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Zinc transporter ZIP10 forms a heteromer with ZIP6 which regulates embryonic development and cell migration. Biochem J 2016; 473:2531-44. [PMID: 27274087 PMCID: PMC4980808 DOI: 10.1042/bcj20160388] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 06/06/2016] [Indexed: 12/18/2022]
Abstract
Zinc is involved in cell migration during embryo development and in cancer. We show that a zinc transporter consisting of two proteins, ZIP6 and ZIP10, stimulates both cell migration and division in mammalian cells and in the zebrafish embryo. There is growing evidence that zinc and its transporters are involved in cell migration during development and in cancer. In the present study, we show that zinc transporter ZIP10 (SLC39A10) stimulates cell motility and proliferation, both in mammalian cells and in the zebrafish embryo. This is associated with inactivation of GSK (glycogen synthase kinase)-3α and -3β and down-regulation of E-cadherin (CDH1). Morpholino-mediated knockdown of zip10 causes delayed epiboly and deformities of the head, eye, heart and tail. Furthermore, zip10 deficiency results in overexpression of cdh1, zip6 and stat3, the latter gene product driving transcription of both zip6 and zip10. The non-redundant requirement of Zip6 and Zip10 for epithelial to mesenchymal transition (EMT) is consistent with our finding that they exist as a heteromer. We postulate that a subset of ZIPs carrying prion protein (PrP)-like ectodomains, including ZIP6 and ZIP10, are integral to cellular pathways and plasticity programmes, such as EMT.
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52
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Fujie T, Segawa Y, Yoshida E, Kimura T, Fujiwara Y, Yamamoto C, Satoh M, Naka H, Kaji T. Induction of metallothionein isoforms by copper diethyldithiocarbamate in cultured vascular endothelial cells. J Toxicol Sci 2016; 41:225-32. [PMID: 26961606 DOI: 10.2131/jts.41.225] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Metallothionein (MT) plays a central role in cellular defense against heavy metals and oxidative stress. Since the induction of MT requires the activation of metal response element (MRE)-binding transcription factor-1 (MTF-1) by binding of zinc ions, inorganic zinc is regarded as a typical MT inducer. However, in a previous report, we showed that inorganic zinc could not induce MT in vascular endothelial cells. While it is suggested that endothelial MT presents mechanisms different from those of other cell types, these remain unclear. In this study, we investigated whether the induction of endothelial MT expression involves the Nrf2-ARE pathway using copper(II) bis(diethyldithiocarbamate), termed Cu10, using a culture system of bovine aortic endothelial cells. Cu10 induced MT-1/2 protein expression and increased the expression of mRNAs for MT-1A, MT-1E, and MT-2, MT isoforms expressed in the cells. Cu10 activated not only the MTF-1-MRE, but also the Nrf2-ARE pathway. MTF-1 knockdown resulted in the repression of Cu10-induced MT-1 and -2 expression. Cu10-induced MT-1 expression was down-regulated by Nrf2 knockdown. However, MT-2 expression was not affected by Nrf2 knockdown. These results suggest that the expression of endothelial MT is up-regulated by the Nrf2-ARE pathway as well as by the MTF-1-MRE pathway. Moreover, MT-1 regulation mechanisms differ from that of MT-2. Specifically, the present data support the hypothesis that MT-1 participates in the biological defense system, while MT-2 mainly regulates intracellular zinc metabolism.
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Affiliation(s)
- Tomoya Fujie
- Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science
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Lee SR, Noh SJ, Pronto JR, Jeong YJ, Kim HK, Song IS, Xu Z, Kwon HY, Kang SC, Sohn EH, Ko KS, Rhee BD, Kim N, Han J. The Critical Roles of Zinc: Beyond Impact on Myocardial Signaling. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 19:389-99. [PMID: 26330751 PMCID: PMC4553398 DOI: 10.4196/kjpp.2015.19.5.389] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/04/2015] [Accepted: 06/08/2015] [Indexed: 12/15/2022]
Abstract
Zinc has been considered as a vital constituent of proteins, including enzymes. Mobile reactive zinc (Zn(2+)) is the key form of zinc involved in signal transductions, which are mainly driven by its binding to proteins or the release of zinc from proteins, possibly via a redox switch. There has been growing evidence of zinc's critical role in cell signaling, due to its flexible coordination geometry and rapid shifts in protein conformation to perform biological reactions. The importance and complexity of Zn(2+) activity has been presumed to parallel the degree of calcium's participation in cellular processes. Whole body and cellular Zn(2+) levels are largely regulated by metallothioneins (MTs), Zn(2+) importers (ZIPs), and Zn(2+) transporters (ZnTs). Numerous proteins involved in signaling pathways, mitochondrial metabolism, and ion channels that play a pivotal role in controlling cardiac contractility are common targets of Zn(2+). However, these regulatory actions of Zn(2+) are not limited to the function of the heart, but also extend to numerous other organ systems, such as the central nervous system, immune system, cardiovascular tissue, and secretory glands, such as the pancreas, prostate, and mammary glands. In this review, the regulation of cellular Zn(2+) levels, Zn(2+)-mediated signal transduction, impacts of Zn(2+) on ion channels and mitochondrial metabolism, and finally, the implications of Zn(2+) in health and disease development were outlined to help widen the current understanding of the versatile and complex roles of Zn(2+).
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Affiliation(s)
- Sung Ryul Lee
- Department of Integrated Biomedical Science, Cardiovascular and Metabolic disease Center, College of Medicine, Inje University, Busan 614-735, Korea
| | - Su Jin Noh
- Department of Physiology, Graduate School of Inje University, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Julius Ryan Pronto
- Department of Physiology, Graduate School of Inje University, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Yu Jeong Jeong
- Department of Physiology, Graduate School of Inje University, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Hyoung Kyu Kim
- Department of Integrated Biomedical Science, Cardiovascular and Metabolic disease Center, College of Medicine, Inje University, Busan 614-735, Korea
| | - In Sung Song
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Zhelong Xu
- Department of Physiology and Pathophysiology, Tianjin Medical University, Tainjin 300070, P.R. China
| | - Hyog Young Kwon
- Soonchunhyang Institute of Medio-bio Science (SIMS), Soonchunhyang University, Cheonan 336-745, Korea
| | - Se Chan Kang
- Department of Life Science, Gachon University, Seongnam 461-701, Korea
| | - Eun-Hwa Sohn
- Department of Herbal Medicine Resource, Kangwon National University, Samcheok 245-711, Korea
| | - Kyung Soo Ko
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Byoung Doo Rhee
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Nari Kim
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Jin Han
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
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Cellular sensing and transport of metal ions: implications in micronutrient homeostasis. J Nutr Biochem 2015; 26:1103-15. [PMID: 26342943 DOI: 10.1016/j.jnutbio.2015.08.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/23/2015] [Accepted: 08/04/2015] [Indexed: 12/15/2022]
Abstract
Micronutrients include the transition metal ions zinc, copper and iron. These metals are essential for life as they serve as cofactors for many different proteins. On the other hand, they can also be toxic to cell growth when in excess. As a consequence, all organisms require mechanisms to tightly regulate the levels of these metal ions. In eukaryotes, one of the primary ways in which metal levels are regulated is through changes in expression of genes required for metal uptake, compartmentalization, storage and export. By tightly regulating the expression of these genes, each organism is able to balance metal levels despite fluctuations in the diet or extracellular environment. The goal of this review is to provide an overview of how gene expression can be controlled at a transcriptional, posttranscriptional and posttranslational level in response to metal ions in lower and higher eukaryotes. Specifically, I review what is known about how these metalloregulatory factors sense fluctuations in metal ion levels and how changes in gene expression maintain nutrient homeostasis.
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Kambe T, Tsuji T, Hashimoto A, Itsumura N. The Physiological, Biochemical, and Molecular Roles of Zinc Transporters in Zinc Homeostasis and Metabolism. Physiol Rev 2015; 95:749-84. [DOI: 10.1152/physrev.00035.2014] [Citation(s) in RCA: 556] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Zinc is involved in a variety of biological processes, as a structural, catalytic, and intracellular and intercellular signaling component. Thus zinc homeostasis is tightly controlled at the whole body, tissue, cellular, and subcellular levels by a number of proteins, with zinc transporters being particularly important. In metazoan, two zinc transporter families, Zn transporters (ZnT) and Zrt-, Irt-related proteins (ZIP) function in zinc mobilization of influx, efflux, and compartmentalization/sequestration across biological membranes. During the last two decades, significant progress has been made in understanding the molecular properties, expression, regulation, and cellular and physiological roles of ZnT and ZIP transporters, which underpin the multifarious functions of zinc. Moreover, growing evidence indicates that malfunctioning zinc homeostasis due to zinc transporter dysfunction results in the onset and progression of a variety of diseases. This review summarizes current progress in our understanding of each ZnT and ZIP transporter from the perspective of zinc physiology and pathogenesis, discussing challenging issues in their structure and zinc transport mechanisms.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tokuji Tsuji
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Ayako Hashimoto
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Naoya Itsumura
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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56
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Examining a new role for zinc in regulating calcium release in cardiac muscle. Biochem Soc Trans 2015; 43:359-63. [DOI: 10.1042/bst20140285] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
It is well established that mammalian cells contain a small but measurable pool of free or labile zinc in the cytosol that is buffered in the high picomolar range. Recent attention has focused on the fact that this pool of free zinc has signalling effects that can be evoked through extracellular stimuli posing the question as to whether zinc should be regarded as a second messenger. Our knowledge of the targets, the biological significance and the molecular mechanisms of zinc signalling is limited but recent evidence suggests that zinc homoeostasis may be intimately linked to intracellular calcium signalling. In this review, we discuss the role of zinc as an intracellular signalling molecule with an emphasis on the potential role of zinc in shaping calcium-dynamics in cardiac muscle. We also consider the evidence that the cardiac ryanodine receptor (RyR2) is a potential zinc signalling target.
