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Zinc in Cognitive Impairment and Aging. Biomolecules 2022; 12:biom12071000. [PMID: 35883555 PMCID: PMC9312494 DOI: 10.3390/biom12071000] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 02/05/2023] Open
Abstract
Zinc, an essential micronutrient for life, was first discovered in 1869 and later found to be indispensable for the normal development of plants and for the normal growth of rats and birds. Zinc plays an important role in many physiological and pathological processes in normal mammalian brain development, especially in the development of the central nervous system. Zinc deficiency can lead to neurodegenerative diseases, mental abnormalities, sleep disorders, tumors, vascular diseases, and other pathological conditions, which can cause cognitive impairment and premature aging. This study aimed to review the important effects of zinc and zinc-associated proteins in cognitive impairment and aging, to reveal its molecular mechanism, and to highlight potential interventions for zinc-associated aging and cognitive impairments.
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2
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ZnT1 is a neuronal Zn 2+/Ca 2+ exchanger. Cell Calcium 2021; 101:102505. [PMID: 34871934 DOI: 10.1016/j.ceca.2021.102505] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/31/2021] [Accepted: 11/22/2021] [Indexed: 01/22/2023]
Abstract
Zinc transporter 1 (ZnT1; SLC30A1) is present in the neuronal plasma membrane, critically modulating NMDA receptor function and Zn2+ neurotoxicity. The mechanism mediating Zn2+ transport by ZnT1, however, has remained elusive. Here, we investigated ZnT1-dependent Zn2+ transport by measuring intracellular changes of this ion using the fluorescent indicator FluoZin-3. In primary mouse cortical neurons, which express ZnT1, transient addition of extracellular Zn2+ triggered a rise in cytosolic Zn2+, followed by its removal. Knockdown of ZnT1 by adeno associated viral (AAV)-short hairpin RNA (shZnT1) markedly increased rates of Zn2+ rise, and decreased rates of its removal, suggesting that ZnT1 is a primary route for Zn2+ efflux in neurons. Although Zn2+ transport by other members of the SLC30A family is dependent on pH gradients across cellular membranes, altered H+ gradients were not coupled to ZnT1-dependent transport. Removal of cytoplasmic Zn2+, against a large inward gradient during the initial loading phase, suggests that Zn2+ efflux requires a large driving force. We therefore asked if Ca2+ gradients across the membrane can facilitate Zn2+ efflux. Elimination of extracellular Ca2+ abolished Zn2+ efflux, while increased extracellular Ca2+ levels enhanced Zn2+ efflux. Intracellular Ca2+ rises, measured in GCaMP6 expressing neurons, closely paralleled cytoplasmic Zn2+ removal. Taken together, these results strongly suggest that ZnT1 functions as a Zn2+/Ca2+ exchanger, thereby regulating the transport of two ions of fundamental importance in neuronal signaling.
