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Paul R, Chakrabarty A, Samanta S, Dey S, Pandey R, Maji S, Pezacki AT, Chang CJ, Datta R, Gupta A. Leishmania major-induced alteration of host cellular and systemic copper homeostasis drives the fate of infection. Commun Biol 2024; 7:1226. [PMID: 39349621 PMCID: PMC11442737 DOI: 10.1038/s42003-024-06716-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 08/12/2024] [Indexed: 10/04/2024] Open
Abstract
Copper plays a key role in host-pathogen interaction. We find that during Leishmania major infection, the parasite-harboring macrophage regulates its copper homeostasis pathway in a way to facilitate copper-mediated neutralization of the pathogen. Copper-ATPase ATP7A transports copper to amastigote-harboring phagolysosomes to induce stress on parasites. Leishmania in order to evade the copper stress, utilizes a variety of manipulative measures to lower the host-induced copper stress. It induces deglycosylation and degradation of host-ATP7A and downregulation of copper importer, CTR1 by cysteine oxidation. Additionally, Leishmania induces CTR1 endocytosis that arrests copper uptake. In mouse model of infection, we report an increase in systemic bioavailable copper in infected animals. Heart acts as the major organ for diverting its copper reserves to systemic circulation to fight-off infection by downregulating its CTR1. Our study explores reciprocal mechanism of manipulation of host copper homeostasis pathway by macrophage and Leishmania to gain respective advantages in host-pathogen interaction.
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Affiliation(s)
- Rupam Paul
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India.
| | - Adrija Chakrabarty
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Suman Samanta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Swastika Dey
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Raviranjan Pandey
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Saptarshi Maji
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Aidan T Pezacki
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Christopher J Chang
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Rupak Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Arnab Gupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India.
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2
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Meron S, Peleg S, Shenberger Y, Hofmann L, Gevorkyan-Airapetov L, Ruthstein S. Tracking Disordered Extracellular Domains of Membrane Proteins in the Cell with Cu(II)-Based Spin Labels. J Phys Chem B 2024; 128:8908-8914. [PMID: 39231533 PMCID: PMC11421077 DOI: 10.1021/acs.jpcb.4c03676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024]
Abstract
In-cell electron paramagnetic resonance (EPR) spectroscopy experiments provide high-resolution data about conformational changes of proteins within the cell. However, one of the limitations of EPR is the requisite of stable paramagnetic centers in a reducing environment. We recently showed that histidine-rich sites in proteins hold a high affinity to Cu(II) ions complexed with a chelator. Using a chelator prevents the reduction of Cu(II) ions. Moreover, this spin-labeling methodology can be performed within the native cellular environment on any overexpressed protein without protein purification and delivery to the cell. Herein, we use this novel methodology to gain spatial information on the extracellular domain of the human copper transporter, hCtr1. Limited structural information on the transmembrane domain of the human Ctr1 (hCtr1) was obtained using X-ray crystallography and cryo-EM. However, these structures are missing information on the disordered extracellular domains of hCtr1. Extracellular domains are sensing or interacting with the environment outside of the cell and therefore play an essential role in any transmembrane protein. Especially in hCtr1, the extracellular domain functions as a gating mechanism for copper ions. Here, we performed EPR experiments revealing structural information about the extracellular N-terminal domain of the full-length hCtr1 in vitro and in situ in insect cells and cell membrane fragments. The comparison revealed that the extracellular domains of the in situ and native membrane hCtr1 are further apart than the structure of the purified protein. These method-related differences highlight the significance of studying membrane proteins in their native environment.
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Affiliation(s)
- Shelly Meron
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Shahaf Peleg
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Yulia Shenberger
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Lukas Hofmann
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Lada Gevorkyan-Airapetov
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
| | - Sharon Ruthstein
- The Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 529002, Israel
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3
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Nishito Y, Hashimoto A, Kambe T. Simple in vitro method to evaluate ZIP zinc transport ability through zinc transporter 1 and metallothionein expression measurements. Methods Enzymol 2023; 687:207-239. [PMID: 37666633 DOI: 10.1016/bs.mie.2023.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Measuring the cellular zinc content and examining the alteration of zinc status are critical for investigating the cellular homeostasis and dynamics of zinc and its involvement in patho-physiological functions. Many Zrt- and Irt-related protein (ZIP) transporters uptake zinc from the extracellular space. Among Zn transporters (ZNTs), ZNT1 effluxes cytosolic zinc. As cytosolic zinc-binding proteins, metallothioneins (MTs) also contribute to the control of cellular zinc homeostasis. Systemic and cellular zinc homeostasis is considered to be maintained by balancing expression and functional activities of these proteins. The zinc transport ability of ZIPs is typically measured by evaluating cellular zinc content with various zinc-detection methods and systems. Many small-molecule fluorescent probes and fluorescence resonance energy transfer-based protein sensors have been exploited for this purpose. Although powerful analytical methods using special instruments have been developed to quantify zinc, they are often not easily accessible. Here, we present a simplified and inexpensive method to estimate the zinc transport ability of ZIP transporters using the expression responses of ZNT1 and MT. This protocol should be effective in several applications because ZNT1 and MT expression are easily evaluated by immunoblotting and immunofluorescence staining as basic biochemical techniques available in most laboratories. This method is advantageous for examining the relative zinc status or alterations mediated by expression changes of ZIPs in cells cultured in normal medium without zinc supplementation. As zinc is an essential micronutrient, extensive research is necessary to improve dietary zinc absorption to promote health. Therefore, we also propose a simple screening method of foods to improve zinc absorption as an application of measuring ZIP-mediated MT expression.
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Affiliation(s)
- Yukina Nishito
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Ayako Hashimoto
- Department of Food and Nutrition, Faculty of Home Economics, Kyoto Women's University, Kyoto, Japan
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
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4
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Guan D, Zhao L, Shi X, Ma X, Chen Z. Copper in cancer: From pathogenesis to therapy. Biomed Pharmacother 2023; 163:114791. [PMID: 37105071 DOI: 10.1016/j.biopha.2023.114791] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023] Open
Abstract
One of the basic trace elements for the structure and metabolism of human tissue is copper. However, as a heavy metal, excessive intake or abnormal accumulation of copper in the body can cause inevitable damage to the organism because copper can result in direct injury to various cell components or disruption of the redox balance, eventually leading to cell death. Interestingly, a growing body of research reports that diverse cancers have raised serum and tumor copper levels. Tumor cells depend on more copper for their metabolism than normal cells, and a decrease in copper or copper overload can have a detrimental effect on tumor cells. New modalities for identifying and characterizing copper-dependent signals offer translational opportunities for tumor therapy, but their mechanisms remain unclear. Therefore, this article summarizes what we currently know about the correlation between copper and cancer and describes the characteristics of copper metabolism in tumor cells and the prospective application of copper-derived therapeutics.
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Affiliation(s)
- Defeng Guan
- The First Clinical Medical School of Lanzhou University, Lanzhou, China; The First Hospital of Lanzhou University, Lanzhou, China; Gansu key Laboratory of Reproductive Medicine and Embryology, Lanzhou, China
| | - Lihui Zhao
- The First Clinical Medical School of Lanzhou University, Lanzhou, China; The First Hospital of Lanzhou University, Lanzhou, China; Gansu key Laboratory of Reproductive Medicine and Embryology, Lanzhou, China
| | - Xin Shi
- The First Clinical Medical School of Lanzhou University, Lanzhou, China; The First Hospital of Lanzhou University, Lanzhou, China; Gansu key Laboratory of Reproductive Medicine and Embryology, Lanzhou, China
| | - Xiaoling Ma
- The First Clinical Medical School of Lanzhou University, Lanzhou, China; The First Hospital of Lanzhou University, Lanzhou, China; Gansu key Laboratory of Reproductive Medicine and Embryology, Lanzhou, China.
| | - Zhou Chen
- The First Clinical Medical School of Lanzhou University, Lanzhou, China; The First Hospital of Lanzhou University, Lanzhou, China.
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5
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Orlov IA, Sankova TP, Skvortsov AN, Klotchenko SA, Sakhenberg EI, Mekhova AA, Kiseleva IV, Ilyechova EY, Puchkova LV. Properties of recombinant extracellular N-terminal domain of human high-affinity copper transporter 1 (hNdCTR1) and its interactions with Cu(II) and Ag(I) ions. Dalton Trans 2023; 52:3403-3419. [PMID: 36815348 DOI: 10.1039/d2dt04060c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
High-affinity copper transporter 1 (CTR1) is a key link in the transfer of copper (Cu) from the extracellular environment to the cell. Violation in the control system of its expression, or mutations in this gene, cause a global copper imbalance. However, the mechanism of copper transfer via CTR1 remains unclear. It has been shown that transformed bacteria synthesizing the fused GB1-NdCTR become resistant to toxic silver ions. According to UV-Vis spectrophotometry and isothermal titration calorimetry, electrophoretically pure GB1-NdCTR specifically and reversibly binds copper and silver ions, and binding is associated with aggregation. Purified NdCTR1 forms SDS-resistant oligomers. The link between nontrivial properties of NdCTR1 and copper import mechanism from extracellular space, as well as potential chelating properties of NdCTR1, are discussed.