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Dechen K, Richards CD, Lye JC, Hwang JEC, Burke R. Compartmentalized zinc deficiency and toxicities caused by ZnT and Zip gene over expression result in specific phenotypes in Drosophila. Int J Biochem Cell Biol 2015; 60:23-33. [PMID: 25562517 DOI: 10.1016/j.biocel.2014.12.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 12/11/2014] [Accepted: 12/22/2014] [Indexed: 11/17/2022]
Abstract
Movement of zinc ions across cellular membranes is achieved mainly by two families of zinc transport genes encoding multi-transmembrane domain proteins. Members of the Zip family generally transport zinc into the cytosol, either from outside the cell or from the lumen of subcellular organelles such as the endoplasmic reticulum, Golgi, endosomes or storage vacuoles. ZnT proteins move zinc in the opposite direction, resulting in efflux from the cell or uptake into organelles. Zinc homeostasis at both the cellular and systemic level is achieved by the coordinated action of numerous Zip and ZnT proteins, twenty-four in mammals and seventeen in the vinegar fly Drosophila melanogaster. Previously, we have identified a zinc toxicity phenotype in the Drosophila eye, caused by targeted over expression of dZip42C.1 (dZip1) combined with knockdown of dZnT63C (dZnT1). In general, this phenotype was rescued by increased zinc efflux or decreased uptake and was exacerbated by decreased efflux or increased uptake. Now we have identified three additional zinc dyshomeostasis phenotypes caused by over expression of dZnT86D, dZnT86D(eGFP) and dZip71B(FLAG). Genetic and dietary manipulation experiments showed that these three phenotypes all differ both from each other and from our original zinc toxicity phenotype. Based on these data and the approximate subcellular localization of each zinc transport protein, we propose that each phenotype represents a different redistribution of zinc within these cells, resulting in a Golgi zinc toxicity, a Golgi zinc deficiency and a combined Golgi/other organelle zinc toxicity respectively. We are able to group the remaining Drosophila Zip and ZnT genes into several functional categories based on their interaction with the three novel zinc dyshomeostasis phenotypes, allowing the role of each zinc transport protein to be defined in greater detail. This research highlights the differential effects that redistribution of zinc can have within a particular tissue and identifies the Golgi as being particularly sensitive to both excess and insufficient zinc.
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Affiliation(s)
- Kesang Dechen
- School of Biological Sciences, Monash University, Victoria, Australia.
| | | | - Jessica C Lye
- School of Biological Sciences, Monash University, Victoria, Australia
| | - Joab E C Hwang
- School of Biological Sciences, Monash University, Victoria, Australia
| | - Richard Burke
- School of Biological Sciences, Monash University, Victoria, Australia.
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58
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Sun Q, Li Q, Zhong W, Zhang J, Sun X, Tan X, Yin X, Sun X, Zhang X, Zhou Z. Dysregulation of hepatic zinc transporters in a mouse model of alcoholic liver disease. Am J Physiol Gastrointest Liver Physiol 2014; 307:G313-22. [PMID: 24924749 PMCID: PMC4121635 DOI: 10.1152/ajpgi.00081.2014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Zinc deficiency is a consistent phenomenon observed in patients with alcoholic liver disease, but the mechanisms have not been well defined. The objective of this study was to determine if alcohol alters hepatic zinc transporters in association with reduction of hepatic zinc levels and if oxidative stress mediates the alterations of zinc transporters. C57BL/6 mice were pair-fed with the Lieber-DeCarli control or ethanol diets for 2, 4, or 8 wk. Chronic alcohol exposure reduced hepatic zinc levels, but increased plasma and urine zinc levels, at all time points. Hepatic zinc finger proteins, peroxisome proliferator-activated receptor-α (PPAR-α) and hepatocyte nuclear factor 4α (HNF-4α), were downregulated in ethanol-fed mice. Four hepatic zinc transporter proteins showed significant alterations in ethanol-fed mice compared with the controls. ZIP5 and ZIP14 proteins were downregulated, while ZIP7 and ZnT7 proteins were upregulated, by ethanol exposure at all time points. Immunohistochemical staining demonstrated that chronic ethanol exposure upregulated cytochrome P-450 2E1 and caused 4-hydroxynonenal accumulation in the liver. For the in vitro study, murine FL-83B hepatocytes were treated with 5 μM 4-hydroxynonenal or 100 μM hydrogen peroxide for 72 h. The results from in vitro studies demonstrated that 4-hydroxynonenal treatment altered ZIP5 and ZIP7 protein abundance, and hydrogen peroxide treatment changed ZIP7, ZIP14, and ZnT7 protein abundance. These results suggest that chronic ethanol exposure alters hepatic zinc transporters via oxidative stress, which might account for ethanol-induced hepatic zinc deficiency.
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Affiliation(s)
- Qian Sun
- 1Department of Nutrition, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina;
| | - Qiong Li
- 2Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; and
| | - Wei Zhong
- 2Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; and
| | - Jiayang Zhang
- 3Department of Chemistry, University of Louisville, Louisville, Kentucky
| | - Xiuhua Sun
- 2Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; and
| | - Xiaobing Tan
- 2Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; and
| | - Xinmin Yin
- 3Department of Chemistry, University of Louisville, Louisville, Kentucky
| | - Xinguo Sun
- 2Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; and
| | - Xiang Zhang
- 3Department of Chemistry, University of Louisville, Louisville, Kentucky
| | - Zhanxiang Zhou
- Department of Nutrition, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina; and
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Xiao G, Wan Z, Fan Q, Tang X, Zhou B. The metal transporter ZIP13 supplies iron into the secretory pathway in Drosophila melanogaster. eLife 2014; 3:e03191. [PMID: 25006035 PMCID: PMC4130162 DOI: 10.7554/elife.03191] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The intracellular iron transfer process is not well understood, and the identity of the iron transporter responsible for iron delivery to the secretory compartments remains elusive. In this study, we show Drosophila ZIP13 (Slc39a13), a presumed zinc importer, fulfills the iron effluxing role. Interfering with dZIP13 expression causes iron-rescuable iron absorption defect, simultaneous iron increase in the cytosol and decrease in the secretory compartments, failure of ferritin iron loading, and abnormal collagen secretion. dZIP13 expression in E. coli confers upon the host iron-dependent growth and iron resistance. Importantly, time-coursed transport assays using an iron isotope indicated a potent iron exporting activity of dZIP13. The identification of dZIP13 as an iron transporter suggests that the spondylocheiro dysplastic form of Ehlers–Danlos syndrome, in which hZIP13 is defective, is likely due to a failure of iron delivery to the secretory compartments. Our results also broaden our knowledge of the scope of defects from iron dyshomeostasis. DOI:http://dx.doi.org/10.7554/eLife.03191.001 Iron is essential for life. Amongst its many important roles, iron is crucial for producing collagen—the protein that provides both strength and elasticity to bones, tendons, ligaments, and skin. Like many other proteins, collagens are produced inside the endoplasmic reticulum—an organelle inside the cell that is enclosed by a membrane that is similar to the plasma membrane that surrounds the cell itself. Two enzymes that are critical for producing collagen need to bind with iron in order to work correctly. To do this, iron in the cytoplasm of the cell has to cross the membrane that surrounds the endoplasmic reticulum. Small molecules are commonly transported across membranes by proteins called transporters, which tend to work on specific types of ions or molecules. However, researchers did not know the identity of the membrane transporter responsible for moving iron into the secretory pathway—including the endoplasmic reticulum—to bind with the enzymes that produce collagen. Xiao, Wan et al. have now investigated the function of the transporter ZIP13 in the fruit fly Drosophila. This transporter was thought to transport zinc across membranes and into the cytoplasm. Instead, Xiao, Wan et al. found that ZIP13 transports iron out of the cytoplasm and into the endoplasmic reticulum. Ehlers–Danlos syndrome is a condition that causes individuals to suffer from frequent joint dislocations, bone deformities, and fragile skin as a result of their body producing collagen incorrectly. One form of Ehlers–Danlos syndrome is caused by ZIP13 transporters working incorrectly. However, this was difficult to understand when it was thought that ZIP13 only transports zinc. The discovery that ZIP13 mostly transports iron rather than zinc can explain the link between this transporter and Ehlers–Danlos syndrome: if ZIP13 doesn't work, the collagen-building enzymes cannot get the iron they need to work properly. Disorders caused by iron deficiencies are normally identified by a few tell-tale symptoms, such as anemia, but these are not seen in Ehlers–Danlos syndrome. Xiao, Wan et al. suggest that iron transport problems could therefore be behind a wider range of diseases and disorders than is currently known. DOI:http://dx.doi.org/10.7554/eLife.03191.002
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Affiliation(s)
- Guiran Xiao
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhihui Wan
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qiangwang Fan
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiaona Tang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Bing Zhou
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China
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Grubman A, Lidgerwood GE, Duncan C, Bica L, Tan JL, Parker SJ, Caragounis A, Meyerowitz J, Volitakis I, Moujalled D, Liddell JR, Hickey JL, Horne M, Longmuir S, Koistinaho J, Donnelly PS, Crouch PJ, Tammen I, White AR, Kanninen KM. Deregulation of subcellular biometal homeostasis through loss of the metal transporter, Zip7, in a childhood neurodegenerative disorder. Acta Neuropathol Commun 2014; 2:25. [PMID: 24581221 PMCID: PMC4029264 DOI: 10.1186/2051-5960-2-25] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 02/19/2014] [Indexed: 12/31/2022] Open
Abstract
Background Aberrant biometal metabolism is a key feature of neurodegenerative disorders including Alzheimer’s and Parkinson’s diseases. Metal modulating compounds are promising therapeutics for neurodegeneration, but their mechanism of action remains poorly understood. Neuronal ceroid lipofuscinoses (NCLs), caused by mutations in CLN genes, are fatal childhood neurodegenerative lysosomal storage diseases without a cure. We previously showed biometal accumulation in ovine and murine models of the CLN6 variant NCL, but the mechanism is unknown. This study extended the concept that alteration of biometal functions is involved in pathology in these disorders, and investigated molecular mechanisms underlying impaired biometal trafficking in CLN6 disease. Results We observed significant region-specific biometal accumulation and deregulation of metal trafficking pathways prior to disease onset in CLN6 affected sheep. Substantial progressive loss of the ER/Golgi-resident Zn transporter, Zip7, which colocalized with the disease-associated protein, CLN6, may contribute to the subcellular deregulation of biometal homeostasis in NCLs. Importantly, the metal-complex, ZnII(atsm), induced Zip7 upregulation, promoted Zn redistribution and restored Zn-dependent functions in primary mouse Cln6 deficient neurons and astrocytes. Conclusions This study demonstrates the central role of the metal transporter, Zip7, in the aberrant biometal metabolism of CLN6 variants of NCL and further highlights the key contribution of deregulated biometal trafficking to the pathology of neurodegenerative diseases. Importantly, our results suggest that ZnII(atsm) may be a candidate for therapeutic trials for NCLs.
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Huang L. Zinc and its transporters, pancreatic β-cells, and insulin metabolism. VITAMINS AND HORMONES 2014; 95:365-90. [PMID: 24559925 DOI: 10.1016/b978-0-12-800174-5.00014-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Zinc is an essential trace metal for life. Two families of zinc transporters, SLC30A (ZNT) and SLC39A (ZIP) are required for maintaining cellular zinc homeostasis. ZNTs function to decrease cytoplasmic zinc concentrations whereas ZIPs do the opposite. Expression of zinc transporters can be tissue/cell-type specific or ubiquitous. Zinc transporters that are limited in tissue/cell distributions usually perform specialized tasks to satisfy biological processes in a given cell. For example, ZNT8 is mainly expressed in β-cells and functions to deliver zinc into granules for insulin maturation and secretion. Many other zinc transporters are also expressed in β-cells. Defects in these zinc transporters have been associated with abnormalities in insulin synthesis, maturation, and secretion and subsequent glucose metabolism. This review focuses on the specific roles of zinc and its transporters in insulin metabolism and describes the current knowledge of the function of zinc transporters in β-cell health in animal knockout mouse models with respect to diabetes development in humans.
