption pathway. Finally, inhibition of KCC-dependent Cl- transport enhanced CTx-induced fluid loss. Altogether, our data indicate that Zn2+ acting via ZnR/GPR39 has a direct role in controlling Cl- absorption via upregulation of basolateral KCC1 in the colon. Moreover, colonocytic ZnR/GPR39 and KCC1 reduce water loss during diarrhea and may therefore serve as effective drug targets.
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Affiliation(s)
- Laxmi Sunuwar
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Mark Donowitz
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
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15
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Abstract
While zinc has had a well-established structural role for many years, it is only during the last two decades that its role as a signaling molecule has been recognized. Ionic zinc, Zn2+, that is endogenously released during physiological activity acts as a first messenger, triggering the activity of a distinct Zn2+-sensing-receptor, ZnR. The ZnR is a member of the Gq-coupled receptor family, and the molecular moiety mediating its activity is GPR39. In this review, we will discuss the role of the ZnR/GPR39 in mediating Zn2+-dependent signaling in epithelial tissues and in neurons, where Zn2+ homeostasis plays physiological as well as pathological roles. Importantly, ZnR/GPR39 activates signaling that regulates a remarkably wide range of cell functions, including proliferation, differentiation and survival, as well as modulation of ion transport, and thereby, regulation of Na+, H+ and Cl- homeostasis. Moreover, signaling activated by ZnR/GPR39 plays a key role in mediating effects of Zn2+ in health and disease. Thus, ZnR/GPR39 provides a unique target for therapeutically modifying the actions of zinc in a specific and selective manner.
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Affiliation(s)
- Laxmi Sunuwar
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion university of the Negev, Beer Sheva, Israel
| | - David Gilad
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion university of the Negev, Beer Sheva, Israel
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion university of the Negev, Beer Sheva, Israel,
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16
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Ben-Kasus Nissim T, Zhang X, Elazar A, Roy S, Stolwijk JA, Zhou Y, Motiani RK, Gueguinou M, Hempel N, Hershfinkel M, Gill DL, Trebak M, Sekler I. Mitochondria control store-operated Ca 2+ entry through Na + and redox signals. EMBO J 2017; 36:797-815. [PMID: 28219928 DOI: 10.15252/embj.201592481] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 12/25/2016] [Accepted: 01/05/2017] [Indexed: 02/05/2023] Open
Abstract
Mitochondria exert important control over plasma membrane (PM) Orai1 channels mediating store-operated Ca2+ entry (SOCE). Although the sensing of endoplasmic reticulum (ER) Ca2+ stores by STIM proteins and coupling to Orai1 channels is well understood, how mitochondria communicate with Orai1 channels to regulate SOCE activation remains elusive. Here, we reveal that SOCE is accompanied by a rise in cytosolic Na+ that is critical in activating the mitochondrial Na+/Ca2+ exchanger (NCLX) causing enhanced mitochondrial Na+ uptake and Ca2+ efflux. Omission of extracellular Na+ prevents the cytosolic Na+ rise, inhibits NCLX activity, and impairs SOCE and Orai1 channel current. We show further that SOCE activates a mitochondrial redox transient which is dependent on NCLX and is required for preventing Orai1 inactivation through oxidation of a critical cysteine (Cys195) in the third transmembrane helix of Orai1. We show that mitochondrial targeting of catalase is sufficient to rescue redox transients, SOCE, and Orai1 currents in NCLX-deficient cells. Our findings identify a hitherto unknown NCLX-mediated pathway that coordinates Na+ and Ca2+ signals to effect mitochondrial redox control over SOCE.
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Affiliation(s)
- Tsipi Ben-Kasus Nissim
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Xuexin Zhang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Assaf Elazar
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Soumitra Roy
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Judith A Stolwijk
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Rajender K Motiani
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Maxime Gueguinou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Nadine Hempel
- Department of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Michal Hershfinkel
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Israel Sekler
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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17
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Roy S, Dey K, Hershfinkel M, Ohana E, Sekler I. Identification of residues that control Li + versus Na + dependent Ca 2+ exchange at the transport site of the mitochondrial NCLX. Biochim Biophys Acta Mol Cell Res 2017; 1864:997-1008. [PMID: 28130126 DOI: 10.1016/j.bbamcr.2017.01.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/07/2017] [Accepted: 01/10/2017] [Indexed: 11/25/2022]
Abstract
BACKGROUND The Na+/Ca2+/Li+ exchanger (NCLX) is a member of the Na+/Ca2+ exchanger family. NCLX is unique in its capacity to transport both Na+ and Li+, unlike other members, which are Na+ selective. The major aim of this study was twofold, i.e., to identify NCLX residues that confer Li+ or Na+ selective Ca2+ transport and map their putative location on NCLX cation transport site. METHOD We combined molecular modeling to map transport site of NCLX with euryarchaeal H+/Ca2+ exchanger, CAX_Af, and fluorescence analysis to monitor Li+ versus Na+ dependent mitochondrial Ca2+ efflux of transport site mutants of NCLX in permeabilized cells. RESULT Mutation of Asn149, Pro152, Asp153, Gly176, Asn467, Ser468, Gly494 and Asn498 partially or strongly abolished mitochondrial Ca2+ exchange activity in intact cells. In permeabilized cells, N149A, P152A, D153A, N467Q, S468T and G494S demonstrated normal Li+/Ca2+ exchange activity but a reduced Na+/Ca2+ exchange activity. On the other hand, D471A showed dramatically reduced Li+/Ca2+ exchange, but Na+/Ca2+ exchange activity was unaffected. Finally, simultaneous mutation of four putative Ca2+ binding residues was required to completely abolish both Na+/Ca2+ and Li+/Ca2+ exchange activities. CONCLUSIONS We identified distinct Na+ and Li+ selective residues in the NCLX transport site. We propose that functional segregation in Li+ and Na+ sites reflects the functional properties of NCLX required for Ca2+ exchange under the unique membrane potential and ion gradient across the inner mitochondrial membrane. GENERAL SIGNIFICANCE The results of this study provide functional insights into the unique Li+ and Na+ selectivity of the mitochondrial exchanger. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Soumitra Roy
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Kuntal Dey
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, 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.
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel.