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3
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Hasna J, Bohic S, Lemoine S, Blugeon C, Bouron A. Zinc Uptake and Storage During the Formation of the Cerebral Cortex in Mice. Mol Neurobiol 2019; 56:6928-6940. [DOI: 10.1007/s12035-019-1581-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/20/2019] [Indexed: 12/17/2022]
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4
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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] [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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5
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Watanabe M, Fukuda A. Development and regulation of chloride homeostasis in the central nervous system. Front Cell Neurosci 2015; 9:371. [PMID: 26441542 PMCID: PMC4585146 DOI: 10.3389/fncel.2015.00371] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/04/2015] [Indexed: 12/22/2022] Open
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the mature central nervous system (CNS). The developmental switch of GABAergic transmission from excitation to inhibition is induced by changes in Cl− gradients, which are generated by cation-Cl− co-transporters. An accumulation of Cl− by the Na+-K+-2Cl− co-transporter (NKCC1) increases the intracellular Cl− concentration ([Cl−]i) such that GABA depolarizes neuronal precursors and immature neurons. The subsequent ontogenetic switch, i.e., upregulation of the Cl−-extruder KCC2, which is a neuron-specific K+-Cl− co-transporter, with or without downregulation of NKCC1, results in low [Cl−]i levels and the hyperpolarizing action of GABA in mature neurons. Development of Cl− homeostasis depends on developmental changes in NKCC1 and KCC2 expression. Generally, developmental shifts (decreases) in [Cl−]i parallel the maturation of the nervous system, e.g., early in the spinal cord, hypothalamus and thalamus, followed by the limbic system, and last in the neocortex. There are several regulators of KCC2 and/or NKCC1 expression, including brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF), and cystic fibrosis transmembrane conductance regulator (CFTR). Therefore, regionally different expression of these regulators may also contribute to the regional developmental shifts of Cl− homeostasis. KCC2 and NKCC1 functions are also regulated by phosphorylation by enzymes such as PKC, Src-family tyrosine kinases, and WNK1–4 and their downstream effectors STE20/SPS1-related proline/alanine-rich kinase (SPAK)-oxidative stress responsive kinase-1 (OSR1). In addition, activation of these kinases is modulated by humoral factors such as estrogen and taurine. Because these transporters use the electrochemical driving force of Na+ and K+ ions, topographical interaction with the Na+-K+ ATPase and its modulators such as creatine kinase (CK) should modulate functions of Cl− transporters. Therefore, regional developmental regulation of these regulators and modulators of Cl− transporters may also play a pivotal role in the development of Cl− homeostasis.
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Affiliation(s)
- Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
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6
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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] [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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7
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Mato S, Sánchez-Gómez MV, Bernal-Chico A, Matute C. Cytosolic zinc accumulation contributes to excitotoxic oligodendroglial death. Glia 2013; 61:750-64. [PMID: 23440871 DOI: 10.1002/glia.22470] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 12/27/2012] [Indexed: 01/01/2023]
Abstract
Dyshomeostasis of cytosolic Zn(2+) is a critical mediator of neuronal damage during excitotoxicity. However, the role of this cation in oligodendrocyte pathophysiology is not well understood. The current study examined the contribution of Zn(2+) deregulation to oligodendrocyte injury mediated by AMPA receptors. Oligodendrocytes loaded with the Zn(2+)-selective indicator FluoZin-3 responded to mild stimulation of AMPA receptors with fast cytosolic Zn(2+) rises that resulted from intracellular release, as they were not blocked by the extracellular Zn(2+) chelator Ca-EDTA. Pharmacological experiments suggested that AMPA-induced Zn(2+) mobilization depends on cytosolic Ca(2+) accumulation, arises from mitochondria and protein-bound pools, and is triggered by mechanisms that do not involve the generation of reactive oxygen species. Moreover, intracellular Zn(2+) rises resulting from AMPA receptor activation seem to be promoted by Ca(2+)-dependent cytosolic acidification. Addition of the cell-permeable Zn(2+) chelator TPEN significantly reduced mitochondrial membrane depolarization, reactive oxygen species production, and cell death by sub-maximal activation of AMPA receptors both in vitro and in situ, suggesting that Zn(2+) deregulation is an important mediator of oligodendrocyte excitotoxicity. These data provide evidence that strategies aimed at maintaining Zn(2+) homeostasis may be useful for the treatment of disorders in which excitotoxicity is an important trigger of oligodendroglial death.
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Affiliation(s)
- Susana Mato
- Departamento de Neurociencias, Universidad del País Vasco-UPV/EHU, E-48940 Leioa, Spain.