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Affiliation(s)
- Iurii A Orlov
- Research centre of advanced functional materials and laser communication systems, ADTS Institute, ITMO, University, 197101 St. Petersburg, Russia.
| | - Tatiana P Sankova
- Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
| | - Alexey N Skvortsov
- Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia.,Laboratory of The Molecular Biology of Stem Cells, Institute of Cytology, RAS, 194064 St. Petersburg, Russia
| | - Sergey A Klotchenko
- Laboratory for the Development of Molecular Diagnostic Systems, Smorodintsev Research Institute of Influenza, 197376 St. Petersburg, Russia
| | - Elena I Sakhenberg
- Laboratory of cell protection mechanisms, Institute of Cytology, RAS, 194064 St. Petersburg, Russia
| | - Aleksandra A Mekhova
- Research centre of advanced functional materials and laser communication systems, ADTS Institute, ITMO, University, 197101 St. Petersburg, Russia. .,Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
| | - Irina V Kiseleva
- Department of Virology, Institute of Experimental Medicine, 197376 St. Petersburg, Russia
| | - Ekaterina Yu Ilyechova
- Research centre of advanced functional materials and laser communication systems, ADTS Institute, ITMO, University, 197101 St. Petersburg, Russia. .,Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia.,Department of Molecular Genetics, Institute of Experimental Medicine, 197376 St. Petersburg, Russia
| | - Ludmila V Puchkova
- Research centre of advanced functional materials and laser communication systems, ADTS Institute, ITMO, University, 197101 St. Petersburg, Russia. .,Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia.,Department of Molecular Genetics, Institute of Experimental Medicine, 197376 St. Petersburg, Russia
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6
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Puig-Pijuan T, Souza LRQ, Pedrosa CDSG, Higa LM, Monteiro FL, Tanuri A, Valverde RHF, Einicker-Lamas M, Rehen SK. Copper regulation disturbance linked to oxidative stress and cell death during Zika virus infection in human astrocytes. J Cell Biochem 2022; 123:1997-2008. [PMID: 36063501 DOI: 10.1002/jcb.30323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 08/11/2022] [Accepted: 08/19/2022] [Indexed: 12/24/2022]
Abstract
The Zika virus (ZIKV) caused neurological abnormalities in more than 3500 Brazilian newborns between 2015 and 2020. Data have pointed to oxidative stress in astrocytes as well as to dysregulations in neural cell proliferation and cell cycle as important events accounting for the cell death and neurological complications observed in Congenital Zika Syndrome. Copper imbalance has been shown to induce similar alterations in other pathologies, and disturbances in copper homeostasis have already been described in viral infections. Here, we investigated copper homeostasis imbalance as a factor that could contribute to the cytotoxic effects of ZIKV infection in astrocytes. Human induced pluripotent stem cell-derived astrocytes were infected with ZIKV; changes in the gene expression of copper homeostasis proteins were analyzed. The effect of the administration of CuCl2 or a copper chelator on oxidative stress, cell viability and percentage of infection were also studied. ZIKV infection leads to a downregulation of one of the transporters mediating copper release, ATP7B protein. We also observed the activation of mechanisms that counteract high copper levels, including the synthesis of copper chaperones and the reduction of the copper importer protein CTR1. Finally, we show that chelator-mediated copper sequestration in ZIKV-infected astrocytes reduces the levels of reactive oxygen species and improves cell viability, but does not change the overall percentage of infected cells. In summary, our results show that copper homeostasis imbalance plays a role in the pathology of ZIKV in astrocytes, indicating that it may also be a factor accounting for the developmental abnormalities in the central nervous system following viral infection. Evaluating micronutrient levels and the use of copper chelators in pregnant women susceptible to ZIKV infection may be promising strategies to manage novel cases of congenital ZIKV syndrome.
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Affiliation(s)
- Teresa Puig-Pijuan
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil.,Laboratory of Biomembranes, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leticia R Q Souza
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | | | - Luiza M Higa
- Department of Genetics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabio Luis Monteiro
- Department of Genetics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Amilcar Tanuri
- Department of Genetics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rafael H F Valverde
- Laboratory of Biomembranes, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcelo Einicker-Lamas
- Laboratory of Biomembranes, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Stevens Kastrup Rehen
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil.,Department of Genetics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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7
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Vitaliti A, De Luca A, Rossi L. Copper-Dependent Kinases and Their Role in Cancer Inception, Progression and Metastasis. Biomolecules 2022; 12:1520. [PMID: 36291728 PMCID: PMC9599708 DOI: 10.3390/biom12101520] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 12/01/2022] Open
Abstract
In recent years, copper function has been expanded beyond its consolidated role as a cofactor of enzyme catalysis. Recent papers have demonstrated a new dynamic role for copper in the regulation of cell signaling pathways through direct interaction with protein kinases, modulating their activity. The activation of these pathways is exacerbated in cancer cells to sustain the different steps of tumor growth and dissemination. This review will focus on a novel proposed role for the transition metal copper as a regulator of cell signaling pathways through direct interaction with known protein kinases, which exhibit binding domains for this metal. Activation of these pathways in cancer cells supports both tumor growth and dissemination. In addition to the description of the results recently reported in the literature on the subject, relevance will be given to the possibility of controlling the cellular levels of copper and its homeostatic regulators. Overall, these findings may be of central relevance in order to propose copper and its homeostatic regulators as possible targets for novel therapies, which may act synergistically to those already existing to control cancer growth and dissemination.
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Affiliation(s)
- Alessandra Vitaliti
- PhD Program in Cellular and Molecular Biology, Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Anastasia De Luca
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Luisa Rossi
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy
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8
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Identification of Copper Transporter 1 as a Receptor for Feline Endogenous Retrovirus ERV-DC14. J Virol 2022; 96:e0022922. [PMID: 35652657 DOI: 10.1128/jvi.00229-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Vertebrates harbor hundreds of endogenous retroviral (ERV) sequences in their genomes, which are considered signs of past infections that occurred during evolution. On rare occasions, ERV genes like env are maintained and coopted by hosts for physiological functions, but they also participate in recombination events with exogenous retroviruses to generate rearranged viruses with novel tropisms. In domestic cats, feline leukemia virus type D (FeLV-D) has been described as a recombinant virus between the infectious FeLV-A and likely the ERV-DC14 env gene that resulted in an extended tropism due to the usage of a new uncharacterized retroviral receptor. Here, we report the identification of SLC31A1 encoding the copper transporter 1 (CTR1) as a susceptibility gene for ERV-DC14 infection. Expression of human CTR1 into nonpermissive cells was sufficient to confer sensitivity to ERV-DC14 pseudotype infection and to increase the binding of an ERV-DC14 Env ligand. Moreover, inactivation of CTR1 by genome editing or cell surface downmodulation of CTR1 by a high dose of copper dramatically decreased ERV-DC14 infection and binding, while magnesium treatment had no effect. We also investigated the role of CTR1 in the nonpermissivity of feline and hamster cells. While feline CTR1 was fully functional for ERV-DC14, we found that binding was strongly reduced upon treatment with conditioned medium of feline cells, suggesting that the observed resistance to infection was a consequence of CTR1 saturation. In contrast, hamster CTR1 was inactive due to the presence of a N-linked glycosylation site at position 27, which is absent in the human ortholog. These results provide evidence that CTR1 is a receptor for ERV-DC14. Along with chimpanzee endogenous retrovirus type 2, ERV-DC14 is the second family of endogenous retrovirus known to have used CTR1 during past infections of vertebrates. IMPORTANCE Receptor usage is an important determinant of diseases induced by pathogenic retroviruses. In the case of feline leukemia viruses, three subgroups (A, B, and C) based on their ability to recognize different cell host receptors, respectively, the thiamine transporter THTR1, the phosphate transporter PiT1, and the heme exporter FLVCR1, are associated with distinct feline diseases. FeLV-A is horizontally transmitted and found in all naturally infected cats, while FeLV-B and FeLV-C have emerged from FeLV-A, respectively, by recombination with endogenous retroviral env sequences or by mutations in the FeLV-A env gene, both leading to a switch in receptor usage and in subsequent in vivo tropism. Here, we set up a genetic screen to identify the retroviral receptor of ERV-DC14, a feline endogenous provirus whose env gene has been captured by infectious FeLV-A to give rise to FeLV-D in a process similar to FeLV-B. Our results reveal that the copper transporter CTR1 was such a receptor and provide new insights into the acquisition of an expanded tropism by FeLV-D.
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9
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Sophisticated expression responses of ZNT1 and MT in response to changes in the expression of ZIPs. Sci Rep 2022; 12:7334. [PMID: 35513474 PMCID: PMC9072671 DOI: 10.1038/s41598-022-10925-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 04/15/2022] [Indexed: 12/16/2022] Open
Abstract
The zinc homeostatic proteins Zn transporter 1 (ZNT1) and metallothionein (MT) function in dampening increases in cytosolic zinc concentrations. Conversely, the expression of ZNT1 and MT is expected to be suppressed during decreases in cytosolic zinc concentrations. Thus, ZNT1/MT homeostatic responses are considered to be essential for maintaining cellular zinc homeostasis because cellular zinc concentrations are readily altered by changes in the expression of several Zrt-/Irt-like proteins (ZIPs) under both physiological and pathological conditions. However, this notion remains to be tested experimentally. Here, we investigated the aforementioned homeostatic process by analyzing ZNT1 and MT protein expression in response to ZIP expression. Overexpression of cell-surface-localized ZIPs, such as ZIP4 and ZIP5, increased the cellular zinc content, which caused an increase in the expression of cell-surface ZNT1 and cytosolic MT in the absence of zinc supplementation in the culture medium. By contrast, elimination of the overexpressed ZIP4 and ZIP5 resulted in decreased expression of ZNT1 but not MT, which suggests that differential regulation of ZNT1 and MT expression at the protein level underlies the homeostatic responses necessary for zinc metabolism under certain conditions. Moreover, increased expression of apically localized ZIP4 facilitated basolateral ZNT1 expression in polarized cells, which indicates that such a coordinated expression mechanism is crucial for vectorial transcellular transport. Our results provide novel insights into the physiological maintenance of cellular zinc homeostasis in response to alterations in cytosolic zinc concentrations caused by changes in the expression of ZIPs.