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Affiliation(s)
- Liping Huang
- United States Department of Agriculture/Agricultural Research Service/Western Human Nutrition Research Center, Obesity and Metabolism Research Unit, Davis, California, USA; Department of Nutrition, University of California Davis, Davis, California, USA.
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A mechanism for epithelial-mesenchymal transition and anoikis resistance in breast cancer triggered by zinc channel ZIP6 and STAT3 (signal transducer and activator of transcription 3). Biochem J 2013; 455:229-37. [PMID: 23919497 PMCID: PMC3789231 DOI: 10.1042/bj20130483] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Genes involved in normal developmental processes attract attention as mediators of tumour progression as they facilitate migration of tumour cells. EMT (epithelial–mesenchymal transition), an essential part of embryonic development, tissue remodelling and wound repair, is crucial for tumour metastasis. Previously, zinc transporter ZIP6 [SLC39A6; solute carrier family 39 (zinc transporter), member 6; also known as LIV-1) was linked to EMT in zebrafish gastrulation through a STAT3 (signal transducer and activator of transcription 3) mechanism, resulting in nuclear localization of transcription factor Snail. In the present study, we show that zinc transporter ZIP6 is transcriptionally induced by STAT3 and unprecedented among zinc transporters, and is activated by N-terminal cleavage which triggers ZIP6 plasma membrane location and zinc influx. This zinc influx inactivates GSK-3β (glycogen synthase kinase 3β), either indirectly or directly via Akt or GSK-3β respectively, resulting in activation of Snail, which remains in the nucleus and acts as a transcriptional repressor of E-cadherin (epithelial cadherin), CDH1, causing cell rounding and detachment. This was mirrored by ZIP6-transfected cells which underwent EMT, detached from monolayers and exhibited resistance to anoikis by their ability to continue proliferating even after detachment. Our results indicate a causative role for ZIP6 in cell motility and migration, providing ZIP6 as a new target for prediction of clinical cancer spread and also suggesting a ZIP6-dependent mechanism of tumour metastasis. We demonstrate a novel mechanism for the ability of cellular zinc to drive cell detachment and migration with implications for breast cancer spread. This mechanism involves a zinc uptake channel ZIP6 (also known as SLC39A6) and a transcription factor, STAT3.
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63
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Myers SA, Nield A, Chew GS, Myers MA. The zinc transporter, Slc39a7 (Zip7) is implicated in glycaemic control in skeletal muscle cells. PLoS One 2013; 8:e79316. [PMID: 24265765 PMCID: PMC3827150 DOI: 10.1371/journal.pone.0079316] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 09/22/2013] [Indexed: 12/12/2022] Open
Abstract
Dysfunctional zinc signaling is implicated in disease processes including cardiovascular disease, Alzheimer's disease and diabetes. Of the twenty-four mammalian zinc transporters, ZIP7 has been identified as an important mediator of the ‘zinc wave’ and in cellular signaling. Utilizing siRNA targeting Zip7 mRNA we have identified that Zip7 regulates glucose metabolism in skeletal muscle cells. An siRNA targeting Zip7 mRNA down regulated Zip7 mRNA 4.6-fold (p = 0.0006) when compared to a scramble control. This was concomitant with a reduction in the expression of genes involved in glucose metabolism including Agl, Dlst, Galm, Gbe1, Idh3g, Pck2, Pgam2, Pgm2, Phkb, Pygm, Tpi1, Gusb and Glut4. Glut4 protein expression was also reduced and insulin-stimulated glycogen synthesis was decreased. This was associated with a reduction in the mRNA expression of Insr, Irs1 and Irs2, and the phosphorylation of Akt. These studies provide a novel role for Zip7 in glucose metabolism in skeletal muscle and highlight the importance of this transporter in contributing to glycaemic control in this tissue.
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Affiliation(s)
- Stephen A. Myers
- Collaborative Research Network and the School of Health Sciences, University of Ballarat, Mount Helen Campus, Victoria, Australia
- * E-mail:
| | - Alex Nield
- Collaborative Research Network and the School of Health Sciences, University of Ballarat, Mount Helen Campus, Victoria, Australia
| | - Guat-Siew Chew
- School of Health Sciences, University of Ballarat, Mount Helen Campus, Victoria, Australia
| | - Mark A. Myers
- Collaborative Research Network and the School of Health Sciences, University of Ballarat, Mount Helen Campus, Victoria, Australia
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Li S, Zhou X, Huang Y, Zhu L, Zhang S, Zhao Y, Guo J, Chen J, Chen R. Identification and characterization of the zinc-regulated transporters, iron-regulated transporter-like protein (ZIP) gene family in maize. BMC PLANT BIOLOGY 2013; 13:114. [PMID: 23924433 PMCID: PMC3751942 DOI: 10.1186/1471-2229-13-114] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 08/01/2013] [Indexed: 05/20/2023]
Abstract
BACKGROUND Zinc (Zn) and iron (Fe) are essential micronutrients for plant growth and development, their deficiency or excess severely impaired physiological and biochemical reactions of plants. Therefore, a tightly controlled zinc and iron uptake and homeostasis network has been evolved in plants. The Zinc-regulated transporters, Iron-regulated transporter-like Proteins (ZIP) are capable of uptaking and transporting divalent metal ion and are suggested to play critical roles in balancing metal uptake and homeostasis, though a detailed analysis of ZIP gene family in maize is still lacking. RESULTS Nine ZIP-coding genes were identified in maize genome. It was revealed that the ZmZIP proteins share a conserved transmembrane domain and a variable region between TM-3 and TM-4. Transiently expression in onion epidermal cells revealed that all ZmZIP proteins were localized to the endoplasmic reticulum and plasma membrane. The yeast complementation analysis was performed to test the Zn or Fe transporter activity of ZmZIP proteins. Expression analysis showed that the ZmIRT1 transcripts were dramatically induced in response to Zn- and Fe-deficiency, though the expression profiles of other ZmZIP changed variously. The expression patterns of ZmZIP genes were observed in different stages of embryo and endosperm development. The accumulations of ZmIRT1 and ZmZIP6 were increased in the late developmental stages of embryo, while ZmZIP4 was up-regulated during the early development of embryo. In addition, the expression of ZmZIP5 was dramatically induced associated with middle stage development of embryo and endosperm. CONCLUSIONS These results suggest that ZmZIP genes encode functional Zn or Fe transporters that may be responsible for the uptake, translocation, detoxification and storage of divalent metal ion in plant cells. The various expression patterns of ZmZIP genes in embryo and endosperm indicates that they may be essential for ion translocation and storage during differential stages of embryo and endosperm development. The present study provides new insights into the evolutionary relationship and putative functional divergence of the ZmZIP gene family during the growth and development of maize.
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Affiliation(s)
- Suzhen Li
- Department of Agronomy, Agricultural University of Hebei/Hebei Sub-center of Chinese National Maize Improvement Center, Baoding 071001, China
- Department of Crop Genomics & Genetic Improvement, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xiaojin Zhou
- Department of Crop Genomics & Genetic Improvement, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yaqun Huang
- Department of Agronomy, Agricultural University of Hebei/Hebei Sub-center of Chinese National Maize Improvement Center, Baoding 071001, China
| | - Liying Zhu
- Department of Agronomy, Agricultural University of Hebei/Hebei Sub-center of Chinese National Maize Improvement Center, Baoding 071001, China
| | - Shaojun Zhang
- Department of Crop Genomics & Genetic Improvement, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yongfeng Zhao
- Department of Agronomy, Agricultural University of Hebei/Hebei Sub-center of Chinese National Maize Improvement Center, Baoding 071001, China
| | - Jinjie Guo
- Department of Agronomy, Agricultural University of Hebei/Hebei Sub-center of Chinese National Maize Improvement Center, Baoding 071001, China
| | - Jingtang Chen
- Department of Agronomy, Agricultural University of Hebei/Hebei Sub-center of Chinese National Maize Improvement Center, Baoding 071001, China
| | - Rumei Chen
- Department of Crop Genomics & Genetic Improvement, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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Groth C, Sasamura T, Khanna MR, Whitley M, Fortini ME. Protein trafficking abnormalities in Drosophila tissues with impaired activity of the ZIP7 zinc transporter Catsup. Development 2013; 140:3018-27. [PMID: 23785054 DOI: 10.1242/dev.088336] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Developmental patterning requires the precise interplay of numerous intercellular signaling pathways to ensure that cells are properly specified during tissue formation and organogenesis. The spatiotemporal function of the Notch signaling pathway is strongly influenced by the biosynthesis and intracellular trafficking of signaling components. Receptors and ligands must be trafficked to the cell surface where they interact, and their subsequent endocytic internalization and endosomal trafficking is crucial for both signal propagation and its down-modulation. In a forward genetic screen for mutations that alter intracellular Notch receptor trafficking in Drosophila epithelial tissues, we recovered mutations that disrupt the Catsup gene, which encodes the Drosophila ortholog of the mammalian ZIP7 zinc transporter. Loss of Catsup function causes Notch to accumulate abnormally in the endoplasmic reticulum (ER) and Golgi compartments, resulting in impaired Notch signaling. In addition, Catsup mutant cells exhibit elevated ER stress, suggesting that impaired zinc homeostasis causes increased levels of misfolded proteins within the secretory compartment.