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18
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Sunuwar L, Medini M, Cohen L, Sekler I, Hershfinkel M. Correction to 'The zinc sensing receptor, ZnR/GPR39, triggers metabotropic calcium signalling in colonocytes and regulates occludin recovery in experimental colitis'. Philos Trans R Soc Lond B Biol Sci 2016; 371:rstb.2016.0331. [PMID: 27502386 DOI: 10.1098/rstb.2016.0331] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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19
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Abramovitch-Dahan C, Asraf H, Bogdanovic M, Sekler I, Bush AI, Hershfinkel M. Amyloid β attenuates metabotropic zinc sensing receptor, mZnR/GPR39, dependent Ca2+
, ERK1/2 and Clusterin signaling in neurons. J Neurochem 2016; 139:221-233. [DOI: 10.1111/jnc.13760] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/02/2016] [Accepted: 08/03/2016] [Indexed: 12/28/2022]
Affiliation(s)
- Chen Abramovitch-Dahan
- Department of Physiology and Cell Biology; Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology; Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
| | - Milos Bogdanovic
- Department of Physiology and Cell Biology; Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology; Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
| | - Ashley I. Bush
- Florey Institute of Neuroscience and Mental Health; University of Melbourne; Parkville Victoria Australia
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology; Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
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20
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Elgazar V, Razanov V, Stoltenberg M, Hershfinkel M, Huleihel M, Nitzan YB, Lunenfeld E, Sekler I, Silverman WF. Zinc-regulating Proteins, ZnT-1, and Metallothionein I/II Are Present in Different Cell Populations in the Mouse Testis. J Histochem Cytochem 2016; 53:905-12. [PMID: 15995149 DOI: 10.1369/jhc.4a6482.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Zinc ions play an important role in testis development and spermatogenesis. Thus, nutritional zinc deficiency leads to aberrant testicular development, reduced spermatogenesis, and male sterility. The precise actions of zinc in mediating these functions and the mechanisms by which zinc is itself regulated in the testis, however, have not been adequately elucidated. We have assessed the distribution of the zinc-regulating proteins ZnT-1 and metallothionein I/II (MT I/II) in the mouse seminiferous tubule. Colabeling for ZnT-1 and MT I/II demonstrated unique patterns of distribution for these proteins, with ZnT-1 present in Sertoli cells in addition to luminal spermatozoa and MT I/II restricted to spermatocytes. These findings were confirmed by dual-label immunofluorescence for ZnT-1 and the Sertoli cell marker, vimentin, and by immunoelectron microscopy. The differential expression patterns of ZnT-1 and MTs support the hypothesis that ZnT-1 and MTs play different roles in the regulation of intracellular zinc in this organ. The specific expression of ZnT-1 in the Sertoli cells, moreover, is consistent with their role in maintaining a nurturing, closely regulated environment for spermatogenesis.
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Affiliation(s)
- Vered Elgazar
- Department of Physiology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 84 105 Israel
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21
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Hershfinkel M, Ford D, Kelleher S, Aizenman E. Seashells by the zinc shore: a meeting report of the International Society for Zinc Biology, Asilomar, CA 2014. Metallomics 2016. [PMID: 26225429 DOI: 10.1039/c5mt90029h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Ben-Gurion University of the Negev, Faculty of Health Sciences, POB 653, Beer-Sheva, 84105, Israel.
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22
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Ganay T, Asraf H, Aizenman E, Bogdanovic M, Sekler I, Hershfinkel M. Regulation of neuronal pH by the metabotropic Zn(2+)-sensing Gq-coupled receptor, mZnR/GPR39. J Neurochem 2015; 135:897-907. [PMID: 26375174 DOI: 10.1111/jnc.13367] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Revised: 09/01/2015] [Accepted: 09/08/2015] [Indexed: 11/29/2022]
Abstract
Synaptically released Zn(2+) acts as a neurotransmitter, in part, by activating the postsynaptic metabotropic Zn(2+)-sensing Gq protein-coupled receptor (mZnR/GPR39). In previous work using epithelial cells, we described crosstalk between Zn(2+) signaling and changes in intracellular pH and/or extracellular pH (pHe). As pH changes accompany neuronal activity under physiological and pathological conditions, we tested whether Zn(2+) signaling is involved in regulation of neuronal pH. Here, we report that up-regulation of a major H(+) extrusion pathway, the Na(+)/H(+) exchanger (NHE), is induced by mZnR/GPR39 activation in an extracellular-regulated kinase 1/2-dependent manner in hippocampal neurons in vitro. We also observed that changes in pHe can modulate neuronal mZnR/GPR39-dependent signaling, resulting in reduced activity at pHe 8 or 6.5. Similarly, Zn(2+)-dependent extracellular-regulated kinase 1/2 phosphorylation and up-regulation of NHE activity were absent at acidic pHe. Thus, our results suggest that when pHe is maintained within the physiological range, mZnR/GPR39 activation can up-regulate NHE-dependent recovery from intracellular acidification. During acidosis, as pHe drops, mZnR/GPR39-dependent NHE activation is inhibited, thereby attenuating further H(+) extrusion. This mechanism may serve to protect neurons from excessive decreases in pHe. Thus, mZnR/GPR39 signaling provides a homeostatic adaptive process for regulation of intracellular and extracellular pH changes in the brain. We show that the postsynaptic metabotropic Zn(2+)-sensing Gq protein-coupled receptor (mZnR/GPR39) activation induces up-regulation of a major neuronal H(+) extrusion pathway, the Na(+)/H(+) exchanger (NHE), thereby enhancing neuronal recovery from intracellular acidification. Changes in extracellular pH (pHe), however, modulate neuronal mZnR/GPR39-dependent signaling, resulting in reduced activity at pHe 8 or 6.5. This mechanism may serve to protect neurons from excessive decreases in pHe during acidosis. Hence, mZnR/GPR39 signaling provides a homeostatic adaptive process for regulation of intracellular and extracellular pH changes in the brain.
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Affiliation(s)
- Thibault Ganay
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hila Asraf
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Elias Aizenman
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Milos Bogdanovic
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology and The Zlotowski Center of Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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23
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Gilad D, Shorer S, Ketzef M, Friedman A, Sekler I, Aizenman E, Hershfinkel M. Homeostatic regulation of KCC2 activity by the zinc receptor mZnR/GPR39 during seizures. Neurobiol Dis 2015; 81:4-13. [PMID: 25562657 PMCID: PMC4490144 DOI: 10.1016/j.nbd.2014.12.020] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/11/2014] [Accepted: 12/23/2014] [Indexed: 12/31/2022] Open
Abstract
The aim of this study was to investigate the role of the synaptic metabotropic zinc receptor mZnR/GPR39 in physiological adaptation to epileptic seizures. We previously demonstrated that synaptic activation of mZnR/GPR39 enhances inhibitory drive in the hippocampus by upregulating neuronal K(+)/Cl(-) co-transporter 2 (KCC2) activity. Here, we first show that mZnR/GPR39 knockout (KO) adult mice have dramatically enhanced susceptibility to seizures triggered by a single intraperitoneal injection of kainic acid, when compared to wild type (WT) littermates. Kainate also substantially enhances seizure-associated gamma oscillatory activity in juvenile mZnR/GPR39 KO hippocampal slices, a phenomenon that can be reproduced in WT tissue by extracellular Zn(2+) chelation. Importantly, kainate-induced synaptic Zn(2+) release enhances surface expression and transport activity of KCC2 in WT, but not mZnR/GPR39 KO hippocampal neurons. Kainate-dependent upregulation of KCC2 requires mZnR/GPR39 activation of the Gαq/phospholipase C/extracellular regulated kinase (ERK1/2) signaling cascade. We suggest that mZnR/GPR39-dependent upregulation of KCC2 activity provides homeostatic adaptation to an excitotoxic stimulus by increasing inhibition. As such, mZnR/GPR39 may provide a novel pharmacological target for dampening epileptic seizure activity.
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Affiliation(s)
- David Gilad
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Sharon Shorer
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Maya Ketzef
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Alon Friedman
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel
| | - Elias Aizenman
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel; Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Faculty of Health Sciences, Beer-Sheva, Israel.