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10
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Copper(II) import and reduction are dependent on His-Met clusters in the extracellular amino terminus of human copper transporter-1. J Biol Chem 2022; 298:101631. [PMID: 35090891 PMCID: PMC8867124 DOI: 10.1016/j.jbc.2022.101631] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 11/22/2022] Open
Abstract
Copper(I) is an essential metal for all life forms. Though Cu(II) is the most abundant and stable state, its reduction to Cu(I) via an unclear mechanism is prerequisite for its bioutilization. In eukaryotes, the copper transporter-1 (CTR1) is the primary high-affinity copper importer, although its mechanism and role in Cu(II) reduction remain uncharacterized. Here we show that extracellular amino-terminus of human CTR1 contains two methionine-histidine clusters and neighboring aspartates that distinctly bind Cu(I) and Cu(II) preceding its import. We determined that hCTR1 localizes at the basolateral membrane of polarized MDCK-II cells and that its endocytosis to Common-Recycling-Endosomes is regulated by reduction of Cu(II) to Cu(I) and subsequent Cu(I) coordination by the methionine cluster. We demonstrate the transient binding of both Cu(II) and Cu(I) during the reduction process is facilitated by aspartates that also act as another crucial determinant of hCTR1 endocytosis. Mutating the first Methionine cluster (7Met-Gly-Met9) and Asp13 abrogated copper uptake and endocytosis upon copper treatment. This phenotype could be reverted by treating the cells with reduced and nonreoxidizable Cu(I). We show that histidine clusters, on other hand, bind Cu(II) and are crucial for hCTR1 functioning at limiting copper. Finally, we show that two N-terminal His-Met-Asp clusters exhibit functional complementarity, as the second cluster is sufficient to preserve copper-induced CTR1 endocytosis upon complete deletion of the first cluster. We propose a novel and detailed mechanism by which the two His-Met-Asp residues of hCTR1 amino-terminus not only bind copper, but also maintain its reduced state, crucial for intracellular uptake.
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11
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Zeng W, Zheng S, Mao Y, Wang S, Zhong Y, Cao W, Su T, Gong M, Cheng J, Zhang Y, Yang H. Elevated N-Glycosylation Contributes to the Cisplatin Resistance of Non-Small Cell Lung Cancer Cells Revealed by Membrane Proteomic and Glycoproteomic Analysis. Front Pharmacol 2022; 12:805499. [PMID: 35002739 PMCID: PMC8728018 DOI: 10.3389/fphar.2021.805499] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 12/06/2021] [Indexed: 02/05/2023] Open
Abstract
Chemoresistance is the major restriction on the clinical use of cisplatin. Aberrant changes in protein glycosylation are closely associated with drug resistance. Comprehensive study on the role of protein glycosylation in the development of cisplatin resistance would contribute to precise elucidation of the complicated mechanism of resistance. However, comprehensive characterization of glycosylated proteins remains a big challenge. In this work, we integrated proteomic and N-glycoproteomic workflow to comprehensively characterize the cisplatin resistance-related membrane proteins. Using this method, we found that proteins implicated in cell adhesion, migration, response to drug, and signal transduction were significantly altered in both protein abundance and glycosylation level during the development of cisplatin resistance in the non-small cell lung cancer cell line. Accordingly, the ability of cell migration and invasion was markedly increased in cisplatin-resistant cells, hence intensifying their malignancy. In contrast, the intracellular cisplatin accumulation was significantly reduced in the resistant cells concomitant with the down-regulation of drug uptake channel protein, LRRC8A, and over-expression of drug efflux pump proteins, MRP1 and MRP4. Moreover, the global glycosylation was elevated in the cisplatin-resistant cells. Consequently, inhibition of N-glycosylation reduced cell resistance to cisplatin, whereas promoting the high-mannose or sialylated type of glycosylation enhanced the resistance, suggesting that critical glycosylation type contributes to cisplatin resistance. These results demonstrate the high efficiency of the integrated proteomic and N-glycoproteomic workflow in discovering drug resistance-related targets, and provide new insights into the mechanism of cisplatin resistance.
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Affiliation(s)
- Wenjuan Zeng
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Shanshan Zheng
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yonghong Mao
- Institute of Thoracic Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Shisheng Wang
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yi Zhong
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Wei Cao
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Tao Su
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Meng Gong
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Jingqiu Cheng
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Yong Zhang
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Sichuan Provincial Engineering Laboratory of Pathology in Clinical Application, West China Hospital, Sichuan University, Chengdu, China
| | - Hao Yang
- NHC Key Laboratory of Transplant Engineering and Immunology, Institutes for Systems Genetics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.,Sichuan Provincial Engineering Laboratory of Pathology in Clinical Application, West China Hospital, Sichuan University, Chengdu, China
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12
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Wen MH, Xie X, Huang PS, Yang K, Chen TY. Crossroads between membrane trafficking machinery and copper homeostasis in the nerve system. Open Biol 2021; 11:210128. [PMID: 34847776 PMCID: PMC8633785 DOI: 10.1098/rsob.210128] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Imbalanced copper homeostasis and perturbation of membrane trafficking are two common symptoms that have been associated with the pathogenesis of neurodegenerative and neurodevelopmental diseases. Accumulating evidence from biophysical, cellular and in vivo studies suggest that membrane trafficking orchestrates both copper homeostasis and neural functions-however, a systematic review of how copper homeostasis and membrane trafficking interplays in neurons remains lacking. Here, we summarize current knowledge of the general trafficking itineraries for copper transporters and highlight several critical membrane trafficking regulators in maintaining copper homeostasis. We discuss how membrane trafficking regulators may alter copper transporter distribution in different membrane compartments to regulate intracellular copper homeostasis. Using Parkinson's disease and MEDNIK as examples, we further elaborate how misregulated trafficking regulators may interplay parallelly or synergistically with copper dyshomeostasis in devastating pathogenesis in neurodegenerative diseases. Finally, we explore multiple unsolved questions and highlight the existing challenges to understand how copper homeostasis is modulated through membrane trafficking.
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Affiliation(s)
- Meng-Hsuan Wen
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Xihong Xie
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Pei-San Huang
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Karen Yang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Tai-Yen Chen
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
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13
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Lutsenko S. Dynamic and cell-specific transport networks for intracellular copper ions. J Cell Sci 2021; 134:272704. [PMID: 34734631 DOI: 10.1242/jcs.240523] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Copper (Cu) homeostasis is essential for the development and function of many organisms. In humans, Cu misbalance causes serious pathologies and has been observed in a growing number of diseases. This Review focuses on mammalian Cu(I) transporters and highlights recent studies on regulation of intracellular Cu fluxes. Cu is used by essential metabolic enzymes for their activity. These enzymes are located in various intracellular compartments and outside cells. When cells differentiate, or their metabolic state is otherwise altered, the need for Cu in different cell compartments change, and Cu has to be redistributed to accommodate these changes. The Cu transporters SLC31A1 (CTR1), SLC31A2 (CTR2), ATP7A and ATP7B regulate Cu content in cellular compartments and maintain Cu homeostasis. Increasing numbers of regulatory proteins have been shown to contribute to multifaceted regulation of these Cu transporters. It is becoming abundantly clear that the Cu transport networks are dynamic and cell specific. The comparison of the Cu transport machinery in the liver and intestine illustrates the distinct composition and dissimilar regulatory response of their Cu transporters to changing Cu levels.
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Affiliation(s)
- Svetlana Lutsenko
- Johns Hopkins Medical Institutes, Department of Physiology, Baltimore, MD 21205, USA
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14
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Maung MT, Carlson A, Olea-Flores M, Elkhadragy L, Schachtschneider KM, Navarro-Tito N, Padilla-Benavides T. The molecular and cellular basis of copper dysregulation and its relationship with human pathologies. FASEB J 2021; 35:e21810. [PMID: 34390520 DOI: 10.1096/fj.202100273rr] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 06/23/2021] [Accepted: 07/07/2021] [Indexed: 12/16/2022]
Abstract
Copper (Cu) is an essential micronutrient required for the activity of redox-active enzymes involved in critical metabolic reactions, signaling pathways, and biological functions. Transporters and chaperones control Cu ion levels and bioavailability to ensure proper subcellular and systemic Cu distribution. Intensive research has focused on understanding how mammalian cells maintain Cu homeostasis, and how molecular signals coordinate Cu acquisition and storage within organs. In humans, mutations of genes that regulate Cu homeostasis or facilitate interactions with Cu ions lead to numerous pathologic conditions. Malfunctions of the Cu+ -transporting ATPases ATP7A and ATP7B cause Menkes disease and Wilson disease, respectively. Additionally, defects in the mitochondrial and cellular distributions and homeostasis of Cu lead to severe neurodegenerative conditions, mitochondrial myopathies, and metabolic diseases. Cu has a dual nature in carcinogenesis as a promotor of tumor growth and an inducer of redox stress in cancer cells. Cu also plays role in cancer treatment as a component of drugs and a regulator of drug sensitivity and uptake. In this review, we provide an overview of the current knowledge of Cu metabolism and transport and its relation to various human pathologies.