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Affiliation(s)
- Casper Groth
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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66
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Kanninen KM, Grubman A, Caragounis A, Duncan C, Parker SJ, Lidgerwood GE, Volitakis I, Ganio G, Crouch PJ, White AR. Altered biometal homeostasis is associated with CLN6 mRNA loss in mouse neuronal ceroid lipofuscinosis. Biol Open 2013; 2:635-46. [PMID: 23789114 PMCID: PMC3683166 DOI: 10.1242/bio.20134804] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 04/23/2013] [Indexed: 12/21/2022] Open
Abstract
Neuronal ceroid lipofuscinoses, the most common fatal childhood neurodegenerative illnesses, share many features with more prevalent neurodegenerative diseases. Neuronal ceroid lipofuscinoses are caused by mutations in CLN genes. CLN6 encodes a transmembrane endoplasmic reticulum protein with no known function. We characterized the behavioural phenotype of spontaneous mutant mice modeling CLN6 disease, and demonstrate progressive motor and visual decline and reduced lifespan in these mice, consistent with symptoms observed in neuronal ceroid lipofuscinosis patients. Alterations to biometal homeostasis are known to play a critical role in pathology in Alzheimer's, Parkinson's, Huntington's and motor neuron diseases. We have previously shown accumulation of the biometals, zinc, copper, manganese and cobalt, in CLN6 Merino and South Hampshire sheep at the age of symptom onset. Here we determine the physiological and disease-associated expression of CLN6, demonstrating regional CLN6 transcript loss, and concurrent accumulation of the same biometals in the CNS and the heart of presymptomatic CLN6 mice. Furthermore, increased expression of the ER/Golgi-localized cation transporter protein, Zip7, was detected in cerebellar Purkinje cells and whole brain fractions. Purkinje cells not only control motor function, an early symptomatic change in the CLN6 mice, but also display prominent neuropathological changes in mouse models and patients with different forms of neuronal ceroid lipofuscinoses. Whole brain fractionation analysis revealed biometal accumulation in fractions expressing markers for ER, Golgi, endosomes and lysosomes of CLN6 brains. These data are consistent with a link between CLN6 expression and biometal homeostasis in CLN6 disease, and provide further support for altered cation transporter regulation as a key factor in neurodegeneration.
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Affiliation(s)
- Katja M Kanninen
- Department of Pathology, The University of Melbourne , Parkville, Victoria 3010 , Australia ; Present address: AI Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio 70211, Finland
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67
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Taniguchi M, Fukunaka A, Hagihara M, Watanabe K, Kamino S, Kambe T, Enomoto S, Hiromura M. Essential role of the zinc transporter ZIP9/SLC39A9 in regulating the activations of Akt and Erk in B-cell receptor signaling pathway in DT40 cells. PLoS One 2013; 8:e58022. [PMID: 23505453 PMCID: PMC3591455 DOI: 10.1371/journal.pone.0058022] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 01/29/2013] [Indexed: 01/08/2023] Open
Abstract
The essential trace element zinc is important for all living organisms. Zinc functions not only as a nutritional factor, but also as a second messenger. However, the effects of intracellular zinc on the B cell-receptor (BCR) signaling pathway remain poorly understood. Here, we present data indicating that the increase in intracellular zinc level induced by ZIP9/SLC39A9 (a ZIP Zrt-/Irt-like protein) plays an important role in the activation of Akt and Erk in response to BCR activation. In DT40 cells, the enhancement of Akt and Erk phosphorylation following BCR activation requires intracellular zinc. To clarify this event, we used chicken ZnT5/6/7-gene-triple-knockout DT40 (TKO) cells and chicken Zip9-knockout DT40 (cZip9KO) cells. The levels of Akt and ERK phosphorylation significantly decreased in cZip9KO cells. In addition, the enzymatic activity of protein tyrosine phosphatase (PTPase) increased in cZip9KO cells. These biochemical events were restored by overexpressing the human Zip9 (hZip9) gene. Moreover, we found that the increase in intracellular zinc level depends on the expression of ZIP9. This observation is in agreement with the increased levels of Akt and Erk phosphorylation and the inhibition of total PTPase activity. We concluded that ZIP9 regulates cytosolic zinc level, resulting in the enhancement of Akt and Erk phosphorylation. Our observations provide new mechanistic insights into the BCR signaling pathway underlying the regulation of intracellular zinc level by ZIP9 in response to the BCR activation.
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Affiliation(s)
- Masanari Taniguchi
- Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science, Kobe, Japan
| | - Ayako Fukunaka
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science, Kobe, Japan
| | - Mitsue Hagihara
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science, Kobe, Japan
| | - Keiko Watanabe
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science, Kobe, Japan
| | - Shinichiro Kamino
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science, Kobe, Japan
| | - Taiho Kambe
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Shuichi Enomoto
- Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science, Kobe, Japan
| | - Makoto Hiromura
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science, Kobe, Japan
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Jeong J, Walker JM, Wang F, Park JG, Palmer AE, Giunta C, Rohrbach M, Steinmann B, Eide DJ. Promotion of vesicular zinc efflux by ZIP13 and its implications for spondylocheiro dysplastic Ehlers-Danlos syndrome. Proc Natl Acad Sci U S A 2012; 109:E3530-8. [PMID: 23213233 PMCID: PMC3529093 DOI: 10.1073/pnas.1211775110] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Zinc is essential but potentially toxic, so intracellular zinc levels are tightly controlled. A key strategy used by many organisms to buffer cytosolic zinc is to store it within vesicles and organelles.It is yet unknown whether vesicular or organellar sites perform this function in mammals. Human ZIP13, a member of the Zrt/Irt-like protein (ZIP) metal transporter family, might provide an answer to this question. Mutations in the ZIP13 gene, SLC39A13, previously were found to cause the spondylocheiro dysplastic form of Ehlers–Danlos syndrome (SCD-EDS), a heritable connective tissue disorder.Those previous studies suggested that ZIP13 transports excess zinc out of the early secretory pathway and that zinc overload in the endoplasmic reticulum (ER) occurs in SCD-EDS patients. In contrast,this study indicates that ZIP13’s role is to release labile zinc from vesicular stores for use in the ER and other compartments. We propose that SCD-EDS is the result of vesicular zinc trapping and ER zinc deficiency rather than overload.
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Affiliation(s)
- Jeeyon Jeong
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
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69
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Yan G, Zhang Y, Yu J, Yu Y, Zhang F, Zhang Z, Wu A, Yan X, Zhou Y, Wang F. Slc39a7/zip7 plays a critical role in development and zinc homeostasis in zebrafish. PLoS One 2012; 7:e42939. [PMID: 22912764 PMCID: PMC3418240 DOI: 10.1371/journal.pone.0042939] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 07/16/2012] [Indexed: 11/30/2022] Open
Abstract
Background Slc39a7/Zip7, also known as Ke4, is a member of solute carrier family 39 (Slc39a) and plays a critical role in regulating cell growth and death. Because the function of Zip7 in vivo was unclear, the present study investigated the function of zip7 in vertebrate development and zinc metabolism using zebrafish as a model organism. Principal Finding Using real-time PCR to determine the gene expression pattern of zip7 during zebrafish development, we found that zip7 mRNA is expressed throughout embryonic development and into maturity. Interestingly, whole mount in situ hybridization revealed that while zip7 mRNA is ubiquitously expressed until 12 hours post-fertilization (hpf); at 24 hpf and beyond, zip7 mRNA was specifically detected only in eyes. Morpholino-antisense (MO) gene knockdown assay revealed that downregulation of zip7 expression resulted in several morphological defects in zebrafish including decreased head size, smaller eyes, shorter palates, and shorter and curved spinal cords. Analysis by synchrotron radiation X-ray fluorescence (SR-XRF) showed reduced concentrations of zinc in brain, eyes, and gills of zip7-MO-injected embryos. Furthermore, incubation of the zip7 knockdown embryos in a zinc-supplemented solution was able to rescue the MO-induced morphological defects. Significance Our data suggest that zip7 is required for eye, brain, and skeleton formation during early embryonic development in zebrafish. Moreover, zinc supplementation can partially rescue defects resulting from zip7 gene knockdown. Taken together, our data provide critical insight into a novel function of zip7 in development and zinc homeostasis in vivo in zebrafish.
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Affiliation(s)
- Guang Yan
- Group of Bio-Metal Metabolism, Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Yuchao Zhang
- Group of Bio-Metal Metabolism, Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, People's Republic of China
- College of Animal Sciences and Technology, Key Laboratory of Swine Genetics and Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Junlei Yu
- Group of Bio-Metal Metabolism, Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, People's Republic of China
- Schools of Life and Food Engineering, Nanchang University, Nanchang, China
| | - Yu Yu
- Group of Bio-Metal Metabolism, Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Fan Zhang
- Group of Bio-Metal Metabolism, Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Zhuzhen Zhang
- Group of Bio-Metal Metabolism, Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Aimin Wu
- Group of Bio-Metal Metabolism, Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Xianghua Yan
- College of Animal Sciences and Technology, Key Laboratory of Swine Genetics and Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Yi Zhou
- Stem Cell Program and Division of Hematology/Oncology Children's Hospital Boston and Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Fudi Wang
- Group of Bio-Metal Metabolism, Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, People's Republic of China
- * E-mail:
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70
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Taylor KM, Hiscox S, Nicholson RI, Hogstrand C, Kille P. Protein kinase CK2 triggers cytosolic zinc signaling pathways by phosphorylation of zinc channel ZIP7. Sci Signal 2012; 5:ra11. [PMID: 22317921 PMCID: PMC3428905 DOI: 10.1126/scisignal.2002585] [Citation(s) in RCA: 189] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The transition element zinc, which has recently been identified as an intracellular second messenger, has been implicated in various signaling pathways, including those leading to cell proliferation. Zinc channels of the ZIP (ZRT1- and IRT1-like protein) family [also known as solute carrier family 39A (SLC39A)] transiently increase the cytosolic free zinc (Zn(2+)) concentration in response to extracellular signals. We show that phosphorylation of evolutionarily conserved residues in endoplasmic reticulum zinc channel ZIP7 is associated with the gated release of Zn(2+) from intracellular stores, leading to activation of tyrosine kinases and the phosphorylation of AKT and extracellular signal-regulated kinases 1 and 2. Through pharmacological manipulation, proximity ligation assay, and mutagenesis, we identified protein kinase CK2 as the kinase responsible for ZIP7 activation. Together, the present results show that transition element channels in eukaryotes can be activated posttranslationally by phosphorylation, as part of a cell signaling cascade. Our study links the regulated release of zinc from intracellular stores to phosphorylation of kinases involved in proliferative responses and cell migration, suggesting a functional role for ZIP7 and zinc signals in these events. The connection with proliferation and migration, as well as the activation of ZIP7 by CK2, a kinase that is antiapoptotic and promotes cell division, suggests that ZIP7 may provide a target for anticancer drug development.
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Affiliation(s)
- Kathryn M Taylor
- Breast Cancer Molecular Pharmacology Group, School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VIIth Avenue, Cardiff CF10 3NB, UK.