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Cohen L, Sekler I, Hershfinkel M. The zinc sensing receptor, ZnR/GPR39, controls proliferation and differentiation of colonocytes and thereby tight junction formation in the colon. Cell Death Dis 2014; 5:e1307. [PMID: 24967969 PMCID: PMC4611734 DOI: 10.1038/cddis.2014.262] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/11/2014] [Accepted: 05/05/2014] [Indexed: 12/21/2022]
Abstract
The intestinal epithelium is a renewable tissue that requires precise balance between proliferation and differentiation, an essential process for the formation of a tightly sealed barrier. Zinc deficiency impairs the integrity of the intestinal epithelial barrier and is associated with ulcerative and diarrheal pathologies, but the mechanisms underlying the role of Zn2+ are not well understood. Here, we determined a role of the colonocytic Zn2+ sensing receptor, ZnR/GPR39, in mediating Zn2+-dependent signaling and regulating the proliferation and differentiation of colonocytes. Silencing of ZnR/GPR39 expression attenuated Zn2+-dependent activation of ERK1/2 and AKT as well as downstream activation of mTOR/p70S6K, pathways that are linked with proliferation. Consistently, ZnR/GPR39 silencing inhibited HT29 and Caco-2 colonocyte proliferation, while not inducing caspase-3 cleavage. Remarkably, in differentiating HT29 colonocytes, silencing of ZnR/GPR39 expression inhibited alkaline phosphatase activity, a marker of differentiation. Furthermore, Caco-2 colonocytes showed elevated expression of ZnR/GPR39 during differentiation, whereas silencing of ZnR/GPR39 decreased monolayer transepithelial electrical resistance, suggesting compromised barrier formation. Indeed, silencing of ZnR/GPR39 or chelation of Zn2+ by the cell impermeable chelator CaEDTA was followed by impaired expression of the junctional proteins, that is, occludin, zonula-1 (ZO-1) and E-cadherin. Importantly, colon tissues of GPR39 knockout mice also showed a decrease in expression levels of ZO-1 and occludin compared with wildtype mice. Altogether, our results indicate that ZnR/GPR39 has a dual role in promoting proliferation of colonocytes and in controlling their differentiation. The latter is followed by ZnR/GPR39-dependent expression of tight junctional proteins, thereby leading to formation of a sealed intestinal epithelial barrier. Thus, ZnR/GPR39 may be a therapeutic target for promoting epithelial function and tight junction barrier integrity during ulcerative colon diseases.
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Affiliation(s)
- L Cohen
- Department of Physiology and Cell Biology, Faculty of Health Science, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - I Sekler
- Department of Physiology and Cell Biology, Faculty of Health Science, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - M Hershfinkel
- Department of Physiology and Cell Biology, Faculty of Health Science, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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25
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Yassin L, Radtke-Schuller S, Asraf H, Grothe B, Hershfinkel M, Forsythe ID, Kopp-Scheinpflug C. Nitric oxide signaling modulates synaptic inhibition in the superior paraolivary nucleus (SPN) via cGMP-dependent suppression of KCC2. Front Neural Circuits 2014; 8:65. [PMID: 24987336 PMCID: PMC4060731 DOI: 10.3389/fncir.2014.00065] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/28/2014] [Indexed: 11/13/2022] Open
Abstract
Glycinergic inhibition plays a central role in the auditory brainstem circuitries involved in sound localization and in the encoding of temporal action potential firing patterns. Modulation of this inhibition has the potential to fine-tune information processing in these networks. Here we show that nitric oxide (NO) signaling in the auditory brainstem (where activity-dependent generation of NO is documented) modulates the strength of inhibition by changing the chloride equilibrium potential. Recent evidence demonstrates that large inhibitory postsynaptic currents (IPSCs) in neurons of the superior paraolivary nucleus (SPN) are enhanced by a very low intracellular chloride concentration, generated by the neuronal potassium chloride co-transporter (KCC2) expressed in the postsynaptic neurons. Our data show that modulation by NO caused a 15 mV depolarizing shift of the IPSC reversal potential, reducing the strength of inhibition in SPN neurons, without changing the threshold for action potential firing. Regulating inhibitory strength, through cGMP-dependent changes in the efficacy of KCC2 in the target neuron provides a postsynaptic mechanism for rapidly controlling the inhibitory drive, without altering the timing or pattern of the afferent spike train. Therefore, this NO-mediated suppression of KCC2 can modulate inhibition in one target nucleus (SPN), without influencing inhibitory strength of other target nuclei (MSO, LSO) even though they are each receiving collaterals from the same afferent nucleus (a projection from the medial nucleus of the trapezoid body, MNTB).
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Affiliation(s)
- Lina Yassin
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University MunichPlanegg-Martinsried, Germany
| | - Susanne Radtke-Schuller
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University MunichPlanegg-Martinsried, Germany
| | - Hila Asraf
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the NegevBeer-Sheva, Israel
| | - Benedikt Grothe
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University MunichPlanegg-Martinsried, Germany
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the NegevBeer-Sheva, Israel
| | - Ian D. Forsythe
- Department of Cell Physiology and Pharmacology, University of LeicesterLeicester, UK
| | - Cornelia Kopp-Scheinpflug
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University MunichPlanegg-Martinsried, Germany
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26
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Nita II, Hershfinkel M, Kantor C, Rutter GA, Lewis EC, Sekler I. Pancreatic β-cell Na+ channels control global Ca2+ signaling and oxidative metabolism by inducing Na+ and Ca2+ responses that are propagated into mitochondria. FASEB J 2014; 28:3301-12. [PMID: 24719357 DOI: 10.1096/fj.13-248161] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Communication between the plasma membrane and mitochondria is essential for initiating the Ca(2+) and metabolic signals required for secretion in β cells. Although voltage-dependent Na(+) channels are abundantly expressed in β cells and activated by glucose, their role in communicating with mitochondria is unresolved. Here, we combined fluorescent Na(+), Ca(2+), and ATP imaging, electrophysiological analysis with tetrodotoxin (TTX)-dependent block of the Na(+) channel, and molecular manipulation of mitochondrial Ca(2+) transporters to study the communication between Na(+) channels and mitochondria. We show that TTX inhibits glucose-dependent depolarization and blocks cytosolic Na(+) and Ca(2+) responses and their propagation into mitochondria. TTX-sensitive mitochondrial Ca(2+) influx was largely blocked by knockdown of the mitochondrial Ca(2+) uniporter (MCU) expression. Knockdown of the mitochondrial Na(+)/Ca(2+) exchanger (NCLX) and Na(+) dose response analysis demonstrated that NCLX mediates the mitochondrial Na(+) influx and is tuned to sense the TTX-sensitive cytosolic Na(+) responses. Finally, TTX blocked glucose-dependent mitochondrial Ca(2+) rise, mitochondrial metabolic activity, and ATP production. Our results show that communication of the Na(+) channels with mitochondria shape both global Ca(2+) and metabolism signals linked to insulin secretion in β cells.- Nita, I. I., Hershfinkel, M., Kantor, C., Rutter, G. A., Lewis, E. C., Sekler, I. Pancreatic β-cell Na(+) channels control global Ca(2+) signaling and oxidative metabolism by inducing Na(+) and Ca(2+) responses that are propagated into mitochondria.