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Affiliation(s)
- May T Maung
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
| | - Alyssa Carlson
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
| | - Monserrat Olea-Flores
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Guerrero, Mexico
| | - Lobna Elkhadragy
- Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA
| | - Kyle M Schachtschneider
- Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA.,Department of Biochemistry & Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA.,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Napoleon Navarro-Tito
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Guerrero, Mexico
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15
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Wandall HH, Nielsen MAI, King-Smith S, de Haan N, Bagdonaite I. Global functions of O-glycosylation: promises and challenges in O-glycobiology. FEBS J 2021; 288:7183-7212. [PMID: 34346177 DOI: 10.1111/febs.16148] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/23/2021] [Accepted: 08/03/2021] [Indexed: 12/13/2022]
Abstract
Mucin type O-glycosylation is one of the most diverse types of glycosylation, playing essential roles in tissue development and homeostasis. In complex organisms, O-GalNAc glycans comprise a substantial proportion of the glycocalyx, with defined functions in hemostatic, gastrointestinal, and respiratory systems. Furthermore, O-GalNAc glycans are important players in host-microbe interactions, and changes in O-glycan composition are associated with certain diseases and metabolic conditions, which in some instances can be used for diagnosis or therapeutic intervention. Breakthroughs in O-glycobiology have gone hand in hand with the development of new technologies, such as advancements in mass spectrometry, as well as facilitation of genetic engineering in mammalian cell lines. High-throughput O-glycoproteomics have enabled us to draw a comprehensive map of O-glycosylation, and mining this information has supported the definition and confirmation of functions related to site-specific O-glycans. This includes protection from proteolytic cleavage, as well as modulation of binding affinity or receptor function. Yet, there is still much to discover, and among the important next challenges will be to define the context-dependent functions of O-glycans in different stages of cellular differentiation, cellular metabolism, host-microbiome interactions, and in disease. In this review, we present the achievements and the promises in O-GalNAc glycobiology driven by technological advances in analytical methods, genetic engineering, and systems biology.
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Affiliation(s)
- Hans H Wandall
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen, Denmark
| | - Mathias A I Nielsen
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen, Denmark
| | - Sarah King-Smith
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen, Denmark
| | - Noortje de Haan
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen, Denmark
| | - Ieva Bagdonaite
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen, Denmark
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16
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Boyd SD, Ullrich MS, Skopp A, Winkler DD. Copper Sources for Sod1 Activation. Antioxidants (Basel) 2020; 9:antiox9060500. [PMID: 32517371 PMCID: PMC7346115 DOI: 10.3390/antiox9060500] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/12/2020] [Accepted: 06/01/2020] [Indexed: 02/06/2023] Open
Abstract
Copper ions (i.e., copper) are a critical part of several cellular processes, but tight regulation of copper levels and trafficking are required to keep the cell protected from this highly reactive transition metal. Cu, Zn superoxide dismutase (Sod1) protects the cell from the accumulation of radical oxygen species by way of the redox cycling activity of copper in its catalytic center. Multiple posttranslational modification events, including copper incorporation, are reliant on the copper chaperone for Sod1 (Ccs). The high-affinity copper uptake protein (Ctr1) is the main entry point of copper into eukaryotic cells and can directly supply copper to Ccs along with other known intracellular chaperones and trafficking molecules. This review explores the routes of copper delivery that are utilized to activate Sod1 and the usefulness and necessity of each.
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17
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Janssen R, Wouters EFM, Janssens W, Daamen WF, Hagedoorn P, de Wit HAJM, Serré J, Gayan-Ramirez G, Franssen FME, Reynaert NL, von der Thüsen JH, Frijlink HW. Copper-Heparin Inhalation Therapy To Repair Emphysema: A Scientific Rationale. Int J Chron Obstruct Pulmon Dis 2019; 14:2587-2602. [PMID: 32063701 PMCID: PMC6884741 DOI: 10.2147/copd.s228411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 10/31/2019] [Indexed: 12/02/2022] Open
Abstract
Current pharmacotherapy of chronic obstructive pulmonary disease (COPD) aims at reducing respiratory symptoms and exacerbation frequency. Effective therapies to reduce disease progression, however, are still lacking. Furthermore, COPD medications showed less favorable effects in emphysema than in other COPD phenotypes. Elastin fibers are reduced and disrupted, whereas collagen levels are increased in emphysematous lungs. Protease/antiprotease imbalance has historically been regarded as the sole cause of emphysema. However, it is nowadays appreciated that emphysema may also be provoked by perturbations in the sequential repair steps following elastolysis. Essentiality of fibulin-5 and lysyl oxidase-like 1 in the elastin restoration process is discussed, and it is argued that copper deficiency is a plausible reason for failing elastin repair in emphysema patients. Since copper-dependent lysyl oxidases crosslink elastin as well as collagen fibers, copper supplementation stimulates accumulation of both proteins in the extracellular matrix. Restoration of abnormal elastin fibers in emphysematous lungs is favorable, whereas stimulating pulmonary fibrosis formation by further increasing collagen concentrations and organization is detrimental. Heparin inhibits collagen crosslinking while stimulating elastin repair and might therefore be the ideal companion of copper for emphysema patients. Efficacy and safety considerations may lead to a preference of pulmonary administration of copper-heparin over systemic administration.
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Affiliation(s)
- Rob Janssen
- Department of Pulmonary Medicine, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands
| | - Emiel FM Wouters
- Department of Respiratory Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Wim Janssens
- Laboratory of Respiratory Diseases, Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Willeke F Daamen
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Paul Hagedoorn
- Department of Pharmaceutical Technology and Biopharmacy, Groningen Research Institute of Pharmacy, Groningen, University of Groningen, Groningen, The Netherlands
| | - Hugo AJM de Wit
- Department of Clinical Pharmacy, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands
| | - Jef Serré
- Laboratory of Respiratory Diseases, Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Ghislaine Gayan-Ramirez
- Laboratory of Respiratory Diseases, Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), KU Leuven, Leuven, Belgium
| | - Frits ME Franssen
- Department of Respiratory Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Niki L Reynaert
- Department of Respiratory Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands
| | | | - Henderik W Frijlink
- Department of Pharmaceutical Technology and Biopharmacy, Groningen Research Institute of Pharmacy, Groningen, University of Groningen, Groningen, The Netherlands
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18
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Nishito Y, Kambe T. Zinc transporter 1 (ZNT1) expression on the cell surface is elaborately controlled by cellular zinc levels. J Biol Chem 2019; 294:15686-15697. [PMID: 31471319 DOI: 10.1074/jbc.ra119.010227] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/20/2019] [Indexed: 12/11/2022] Open
Abstract
Zinc transporter 1 (ZNT1) is the only zinc transporter predominantly located on the plasma membrane, where it plays a pivotal role exporting cytosolic zinc to the extracellular space. Numerous studies have focused on the physiological and pathological functions of ZNT1. However, its biochemical features remain poorly understood. Here, we investigated the regulation of ZNT1 expression in human and vertebrate cells, and found that ZNT1 expression is posttranslationally regulated by cellular zinc status. We observed that under zinc-sufficient conditions, ZNT1 accumulates on the plasma membrane, consistent with its zinc efflux function. In contrast, under zinc-deficient conditions, ZNT1 molecules on the plasma membrane were endocytosed and degraded through both the proteasomal and lysosomal pathways. Zinc-responsive ZNT1 expression corresponded with that of metallothionein, supporting the idea that ZNT1 and metallothionein cooperatively regulate cellular zinc homeostasis. ZNT1 is N-glycosylated on Asn299 in the extracellular loop between transmembrane domains V and VI, and this appears to be involved in the regulation of ZNT1 stability, as nonglycosylated ZNT1 is more stable. However, this posttranslational modification had no effect on ZNT1's ability to confer cellular resistance against high zinc levels or its subcellular localization. Our results provide molecular insights into ZNT1-mediated regulation of cellular zinc homeostasis, and indicate that the control of cellular and systemic zinc homeostasis via dynamic regulation of ZNT1 expression is more sophisticated than previously thought.
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Affiliation(s)
- Yukina Nishito
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
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19
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Yong L, Ma Y, Liang C, He G, Zhao Z, Yang C, Hai B, Pan X, Liu Z, Liu X. Oleandrin sensitizes human osteosarcoma cells to cisplatin by preventing degradation of the copper transporter 1. Phytother Res 2019; 33:1837-1850. [PMID: 31050072 DOI: 10.1002/ptr.6373] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 03/19/2019] [Accepted: 04/01/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Lei Yong
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
| | - Yunlong Ma
- The Center for Pain MedicinePeking University Third Hospital Beijing 100191 China
| | - Chen Liang
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
| | - Guanping He
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
| | - Zhigang Zhao
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
| | - Chenlong Yang
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
| | - Bao Hai
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
| | - Xiaoyu Pan
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
| | - Zhongjun Liu
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
| | - Xiaoguang Liu
- Department of OrthopedicsPeking University Third Hospital Beijing 100191 China
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20
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Ren F, Logeman BL, Zhang X, Liu Y, Thiele DJ, Yuan P. X-ray structures of the high-affinity copper transporter Ctr1. Nat Commun 2019; 10:1386. [PMID: 30918258 PMCID: PMC6437178 DOI: 10.1038/s41467-019-09376-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/06/2019] [Indexed: 02/02/2023] Open
Abstract
Copper (Cu) is an essential trace element for growth and development and abnormal Cu levels are associated with anemia, metabolic disease and cancer. Evolutionarily conserved from fungi to humans, the high-affinity Cu+ transporter Ctr1 is crucial for both dietary Cu uptake and peripheral distribution, yet the mechanisms for selective permeation of potentially toxic Cu+ ions across cell membranes are unknown. Here we present X-ray crystal structures of Ctr1 from Salmo salar in both Cu+-free and Cu+-bound states, revealing a homo-trimeric Cu+-selective ion channel-like architecture. Two layers of methionine triads form a selectivity filter, coordinating two bound Cu+ ions close to the extracellular entrance. These structures, together with Ctr1 functional characterization, provide a high resolution picture to understand Cu+ import across cellular membranes and suggest therapeutic opportunities for intervention in diseases characterized by inappropriate Cu accumulation. Copper (Cu) is an essential trace element for growth and development and the Cu+ transporter Ctr1 is crucial for both dietary Cu uptake and peripheral distribution. Here authors solve Cu+ -free and Cu+ -bound Ctr1 structures which adopt a homo-trimeric Cu+ -selective ion channel-like architecture
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Affiliation(s)
- Feifei Ren
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA.,Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Brandon L Logeman
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, 27710, USA.,Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - Xiaohui Zhang
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Yongjian Liu
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, 27710, USA.,Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA.,Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Peng Yuan
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA. .,Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, 63110, USA.