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71
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TANIGUCHI M, KAMINO S, HIROMURA M, ENOMOTO S. Dynamics and Multiple Molecular Imaging of Bio-trace Elements. BUNSEKI KAGAKU 2012. [DOI: 10.2116/bunsekikagaku.61.1013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Masanari TANIGUCHI
- Division of Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science
| | - Shinichiro KAMINO
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science
| | - Makoto HIROMURA
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science
| | - Shuichi ENOMOTO
- Division of Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
- Multiple Molecular Imaging Research Laboratory, RIKEN Center for Molecular Imaging Science
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72
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Wang Z, Ferdousy F, Lawal H, Huang Z, Daigle JG, Izevbaye I, Doherty O, Thomas J, Stathakis DG, O'Donnell JM. Catecholamines up integrates dopamine synthesis and synaptic trafficking. J Neurochem 2011; 119:1294-305. [PMID: 21985068 DOI: 10.1111/j.1471-4159.2011.07517.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The highly reactive nature of dopamine renders dopaminergic neurons vulnerable to oxidative damage. We recently demonstrated that loss-of-function mutations in the Drosophila gene Catecholamines up (Catsup) elevate dopamine pools but, paradoxically, also confer resistance to paraquat, an herbicide that induces oxidative stress-mediated toxicity in dopaminergic neurons. We now report a novel association of the membrane protein, Catsup, with GTP cyclohydrolase rate-limiting enzyme for tetrahydrobiopterin (BH(4)) biosynthesis and tyrosine hydroxylase, rate-limiting enzyme for dopamine biosynthesis, which requires BH(4) as a cofactor. Loss-of-function Catsup mutations cause dominant hyperactivation of both enzymes. Elevated dopamine levels in Catsup mutants coincide with several distinct characteristics, including hypermobility, minimal basal levels of 3,4-dihydroxy-phenylacetic acid, an oxidative metabolite of dopamine, and resistance to the vesicular monoamine transporter inhibitor, reserpine, suggesting that excess dopamine is synaptically active and that Catsup functions in the regulation of synaptic vesicle loading and release of dopamine. We conclude that Catsup regulates and links the dopamine synthesis and transport networks.
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Affiliation(s)
- Zhe Wang
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama 35487, USA
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73
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Bin BH, Fukada T, Hosaka T, Yamasaki S, Ohashi W, Hojyo S, Miyai T, Nishida K, Yokoyama S, Hirano T. Biochemical characterization of human ZIP13 protein: a homo-dimerized zinc transporter involved in the spondylocheiro dysplastic Ehlers-Danlos syndrome. J Biol Chem 2011; 286:40255-65. [PMID: 21917916 DOI: 10.1074/jbc.m111.256784] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human SLC39A13 gene encodes ZIP13, a member of the LZT (LIV-1 subfamily of ZIP zinc transporters) family. The ZIP13 protein is important for connective tissue development, and its loss of function is causative for the spondylocheiro dysplastic form of Ehlers-Danlos syndrome. However, this protein has not been characterized in detail. Here we report the first detailed biochemical characterization of the human ZIP13 protein using its ectopic expressed and the purified recombinant protein. Protease accessibility, microscopic, and computational analyses demonstrated that ZIP13 contains eight putative transmembrane domains and a unique hydrophilic region and that it resides with both its N and C termini facing the luminal side on the Golgi. Analyses including cross-linking, immunoprecipitation, Blue Native-PAGE, and size-exclusion chromatography experiments indicated that the ZIP13 protein may form a homo-dimer. We also demonstrated that ZIP13 mediates zinc influx, as assessed by monitoring the expression of the metallothionein gene and by detecting the intracellular zinc level with a zinc indicator, FluoZin-3. Our data indicate that ZIP13 is a homo-dimerized zinc transporter that possesses some domains that are not found in other LZT family members. This is the first biochemical characterization of the physiologically important protein ZIP13 and the demonstration of homo-dimerization for a mammalian ZIP zinc transporter family member. This biochemical characterization of the human ZIP13 protein provides important information for further investigations of its structural characteristics and function.
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Affiliation(s)
- Bum-Ho Bin
- Laboratory for Cytokine Signaling, RIKEN Research Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045, Japan
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Thornton JK, Taylor KM, Ford D, Valentine RA. Differential subcellular localization of the splice variants of the zinc transporter ZnT5 is dictated by the different C-terminal regions. PLoS One 2011; 6:e23878. [PMID: 21887337 PMCID: PMC3161073 DOI: 10.1371/journal.pone.0023878] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 07/26/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Zinc is emerging as an important intracellular signaling molecule, as well as fulfilling essential structural and catalytic functions through incorporation in a myriad of zinc metalloproteins so it is important to elucidate the molecular mechanisms of zinc homeostasis, including the subcellular localizations of zinc transporters. PRINCIPAL FINDINGS Two splice variants of the human SLC30A5 Zn transporter gene (ZnT5) have been reported in the literature. These variants differ at their N- and C-terminal regions, corresponding with the use of different 5' and 3' exons. We demonstrate that full length human ZnT5 variant B is a genuine transcript in human intestinal cells and confirm expression of both variant A and variant B in a range of untreated human tissues by splice variant-specific RT-PCR. Using N- or C-terminal GFP or FLAG fusions of both isoforms of ZnT5 we identify that the differential subcellular localization to the Golgi apparatus and ER respectively is a function of their alternative C-terminal sequences. These different C-terminal regions result from the incorporation into the mature transcript of either the whole of exon 14 (variant B) or only the 5' region of exon 14 plus exons 15-17 (variant A). CONCLUSIONS We thus propose that exons 15 to 17 include a signal that results in trafficking of ZnT5 to the Golgi apparatus and that the 3' end of exon 14 includes a signal that leads to retention in the ER.
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Affiliation(s)
- Jared K. Thornton
- The Human Nutrition Research Centre, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- School of Dental Sciences, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Kathryn M. Taylor
- Tenovus Cancer Research Centre, Welsh School of Pharmacy, Cardiff University, Cardiff , United Kingdom
| | - Dianne Ford
- The Human Nutrition Research Centre, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Ruth A. Valentine
- The Human Nutrition Research Centre, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- School of Dental Sciences, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- * E-mail:
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75
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Nam H, Knutson MD. Effect of dietary iron deficiency and overload on the expression of ZIP metal-ion transporters in rat liver. Biometals 2011; 25:115-24. [PMID: 21826460 DOI: 10.1007/s10534-011-9487-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 07/31/2011] [Indexed: 01/22/2023]
Abstract
The mammalian ZIP (Zrt-, Irt-like Protein) family of transmembrane transport proteins consists of 14 members that share considerable homology. ZIP proteins have been shown to mediate the cellular uptake of the essential trace elements zinc, iron, and manganese. The aim of the present study was to determine the effect of dietary iron deficiency and overload on the expression of all 14 ZIP transporters in the liver, the main site of iron storage. Weanling male rats (n = 6/group) were fed iron-deficient (FeD), iron-adequate (FeA), or iron-overloaded (FeO) diets in two independent feeding studies. In study 1, diets were based on the TestDiet 5755 formulation and contained iron at 9 ppm (FeD), 215 ppm (FeA), and 27,974 ppm (3% FeO). In study 2, diets were based on the AIN-93G formulation and contained iron at 9 ppm Fe (FeD), 50 ppm Fe (FeA), or 18916 ppm (2% FeO). After 3 weeks, the FeD diets depleted liver non-heme iron stores and induced anemia, whereas FeO diets resulted in hepatic iron overload. Quantitative RT-PCR revealed that ZIP5 mRNA levels were 3- and 8-fold higher in 2% FeO and 3% FeO livers, respectively, compared with FeA controls. In both studies, a consistent downregulation of ZIP6, ZIP7, and ZIP10 was also observed in FeO liver relative to FeA controls. Studies in H4IIE hepatoma cells further documented that iron loading affects the expression of these ZIP transporters. Overall, our data suggest that ZIP5, ZIP6, ZIP7, and ZIP10 are regulated by iron, indicating that they may play a role in hepatic iron/metal homeostasis during iron deficiency and overload.
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Affiliation(s)
- Hyeyoung Nam
- Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA
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76
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Schmidt A, Hagen M, Schütze E, Schmidt A, Kothe E. In silico prediction of potential metallothioneins and metallohistins in actinobacteria. J Basic Microbiol 2011; 50:562-9. [PMID: 21077111 DOI: 10.1002/jobm.201000055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Metallothioneins and metallohistins are short peptides with a high cysteine and/or histidine content able to coordinate metals intracellularly, thereby increasing the tolerance against elevated concentrations of metals. Because of their features, they can be detected by in silico prediction from proteomes annotated from sequenced genomes. Here, we analyzed 73 sequenced actinobacterial genomes for peptides (≤ 100 amino acids) with a high content of cysteine and histidine (≥ 15%) and identified 103 putative metallothioneins and metallohistins. For 45 of these peptides, we found similarities to metal binding protein domains, including zinc fingers, heavy metal transporters or eukaryotic metallothioneins, which can serve as proof-of-principle in underscoring a potential function as metal binding peptides. An evolutionary origin from metal containing domains of enzymes is discussed and metallohistins not containing cysteine are described for the first time for bacteria.
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Affiliation(s)
- Andre Schmidt
- Microbial Phytopathology, Institute of Microbiology, Faculty of Biology and Pharmacy, Friedrich-Schiller-University, Jena, Germany
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77
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Hojyo S, Fukada T, Shimoda S, Ohashi W, Bin BH, Koseki H, Hirano T. The zinc transporter SLC39A14/ZIP14 controls G-protein coupled receptor-mediated signaling required for systemic growth. PLoS One 2011; 6:e18059. [PMID: 21445361 PMCID: PMC3062567 DOI: 10.1371/journal.pone.0018059] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 02/20/2011] [Indexed: 01/05/2023] Open
Abstract
Aberrant zinc (Zn) homeostasis is associated with abnormal control of mammalian growth, although the molecular mechanisms of Zn's roles in regulating systemic growth remain to be clarified. Here we report that the cell membrane-localized Zn transporter SLC39A14 controls G-protein coupled receptor (GPCR)-mediated signaling. Mice lacking Slc39a14 (Slc39a14-KO mice) exhibit growth retardation and impaired gluconeogenesis, which are attributable to disrupted GPCR signaling in the growth plate, pituitary gland, and liver. The decreased signaling is a consequence of the reduced basal level of cyclic adenosine monophosphate (cAMP) caused by increased phosphodiesterase (PDE) activity in Slc39a14-KO cells. We conclude that SLC39A14 facilitates GPCR-mediated cAMP-CREB signaling by suppressing the basal PDE activity, and that this is one mechanism for Zn's involvement in systemic growth processes. Our data highlight SLC39A14 as an important novel player in GPCR-mediated signaling. In addition, the Slc39a14-KO mice may be useful for studying the GPCR-associated regulation of mammalian systemic growth.