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Affiliation(s)
| | | | - Chase Kantor
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, London, UK
| | - Guy A Rutter
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, London, UK
| | - Eli C Lewis
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel; and
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27
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Asraf H, Salomon S, Nevo A, Sekler I, Mayer D, Hershfinkel M. The ZnR/GPR39 Interacts With the CaSR to Enhance Signaling in Prostate and Salivary Epithelia. J Cell Physiol 2014; 229:868-77. [DOI: 10.1002/jcp.24514] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 11/18/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Hila Asraf
- Department of Physiology and Cell Biology, Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
| | - Shimrit Salomon
- Department of Physiology and Cell Biology, Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
| | - Andrey Nevo
- Department of Physiology and Cell Biology, Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
| | - Doris Mayer
- Hormones and Signal Transduction Group; German Cancer Research Center (DKFZ); Heidelberg Germany
| | - Michal Hershfinkel
- Department of Physiology and Cell Biology, Faculty of Health Sciences; Ben-Gurion University of the Negev; Beer-Sheva Israel
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28
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Grebhardt S, Müller-Decker K, Bestvater F, Hershfinkel M, Mayer D. Impact of S100A8/A9 Expression on Prostate Cancer Progression In Vitro and In Vivo. J Cell Physiol 2014; 229:661-71. [DOI: 10.1002/jcp.24489] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 10/03/2013] [Indexed: 12/27/2022]
Affiliation(s)
- Sina Grebhardt
- Hormones and Signal Transduction Group; DKFZ-ZMBH Alliance, German Cancer Research Center; Heidelberg Germany
| | - Karin Müller-Decker
- Core Facility Tumor Models; German Cancer Research Center; Heidelberg Germany
| | - Felix Bestvater
- DKFZ Light Microscopy Facility; German Cancer Research Center; Heidelberg Germany
| | | | - Doris Mayer
- Hormones and Signal Transduction Group; DKFZ-ZMBH Alliance, German Cancer Research Center; Heidelberg Germany
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29
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Sekler I, Hershfinkel M, Nita II. The mitochondrial Na+/Ca2+ exchanger‐NCLX is an integrating hub for glucose dependent Na+ and Ca2+ signaling in pancreatic β cells. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.918.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Israel Sekler
- Physiology and Cell biologyBen‐Gurion universityBeer‐ShevaIsrael
| | | | - Inlia I. Nita
- Physiology and Cell biologyBen Gurion UniversityBeer‐ShevaIsrael
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Cohen L, Asraf H, Sekler I, Hershfinkel M. Extracellular pH regulates zinc signaling via an Asp residue of the zinc-sensing receptor (ZnR/GPR39). J Biol Chem 2012; 287:33339-50. [PMID: 22879599 DOI: 10.1074/jbc.m112.372441] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Zinc activates a specific Zn(2+)-sensing receptor, ZnR/GPR39, and thereby triggers cellular signaling leading to epithelial cell proliferation and survival. Epithelial cells that express ZnR, particularly colonocytes, face frequent changes in extracellular pH that are of physiological and pathological implication. Here we show that the ZnR/GPR39-dependent Ca(2+) responses in HT29 colonocytes were maximal at pH 7.4 but were reduced by about 50% at pH 7.7 and by about 62% at pH 7.1 and were completely abolished at pH 6.5. Intracellular acidification did not attenuate ZnR/GPR39 activity, indicating that the pH sensor of this protein is located on an extracellular domain. ZnR/GPR39-dependent activation of extracellular-regulated kinase (ERK)1/2 or AKT pathways was abolished at acidic extracellular pH of 6.5. A similar inhibitory effect was monitored for the ZnR/GPR39-dependent up-regulation of Na(+)/H(+) exchange activity at pH 6.5. Focusing on residues putatively facing the extracellular domain, we sought to identify the pH sensor of ZnR/GPR39. Replacing the histidine residues forming the Zn(2+) binding site, His(17) or His(19), or other extracellular-facing histidines to alanine residues did not abolish the pH dependence of ZnR/GPR39. In contrast, replacing Asp(313) with alanine resulted in similar Ca(2+) responses triggered by ZnR/GPR39 at pH 7.4 or 6.5. This mutant also showed similar activation of ERK1/2 and AKT pathways, and ZnR-dependent up-regulation of Na(+)/H(+) exchange at pH 7.4 and pH 6.5. Substitution of Asp(313) to His or Glu residues restored pH sensitivity of the receptor. This indicates that Asp(313), which was shown to modulate Zn(2+) binding, is an essential residue of the pH sensor of GPR39. In conclusion, ZnR/GPR39 is tuned to sense physiologically relevant changes in extracellular pH that thus regulate ZnR-dependent signaling and ion transport activity.
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Affiliation(s)
- Limor Cohen
- Department of Morphology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva 84105, Israel
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31
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Abstract
The mitochondrial membrane potential that powers the generation of ATP also facilitates mitochondrial Ca(2+) shuttling. This process is fundamental to a wide range of cellular activities, as it regulates ATP production, shapes cytosolic and endoplasmic recticulum Ca(2+) signaling, and determines cell fate. Mitochondrial Ca(2+) transport is mediated primarily by two major transporters: a Ca(2+) uniporter that mediates Ca(2+) uptake and a Na(+)/Ca(2+) exchanger that subsequently extrudes mitochondrial Ca(2+). In this minireview, we focus on the specific role of the mitochondrial Na(+)/Ca(2+) exchanger and describe its ion exchange mechanism, regulation by ions, and putative partner proteins. We discuss the recent molecular identification of the mitochondrial exchanger and how its activity is linked to physiological and pathophysiological processes.
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Affiliation(s)
- Raz Palty
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA. palty35@berkeley
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32
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Saadi RA, He K, Hartnett KA, Kandler K, Hershfinkel M, Aizenman E. SNARE-dependent upregulation of potassium chloride co-transporter 2 activity after metabotropic zinc receptor activation in rat cortical neurons in vitro. Neuroscience 2012; 210:38-46. [PMID: 22441041 PMCID: PMC3358579 DOI: 10.1016/j.neuroscience.2012.03.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/29/2012] [Accepted: 03/01/2012] [Indexed: 01/11/2023]
Abstract
The major outward chloride transporter in neurons is the potassium chloride co-transporter 2 (KCC2), critical for maintaining an inhibitory reversal potential for GABA(A) receptor channels. In a recent study, we showed that Zn(2+) regulates GABA(A) reversal potentials in the hippocampus by enhancing the activity of KCC2 through an increase in its surface expression. Zn(2+) initiates this process by activating the Gq-coupled metabotropic Zn(2+) receptor/G protein-linked receptor 39 (mZnR/GPR39). Here, we first demonstrated that mZnR/GPR39 is functional in cortical neurons in culture, and then tested the hypothesis that the increase in KCC2 activity is mediated through a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-dependent process. We established the presence of functional mZnR in rat cultured cortical neurons by loading cells with a Ca(2+) indicator and exposing cells to Zn(2+), which triggered consistent Ca(2+) responses that were blocked by the Gq antagonist YM-254890, but not by the metabotropic glutamate receptor antagonist (RS)-α-methyl-4-carboxyphenylglycine (MCPG). Importantly, Zn(2+) treatment under these conditions did not increase the intracellular concentrations of Zn(2+) itself. We then measured KCC2 activity by monitoring both the rate and relative amount of furosemide-sensitive NH(4)(+) influx through the co-transporter using an intracellular pH-sensitive fluorescent indicator. We observed that Zn(2+) pretreatment induced a Ca(2+)-dependent increase in KCC2 activity. The effects of Zn(2+) on KCC2 activity were also observed in wild-type mouse cortical neurons in culture, but not in neurons obtained from mZnR/GPR39(-/-) mice, suggesting that Zn(2+) acts through mZnR/GPR39 activation to upregulate KCC2 activity. We next transfected rat cortical neurons with a plasmid encoding botulinum toxin C1 (Botox C1), which cleaves the SNARE proteins syntaxin 1 and synaptosomal-associated protein 25 (SNAP-25). Basal KCC2 activity was similar in both transfected and non-transfected neurons. Non-transfected cells, or cells transfected with marker vector alone, showed a Zn(2+)-dependent increase in KCC2 activity. In contrast, KCC2 activity in neurons expressing Botox C1 was unchanged by Zn(2+). These results suggest that SNARE proteins are necessary for the increased activity of KCC2 after Zn(2+) stimulation of mZnR/GPR39.