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8
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In vivo zinc toxicity phenotypes provide a sensitized background that suggests zinc transport activities for most of the Drosophila Zip and ZnT genes. J Biol Inorg Chem 2013; 18:323-32. [DOI: 10.1007/s00775-013-0976-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 01/03/2013] [Indexed: 12/12/2022]
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9
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Chamma I, Chevy Q, Poncer JC, Lévi S. Role of the neuronal K-Cl co-transporter KCC2 in inhibitory and excitatory neurotransmission. Front Cell Neurosci 2012; 6:5. [PMID: 22363264 PMCID: PMC3282916 DOI: 10.3389/fncel.2012.00005] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 01/30/2012] [Indexed: 01/06/2023] Open
Abstract
The K-Cl co-transporter KCC2 plays multiple roles in the physiology of central neurons and alterations of its function and/or expression are associated with several neurological conditions. By regulating intraneuronal chloride homeostasis, KCC2 strongly influences the efficacy and polarity of the chloride-permeable γ-aminobutyric acid (GABA) type A and glycine receptor (GlyR) mediated synaptic transmission. This appears particularly critical for the development of neuronal circuits as well as for the dynamic control of GABA and glycine signaling in mature networks. The activity of the transporter is also associated with transmembrane water fluxes which compensate solute fluxes associated with synaptic activity. Finally, KCC2 interaction with the actin cytoskeleton appears critical both for dendritic spine morphogenesis and the maintenance of glutamatergic synapses. In light of the pivotal role of KCC2 in the maturation and function of central synapses, it is of particular importance to understand the cellular and molecular mechanisms underlying its regulation. These include development and activity-dependent modifications both at the transcriptional and post-translational levels. We emphasize the importance of post-translational mechanisms such as phosphorylation and dephosphorylation, oligomerization, cell surface stability, clustering and membrane diffusion for the rapid and dynamic regulation of KCC2 function.
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10
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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] [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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11
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Altered expression and distribution of zinc transporters in APP/PS1 transgenic mouse brain. Neurobiol Aging 2010; 31:74-87. [DOI: 10.1016/j.neurobiolaging.2008.02.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 02/19/2008] [Accepted: 02/22/2008] [Indexed: 11/20/2022]
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13
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Levy S, Beharier O, Etzion Y, Mor M, Buzaglo L, Shaltiel L, Gheber LA, Kahn J, Muslin AJ, Katz A, Gitler D, Moran A. Molecular basis for zinc transporter 1 action as an endogenous inhibitor of L-type calcium channels. J Biol Chem 2009; 284:32434-43. [PMID: 19767393 DOI: 10.1074/jbc.m109.058842] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The L-type calcium channel (LTCC) has a variety of physiological roles that are critical for the proper function of many cell types and organs. Recently, a member of the zinc-regulating family of proteins, ZnT-1, was recognized as an endogenous inhibitor of the LTCC, but its mechanism of action has not been elucidated. In the present study, using two-electrode voltage clamp recordings in Xenopus oocytes, we demonstrate that ZnT-1-mediated inhibition of the LTCC critically depends on the presence of the LTCC regulatory beta-subunit. Moreover, the ZnT-1-induced inhibition of the LTCC current is also abolished by excess levels of the beta-subunit. An interaction between ZnT-1 and the beta-subunit, as demonstrated by co-immunoprecipitation and by fluorescence resonance energy transfer, is consistent with this result. Using surface biotinylation and total internal reflection fluorescence microscopy in HEK293 cells, we show a ZnT-1-dependent decrease in the surface expression of the pore-forming alpha(1)-subunit of the LTCC. Similarly, a decrease in the surface expression of the alpha(1)-subunit is observed following up-regulation of the expression of endogenous ZnT-1 in rapidly paced cultured cardiomyocytes. We conclude that ZnT-1-mediated inhibition of the LTCC is mediated through a functional interaction of ZnT-1 with the LTCC beta-subunit and that it involves a decrease in the trafficking of the LTCC alpha(1)-subunit to the surface membrane.