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21
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Lv X, Song J, Xue K, Li Z, Li M, Zahid D, Cao H, Wang L, Song W, Ma T, Gu J, Li W. Core fucosylation of copper transporter 1 plays a crucial role in cisplatin-resistance of epithelial ovarian cancer by regulating drug uptake. Mol Carcinog 2019; 58:794-807. [PMID: 30614075 DOI: 10.1002/mc.22971] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/13/2018] [Accepted: 12/27/2018] [Indexed: 12/13/2022]
Abstract
Core fucosylation catalyzed by core fucosyltransferase (Fut8) contributes to the progressions of epithelial ovarian cancer (EOC). Copper transporter 1 (CTR1), which contains one N-glycan on Asn15 , mediates cellular transport of cisplatin (cDDP), and plays an important role in the process of cDDP-resistance in EOC. In the present study, we found that the core fucosylation level elevated significantly in the sera of cDDP-treated EOC patients. The in vitro assays also indicate that core fucosylation of CTR1 was significantly upregulated in cDDP-resistant A2780CP cells compared to the cDDP-sensitive A2780S cells. Intriguingly, the hyper core fucosylation suppressed the CTR1-cDDP interactions and cDDP-uptake into A2780CP cells. Conversely, contrast to the Fut8+/+ mouse ovarian epithelial cells, the Fut8-deleted (Fut8-/- ) cells obviously showed higher cDDP-uptake. Furthermore, the recovered core fucosylation induced the suppression of cDDP-uptake in Fut8-restored ovarian epithelial cells. In addition, the core fucosylation could regulate the phosphorylation of cDDP-resistance-associated molecules, such as AKT, ERK, JNK, and mTOR. Our findings suggest that the core fucosylation of CTR1 plays an important role in the cellular cDDP-uptake and thus provide new strategies for improving the outcome of cDDP based chemotherapy of EOC.
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Affiliation(s)
- Xiaoxue Lv
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
| | - Jiazhe Song
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
| | - Kai Xue
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
| | - Zhi Li
- Clinical Laboratory, Dalian Municipal Central Hospital, Dalian, Liaoning, China
| | - Ming Li
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
| | - Danishi Zahid
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
| | - Hongyu Cao
- College of Life Science and Technology, Dalian University, Liaoning, China
| | - Lu Wang
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
| | - Wanli Song
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
| | - Tonghui Ma
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
| | - Jianguo Gu
- Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Miyagi, Japan
| | - Wenzhe Li
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China
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22
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Fukai T, Ushio-Fukai M, Kaplan JH. Copper transporters and copper chaperones: roles in cardiovascular physiology and disease. Am J Physiol Cell Physiol 2018; 315:C186-C201. [PMID: 29874110 DOI: 10.1152/ajpcell.00132.2018] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Copper (Cu) is an essential micronutrient but excess Cu is potentially toxic. Its important propensity to cycle between two oxidation states accounts for its frequent presence as a cofactor in many physiological processes through Cu-containing enzymes, including mitochondrial energy production (via cytochrome c-oxidase), protection against oxidative stress (via superoxide dismutase), and extracellular matrix stability (via lysyl oxidase). Since free Cu is potentially toxic, the bioavailability of intracellular Cu is tightly controlled by Cu transporters and Cu chaperones. Recent evidence reveals that these Cu transport systems play an essential role in the physiological responses of cardiovascular cells, including cell growth, migration, angiogenesis and wound repair. In response to growth factors, cytokines, and hypoxia, their expression, subcellular localization, and function are tightly regulated. Cu transport systems and their regulators have also been linked to various cardiovascular pathophysiologies such as hypertension, inflammation, atherosclerosis, diabetes, cardiac hypertrophy, and cardiomyopathy. A greater appreciation of the central importance of Cu transporters and Cu chaperones in cell signaling and gene expression in cardiovascular biology offers the possibility of identifying new therapeutic targets for cardiovascular disease.
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Affiliation(s)
- Tohru Fukai
- Vascular Biology Center, Medical College of Georgia at Augusta University , Augusta, Georgia.,Departments of Pharmacology and Toxicology, Medical College of Georgia at Augusta University , Augusta, Georgia.,Charlie Norwood Veterans Affairs Medical Center , Augusta Georgia
| | - Masuko Ushio-Fukai
- Vascular Biology Center, Medical College of Georgia at Augusta University , Augusta, Georgia.,Department of Medicine (Cardiology), Medical College of Georgia at Augusta University , Augusta, Georgia
| | - Jack H Kaplan
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine , Chicago, Illinois
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23
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Yuan S, Sharma AK, Richart A, Lee J, Kim BE. CHCA-1 is a copper-regulated CTR1 homolog required for normal development, copper accumulation, and copper-sensing behavior in Caenorhabditis elegans. J Biol Chem 2018; 293:10911-10925. [PMID: 29784876 DOI: 10.1074/jbc.ra118.003503] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Indexed: 01/11/2023] Open
Abstract
Copper plays key roles in catalytic and regulatory biochemical reactions essential for normal growth, development, and health. Dietary copper deficiencies or mutations in copper homeostasis genes can lead to abnormal musculoskeletal development, cognitive disorders, and poor growth. In yeast and mammals, copper is acquired through the activities of the CTR1 family of high-affinity copper transporters. However, the mechanisms of systemic responses to dietary or tissue-specific copper deficiency remain unclear. Here, taking advantage of the animal model Caenorhabditis elegans for studying whole-body copper homeostasis, we investigated the role of a C. elegans CTR1 homolog, CHCA-1, in copper acquisition and in worm growth, development, and behavior. Using sequence homology searches, we identified 10 potential orthologs to mammalian CTR1 Among these genes, we found that chca-1, which is transcriptionally up-regulated in the intestine and hypodermis of C. elegans during copper deficiency, is required for normal growth, reproduction, and maintenance of systemic copper balance under copper deprivation. The intestinal copper transporter CUA-1 normally traffics to endosomes to sequester excess copper, and we found here that loss of chca-1 caused CUA-1 to mislocalize to the basolateral membrane under copper overload conditions. Moreover, animals lacking chca-1 exhibited significantly reduced copper avoidance behavior in response to toxic copper conditions compared with WT worms. These results establish that CHCA-1-mediated copper acquisition in C. elegans is crucial for normal growth, development, and copper-sensing behavior.
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Affiliation(s)
- Sai Yuan
- From the Department of Animal and Avian Sciences and
| | | | | | - Jaekwon Lee
- the Redox Biology Center, Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Byung-Eun Kim
- From the Department of Animal and Avian Sciences and .,Biological Sciences Graduate Program, University of Maryland, College Park, Maryland 20742 and
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24
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Organ-specific regulation of ATP7A abundance is coordinated with systemic copper homeostasis. Sci Rep 2017; 7:12001. [PMID: 28931909 PMCID: PMC5607234 DOI: 10.1038/s41598-017-11961-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 09/01/2017] [Indexed: 01/31/2023] Open
Abstract
Copper (Cu) is an essential cofactor for various enzymatic activities including mitochondrial electron transport, iron mobilization, and peptide hormone maturation. Consequently, Cu dysregulation is associated with fatal neonatal disease, liver and cardiac dysfunction, and anemia. While the Cu transporter ATP7A plays a major role in both intestinal Cu mobilization to the periphery and prevention of Cu over-accumulation, it is unclear how regulation of ATP7A contributes to Cu homeostasis in response to systemic Cu fluctuation. Here we show, using Cu-deficient mouse models, that steady-state levels of ATP7A are lower in peripheral tissues (including the heart, spleen, and liver) under Cu deficiency and that subcutaneous administration of Cu to these animals restore normal ATP7A levels in these tissues. Strikingly, ATP7A in the intestine is regulated in the opposite manner - low systemic Cu increases ATP7A while subcutaneous Cu administration decreases ATP7A suggesting that intestine-specific non-autonomous regulation of ATP7A abundance may serve as a key homeostatic control for Cu export into the circulation. Our results support a systemic model for how a single transporter can be inversely regulated in a tissue-specific manner to maintain organismal Cu homeostasis.
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Öhrvik H, Aaseth J, Horn N. Orchestration of dynamic copper navigation – new and missing pieces. Metallomics 2017; 9:1204-1229. [DOI: 10.1039/c7mt00010c] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A general principle in all cells in the body is that an essential metal – here copper – is taken up at the plasma membrane, directed through cellular compartments for use in specific enzymes and pathways, stored in specific scavenging molecules if in surplus, and finally expelled from the cells.