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Affiliation(s)
- Robert A. Saadi
- Department of Neurobiology, University of University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
| | - Kai He
- Department of Neurobiology, University of University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
| | - Karen A. Hartnett
- Department of Neurobiology, University of University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
| | - Karl Kandler
- Department of Neurobiology, University of University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
- Department of Otolaryngology, University of University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
| | - Michal Hershfinkel
- Department of Morphology, Ben-Gurion University, Faculty of Health Sciences, Beer-Sheva 84105, Israel
| | - Elias Aizenman
- Department of Neurobiology, University of University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, U.S.A
- Department of Morphology, Ben-Gurion University, Faculty of Health Sciences, Beer-Sheva 84105, Israel
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Chorin E, Vinograd O, Fleidervish I, Gilad D, Herrmann S, Sekler I, Aizenman E, Hershfinkel M. Upregulation of KCC2 activity by zinc-mediated neurotransmission via the mZnR/GPR39 receptor. J Neurosci 2011; 31:12916-26. [PMID: 21900570 PMCID: PMC3227684 DOI: 10.1523/jneurosci.2205-11.2011] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/12/2011] [Accepted: 07/14/2011] [Indexed: 12/15/2022] Open
Abstract
Vesicular Zn(2+) regulates postsynaptic neuronal excitability upon its corelease with glutamate. We previously demonstrated that synaptic Zn(2+) acts via a distinct metabotropic zinc-sensing receptor (mZnR) in neurons to trigger Ca(2+) responses in the hippocampus. Here, we show that physiological activation of mZnR signaling induces enhanced K(+)/Cl(-) cotransporter 2 (KCC2) activity and surface expression. As KCC2 is the major Cl(-) outward transporter in neurons, Zn(2+) also triggers a pronounced hyperpolarizing shift in the GABA(A) reversal potential. Mossy fiber stimulation-dependent upregulation of KCC2 activity is eliminated in slices from Zn(2+) transporter 3-deficient animals, which lack synaptic Zn(2+). Importantly, activity-dependent ZnR signaling and subsequent enhancement of KCC2 activity are also absent in slices from mice lacking the G-protein-coupled receptor GPR39, identifying this protein as the functional neuronal mZnR. Our work elucidates a fundamentally important role for synaptically released Zn(2+) acting as a neurotransmitter signal via activation of a mZnR to increase Cl(-) transport, thereby enhancing inhibitory tone in postsynaptic cells.
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MESH Headings
- Animals
- Blotting, Western
- CA3 Region, Hippocampal/cytology
- CA3 Region, Hippocampal/physiology
- Electrophysiological Phenomena
- Excitatory Postsynaptic Potentials/physiology
- Female
- Genotype
- In Vitro Techniques
- Male
- Mice
- Mice, Knockout
- Microscopy, Fluorescence
- Mossy Fibers, Hippocampal/physiology
- Patch-Clamp Techniques
- Receptors, Cell Surface/metabolism
- Receptors, G-Protein-Coupled/drug effects
- Receptors, G-Protein-Coupled/genetics
- Receptors, GABA-A/drug effects
- Reverse Transcriptase Polymerase Chain Reaction
- Symporters/biosynthesis
- Symporters/physiology
- Synapses/metabolism
- Synaptic Transmission/drug effects
- Up-Regulation/drug effects
- Zinc/metabolism
- Zinc/pharmacology
- K Cl- Cotransporters
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Affiliation(s)
| | | | - Ilya Fleidervish
- Physiology, Faculty of Health Sciences and The Zlotowski Center of Neuroscience, Ben-Gurion University, Beer-Sheva, 84015, Israel, and
| | | | - Sharon Herrmann
- Physiology, Faculty of Health Sciences and The Zlotowski Center of Neuroscience, Ben-Gurion University, Beer-Sheva, 84015, Israel, and
| | - Israel Sekler
- Physiology, Faculty of Health Sciences and The Zlotowski Center of Neuroscience, Ben-Gurion University, Beer-Sheva, 84015, Israel, and
| | - Elias Aizenman
- Departments of Morphology and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
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Abstract
"Oh, Jerusalem of gold, and of light, and of bronze..." goes the popular song. But it was another metal that towered above the Jerusalem landscape during the meeting of the International Society for Zinc Biology (ISZB; http://www.iszb.org/), held at Mishkenot Sha'ananim, a whisper away from the Old City walls. More than 100 scientists gathered on 1 to 5 December 2009 to discuss their research on the biology of this metal. Zinc is a double-edged sword. Zinc supplementation accelerates wound healing and growth and promotes an effective immune response. On the other hand, zinc deficiency leads to growth retardation and impaired learning and memory function, and has been linked to mood disorders. At the cellular level, however, uncontrolled increases in zinc concentrations can lead to neuronal cell death and may be involved in neurodegenerative disorders. Through regulation of various intracellular signaling pathways, zinc can accelerate cell growth and possibly contribute to cancer. However, despite the physiological and clinical importance of this metal, research on the molecular basis of these effects is still in its infancy. The 2009 ISZB meeting provided a venue for investigators working on various zinc-related issues to share their thoughts and ideas and to promote the growth of this field.
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Affiliation(s)
- Michal Hershfinkel
- Department of Morphology, Ben Gurion University, Beer Sheva, 84105, Israel
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35
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Sharir H, Zinger A, Nevo A, Sekler I, Hershfinkel M. Zinc released from injured cells is acting via the Zn2+-sensing receptor, ZnR, to trigger signaling leading to epithelial repair. J Biol Chem 2010; 285:26097-106. [PMID: 20522546 DOI: 10.1074/jbc.m110.107490] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
A role for Zn(2+) in accelerating wound healing is established, yet, the signaling pathways linking Zn(2+) to tissue repair are not well known. We show that in the human HaCaT keratinocytes extracellular Zn(2+) induces a metabotropic Ca(2+) response that is abolished by silencing the expression of the G-protein-coupled receptor GPR39, suggesting that this Zn(2+)-sensing receptor, ZnR, is mediating the response. Keratinocytic-ZnR signaling is highly selective for Zn(2+) and can be triggered by nanomolar concentrations of this ion. Interestingly, Zn(2+) was also released following cellular injury, as monitored by a specific non-permeable fluorescent Zn(2+) probe, ZnAF-2. Chelation of Zn(2+) and scavenging of ATP from conditioned medium, collected from injured epithelial cultures, was sufficient to eliminate the metabotropic Ca(2+) signaling. The signaling triggered by Zn(2+), via ZnR, or by ATP further activated MAP kinase and induced up-regulation of the sodium/proton exchanger NHE1 activity. Finally, activation of ZnR/GPR39 signaling or application of ATP enhanced keratinocytes scratch closure in an in vitro model. Thus our results indicate that extracellular Zn(2+), which is either applied or released following injury, activates ZnR/GPR39 to promote signaling leading to epithelial repair.