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Affiliation(s)
- Shintaro Hojyo
- Laboratory for Cytokine Signaling, RIKEN Research Center for Allergy and Immunology, Suehiro, Tsurumi, Yokohama, Kanagawa, Japan
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78
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Schulte L, Glanfield A, Nawaratna S, Gobert GN, McManus DP, Jones MK. Molecular analysis of zinc transporters in Schistosoma japonicum. Exp Parasitol 2011; 127:768-76. [PMID: 21255570 DOI: 10.1016/j.exppara.2011.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 11/19/2010] [Accepted: 01/11/2011] [Indexed: 11/30/2022]
Abstract
Members of the zinc-regulated transporter/iron-regulated transporter-like protein (ZIP) family of proteins transport metal ions across cell membranes. Genes encoding ZIPs are present in the genomes of schistosomes. Here, we describe molecular characterisation of six ZIPs (SjZIPA-F) from Schistosoma japonicum. Quantitative PCR analyses of these ZIPs through the lifecycle showed that each is expressed predominantly during the intramammalian stage and are particularly enriched in adult females. Using laser microdissected tissue as template, SjZIPA-D were transcriptionally enriched in female reproductive tissues, SjZIPE was not expressed in specific tissues and SjZIPF was expressed similarly in each tissue. Whole mount in situ hybridization revealed that SjZIPA and SjZIPB were localised to the oesophageal gland of adults and the vitellaria. We have shown that multiple ZIPs are expressed by schistosomes during the intramammalian parasitic phases and propose that the encoded products perform diverse cellular functions related to metal transport in different cells of S. japonicum.
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Affiliation(s)
- Leigh Schulte
- Queensland Institute of Medical Research, 300 Herston Road, Herston, Qld 4006, Australia
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79
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Thornton JK, Taylor KM, Ford D, Valentine RA. Differential subcellular localization of the splice variants of the zinc transporter ZnT5 is dictated by the different C-terminal regions. PLoS One 2011; 6:e23878. [PMID: 21887337 DOI: 10.1371/journal.pone.002387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 07/26/2011] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Zinc is emerging as an important intracellular signaling molecule, as well as fulfilling essential structural and catalytic functions through incorporation in a myriad of zinc metalloproteins so it is important to elucidate the molecular mechanisms of zinc homeostasis, including the subcellular localizations of zinc transporters. PRINCIPAL FINDINGS Two splice variants of the human SLC30A5 Zn transporter gene (ZnT5) have been reported in the literature. These variants differ at their N- and C-terminal regions, corresponding with the use of different 5' and 3' exons. We demonstrate that full length human ZnT5 variant B is a genuine transcript in human intestinal cells and confirm expression of both variant A and variant B in a range of untreated human tissues by splice variant-specific RT-PCR. Using N- or C-terminal GFP or FLAG fusions of both isoforms of ZnT5 we identify that the differential subcellular localization to the Golgi apparatus and ER respectively is a function of their alternative C-terminal sequences. These different C-terminal regions result from the incorporation into the mature transcript of either the whole of exon 14 (variant B) or only the 5' region of exon 14 plus exons 15-17 (variant A). CONCLUSIONS We thus propose that exons 15 to 17 include a signal that results in trafficking of ZnT5 to the Golgi apparatus and that the 3' end of exon 14 includes a signal that leads to retention in the ER.
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Affiliation(s)
- Jared K Thornton
- The Human Nutrition Research Centre, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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80
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Wang M, Xu Q, Yu J, Yuan M. The putative Arabidopsis zinc transporter ZTP29 is involved in the response to salt stress. PLANT MOLECULAR BIOLOGY 2010; 73:467-79. [PMID: 20358261 DOI: 10.1007/s11103-010-9633-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 03/21/2010] [Indexed: 05/20/2023]
Abstract
Salt stress leads to a stress response, called the unfolded protein response (UPR), in the endoplasmic reticulum (ER). UPR is also induced in a wide range of organisms by zinc deficiency. However, it is not clear whether regulation of zinc levels is involved in the initiation of the UPR in plant response to salt stress. In this study, a putative zinc transporter, ZTP29, was identified in Arabidopsis thaliana. ZTP29 localizes to the ER membrane and is expressed primarily in hypocotyl and cotyledon tissues, but its expression can be induced in root tissue by salt stress. T-DNA insertion into the ZTP29 gene led to NaCl hypersensitivity in seed germination and seedling growth, leaf etiolation, and widening of cells in the root elongation zone. In addition, in ztp29 mutant plants, salt stress-induced upregulation of the UPR pathway genes BiP2 and bZIP60 was inhibited. Furthermore, under conditions of salt stress, upregulation of BiP2 and bZIP60 was inhibited by treatment with high concentrations of zinc in both control and ztp29 plants. However, zinc chelation restored salt stress-induced BiP2 and bZIP60 upregulation in ztp29 mutant plants. These experimental results suggest that ZTP29 is involved in the response to salt stress, perhaps through regulation of zinc levels required to induce the UPR pathway.
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Affiliation(s)
- Miaoying Wang
- State Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
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81
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Abstract
Studies on dietary zinc absorption are of fundamental nutritional significance, owing to the ubiquity of zinc in biological processes and the severe outcomes of zinc deficiency in humans. Insights into the molecular basis of dietary zinc absorption have advanced in recent years through functional characterization of zinc transporters in cell culture, immunohistochemical studies on rodent intestine and analysis of gene knockout mice. Zinc transporters with manifested expression in enterocytes include ZnT1, ZnT2, ZnT4, ZnT5, ZnT6, ZnT7, Zip4, and Zip5. Among them, ZIP4, the gene responsible for Acrodermatitis enteropathica, an inherited human zinc deficiency, mediates dietary zinc uptake into enterocytes across the apical membrane, while ZnT1 is involved in zinc efflux from enterocytes across the basolateral membrane into circulation. The intracellular trafficking pathways for zinc retention and movement between apical and basolateral sides of the enterocytes have yet to be defined. The utilization of Drosophila model in elucidating molecular mechanisms of dietary zinc absorption is also discussed in this review.
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82
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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] [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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83
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Lichten LA, Cousins RJ. Mammalian zinc transporters: nutritional and physiologic regulation. Annu Rev Nutr 2009; 29:153-76. [PMID: 19400752 DOI: 10.1146/annurev-nutr-033009-083312] [Citation(s) in RCA: 523] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Research advances defining how zinc is transported into and out of cells and organelles have increased exponentially within the past five years. Research has progressed through application of molecular techniques including genomic analysis, cell transfection, RNA interference, kinetic analysis of ion transport, and application of cell and animal models including knockout mice. The knowledge base has increased for most of 10 members of the ZnT family and 14 members of the Zrt-, Irt-like protein (ZIP) family. Relative to the handling of dietary zinc is the involvement of ZnT1, ZIP4, and ZIP5 in intestinal zinc transport, involvement of ZIP10 and ZnT1 in renal zinc reabsorption, and the roles of ZIP5, ZnT2, and ZnT1 in pancreatic release of endogenous zinc. These events are major factors in regulation of zinc homeostasis. Other salient findings are the involvement of ZnT2 in lactation, ZIP14 in the hypozincemia of inflammation, ZIP6, ZIP7, and ZIP10 in metastatic breast cancer, and ZnT8 in insulin processing and as an autoantigen in diabetes.
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Affiliation(s)
- Louis A Lichten
- Nutritional Genomics Laboratory, Food Science and Human Nutrition Department and Center for Nutritional Sciences, University of Florida, Gainesville, FL 32611-2710, USA
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84
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Chen ZG, Ma ZX, Zuo B, Lei MG, Xiong YZ. Molecular characterization and association with carcass traits of the porcine SLC39A7 gene. J Anim Breed Genet 2009; 126:288-95. [PMID: 19630879 DOI: 10.1111/j.1439-0388.2008.00740.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In this study, the molecular characterization and potential association of SLC39A7 gene with carcass traits were investigated in pigs. The sequence of SLC39A7 cDNA was obtained by in silico cloning and RT-polymerase chain reaction (PCR). Two transcripts, variant 1 (2398 bp) and variant 2 (2088 bp), of the SLC39A7 gene were identified. Expression analysis of SLC39A7 in 10 different tissues by RT-PCR showed that variant 1 was ubiquitously expressed in all tissues analysed, but variant 2 was not found in fat tissue. The cDNA regions of variant 1 and 2 were organized in seven and eight exons respectively. A c.205G>A substitution in exon 3, which changes a codon for glycine into a codon for arginine, (p.Gly69Arg) and a c.1138-216T>C substitution in intron 6 were detected by PCR-HpaII-restriction fragment length polymorphisms (RFLP) and PCR-cofI-RFLP respectively. Significant differences were found in the allele frequencies of c.205G>A among six Chinese indigenous pig breeds and two commercial pig breeds. Linkage analysis showed that the c.205G>A polymorphism within the SLC39A7 gene was closely linked to the marker Sw1856 on pig chromosome 7 in a Large White x Meishan F(2) resource population. The QTL and association studies between polymorphisms of the SLC39A7 gene and carcass traits were carried out. Significant associations of the SLC39A7 polymorphisms with backfat thickness at thorax-waist (p < 0.05), average backfat thickness (p < 0.05) and leaf fat weight (p < 0.01) were found. Additional F-drop test or marker assisted association analyses also supported the association of the mutation in SLC39A7 with the above traits. Together, the present study provided the useful information for the characterization of SLC39A7 gene and potential association with carcass traits in pigs.
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Affiliation(s)
- Z G Chen
- Key Laboratory of Swine Genetics and Breeding, Ministry of Agriculture, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
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85
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Qian L, Lopez V, Seo YA, Kelleher SL. Prolactin regulates ZNT2 expression through the JAK2/STAT5 signaling pathway in mammary cells. Am J Physiol Cell Physiol 2009; 297:C369-77. [PMID: 19494234 DOI: 10.1152/ajpcell.00589.2008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The zinc transporter ZnT2 (SLC30A2) plays an important role in zinc secretion into milk during lactation. The physiological process of mammary gland secretion is regulated through complex integration of multiple lactogenic hormones. Prolactin plays a primary role in this regulation through the activation of various signaling cascades including Jak2/STAT5, mitogen-activated protein kinase (MAPK), p38, and phosphatidylinositol 3-kinase (PI3K). The precise mechanisms that regulate the transfer of specific nutrients such as zinc into milk are not well understood. Herein we report that prolactin increased ZnT2 abundance transcriptionally in cultured mammary epithelial (HC11) cells. To delineate the responsible mechanisms, we first determined that prolactin-mediated ZnT2 induction was inhibited by pretreatment with the Jak2 inhibitor AG490 but not by the MAPK inhibitor PD-98059. Using a luciferase reporter assay, we demonstrated that ZnT2 promoter activity was increased by prolactin treatment, which was subsequently abolished by expression of a dominant-negative STAT5 construct, implicating the Jak2/STAT5 signaling pathway in the transcriptional regulation of ZnT2. Two putative consensus STAT5 binding sequences in the ZnT2 promoter were identified (GAS1:-674 to -665 and GAS2:-377 to -368). Mutagenesis of the proximal GAS2 element resulted in complete abrogation of PRL-induced ZnT2 promoter activity. The promoter incorporating the distal GAS1 mutation was only able to respond to very high PRL concentrations. Results from both the mutagenesis and gel shift assays indicated that a cooperative relationship exists between GAS1 and GAS2 for PRL-induced activation; however, the proximal GAS2 plays a more critical role in STAT5-mediated signal transduction compared with the GAS1 element. Finally, chromosome immunoprecipition assay further confirmed that prolactin activates STAT5 binding to the ZnT2 promoter in vivo. Taken together, these results illustrate that prolactin regulates the transcription of ZnT2 through activation of the Jak2/STAT5 signaling pathway to assist in providing optimal zinc for secretion into milk during lactation.