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Affiliation(s)
- Shiri Levy
- Department of Physiology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84101, Israel
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14
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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] [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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15
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Role of Zinc and Selenium in Oxidative Stress and Immunosenescence: Implications for Healthy Ageing and Longevity. HANDBOOK ON IMMUNOSENESCENCE 2008. [PMCID: PMC7122608 DOI: 10.1007/978-1-4020-9063-9_66] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Ageing is an inevitable biological process with gradual and spontaneous biochemical and physiological changes and increased susceptibility to diseases. Some nutritional factors (zinc and selenium) may remodel these changes leading to a possible escaping of diseases with subsequent healthy ageing, because they are especially involved in improving immune functions as well as antioxidant defense. Experiments performed “in vitro” (human lymphocytes exposed to endotoxins) and “in vivo” (old mice or young mice fed with low zinc dietary intake) show that zinc is important for immune response both innate and adoptive. Selenium provokes zinc release by Metallothioneins (MT), via reduction of glutathione peroxidase. This fact is crucial in ageing because high MT may be unable to release zinc with subsequent low intracellular free zinc ion availability for immune response. Taking into account the existence of zinc transporters (ZnT and ZIP family) for cellular zinc efflux and influx, respectively, the association between ZnT and MT is important in maintaining satisfactory intracellular zinc homeostasis in ageing. Improved immune performance occur in elderly after physiological zinc supplementation, which also induces prolonged survival in old, nude and neonatal thymectomized mice. The association “zinc plus selenium” improves humoral immunity in old subjects after influenza vaccination. Therefore, zinc and selenium are relevant for immunosenescence in order to achieve healthy ageing and longevity.
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16
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Zhang LH, Wang X, Stoltenberg M, Danscher G, Huang L, Wang ZY. Abundant expression of zinc transporters in the amyloid plaques of Alzheimer's disease brain. Brain Res Bull 2008; 77:55-60. [PMID: 18639746 DOI: 10.1016/j.brainresbull.2008.03.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Accepted: 03/25/2008] [Indexed: 10/22/2022]
Abstract
The pathological key features of Alzheimer's disease (AD) are beta-amyloid peptide (Abeta)-containing senile plaques (SP) and neurofibrillary tangles. Previous studies have suggested that an extracellular elevation of the zinc concentration can initiate the deposition of Abeta and lead to the formation of SP. In the present study, we present data showing a correlation between zinc ions, zinc transporters (ZNTs) and AD, using immersion autometallography (AMG) and double immunofluorescence for the ZNTs and Abeta. We found that all the ZNTs tested (ZNT1, 3, 4, 5, 6, 7) were extensively present in the Abeta-positive plaques in the cortex of human AD brains, and the density of autometallographic silver enhanced zinc-sulphur nanoparticles were much higher in the plaques than in the surrounding zinc enriched (ZEN) terminals. Moreover, we found an abundant expression of ZNT3 and autometallographic grains in the amyloid angiopathic vessels. The subcellular localization of ZNTs and zinc ions were not detected, due to the limited tissue preservation in the present study. In conclusion, our data provided significant morphological evidence of zinc ions and ZNTs being actively involved in the pathological processes that lead to plaque formation.
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Affiliation(s)
- Li-Hong Zhang
- Department of Histology and Embryology, China Medical University, Shenyang 110001, PR China.