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Affiliation(s)
- Haleli Sharir
- Departments of Morphology, Ben Gurion University, Beer-Sheva 84105, Israel
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Karol N, Brodski C, Bibi Y, Kaisman T, Forberg M, Hershfinkel M, Sekler I, Silverman WF. Zinc homeostatic proteins in the CNS are regulated by crosstalk between extracellular and intracellular zinc. J Cell Physiol 2010; 224:567-74. [DOI: 10.1002/jcp.22168] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Barkalifa R, Hershfinkel M, Friedman JE, Kozak A, Sekler I. The lipophilic zinc chelator DP-b99 prevents zinc induced neuronal death. Eur J Pharmacol 2009; 618:15-21. [PMID: 19622352 DOI: 10.1016/j.ejphar.2009.07.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 06/29/2009] [Accepted: 07/09/2009] [Indexed: 10/20/2022]
Abstract
Zinc plays a key pathophysiological role in major neurological disorders as well as diabetes, while being essential for the activity of numerous zinc binding proteins. A major challenge in chelation based therapy must take into consideration these apparently conflicting effects of zinc. One approach is to limit the activity of the chelator to regions and levels of zinc pathology, making normal zinc-dependent processes invisible to the chelator. Combining fluorescent zinc imaging with cytotoxicity assays we studied the zinc chelation efficacy and neuroprotective effect of the lipophilic divalent transition metal chelator DP-b99 (1,2-Bis(2-amino-phenoxy)ethane-N,N,N',N'-tetraacetic acid-N-N'-di[2-(octyloxy)ethyl ester],-N,N'-disodium salt). The affinity of DP-b99 to Zn(2+) and Ca(2+) ions is moderate in water and enhanced significantly in the lipid milieu. Application of DP-b99 to MIN6 beta-cells that were preloaded with zinc was followed by a decrease in fluorescence of the intracellular Zn(2+) sensitive dye, ZnAF-2DA, to resting levels. Preloading of MIN6 cells with DP-b99 was also effective in attenuating subsequent cellular zinc rise. Concentration-dependence analysis of zinc accumulation indicated that DP-b99 acts as a zinc chelator with moderate affinity. DP-b99 preapplication attenuated both Zn(2+) and Ca(2+) rise in neuronal cultures and also Zn(2+) rise in brain slices. Finally, DP-b99 attenuated Zn(2+)-induced neuronal death. Our results indicate that DP-b99 is effective in attenuating Zn(2+) and Ca(2+) surges and protecting neurons against a toxic Zn(2+)-rise. This may underlie the efficacy of DP-b99 in stroke treatment.
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Affiliation(s)
- Ronit Barkalifa
- Morphology, and the Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Kaisman-Elbaz T, Sekler I, Fishman D, Karol N, Forberg M, Kahn N, Hershfinkel M, Silverman WF. Cell death induced by zinc and cadmium is mediated by clusterin in cultured mouse seminiferous tubules. J Cell Physiol 2009; 220:222-9. [DOI: 10.1002/jcp.21754] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Hershfinkel M, Kandler K, Knoch ME, Dagan-Rabin M, Aras MA, Abramovitch-Dahan C, Sekler I, Aizenman E. Intracellular zinc inhibits KCC2 transporter activity. Nat Neurosci 2009; 12:725-7. [PMID: 19430470 PMCID: PMC2737597 DOI: 10.1038/nn.2316] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 03/23/2009] [Indexed: 11/09/2022]
Abstract
We found that K(+)/Cl(-) co-transporter 2 (KCC2) activity, monitored with wide-field fluorescence, was inhibited by intracellular Zn(2+), a major component of neuronal injury. Zn(2+)-mediated KCC2 inhibition produced a depolarizing shift of GABA(A) reversal potentials in rat cortical neurons. Moreover, oxygen-glucose deprivation attenuated KCC2 activity in a Zn(2+)-dependent manner. The link between Zn(2+) and KCC2 activity provides a previously unknown target for neuroprotection and may be important in activity-dependent regulation of inhibitory synaptic transmission.
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Ohana E, Hoch E, Keasar C, Kambe T, Yifrach O, Hershfinkel M, Sekler I. Identification of the Zn2+ binding site and mode of operation of a mammalian Zn2+ transporter. J Biol Chem 2009; 284:17677-86. [PMID: 19366695 DOI: 10.1074/jbc.m109.007203] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vesicular zinc transporters (ZnTs) play a critical role in regulating Zn2+ homeostasis in various cellular compartments and are linked to major diseases ranging from Alzheimer disease to diabetes. Despite their importance, the intracellular localization of ZnTs poses a major challenge for establishing the mechanisms by which they function and the identity of their ion binding sites. Here, we combine fluorescence-based functional analysis and structural modeling aimed at elucidating these functional aspects. Expression of ZnT5 was followed by both accelerated removal of Zn2+ from the cytoplasm and its increased vesicular sequestration. Further, activity of this zinc transport was coupled to alkalinization of the trans-Golgi network. Finally, structural modeling of ZnT5, based on the x-ray structure of the bacterial metal transporter YiiP, identified four residues that can potentially form the zinc binding site on ZnT5. Consistent with this model, replacement of these residues, Asp599 and His451, with alanine was sufficient to block Zn2+ transport. These findings indicate, for the first time, that Zn2+ transport mediated by a mammalian ZnT is catalyzed by H+/Zn2+ exchange and identify the zinc binding site of ZnT proteins essential for zinc transport.
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Affiliation(s)
- Ehud Ohana
- Department of Physiology, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, Israel
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41
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Zehorai E, Eitan E, Hershfinkel M, Sekler I, Priel E. Glutamate regulates the activity of topoisomerase I in mouse cerebellum. Mol Neurobiol 2008; 38:242-52. [PMID: 18982460 DOI: 10.1007/s12035-008-8044-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 10/10/2008] [Indexed: 10/21/2022]
Abstract
Topoisomerase I (topo I) is a nuclear enzyme which participates in most DNA transactions. It was shown to be inhibited in depolarized neurons by poly adenosine diphosphate (ADP)-ribosylation of the enzyme protein. We demonstrated previously an age and sex dependent topo I activity and enzyme protein level in the various regions of mouse brain. A specific distribution pattern of topo I was observed and the inhibitory neurons exhibited the highest enzyme activity and protein level in both the nucleus and the cytoplasm. Here, we show that neurotransmitters (glutamate and gamma-aminobutyric acid (GABA)) regulate the activity of topo I in mouse cerebellum sections. Glutamate exhibited a significant time-dependent inhibition of topo I activity but no effect of the enzyme protein level. GABA in contrary only slightly and transiently inhibited topo I activity. The inhibitory effect of glutamate was mediated by Ca(+2) and by ADP-ribosylation of topo I protein and the glutamate ionotropic receptors were involved. Glutamate also diminished the inhibitory effect of topotecan on topo I. These results point to distinct and highly specific effects of the major neurotransmitters on topo I activity in the cerebellum suggesting that topo I possesses a specific role in the brain which differs from its known biological functions.
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Affiliation(s)
- Eldar Zehorai
- The Shraga Segal Department of Microbiology & Immunology, Ben-Gurion University Cancer Research Center, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84105, Israel
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42
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Fedida-Metula S, Elhyany S, Tsory S, Segal S, Hershfinkel M, Sekler I, Fishman D. Targeting lipid rafts inhibits protein kinase B by disrupting calcium homeostasis and attenuates malignant properties of melanoma cells. Carcinogenesis 2008; 29:1546-54. [PMID: 18579561 DOI: 10.1093/carcin/bgn146] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Failure of current therapeutic modalities to treat melanoma remains a challenge for clinical and experimental oncology. The aggressive growth and apoptotic resistance of this tumor are mediated, in part, by aberrantly activated protein kinase B/Akt (PKB). In many cells, PKB signaling depends on integrity of cholesterol-enriched membrane microdomains (rafts). However, it is still unclear if rafts support deregulated PKB activity in melanoma. In this study, ablation of rafts in murine (B16BL6-8, JB/RH1) and human (GA) melanoma lines by cholesterol-chelating methyl-beta-cyclodextrin (MbetaCD) reduced levels of constitutively active PKB in a dose- and time-dependent manner, while reconstitution of microdomains restored PKB activity. PKB was sensitive to the membrane-permeable Ca2+ chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N'N'-tetraacetic acid tetra (acetocymethyl) ester and to the calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphtalenesulfonamide (W7) implying the contribution of Ca2+ signaling to PKB deregulation. Indeed, malignant and apoptosis-resistant clone of B16BL6 melanoma (B16BL6-8) displayed significantly higher [Ca2+](i) and store-operated Ca2+ influx (SOC) relative to non-malignant apoptosis-sensitive B16BL6 clone (Kb30) expressing barely detectable basal levels of active PKB. Raft ablation in B16BL6-8 cells robustly inhibited SOC and decreased [Ca2+](i) to levels comparable with those detected in Kb30 cells. Treating cells by PKB-inhibiting doses of M beta CD dramatically impaired their apoptotic resistance and capacity to generate tumors. Furthermore, weekly intraperitoneal injections of M beta CD to mice grafted with melanoma cells at doses of 300 and 800 mg/kg significantly attenuated tumor development. Our data implicate membrane rafts in enhancing the resistance of melanoma to apoptosis and indicate that targeting raft microdomains is a potentially effective strategy to cure this frequently fatal form of cancer.