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Affiliation(s)
- Helena Öhrvik
- Medical Biochemistry and Microbiology
- Uppsala University
- Sweden
| | - Jan Aaseth
- Innlandet Hospital Trust and Inland Norway University of Applied Sciences
- Norway
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Kaplan JH, Maryon EB. How Mammalian Cells Acquire Copper: An Essential but Potentially Toxic Metal. Biophys J 2016; 110:7-13. [PMID: 26745404 PMCID: PMC4805867 DOI: 10.1016/j.bpj.2015.11.025] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 10/28/2015] [Accepted: 11/09/2015] [Indexed: 12/18/2022] Open
Abstract
Cu is an essential micronutrient, and its role in an array of critical physiological processes is receiving increasing attention. Among these are wound healing, angiogenesis, protection against reactive oxygen species, neurotransmitter synthesis, modulation of normal cell and tumor growth, and many others. Free Cu is absent inside cells, and a network of proteins has evolved to deliver this essential, but potentially toxic, metal ion to its intracellular target sites following uptake. Although the total body content is low (∼100 mg), dysfunction of proteins involved in Cu homeostasis results in several well-characterized human disease states. The initial step in cellular Cu handling is its transport across the plasma membrane, a subject of study for only about the last 25 years. This review focuses on the initial step in Cu homeostasis, the properties of the major protein, hCTR1, that mediates Cu uptake, and the status of our understanding of this highly specialized transport system. Although a high-resolution structure of the protein is still lacking, an array of biochemical and biophysical studies have provided a picture of how hCTR1 mediates Cu(I) transport and how Cu is delivered to the proteins in the intracellular milieu. Recent studies provide evidence that the transporter also plays a key protective role in the regulation of cellular Cu via regulatory endocytosis, lowering its surface expression, in response to elevated Cu loads.
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Affiliation(s)
- Jack H Kaplan
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, Illinois.
| | - Edward B Maryon
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, Illinois
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27
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Öhrvik H, Logeman B, Turk B, Reinheckel T, Thiele DJ. Cathepsin Protease Controls Copper and Cisplatin Accumulation via Cleavage of the Ctr1 Metal-binding Ectodomain. J Biol Chem 2016; 291:13905-13916. [PMID: 27143361 DOI: 10.1074/jbc.m116.731281] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Indexed: 11/06/2022] Open
Abstract
Copper is an essential metal ion for embryonic development, iron acquisition, cardiac function, neuropeptide biogenesis, and other critical physiological processes. Ctr1 is a high affinity Cu(+) transporter on the plasma membrane and endosomes that exists as a full-length protein and a truncated form of Ctr1 lacking the methionine- and histidine-rich metal-binding ectodomain, and it exhibits reduced Cu(+) transport activity. Here, we identify the cathepsin L/B endolysosomal proteases functioning in a direct and rate-limiting step in the Ctr1 ectodomain cleavage. Cells and mice lacking cathepsin L accumulate full-length Ctr1 and hyper-accumulate copper. As Ctr1 also transports the chemotherapeutic drug cisplatin via direct binding to the ectodomain, we demonstrate that the combination of cisplatin with a cathepsin L/B inhibitor enhances cisplatin uptake and cell killing. These studies identify a new processing event and the key protease that cleaves the Ctr1 metal-binding ectodomain, which functions to regulate cellular Cu(+) and cisplatin acquisition.
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Affiliation(s)
- Helena Öhrvik
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710.
| | - Brandon Logeman
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710
| | - Boris Turk
- Department of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia; Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Thomas Reinheckel
- Institute of Molecular Medicine and Cell Research, Medical Faculty, Freiburg 79104 Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg 79104 Germany
| | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710; Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710; Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina 27710.
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Chia J, Goh G, Bard F. Short O-GalNAc glycans: regulation and role in tumor development and clinical perspectives. Biochim Biophys Acta Gen Subj 2016; 1860:1623-39. [PMID: 26968459 DOI: 10.1016/j.bbagen.2016.03.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/03/2016] [Accepted: 03/03/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND While the underlying causes of cancer are genetic modifications, changes in cellular states mediate cancer development. Tumor cells display markedly changed glycosylation states, of which the O-GalNAc glycans called the Tn and TF antigens are particularly common. How these antigens get over-expressed is not clear. The expression levels of glycosylation enzymes fail to explain it. SCOPE OF REVIEW We describe the regulation of O-GalNAc glycosylation initiation and extension with emphasis on the initiating enzymes ppGalNAcTs (GALNTs), and introduce the GALA pathway--a change in GALNTs compartmentation within the secretory pathway that regulates Tn levels. We discuss the roles of O-GalNAc glycans and GALNTs in tumorigenic processes and finally consider diagnostic and therapeutic perspectives. MAJOR CONCLUSIONS Contrary to a common hypothesis, short O-glycans in tumors are not the result of an incomplete glycosylation process but rather reveal the activation of regulatory pathways. Surprisingly, high Tn levels reveal a major shift in the O-glycoproteome rather than a shortening of O-glycans. These changes are driven by membrane trafficking events. GENERAL SIGNIFICANCE Many attempts to use O-glycans for biomarker, antibody and therapeutic vaccine development have been made, but suffer limitations including poor sensitivity and/or specificity that may in part derive from lack of a mechanistic understanding. Deciphering how short O-GalNAc glycans are regulated would open new perspectives to exploit this biology for therapeutic usage. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.
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Affiliation(s)
- Joanne Chia
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673, Singapore
| | - Germaine Goh
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673, Singapore
| | - Frederic Bard
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673, Singapore; Department of Biochemistry, National University of Singapore, 21 Lower Kent Ridge, Road, 119077, Singapore.
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Clifford RJ, Maryon EB, Kaplan JH. Dynamic internalization and recycling of a metal ion transporter: Cu homeostasis and CTR1, the human Cu⁺ uptake system. J Cell Sci 2016; 129:1711-21. [PMID: 26945057 DOI: 10.1242/jcs.173351] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 03/02/2016] [Indexed: 01/01/2023] Open
Abstract
Cu ion (Cu) entry into human cells is mediated by CTR1 (also known as SLC31A1), the high-affinity Cu transporter. When extracellular Cu is raised, the cell is protected against excess accumulation by rapid internalization of the transporter. When Cu is lowered, the transporter returns to the membrane. We show in HEK293 cells overexpressing CTR1 that expression of either the C-terminal domain of AP180 (also known as SNAP91), a clathrin-coat assembly protein that sequesters clathrin, or a dominant-negative mutant of dynamin, decreases Cu-induced endocytosis of CTR1, as does a dynamin inhibitor and clathrin knockdown using siRNA. Utilizing imaging, siRNA techniques and a new high-throughput assay for endocytosis employing CLIP-tag methodology, we show that internalized CTR1 accumulates in early sorting endosomes and recycling compartments (containing Rab5 and EEA1), but not in late endosomes or lysosomal pathways. Using live cell fluorescence, we find that upon extracellular Cu removal CTR1 recycles to the cell surface through the slower-recycling Rab11-mediated pathway. These processes enable cells to dynamically alter transporter levels at the plasma membrane and acutely modulate entry as a safeguard against excess cellular Cu.
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Affiliation(s)
- Rebecca J Clifford
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, IL 60607, USA
| | - Edward B Maryon
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, IL 60607, USA
| | - Jack H Kaplan
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, IL 60607, USA
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Hashimoto A, Ohkura K, Takahashi M, Kizu K, Narita H, Enomoto S, Miyamae Y, Masuda S, Nagao M, Irie K, Ohigashi H, Andrews GK, Kambe T. Soybean extracts increase cell surface ZIP4 abundance and cellular zinc levels: a potential novel strategy to enhance zinc absorption by ZIP4 targeting. Biochem J 2015; 472:183-93. [PMID: 26385990 DOI: 10.1042/bj20150862] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 09/17/2015] [Indexed: 12/16/2023]
Abstract
Dietary zinc deficiency puts human health at risk, so we explored strategies for enhancing zinc absorption. In the small intestine, the zinc transporter ZIP4 functions as an essential component of zinc absorption. Overexpression of ZIP4 protein increases zinc uptake and thereby cellular zinc levels, suggesting that food components with the ability to increase ZIP4 could potentially enhance zinc absorption via the intestine. In the present study, we used mouse Hepa cells, which regulate mouse Zip4 (mZip4) in a manner indistinguishable from that in intestinal enterocytes, to screen for suitable food components that can increase the abundance of ZIP4. Using this ZIP4-targeting strategy, two such soybean extracts were identified that were specifically able to decrease mZip4 endocytosis in response to zinc. These soybean extracts also effectively increased the abundance of apically localized mZip4 in transfected polarized Caco2 and Madin-Darby canine kidney cells and, moreover, two apically localized mZip4 acrodermatitis enteropathica mutants. Soybean components were purified from one extract and soyasaponin Bb was identified as an active component that increased both mZip4 protein abundance and zinc levels in Hepa cells. Finally, we confirmed that soyasaponin Bb is capable of enhancing cell surface endogenous human ZIP4 in human cells. Our results suggest that ZIP4 targeting may represent a new strategy to improve zinc absorption in humans.