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Affiliation(s)
- Linxi Qian
- Department of Nutritional Sciences, the Pennsylvania State University, University Park, PA 16802, USA
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86
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SLC39A9 (ZIP9) regulates zinc homeostasis in the secretory pathway: characterization of the ZIP subfamily I protein in vertebrate cells. Biosci Biotechnol Biochem 2009; 73:1142-8. [PMID: 19420709 DOI: 10.1271/bbb.80910] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The SLC39A family of zinc transporters can be divided into four subfamilies (I, II, LIV-1, and gufA) in vertebrates, but studies of their functions have been restricted exclusively to members of subfamilies II and LIV-1. In this study, we characterized SLC39A9 (ZIP9), the only member of subfamily I in vertebrates. Confocal microscopy demonstrated that transiently expressed, HA-tagged human ZIP9 (hZIP9-HA) was localized to the trans-Golgi network regardless of zinc status. Disruption of the ZIP9 gene in DT40 cells did not change the growth rate, sensitivity to high zinc and manganese concentrations during long-term culture, or cellular zinc status after short-term incubation with zinc. The alkaline phosphatase activity of ZIP9(-/-) cells did not change in cells cultured in medium containing normal zinc levels. In contrast, the activity of this enzyme decreased in wild-type cells cultured in zinc deficient medium but less so in ZIP9(-/-) cells under these conditions. Stable over-expression of hZIP9-HA moderately decreased alkaline phophatase activity. These results suggest that ZIP9 functions to regulate zinc homeostasis in the secretory pathway without significantly altering cytosolic zinc homeostasis.
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87
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Zinc transporters and cancer: a potential role for ZIP7 as a hub for tyrosine kinase activation. Trends Mol Med 2009; 15:101-11. [PMID: 19246244 DOI: 10.1016/j.molmed.2009.01.004] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 01/09/2009] [Accepted: 01/09/2009] [Indexed: 12/17/2022]
Abstract
Zinc, which is essential for many cellular processes, is controlled by zinc transporters and through buffering by metallothioneins and glutathione. Although zinc is increasingly implicated in disease states, little is known about how zinc regulates cellular biochemical pathways. Recent seminal articles have revealed discrete zinc-trafficking pathways that are linked to signalling cascades, particularly those involving protein phosphatase inhibition and downstream activation of mitogen-activated protein kinases and tyrosine kinases. Here, we discuss the mechanisms of cellular zinc homeostasis, and we propose an important role for the zinc transporter solute carrier family 39, member 7 (SLC39A7; commonly referred to as ZIP7). ZIP7 releases zinc from the endoplasmic reticulum and might be required for tyrosine kinase activation. These observations position ZIP7 at a critical node in zinc-mediated tyrosine kinase signalling and suggest that this protein might form a novel target for diseases such as cancer where prevention of tyrosine kinase activation would be therapeutically advantageous.
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88
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Abstract
Zinc, essential for normal cell growth, is tightly controlled in cells by two families of zinc transporters. The aberrant expression of zinc transporters from the LIV-1 family of ZIP (Zrt/Irt-like protein) transporters is increasingly being implicated in a variety of disease states. In the present paper, I describe a mechanism for the role of ZIP7 in the progression of breast cancer, identifying it as a new target in breast cancer. Furthermore, I document a link between another zinc transporter, LIV-1, and breast cancer metastasis, identifying it as a potential new prognostic indicator of breast cancer spread.
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89
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Novel proteolytic processing of the ectodomain of the zinc transporter ZIP4 (SLC39A4) during zinc deficiency is inhibited by acrodermatitis enteropathica mutations. Mol Cell Biol 2008; 29:129-39. [PMID: 18936158 DOI: 10.1128/mcb.00963-08] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The zinc transporter ZIP4 (SLC39A4) is mutated in humans with the rare, autosomal recessive genetic disease acrodermatitis enteropathica. In mice, this gene is essential during early embryonic development. ZIP4 is dynamically regulated by multiple posttranscriptional mechanisms, and studies of mouse ZIP4 reported herein reveal that the ectodomain, the extracellular amino-terminal half of the protein, is proteolytically removed during prolonged zinc deficiency while the remaining eight-transmembrane carboxyl-terminal half of the protein is accumulated on the plasma membrane as an abundant form of ZIP4. This novel ZIP4 processing occurs in vivo in the intestine and visceral endoderm, in mouse Hepa cells that express the endogenous Slc39a4 gene and in transfected MDCK and CaCo2 cells, but not HEK293 cells. In transfected MDCK and CaCo2 cells, the ectodomain accumulated and remained associated with membranes when zinc was deficient. ZIP4 cleavage was attenuated by inhibitors of endocytosis, which suggests that the processed protein is recycled back to the plasma membrane and that the ectodomain may be internalized. Ectodomain cleavage is inhibited by acrodermatitis enteropathica mutations near a predicted metalloproteinase cleavage site which is also essential for proper ectodomain cleavage, and overexpression of processed ZIP4 or ZIP4 with ectodomain truncations rendered the mouse Mt1 gene hypersensitive to zinc. These finding suggest that the processing of ZIP4 may represent a significant regulatory mechanism controlling its function.
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90
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Kirschke CP, Huang L. Expression of the ZNT (SLC30) family members in the epithelium of the mouse prostate during sexual maturation. J Mol Histol 2008; 39:359-70. [PMID: 18548323 DOI: 10.1007/s10735-008-9174-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Accepted: 05/22/2008] [Indexed: 10/22/2022]
Abstract
A prostate contains approximately 10-fold higher zinc than other soft organs. The function of the prostate is to produce a zinc-enriched seminal fluid. To establish a protein expression profile for zinc transporters involved in zinc efflux and intracellular sequestration/storage in the mouse prostate during sexual maturation, ZNT expression were investigated by immunohistochemistry. Our study demonstrated that ZNT proteins were differentially expressed in the prostate during sexual maturation. ZNT1 was mainly detected on the lateral membrane of the epithelium. Other ZNTs examined resided intracellularly. Among differences were a staining of ZNT2/ZNT5 in the ER-rich area of the epithelium in the anterior lobe, a staining of ZNT2 along the lateral and apical membrane, a luminal border staining of ZNT4, a staining of ZNT5 in the Golgi area of the epithelium in the ventral lobe, a uniform expression of ZNT6 across the lobes and ages, and a staining of ZNT7 in all lobes across ages.
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Affiliation(s)
- Catherine P Kirschke
- USDA, ARS, Western Human Nutrition Research Center, UC Davis, 430 West Health Sciences Drive, Davis, CA, 95616, USA
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91
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Spondylocheiro dysplastic form of the Ehlers-Danlos syndrome--an autosomal-recessive entity caused by mutations in the zinc transporter gene SLC39A13. Am J Hum Genet 2008; 82:1290-305. [PMID: 18513683 DOI: 10.1016/j.ajhg.2008.05.001] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 04/29/2008] [Accepted: 05/02/2008] [Indexed: 02/02/2023] Open
Abstract
We present clinical, radiological, biochemical, and genetic findings on six patients from two consanguineous families that show EDS-like features and radiological findings of a mild skeletal dysplasia. The EDS-like findings comprise hyperelastic, thin, and bruisable skin, hypermobility of the small joints with a tendency to contractures, protuberant eyes with bluish sclerae, hands with finely wrinkled palms, atrophy of the thenar muscles, and tapering fingers. The skeletal dysplasia comprises platyspondyly with moderate short stature, osteopenia, and widened metaphyses. Patients have an increased ratio of total urinary pyridinolines, lysyl pyridinoline/hydroxylysyl pyridinoline (LP/HP), of approximately 1 as opposed to approximately 6 in EDS VI or approximately 0.2 in controls. Lysyl and prolyl residues of collagens were underhydroxylated despite normal lysyl hydroxylase and prolyl 4-hydroxylase activities; underhydroxylation was a generalized process as shown by mass spectrometry of the alpha1(I)- and alpha2(I)-chain-derived peptides of collagen type I and involved at least collagen types I and II. A genome-wide SNP scan and sequence analyses identified in all patients a homozygous c.483_491 del9 SLC39A13 mutation that encodes for a membrane-bound zinc transporter SLC39A13. We hypothesize that an increased Zn(2+) content inside the endoplasmic reticulum competes with Fe(2+), a cofactor that is necessary for hydroxylation of lysyl and prolyl residues, and thus explains the biochemical findings. These data suggest an entity that we have designated "spondylocheiro dysplastic form of EDS (SCD-EDS)" to indicate a generalized skeletal dysplasia involving mainly the spine (spondylo) and striking clinical abnormalities of the hands (cheiro) in addition to the EDS-like features.
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92
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Zinc transporter mRNA expression in the RWPE-1 human prostate epithelial cell line. Biometals 2007; 21:405-16. [PMID: 18097638 DOI: 10.1007/s10534-007-9129-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 12/07/2007] [Indexed: 10/22/2022]
Abstract
The human prostate gland undergoes a prominent alteration in Zn+2 homeostasis during the development of prostate cancer. The goal of the present study was to determine if the immortalized human prostate cell line (RWPE-1) could serve as a model system to study the role of zinc in prostate cancer. The study examined the expression of mRNA for 19 members of the zinc transporter gene family in normal prostate tissue, the prostate RWPE-1 cell line, and the LNCaP, DU-145 and PC-3 prostate cancer cell lines. The study demonstrated that the expression of the 19 zinc transporters was similar between the RWPE-1 cell line and the in situ prostate gland. Of the 19 zinc transporters, only 5 had levels that were different between the RWPE-1 cells and the tissue samples; all five being increased (ZnT-6, Zip-1, Zip-3A, Zip-10, and Zip-14). The response of the 19 transporters was also determined when the cell lines were exposed to 75 microM Zn+2 for 24 h. It was shown for the RWPE-1 cells that only 5 transporters responded to Zn+2 with mRNA for ZnT-1 and ZnT-2 being increased while mRNA for ZnT-7, Zip-7 and Zip-10 transporters were decreased. It was shown for the LNCaP, DU-145 and PC-3 cells that Zn+2 had no effect on the mRNA levels of all 19 transporters except for an induction of ZnT-1 in PC-3 cells. Overall, the study suggests that the RWPE-1 cells could be a valuable model for the study of the zinc transporter gene family in the prostate.