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17
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Sekler I, Sensi SL, Hershfinkel M, Silverman WF. Mechanism and regulation of cellular zinc transport. Mol Med 2007. [PMID: 17622322 DOI: 10.2119/2007-00037.sekler] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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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18
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Sekler I, Sensi SL, Hershfinkel M, Silverman WF. Mechanism and regulation of cellular zinc transport. MOLECULAR MEDICINE (CAMBRIDGE, MASS.) 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] [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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Priel T, Aricha-Tamir B, Sekler I. Clioquinol attenuates zinc-dependent beta-cell death and the onset of insulitis and hyperglycemia associated with experimental type I diabetes in mice. Eur J Pharmacol 2007; 565:232-9. [PMID: 17434477 DOI: 10.1016/j.ejphar.2007.02.064] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 02/11/2007] [Accepted: 02/13/2007] [Indexed: 11/30/2022]
Abstract
Zinc in the pancreas is co-released with insulin from beta-cells reaching concentrations similar to those found in the vicinity of glutamatergic synapses. In the brain, the role of zinc in excitotoxic brain damage is well established. In contrast, its role in islet destruction during diabetes is poorly understood. We have studied the efficacy of zinc homeostatic proteins and an intracellular zinc chelator, clioquinol, in conferring resistance against zinc toxicity in pancreatic islets. We further assessed the ability of clioquinol to protect the islets in an experimental model of type I diabetes. Our results indicate that endogenous mechanisms for lowering [Zn]i are deficient in the insulinoma cell line, MIN6, and that permeation of Zn2+ triggered cell death. Application of the low affinity, intracellular zinc chelator, clioquinol, reduced Zn2+-induced cell death by 80%. In addition, chelation of zinc ions by clioquinol in vivo prevented onset of multiple low dose streptozotocin-induced diabetes, and reduced the insulitis and hyperglycemia associated with this model. Furthermore, the glucose tolerance test (GTT) score of multiple low dose streptozotocin (MLD-STZ) mice pretreated with clioquinol was, statistically indistinguishable from that of untreated, control mice. Taken together, our results point to the potential utility of in vivo zinc chelation as a therapeutic strategy for treatment of idiopathic type I diabetes.
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Affiliation(s)
- Tsvia Priel
- Department of Physiology and Zlotowski Center for Neurosciences, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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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] [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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Wang ZY, Stoltenberg M, Huang L, Danscher G, Dahlström A, Shi Y, Li JY. Abundant expression of zinc transporters in Bergman glia of mouse cerebellum. Brain Res Bull 2005; 64:441-8. [PMID: 15607832 DOI: 10.1016/j.brainresbull.2004.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 09/28/2004] [Accepted: 10/05/2004] [Indexed: 11/20/2022]
Abstract
Zinc transporters (ZnTs) are membrane proteins involved in zinc ion transportation in mammalian cells. Seven members of ZnT family, ZnT1-7, have been cloned and characterized. These transporter proteins have different cellular and sub-cellular locations, suggesting that they may play different roles in zinc homeostasis in normal and pathological conditions in different tissues. Cerebellum is one of the most zinc-enriched regions in the central nervous system, but little is known about zinc metabolism in the cerebellum. In the present study, we investigated the detailed distributions of four members (ZnT1, ZnT3, ZnT4 and ZnT6) of the ZnT family, in the mouse cerebellum. Immunostaining and confocal microscopic observations revealed a similar staining pattern of ZnTs in the molecular layer and the Purkinje cell layer. Double labeling with anti-S-100beta or anti-MAP2 and anti-ZnTs clearly showed that the Bergman glial cell bodies in the Purkinje cell layer and their radial processes in the molecular layer exhibited strong immunofluorescence of all the tested ZnTs. However, the somata of the Purkinje cells contained a moderate immunostaining for ZnT1, but virtually lack of other three ZnTs. In the granular layer, ZnTs appeared with different immunostaining patterns. ZnT1 was expressed in a small number of neuronal cell bodies and their primary dendrites, whereas ZnT3 and ZnT4 were present in nerve terminals but not in the neuronal somata. ZnT6 was undetectable in either the cell bodies or processes in the granular layer. The present results indicate that the Bergman glial cells may play an important role in zinc metabolism in the mouse cerebellar cortex.
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Affiliation(s)
- Zhan-You Wang
- Department of Histology and Embryology, China Medical University, 92 Bei-Er-Road, Heping District, Shenyang 110001, PR China.