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Affiliation(s)
- Ayako Hashimoto
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Katsuma Ohkura
- Department of Bioscience, Fukui Prefectural University, Fukui, Japan
| | | | - Kumiko Kizu
- Department of Life and Living, Osaka Seikei College, Osaka, Japan
| | - Hiroshi Narita
- Department of Food Science, Kyoto Women's University, Kyoto, Japan
| | - Shuichi Enomoto
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan Center for Molecular Imaging Science, RIKEN Kobe Institute, Kobe, Japan
| | - Yusaku Miyamae
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Seiji Masuda
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Masaya Nagao
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kazuhiro Irie
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hajime Ohigashi
- Department of Bioscience, Fukui Prefectural University, Fukui, Japan
| | - Glen K Andrews
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, U.S.A
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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31
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Tsai CY, Liebig JK, Tsigelny IF, Howell SB. The copper transporter 1 (CTR1) is required to maintain the stability of copper transporter 2 (CTR2). Metallomics 2015. [PMID: 26205368 DOI: 10.1039/c5mt00131e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mammalian cells have two influx Cu transporters that form trimers in membranes. CTR1 is the high affinity transporter that resides largely in the plasma membrane, and CTR2 is the low affinity transporter that is primarily associated with vesicular structures inside the cell. The major differences between CTR1 and CTR2 are that CTR1 contains a HIS/MET-rich domain N-terminal of the METS that participate in the first two stacked rings that form the pore, and a longer C-terminal tail that includes a Cu binding HIS-CYS-HIS (HCH) motif right at the end. It has been reported that CTR1 and CTR2 are physically associated with each other in the cell. We used the CRISPR-Cas9 technology to knock out either CTR1 or CTR2 in fully malignant HEK293T and OVCAR8 human ovarian cancer cells to investigate the interaction of CTR1 and CTR2. We report here that the level of CTR2 protein is markedly decreased in CTR1 knockout clones while the CTR2 transcript level remains unchanged. CTR2 was found to be highly ubiquitinated in the CTR1 knock out cells, and inhibition of the proteasome prevented the degradation of CTR2 when CTR1 was not present while inhibition of autophagy had no effect. Re-expression of CTR1 rescued CTR2 from degradation in the CTR1 knockout cells. We conclude that CTR1 is essential to maintain the stability of CTR2 and that in the absence of CTR1 CTR2 is degraded by the proteasome. This reinforces the concept that the functions of CTR1 and CTR2 are inter-dependent within the Cu homeostasis system.
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Affiliation(s)
- Cheng-Yu Tsai
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0819, La Jolla, CA 92093-0819, USA.
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Chen HHW, Chen WC, Liang ZD, Tsai WB, Long Y, Aiba I, Fu S, Broaddus R, Liu J, Feun LG, Savaraj N, Kuo MT. Targeting drug transport mechanisms for improving platinum-based cancer chemotherapy. Expert Opin Ther Targets 2015; 19:1307-17. [PMID: 26004625 DOI: 10.1517/14728222.2015.1043269] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Platinum (Pt)-based antitumor agents remain important chemotherapeutic agents for treating many human malignancies. Elevated expression of the human high-affinity copper transporter 1 (hCtr1), resulting in enhanced Pt drug transport into cells, has been shown to be associated with improved treatment efficacy. Thus, targeting hCtr1 upregulation is an attractive strategy for improving the treatment efficacy of Pt-based cancer chemotherapy. AREA COVERED Regulation of hCtr1 expression by cellular copper homeostasis is discussed. Association of elevated hCtr1 expression with intrinsic sensitivity of ovarian cancer to Pt drugs is presented. Mechanism of copper-lowering agents in enhancing hCtr1-mediated cis-diamminedichloroplatinum (II) (cisplatin, cDDP) transport is reviewed. Applications of copper chelation strategy in overcoming cDDP resistance through enhanced hCtr1 expression are evaluated. EXPERT OPINION While both transcriptional and post-translational mechanisms of hCtr1 regulation by cellular copper bioavailability have been proposed, detailed molecular insights into hCtr1 regulation by copper homeostasis remain needed. Recent clinical study using a copper-lowering agent in enhancing hCtr1-mediated drug transport has achieved incremental improvement in overcoming Pt drug resistance. Further improvements in identifying predictive measures in the subpopulation of patients that can benefit from the treatment are needed.
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Affiliation(s)
- Helen H W Chen
- a 1 National Cheng Kung University, National Cheng Kung University Hospital, College of Medicine, Department of Radiation Oncology , Tainan, Taiwan
| | - Wen-Chung Chen
- b 2 National Cheng Kung University, National Cheng Kung University Hospital, College of Medicine, Department of Pathology , Tainan, Taiwan
| | - Zhang-Dong Liang
- c 3 The University of Texas MD Anderson Cancer Center, Department of Translational Molecular Pathology , Houston, TX 77030, USA
| | - Wen-Bin Tsai
- c 3 The University of Texas MD Anderson Cancer Center, Department of Translational Molecular Pathology , Houston, TX 77030, USA
| | - Yan Long
- d 4 The University of Texas MD Anderson Cancer Center, Department of Translational Molecular Pathology , Houston, TX 77030, USA
| | - Isamu Aiba
- e 5 The University of Texas MD Anderson Cancer Center, Department of Translational Molecular Pathology , Houston, TX 77030, USA
| | - Siqing Fu
- f 6 The University of Texas MD Anderson Cancer Center, Departments of Investigative Cancer Therapeutics , Houston, TX, USA
| | - Russell Broaddus
- g 7 The University of Texas MD Anderson Cancer Center, Departments of Pathology , Houston, TX, USA
| | - Jinsong Liu
- g 7 The University of Texas MD Anderson Cancer Center, Departments of Pathology , Houston, TX, USA
| | - Lynn G Feun
- h 8 University of Miami, Sylvester Comprehensive Cancer Center , 1475 NW 12th Avenue, Miami, FL 33136, USA
| | - Niramol Savaraj
- h 8 University of Miami, Sylvester Comprehensive Cancer Center , 1475 NW 12th Avenue, Miami, FL 33136, USA
| | - Macus Tien Kuo
- i 9 The University of Texas MD Anderson Cancer Center, Department of Translational Molecular Pathology , Unit 2951, LSP 9.4206, 2130 W. Holcombe Blvd, Houston, TX 77030, USA +1 713 834 6038 ; +1 713 834 6085 ;
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33
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Öhrvik H, Thiele DJ. How copper traverses cellular membranes through the mammalian copper transporter 1, Ctr1. Ann N Y Acad Sci 2014; 1314:32-41. [PMID: 24697869 PMCID: PMC4158275 DOI: 10.1111/nyas.12371] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The copper transporter 1, Ctr1, is part of a major pathway for cellular copper (Cu) uptake in the intestinal epithelium, in hepatic and cardiac tissue, and likely in many other mammalian cells and tissues. Here, we summarize what is currently known about how extracellular Cu travels across the plasma membrane to enter the cytoplasm for intracellular distribution and for use by proteins and enzymes, the physiological roles of Ctr1, and its regulation. As a critical Cu importer, Ctr1 occupies a strategic position to exert a strong modifying influence on diseases and pathophysiological states caused by imbalances in Cu homeostasis. A more thorough understanding of the mechanisms that regulate Ctr1 abundance, trafficking, and function will provide new insights and opportunities for disease therapies.
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Affiliation(s)
- Helena Öhrvik
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27708, USA
| | - Dennis J. Thiele
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27708, USA
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34
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Quail JF, Tsai CY, Howell SB. Characterization of a monoclonal antibody capable of reliably quantifying expression of human Copper Transporter 1 (hCTR1). J Trace Elem Med Biol 2014; 28:151-159. [PMID: 24447817 PMCID: PMC3989404 DOI: 10.1016/j.jtemb.2013.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 11/16/2013] [Accepted: 12/10/2013] [Indexed: 12/20/2022]
Abstract
Human copper transporter 1 (hCTR1) is the high-affinity copper influx transporter in mammalian cells that also mediates the influx of cisplatin. Loss of hCTR1 expression has been implicated in the development of resistance to this cancer chemotherapeutic agent. It has turned out to be very difficult to develop antibodies to hCTR1 and polyclonal antibodies produced by different laboratories have yielded conflicting results. We have characterized a newly-available rabbit monoclonal antibody that reacts with an epitope on the N-terminal end of hCTR1 that now permits rigorous identification and quantification of hCTR1 using Western blot analysis. Postnuclear membrane (PNM) preparations made from cells engineered to express high levels of myc-tagged hCTR1, and cells in which the expression of hCTR1 was knocked down, were used to characterize the antibody. The identity of the bands detected was confirmed by immunoprecipitation, surface biotinylation and deglycosylation of myc-tagged hCTR1. Despite the specificity expected of a monoclonal antibody, the anti-hCTR1 detected a variety of bands in whole cell lysates (WCL), which made it difficult to quantify hCTR1. This problem was overcome by isolating post-nuclear membranes and using these for further analysis. Three bands were identified using this antibody in PNM preparations that migrated at 28, 33-35 and 62-64kDa. Multiple lines of evidence presented here suggest that the 33-35 and 62-64kDa bands are hCTR1 whereas the 28kDa band is a cross-reacting protein of unknown identify. The 33-35kDa band is consistent with the expected MW of the glycosylated hCTR1 monomer. This analysis now permits rigorous identification and quantification of hCTR1.
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Affiliation(s)
- Jacob F Quail
- Moores UCSD Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093, United States
| | - Cheng-Yu Tsai
- Moores UCSD Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093, United States
| | - Stephen B Howell
- Moores UCSD Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093, United States.
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35
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Öhrvik H, Thiele DJ. The role of Ctr1 and Ctr2 in mammalian copper homeostasis and platinum-based chemotherapy. J Trace Elem Med Biol 2014; 31:178-82. [PMID: 24703712 PMCID: PMC4175275 DOI: 10.1016/j.jtemb.2014.03.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/13/2014] [Indexed: 12/31/2022]
Abstract
Copper (Cu) is an essential metal for growth and development that has the potential to be toxic if levels accumulate beyond the ability of cells to homeostatically balance uptake with detoxification. One system for Cu acquisition is the integral membrane Cu(+) transporter, Ctr1, which has been quite well characterized in terms of its function and physiology. The mammalian Ctr2 protein has been a conundrum for the copper field, as it is structurally closely related to the high affinity Cu transporter Ctr1, sharing important motifs for Cu transport activity. However, in contrast to mammalian Ctr1, Ctr2 fails to suppress the Cu-dependent growth phenotype of yeast cells defective in Cu(+) import, nor does it appreciably stimulate Cu acquisition when over-expressed in mammalian cells, underscoring important functional dissimilarities between the two proteins. Several roles for the mammalian Ctr2 have been suggested both in vitro and in vivo. Here, we summarize and discuss current insights into the Ctr2 protein and its interaction with Ctr1, its functions in mammalian Cu homeostasis and platinum-based chemotherapy.