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Affiliation(s)
- Shlomit Fedida-Metula
- Department of Microbiology and Immunology, Ben-Gurion University Cancer Research Center, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 84105, Israel
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43
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Dubi N, Gheber L, Fishman D, Sekler I, Hershfinkel M. Extracellular zinc and zinc-citrate, acting through a putative zinc-sensing receptor, regulate growth and survival of prostate cancer cells. Carcinogenesis 2008; 29:1692-700. [PMID: 18310092 DOI: 10.1093/carcin/bgn027] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Prostate Zn(2+) concentrations are among the highest in the body, and a marked decrease in the level of this ion is observed in prostate cancer. Extracellular Zn(2+) is known to regulate cell survival and proliferation in numerous tissues. In spite of this, a signaling role for extracellular Zn(2+) in prostate cancer has not been established. In the present study, we demonstrate that prostate metastatic cells are impermeable to Zn(2+), but extracellular Zn(2+) triggers a metabotropic Ca(2+) rise that is also apparent in the presence of citrate. Employing fluorescent imaging, we measured this activity in androgen-insensitive metastatic human cell lines, PC-3 and DU-145, and in mouse prostate tumor TRAMP-1 cells but not in androgen-sensitive LNCaP cells. The Ca(2+) response was inhibited by Galphaq and phospholipase C (PLC) inhibitors as well as by intracellular Ca(2+) store depletion, indicating that it is mediated by a Gq-coupled receptor that activates the inositol phosphate (IP(3)) pathway consistent with the previously identified zinc-sensing receptor (ZnR). Zn(2+)-dependent extracellular signal-regulated kinase and AKT activation, as well as enhanced Zn(2+)-dependent cell growth and survival, were observed in PC-3 cells that exhibit ZnR activity, but not in a ZnR activity-deficient PC-3 subline. Interestingly, application of Zn(2+)-citrate (Zn(2+)Cit), at physiological concentrations, was followed by a profound functional desensitization of extracellular Zn(2+)-dependent signaling and attenuation of Zn(2+)-dependent cell growth. Our results indicate that extracellular Zn(2+) and Zn(2+)Cit, by triggering or desensitizing ZnR activity, distinctly regulate prostate cancer cell growth. Thus, therapeutic strategies based either on Zn(2+) chelation or administration of Zn(2+)Cit may be effective in attenuating prostate tumor growth.
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Affiliation(s)
- Noga Dubi
- Department of Morphology, Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University, PO Box 653, Beer Sheva 84105, Israel
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Abstract
Zinc is an essential cofactor for the activity and folding of up to ten percent of mammalian proteins and can modulate the function of many others. Because of the pleiotropic effects of zinc on every aspect of cell physiology, deficits of cellular zinc content, resulting from zinc deficiency or excessive rise in its cellular concentration, can have catastrophic consequences and are linked to major patho-physiologies including diabetes and stroke. Thus, the concentration of cellular zinc requires establishment of discrete, active cellular gradients. The cellular distribution of zinc into organelles is precisely managed to provide the zinc concentration required by each cell compartment. The complexity of zinc homeostasis is reflected by the surprisingly large variety and number of zinc homeostatic proteins found in virtually every cell compartment. Given their ubiquity and importance, it is surprising that many aspects of the function, regulation, and crosstalk by which zinc transporters operate are poorly understood. In this mini-review, we will focus on the mechanisms and players required for generating physiologically appropriate zinc gradients across the plasma membrane and vesicular compartments. We will also highlight some of the unsolved issues regarding their role in cellular zinc homeostasis.
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Affiliation(s)
- Israel Sekler
- Department of Physiology, Faculty of Health Science, and The Zlotowski Center for Neuroscience, Ben Gurion University of the Negev, POB 653, Beer-Sheva, Israel.
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45
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Hershfinkel M, Silverman WF, Sekler I. The zinc sensing receptor, a link between zinc and cell signaling. Mol Med 2007; 13:331-6. [PMID: 17728842 PMCID: PMC1952663 DOI: 10.2119/2006-00038.hershfinkel] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 06/12/2007] [Indexed: 11/06/2022] Open
Abstract
Zinc is essential for cell growth. For many years it has been used to treat various epithelial disorders, ranging from wound healing to diarrhea and ulcerative colon disease. The physiological/molecular mechanisms linking zinc and cell growth, however, are not well understood. In recent years, Zn2+ has emerged as an important signaling molecule, activating intracellular pathways and regulating cell fate. We have functionally identified an extracellular zinc sensing receptor, called zinc sensing receptor (ZnR), that is specifically activated by extracellular Zn2+ at physiological concentrations. The putative ZnR is pharmacologically coupled to a Gq-protein which triggers release of Ca2+ from intracellular stores via the Inositol 1,4,5-trisphosphate (IP3) pathway. This, in turn results in downstream signaling via the MAP and phosphatidylinositol 3-kinase (PI3 kinase) pathways that are linked to cell proliferation. In some cell types, e.g., colonocytes, ZnR activity also upregulates Na+/H+ exchange, mediated by Na+/H+ exchanger isoform 1 (NHE1), which is involved in cellular ion homeostasis in addition to cell proliferation. Our overall hypothesis, as discussed below, is that a ZnR, found in organs where dynamic zinc homeostasis is observed, enables extracellular Zn2+ to trigger intracellular signaling pathways regulating key cell functions. These include cell proliferation and survival, vectorial ion transport and hormone secretion. Finally, we suggest that ZnR activity found in colonocytes is well positioned to attenuate erosion of the epithelial lining of the colon, thereby preventing or ameliorating diarrhea, but, by signaling through the same pathways, a ZnR may enhance tumor progression in neoplastic disease.
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Affiliation(s)
- Michal Hershfinkel
- Department of Morphology, Ben Gurion University of the Negev, POB 653, Beer-Sheva, Israel.
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46
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Sekler I, Sensi SL, Hershfinkel M, Silverman WF. Mechanism and regulation of cellular zinc transport. Mol Med 2007; 13:337-43. [PMID: 17622322 PMCID: PMC1952664 DOI: 10.2119/2007–00037.sekler] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 05/30/2007] [Indexed: 11/06/2022]
Abstract
Zinc is an essential cofactor for the activity and folding of up to ten percent of mammalian proteins and can modulate the function of many others. Because of the pleiotropic effects of zinc on every aspect of cell physiology, deficits of cellular zinc content, resulting from zinc deficiency or excessive rise in its cellular concentration, can have catastrophic consequences and are linked to major patho-physiologies including diabetes and stroke. Thus, the concentration of cellular zinc requires establishment of discrete, active cellular gradients. The cellular distribution of zinc into organelles is precisely managed to provide the zinc concentration required by each cell compartment. The complexity of zinc homeostasis is reflected by the surprisingly large variety and number of zinc homeostatic proteins found in virtually every cell compartment. Given their ubiquity and importance, it is surprising that many aspects of the function, regulation, and crosstalk by which zinc transporters operate are poorly understood. In this mini-review, we will focus on the mechanisms and players required for generating physiologically appropriate zinc gradients across the plasma membrane and vesicular compartments. We will also highlight some of the unsolved issues regarding their role in cellular zinc homeostasis.