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Abstract
There is considerable evidence that the transition metal zinc plays an important role in mammalian neural development, physiology and pathology. The most compelling evidence for a synaptic role for zinc comes from hippocampal studies: zinc is concentrated in the synaptic vesicles of some glutamatergic neurons, zinc can be released during neural activity and zinc can modulate postsynaptic GABA and glutamate receptors. The possibility that zinc is involved in cerebellar synaptic transmission is supported by the expression of specific zinc transporters (ZnT, including the synaptic vesicle transporter ZnT-3) in the cerebellar cortex. Furthermore, some subtypes of neurotransmitter receptors, expressed by cerebellar neurones, are highly sensitive to low concentrations of exogenous zinc. However there appears to be little chelatable (synaptic) zinc in the cerebellum, deletion of the ZnT-3 gene has no effect on motor phenotype and there is currently no evidence that zinc is released from cerebellar neurones to have physiological actions. Thus it is possible that the different types of zinc transporter found in the cerebellum play a neuroprotective rather than a signalling role.
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Affiliation(s)
- Mark J Wall
- Neuroscience Group, Department of Biological Sciences, University of Warwick, Coventry, UK.
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Abstract
New insights into mammalian zinc metabolism have been acquired through the identification and characterization of zinc transporters. These proteins all have transmembrane domains, and are encoded by two solute-linked carrier (SLC) gene families: ZnT (SLC30) and Zip (SLC39). There are at least 9 ZnT and 15 Zip transporters in human cells. They appear to have opposite roles in cellular zinc homeostasis. ZnT transporters reduce intracellular zinc availability by promoting zinc efflux from cells or into intracellular vesicles, while Zip transporters increase intracellular zinc availability by promoting extracellular zinc uptake and, perhaps, vesicular zinc release into the cytoplasm. Both the ZnT and Zip transporter families exhibit unique tissue-specific expression, differential responsiveness to dietary zinc deficiency and excess, and differential responsiveness to physiologic stimuli via hormones and cytokines.
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Affiliation(s)
- Juan P Liuzzi
- Nutrition Genomics Laboratory and Center for Nutritional Sciences, University of Florida, Gainesville, Florida, 32611-0370, USA.
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Segal D, Ohana E, Besser L, Hershfinkel M, Moran A, Sekler I. A role for ZnT-1 in regulating cellular cation influx. Biochem Biophys Res Commun 2004; 323:1145-50. [PMID: 15451416 DOI: 10.1016/j.bbrc.2004.08.211] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2004] [Indexed: 10/26/2022]
Abstract
The ZnTs are a growing family of proteins involved in lowering or sequestration of cellular zinc. Using fluorescent measurements of zinc transport we have addressed the mechanism of action of the most ubiquitously expressed member of this family, ZnT-1. This protein has been shown to lower levels of intracellular zinc though the mechanism has remained elusive. The rate of zinc efflux in HEK293 cells expressing ZnT-1 was not accelerated in comparison to control cells, suggesting that ZnT-1 may be involved in regulating influx rather than efflux of zinc. Co-expression of the L-type calcium channel, a major route for zinc influx, and ZnT-1 resulted in a 3-fold reduction in the rate of zinc influx in HEK293 and PC-12 cells, indicating that ZnT-1 modulates zinc permeation through this channel. Immunoblot analysis indicates that ZnT-1 expression does not modulate LTCC expression. Our findings therefore indicate that ZnT-1 modulates the permeation of cations through LTCC, thereby, regulating cation homeostasis through this pathway. Furthermore, ZnT-1 may play a role in cellular ion homeostasis and thereby confer protection against pathophysiological events linked to cellular Ca(2+) or Zn(2+) permeation and cell death.