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93
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Huang L, Yu YY, Kirschke CP, Gertz ER, Lloyd KK. Znt7 (Slc30a7)-deficient Mice Display Reduced Body Zinc Status and Body Fat Accumulation. J Biol Chem 2007; 282:37053-63. [DOI: 10.1074/jbc.m706631200] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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94
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Taylor KM, Morgan HE, Smart K, Zahari NM, Pumford S, Ellis IO, Robertson JFR, Nicholson RI. The emerging role of the LIV-1 subfamily of zinc transporters in breast cancer. Mol Med 2007; 13:396-406. [PMID: 17673939 PMCID: PMC1936980 DOI: 10.2119/2007-00040.taylor] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 06/22/2007] [Indexed: 12/25/2022] Open
Abstract
Zinc transporter LIV-1 (SLC39A6) is estrogen regulated and present in increased amounts in estrogen receptor-positive breast cancer as well as in tumors that spread to the lymph nodes. The LIV-1 subfamily of ZIP zinc transporters consists of nine human sequences that share considerable homology across transmembrane domains. Many of these sequences have been shown to transport zinc and/or other ions across cell membranes. Increasingly, studies have implicated members of the LIV-1 transporter subfamily in a variety of diseases. We review these studies and report our own investigations of the role in breast cancer of the nine LIV-1 zinc transporters. We have documented the response of these transporters to estrogen and antiestrogens, and also their presence in our models of resistance to antiestrogens. Resistance to antiestrogen drugs such as tamoxifen and fulvestrant often occurs in advanced breast cancer. In these models we observed differential expression of individual LIV-1 family members, which may be related to their observed variable tissue expression. We were unable detect ZIP4, which is known to be expressed in the intestine. HKE4/SLC39A7 had elevated expression in both antiestrogen-resistant cell lines, and ZIP8 had elevated expression in fulvestrant-resistant cells. In addition, we investigated the expression of the nine LIV-1 family members in a clinical breast cancer series. Although a number of different LIV-1 family members showed some association with growth factor receptors, LIV-1 was solely associated with estrogen receptor and a variety of growth factors commonly associated with clinical breast cancer. HKE4, however, did show an association with the marker of cell proliferation Ki67 the spread of breast cancer to lymph nodes.
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Affiliation(s)
- Kathryn M Taylor
- Tenovus Centre for Cancer Research, Welsh School of Pharmacy, Cardiff University, Cardiff, United Kingdom.
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95
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Abstract
It has been demonstrated that the plasma membrane expression of ZIP1 is regulated by endocytic mechanisms. In the zinc-replete condition, the level of surface expressed ZIP1 is low due to the rapid internalization of ZIP1. The present study aimed to identify a sorting signal(s) in ZIP1 that mediated endocytosis of ZIP1. Four potential sorting signals (three di-leucine-and one tyrosine-based) were found by searching the eukaryotic linear motif resource for functional sites in proteins (http://elm.eu.org). Site-directed mutagenesis and immunofluorescence microscopic analyses demonstrated that the di-leucine sorting signal, ETRALL144-149, located in the variable loop region of ZIP1, was required for the ZIP1 internalization and lysosomal degradation. Substitutions of alanines for the di-leucine residues (LL148,149/AA) severely impaired the internalization of ZIP1 and subsequent protein degradation, leading to an accumulation of the mutant ZIP1 on the cell surface, as well as inside the cell. Using chimeric proteins composed of an alpha-chain of interleukin-2 receptor fused to the peptides derived from the variable loop region of ZIP1, we found that the di-leucine sorting signal of ZIP1 was required and sufficient for endocytosis of the chimeric proteins.
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Affiliation(s)
- Liping Huang
- United States Department of Agriculture, Agriculture Research Service, Western Human Nutrition Research Center, Davis, CA, USA.
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96
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Yu YY, Kirschke CP, Huang L. Immunohistochemical Analysis of ZnT1, 4, 5, 6, and 7 in the Mouse Gastrointestinal Tract. J Histochem Cytochem 2006; 55:223-34. [PMID: 17101726 DOI: 10.1369/jhc.6a7032.2006] [Citation(s) in RCA: 61] [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
Expression of five zinc transporters (ZnT1, 4, 5, 6, and 7) of the Slc30 family in the mouse gastrointestinal tract was studied by immunohistochemical analysis. Results demonstrated unique expression patterns, levels, and cellular localization among ZnT proteins in the mouse gastrointestinal tract with some overlapping. ZnT1 was abundantly expressed in the epithelium of the esophagus, duodenum of the small intestine, and cecum of the large intestine. ZnT4 was predominantly detected in the large intestine. ZnT5 was mainly expressed in the parietal cell of the stomach and in the absorptive epithelium of the duodenum and jejunum. ZnT6 was predominantly detected in the chief cell of the stomach, columnar epithelial cells of the jejunum, cecum, colon, and rectum. Lastly, ZnT7 was observed in all epithelia of the mouse gastrointestinal tract with the highest expression in the small intestine. Expression of ZnT proteins in the absorptive epithelial cell of the gastrointestinal tract suggests that ZnT proteins may play important roles in zinc absorption and endogenous zinc secretion.
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Affiliation(s)
- Yan Yiu Yu
- Department of Nutrition, University of California at Davis, Davis, California, USA
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97
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Taylor K, Nicholson R. Fear of intimacy--a close LIV-1 acquaintancy? Development 2006; 133:3053. [PMID: 16873580 DOI: 10.1242/dev.02489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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98
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Kambe T, Suzuki T, Nagao M, Yamaguchi-Iwai Y. Sequence similarity and functional relationship among eukaryotic ZIP and CDF transporters. GENOMICS PROTEOMICS & BIOINFORMATICS 2006; 4:1-9. [PMID: 16689696 PMCID: PMC5053974 DOI: 10.1016/s1672-0229(06)60010-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
ZIP (ZRT/IRT-like Protein) and CDF (Cation Diffusion Facilitator) are two large metal transporter families mainly transporting zinc into and out of the cytosol. Several ZIP and CDF transporters have been characterized in mammals and various model organisms, such as yeast, nematode, fruit fly, and zebrafish, and many candidate genes have been identified by genome projects. Unexpected functions of ZIP and CDF transporters have been recently reported in some model organisms, leading to major advances in our understanding of the functions of mammalian counterparts. Here, we review the recent information on the sequence similarity and functional relationship among eukaryotic ZIP and CDF transporters obtained from the representative model organisms.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
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99
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Qiu A, Hogstrand C. Functional expression of a low-affinity zinc uptake transporter (FrZIP2) from pufferfish (Takifugu rubripes) in MDCK cells. Biochem J 2006; 390:777-86. [PMID: 15907194 PMCID: PMC1199671 DOI: 10.1042/bj20050568] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Zinc is a vital micronutrient to all organisms and it is therefore very important to determine the mechanisms that regulate cellular zinc uptake. Previously, we reported on zinc uptake transporters from zebrafish (Danio rerio; DrZIP1) and Fugu pufferfish (Takifugu rubripes; FrZIP1) that facilitated cellular zinc uptake of high affinity (K(m)<0.5 microM) in both CHSE214 [chinook salmon (Oncorhynchus tshawytscha) embryonic 214] cells and Xenopus laevis oocytes. To investigate additional biochemical pathways of zinc uptake in fish, we molecularly cloned the second fish member (FrZIP2) of the SLC39 subfamily II from Fugu pufferfish gill. Functional characterization suggests that FrZIP2 stimulated zinc uptake in a temperature-, time-, concentration- and pH-dependent manner when overexpressed in MDCK cells (Madin-Darby canine kidney cells). In comparison with FrZIP1 and DrZIP1 (<0.5 microM), FrZIP2 appears to represent a low-affinity zinc uptake transporter (K(m)=13.6 microM) in pufferfish. FrZIP2 protein was selective for zinc, but it might also transport Cu2+, since 20 times excess of Cu2+ completely abolished its zinc uptake activity. The zinc uptake by FrZIP2 was stimulated in a slightly acidic medium (pH 5.5-6.5) and was completely blocked at pH 7.5 and above, suggesting that an inward H+ gradient might provide a driving force for zinc transport by FrZIP2. Furthermore, FrZIP2-mediated zinc uptake activity was slightly inhibited by 0.5 mM HCO3-, indicating that FrZIP2 may employ a different mechanism of zinc translocation from the assumed HCO3--coupled zinc transport used by human SLC39A2. The FrZIP2 gene was expressed in all the tissues studied herein, with especially high levels in the ovary and intestines. Thus FrZIP2 may be a prominent zinc uptake transporter of low affinity in many cell types of Fugu pufferfish.
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Affiliation(s)
- Andong Qiu
- King's College London, Nutritional Sciences Research Division, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, U.K
| | - Christer Hogstrand
- King's College London, Nutritional Sciences Research Division, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, U.K
- To whom correspondence should be addressed, at School of Health and Life Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NN, U.K. (email )
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100
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Kasper G, Weiser AA, Rump A, Sparbier K, Dahl E, Hartmann A, Wild P, Schwidetzky U, Castaños-Vélez E, Lehmann K. Expression levels of the putative zinc transporter LIV-1 are associated with a better outcome of breast cancer patients. Int J Cancer 2005; 117:961-73. [PMID: 15986450 DOI: 10.1002/ijc.21235] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We investigated the expression pattern of the breast cancer associated gene LIV-1 on mRNA and protein level in 111 human breast cancer patients by in situ hybridization as well as immunohistochemistry and focused on the unknown potential of LIV-1 expression levels as a prognostic marker. To our knowledge, this is the first study on endogenous LIV-1 protein expression. Results of our study indicate that LIV-1 mRNA and protein expression levels are only weakly correlated, suggesting posttranscriptional regulatory mechanisms. Furthermore, LIV-1 mRNA quantity in combination with a positive ER status seem to represent a better marker than the progesterone receptor status according to the prognostic significance for relapse free survival (RFS). A negative correlation of LIV-1 protein levels with tumor size, grade and stage reflects an association of LIV-1 protein expression with less aggressive tumors. High LIV-1 protein expression seems to be associated with a longer relapse free and overall survival in breast cancer patients with invasive ductal carcinoma. This association, however, seems to be dependent from other prognostic markers. Our data suggest that LIV-1 is a promising candidate for a novel marker for breast cancer patients with better outcome. Furthermore, our study presents a revised cDNA sequence of LIV-1 and demonstrates the localization of endogenous LIV-1 in the endoplasmic reticulum.
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Affiliation(s)
- Grit Kasper
- Center for Musculoskeletal Surgery, Charité-University Medicine Berlin, Berlin, Germany.
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