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Affiliation(s)
- Israel Sekler
- Department of Physiology, Faculty of Health Science, and The Zlotowski Center for Neuroscience, Ben Gurion University of the Negev, POB 653, Beer-Sheva, Israel.
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47
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Crivat G, Kikuchi K, Nagano T, Priel T, Hershfinkel M, Sekler I, Rosenzweig N, Rosenzweig Z. Fluorescence-based zinc ion sensor for zinc ion release from pancreatic cells. Anal Chem 2007; 78:5799-804. [PMID: 16906726 DOI: 10.1021/ac060764i] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we describe the synthesis and characterization of analytical properties of fluorescence-based zinc ion-sensing glass slides and their application in monitoring zinc ion release from beta pancreatic cells in cell cultures. To fabricate the sensors, the zinc ion indicator ZnAF-2 {6-[N-[N',N'-bis(2-pyridinylmethyl)-2-aminoethyl]amino-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one} was modified to include a sufficiently long linking aliphatic chain with a terminal carboxyl functional group. The recently synthesized ZnAF-2 zinc ion indicator provided high zinc ion selectivity in physiological solutions containing millimolar levels of calcium and other possible interfering cations. The carboxyl-modified ZnAF-2 was conjugated to the activated surface of glass slides, which then served as zinc ion sensors. It was possible to grow pancreatic cells directly on the zinc-sensing glass slide or on a membrane placed on these glass slides. The sensors were used to monitor zinc ion release events from glucose-stimulated pancreatic cells. The study showed that the zinc ion sensors responded effectively to the release of zinc ions from pancreatic cells at the nanomolar level with high selectivity and rapid subsecond response time.
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Affiliation(s)
- Georgeta Crivat
- Department of Chemistry and the Advanced Materials Research Institute, University of New Orleans, New Orleans, Louisiana 70148, USA
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Palty R, Hershfinkel M, Yagev O, Saar D, Barkalifa R, Khananshvili D, Peretz A, Grossman Y, Sekler I. Single alpha-domain constructs of the Na+/Ca2+ exchanger, NCLX, oligomerize to form a functional exchanger. Biochemistry 2006; 45:11856-66. [PMID: 17002286 DOI: 10.1021/bi060633b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spliced isoforms of the Na+/Ca2+ exchanger, NCLX, truncated at the alpha-repeat region have been identified. The activity and functional organization of such proteins are, however, poorly understood. In the present work, we have studied Na+/Ca2+ exchange mediated by single alpha-repeat constructs (alpha1 and alpha2) of NCLX. Sodium-dependent calcium transport was fluorescently detected in both the reversal and forward modes; calcium-dependent outward currents were also recorded using a whole cell patch configuration in HEK293 cells heterologously expressing either the alpha1 or alpha2 single-domain proteins. In contrast, calcium transport and reversal currents were not detected when cells were transfected with a vector or with an alpha2 mutant (alpha2-S273T). Thus, our data indicate that the single alpha-domain constructs mediate electrogenic Na+/Ca2+ exchange. The alpha1 domain, but not the alpha2, exhibited partial sensitivity to the NCX inhibitor, KB-R7943, while Li+-dependent Ca2+ efflux was detected in cells expressing either the alpha1 or alpha2 construct. The functional organization of the single alpha-domain constructs was assessed using a dominant-negative approach. Coexpression of the alpha1 or alpha2 constructs with the nonfunctional alpha2-S273T mutant had a synergistic inhibitory effect on Na+/Ca2+ transport. Dose-dependence analysis of the inhibition of alpha2 construct activity by the alpha2-S273T mutant indicated that the functional unit is either a dimer or a trimer. Immunoprecipitation analysis indicated that the alpha2 construct indeed interacts with the alpha2-S273T mutant. Taken together, our data indicate that although single alpha1 or alpha2 domain constructs are independently capable of Na+/Ca2+ exchange, oligomerization is required for their activity. Such organization may give rise to transport activity with distinct kinetic parameters and physiological roles.
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Affiliation(s)
- Raz Palty
- Department of Physiology, Zlotowski Center for Neuroscience, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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49
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Frederickson CJ, Giblin LJ, Balaji RV, Masalha R, Frederickson CJ, Zeng Y, Lopez EV, Koh JY, Chorin U, Besser L, Hershfinkel M, Li Y, Thompson RB, Krężel A. Corrigendum to “Synaptic release of zinc from brain slices: Factors governing release, imaging, and accurate calculation of concentration” [J. Neurosci. Meth. 154 (2006) 19–29]. J Neurosci Methods 2006. [DOI: 10.1016/j.jneumeth.2006.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ohana E, Sekler I, Kaisman T, Kahn N, Cove J, Silverman WF, Amsterdam A, Hershfinkel M. Silencing of ZnT-1 expression enhances heavy metal influx and toxicity. J Mol Med (Berl) 2006; 84:753-63. [PMID: 16741752 DOI: 10.1007/s00109-006-0062-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Accepted: 02/14/2006] [Indexed: 10/24/2022]
Abstract
ZnT-1 reduces intracellular zinc accumulation and confers resistance against cadmium toxicity by a mechanism which is still unresolved. A functional link between the L-type calcium channels (LTCC) and ZnT-1 has been suggested, indicating that ZnT-1 may regulate ion permeation through this pathway. In the present study, immunohistochemical analysis revealed a striking overlap of the expression pattern of LTCC and ZnT-1 in cardiac tissue and brain. Using siRNA to silence ZnT-1 expression, we then assessed the role of ZnT-1 in regulating cation permeation through the L-type Ca(2+) channels in cells that are vulnerable to heavy metal permeation. Transfection of cortical neurons with ZnT-1 siRNA resulted in about 70% reduction of ZnT-1 expression and increased Ca(2+) influx via LTCC by approximately fourfold. Moreover, ZnT-1 siRNA transfected neurons showed approximately 30% increase in synaptic release, monitored using the FM1-43 dye. An increased cation influx rate, through the LTCC, was also recorded for Zn(2+) and Cd(2+) in cells treated with the ZnT-1 siRNA. Furthermore, Cd(2+)-induced neuronal death increased by approximately twofold after transfection with ZnT-1 siRNA. In addition, ZnT-1 siRNA transfection of the ovarian granulosa cell line, POGRS1, resulted in a twofold increase in Cd(2+) influx rate via the LTCC. Finally, a robust nimodipine-sensitive Cd(2+) influx was observed using a low extracellular Cd(2+) concentration (5 muM) in neurons and testicular slice cultures, attesting to the relevance of the LTCC pathway to heavy metal toxicity. Taken together, our results indicate that endogenously-expressed ZnT-1, by modulating LTCC, has a dual role: regulating calcium influx, and attenuating Cd(2+) and Zn(2+) permeation and toxicity in neurons and other cell types.
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Affiliation(s)
- Ehud Ohana
- Department of Physiology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, 84105, Israel
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