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Affiliation(s)
- Dror Segal
- Department of Physiology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
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Seve M, Chimienti F, Devergnas S, Favier A. In silico identification and expression of SLC30 family genes: an expressed sequence tag data mining strategy for the characterization of zinc transporters' tissue expression. BMC Genomics 2004; 5:32. [PMID: 15154973 PMCID: PMC428573 DOI: 10.1186/1471-2164-5-32] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2004] [Accepted: 05/23/2004] [Indexed: 11/15/2022] Open
Abstract
Background Intracellular zinc concentration and localization are strictly regulated by two main protein components, metallothioneins and membrane transporters. In mammalian cells, two membrane transporters family are involved in intracellular zinc homeostasis: the uptake transporters called SLC39 or Zip family and the efflux transporters called SLC30 or ZnT family. ZnT proteins are members of the cation diffusion facilitator (CDF) family of metal ion transporters. Results From genomic databanks analysis, we identified the full-length sequences of two novel SLC30 genes, SLC30A8 and SLC30A10, extending the SLC30 family to ten members. We used an expressed sequence tag (EST) data mining strategy to determine the pattern of ZnT genes expression in tissues. In silico results obtained for already studied ZnT sequences were compared to experimental data, previously published. We determined an overall good correlation with expression pattern obtained by RT-PCR or immunomethods, particularly for highly tissue specific genes. Conclusion The method presented herein provides a useful tool to complete gene families from sequencing programs and to produce preliminary expression data to select the proper biological samples for laboratory experimentation.
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Affiliation(s)
- Michel Seve
- DRFMC/SCIB/LAN, CEA/Grenoble, Grenoble, France
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Nitzan YB, Sekler I, Silverman WF. Histochemical and histofluorescence tracing of chelatable zinc in the developing mouse. J Histochem Cytochem 2004; 52:529-39. [PMID: 15034004 DOI: 10.1177/002215540405200411] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Zinc is an essential element in mammalian development. However, little is known about concentrations of zinc in specific regions/organs in the embryo. We have employed selenite autometallography (AMG) and TSQ histofluoroscence to detect histochemically reactive (chelatable) zinc in whole midsagittal embryos and sections from neonatal mice. Chelatable zinc exhibited a broad distribution, being particularly localized to rapidly proliferating tissues, such as skin and gastrointestinal epithelium. Zinc was also observed in various types of tissues such as bone and liver. In the perinatal central nervous system, zinc was present almost exclusively in choroid plexus. The two methods used demonstrated generally similar distributions with some exceptions, e.g., in liver and blood. The ubiquity of zinc in the embryo, particularly in rapidly proliferating tissues, suggests a widespread role in fetal physiology.
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Affiliation(s)
- Yuval B Nitzan
- Departments of Morphology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
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Palty R, Ohana E, Hershfinkel M, Volokita M, Elgazar V, Beharier O, Silverman WF, Argaman M, Sekler I. Lithium-calcium exchange is mediated by a distinct potassium-independent sodium-calcium exchanger. J Biol Chem 2004; 279:25234-40. [PMID: 15060069 DOI: 10.1074/jbc.m401229200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Sodium-calcium exchangers have long been considered inert with respect to monovalent cations such as lithium, choline, and N-methyl-d-glucamine. A key question that has remained unsolved is how despite this, Li(+) catalyzes calcium exchange in mammalian tissues. Here we report that a Na(+)/Ca(2+) exchanger, NCLX cloned from human cells (known as FLJ22233), is distinct from both known forms of the exchanger, NCX and NCKX in structure and kinetics. Surprisingly, NCLX catalyzes active Li(+)/Ca(2+) exchange, thereby explaining the exchange of these ions in mammalian tissues. The NCLX protein, detected as both 70- and 55-KDa polypeptides, is highly expressed in rat pancreas, skeletal muscle, and stomach. We demonstrate, moreover, that NCLX is a K(+)-independent exchanger that catalyzes Ca(2+) flux at a rate comparable with NCX1 but without promoting Na(+)/Ba(2+) exchange. The activity of NCLX is strongly inhibited by zinc, although it does not transport this cation. NCLX activity is only partially inhibited by the NCX inhibitor, KB-R7943. Our results provide a cogent explanation for a fundamental question. How can Li(+) promote Ca(2+) exchange whereas the known exchangers are inert to Li(+) ions? Identification of this novel member of the Na(+)/Ca(2+) superfamily, with distinct characteristics, including the ability to transport Li(+), may provide an explanation for this phenomenon.
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Affiliation(s)
- Raz Palty
- Department of Physiology, Faculty of Health Sciences, The National Institute for Molecular Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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