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Affiliation(s)
- Helena Öhrvik
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
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36
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Zimnicka AM, Tang H, Guo Q, Kuhr FK, Oh MJ, Wan J, Chen J, Smith KA, Fraidenburg DR, Choudhury MSR, Levitan I, Machado RF, Kaplan JH, Yuan JXJ. Upregulated copper transporters in hypoxia-induced pulmonary hypertension. PLoS One 2014; 9:e90544. [PMID: 24614111 PMCID: PMC3948681 DOI: 10.1371/journal.pone.0090544] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 02/02/2014] [Indexed: 11/18/2022] Open
Abstract
Pulmonary vascular remodeling and increased arterial wall stiffness are two major causes for the elevated pulmonary vascular resistance and pulmonary arterial pressure in patients and animals with pulmonary hypertension. Cellular copper (Cu) plays an important role in angiogenesis and extracellular matrix remodeling; increased Cu in vascular smooth muscle cells has been demonstrated to be associated with atherosclerosis and hypertension in animal experiments. In this study, we show that the Cu-uptake transporter 1, CTR1, and the Cu-efflux pump, ATP7A, were both upregulated in the lung tissues and pulmonary arteries of mice with hypoxia-induced pulmonary hypertension. Hypoxia also significantly increased expression and activity of lysyl oxidase (LOX), a Cu-dependent enzyme that causes crosslinks of collagen and elastin in the extracellular matrix. In vitro experiments show that exposure to hypoxia or treatment with cobalt (CoCl2) also increased protein expression of CTR1, ATP7A, and LOX in pulmonary arterial smooth muscle cells (PASMC). In PASMC exposed to hypoxia or treated with CoCl2, we also confirmed that the Cu transport is increased using 64Cu uptake assays. Furthermore, hypoxia increased both cell migration and proliferation in a Cu-dependent manner. Downregulation of hypoxia-inducible factor 1α (HIF-1α) with siRNA significantly attenuated hypoxia-mediated upregulation of CTR1 mRNA. In summary, the data from this study indicate that increased Cu transportation due to upregulated CTR1 and ATP7A in pulmonary arteries and PASMC contributes to the development of hypoxia-induced pulmonary hypertension. The increased Cu uptake and elevated ATP7A also facilitate the increase in LOX activity and thus the increase in crosslink of extracellular matrix, and eventually leading to the increase in pulmonary arterial stiffness.
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Affiliation(s)
- Adriana M. Zimnicka
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Haiyang Tang
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Qiang Guo
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Frank K. Kuhr
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Myung-Jin Oh
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Jun Wan
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Jiwang Chen
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Kimberly A. Smith
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Dustin R. Fraidenburg
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Moumita S. R. Choudhury
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Irena Levitan
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Roberto F. Machado
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Jack H. Kaplan
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Jason X.-J. Yuan
- Department of Medicine, Section of Pulmonary, Critical Care, Sleep and Allergy Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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Schweigel-Röntgen M. The families of zinc (SLC30 and SLC39) and copper (SLC31) transporters. CURRENT TOPICS IN MEMBRANES 2014; 73:321-55. [PMID: 24745988 DOI: 10.1016/b978-0-12-800223-0.00009-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The solute carriers families 30 (SLC30; ZnT), 39 (SLC39; ZIP), and 31 (SLC31; CTR) are involved in the essential maintenance of cellular zinc (Zn²⁺) and copper (Cu²⁺) homeostasis, respectively. ZnTs mediate Zn²⁺ extrusion from cells (SLC30A1) or transport Zn²⁺ into organelles and secretory vesicles/granules (SLC30A2-SLC30A8). SLC39 family members are predominantly localized to the cell membrane where they perform Zn²⁺ uptake and increase the availability of cytosolic Zn²⁺. SLC39A1 is ubiquitously expressed, whereas other ZIP transporters (e.g., SLC39A2 and SLC39A3) show a more tissue-restricted expression consistent with organ-specific functions of these proteins. The members A1 (CTR1) and A2 (CTR2) of the SLC31 family of solute carriers belong to a network of proteins that acts to regulate the intracellular Cu²⁺ concentration within a certain range. SLC31A1 is predominantly localized to the plasma membrane, whereas SLC31A2 is mainly found in intracellular membranes of the late endosome and lysosome. The specific function of SLC31A2 is not known. SLC31A1 is ubiquitously expressed and has been characterized as a high-affinity importer of reduced copper (Cu⁺). Cu²⁺ transport function of CTR proteins is associated with oligomerization; SLC31A1 trimerizes and thereby forms a channel-like structure enabling Cu²⁺ translocation across the cell membrane. The molecular characteristics and structural details (e.g., membrane topology, conserved Zn²⁺, and Cu²⁺ binding sites) and mechanisms of translational and posttranslational regulation of expression and/or activity have been described for SLC30 and SLC39 family members, and for SLC31A1. For SLC31A1, data on tissue-specific functions (e.g., in the intestine, heart, and liver) are also available. A link between SLC31A1, immune function, and disorders such as Alzheimer's disease or cancer makes the protein a candidate therapeutic target. In secretory tissues (e.g., the mammary gland and pancreas), Zn²⁺ transporters of SLC families 30 and 39 are involved in specific functions such as insulin synthesis and secretion, metallation of digestive proenzymes, and transfer of nutrients into milk. Defective or dysregulated Zn²⁺ metabolism in these organs is associated with disorders such as diabetes and cancer, and impaired Zn²⁺ secretion into milk.
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Affiliation(s)
- Monika Schweigel-Röntgen
- Institute for Muscle Biology & Growth, Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany.
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38
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Freestone D, Cater MA, Ackland ML, Paterson D, Howard DL, de Jonge MD, Michalczyk A. Copper and lactational hormones influence the CTR1 copper transporter in PMC42-LA mammary epithelial cell culture models. J Nutr Biochem 2013; 25:377-87. [PMID: 24485600 DOI: 10.1016/j.jnutbio.2013.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 10/23/2013] [Accepted: 11/22/2013] [Indexed: 01/30/2023]
Abstract
Adequate amounts of copper in milk are critical for normal neonatal development, however the mechanisms regulating copper supply to milk have not been clearly defined. PMC42-LA cell cultures representative of resting, lactating and suckled mammary epithelia were used to investigate the regulation of the copper uptake protein, CTR1. Both the degree of mammary epithelial differentiation (functionality) and extracellular copper concentration greatly impacted upon CTR1 expression and its plasma membrane association. In all three models (resting, lactating and suckling) there was an inverse correlation between extracellular copper concentration and the level of CTR1. Cell surface biotinylation studies demonstrated that as extracellular copper concentration increased membrane associated CTR1 was reduced. There was a significant increase in CTR1 expression (total and membrane associated) in the suckled gland model in comparison to the resting gland model, across all copper concentrations investigated (0-50 μM). Regulation of CTR1 expression was entirely post-translational, as quantitative real-time PCR analyses showed no change to CTR1 mRNA between all models and culture conditions. X-ray fluorescence microscopy on the differentiated PMC42-LA models revealed that organoid structures distinctively accumulated copper. Furthermore, as PMC42-LA cell cultures became progressively more specialised, successively more copper accumulated in organoids (resting<lactating<suckling), indicating a link between function and copper requirement. Based on previous data showing a function for CTR1 in copper uptake, we have concluded that under the influence of hormones and increased extracellular copper levels, CTR1 participates in uptake of copper by mammary epithelial cells, as a prerequisite for secretion of copper into milk.
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Affiliation(s)
- David Freestone
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3121, Australia
| | - Michael A Cater
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3121, Australia; Department of Pathology, the University of Melbourne, Parkville, Victoria 3010, Australia
| | - M Leigh Ackland
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3121, Australia
| | - David Paterson
- Australian Synchrotron, Melbourne, Victoria 3068, Australia
| | - Daryl L Howard
- Australian Synchrotron, Melbourne, Victoria 3068, Australia
| | | | - Agnes Michalczyk
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3121, Australia.
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Ctr2 regulates biogenesis of a cleaved form of mammalian Ctr1 metal transporter lacking the copper- and cisplatin-binding ecto-domain. Proc Natl Acad Sci U S A 2013; 110:E4279-88. [PMID: 24167251 DOI: 10.1073/pnas.1311749110] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Copper is an essential catalytic cofactor for enzymatic activities that drive a range of metabolic biochemistry including mitochondrial electron transport, iron mobilization, and peptide hormone maturation. Copper dysregulation is associated with fatal infantile disease, liver, and cardiac dysfunction, neuropathy, and anemia. Here we report that mammals regulate systemic copper acquisition and intracellular mobilization via cleavage of the copper-binding ecto-domain of the copper transporter 1 (Ctr1). Although full-length Ctr1 is critical to drive efficient copper import across the plasma membrane, cleavage of the ecto-domain is required for Ctr1 to mobilize endosomal copper stores. The biogenesis of the truncated form of Ctr1 requires the structurally related, previously enigmatic copper transporter 2 (Ctr2). Ctr2(-/-) mice are defective in accumulation of truncated Ctr1 and exhibit increased tissue copper levels, and X-ray fluorescence microscopy demonstrates that copper accumulates as intracellular foci. These studies identify a key regulatory mechanism for mammalian copper transport through Ctr2-dependent accumulation of a Ctr1 variant lacking the copper- and cisplatin-binding ecto-domain.
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40
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Liang ZD, Long Y, Chen HHW, Savaraj N, Kuo MT. Regulation of the high-affinity copper transporter (hCtr1) expression by cisplatin and heavy metals. J Biol Inorg Chem 2013; 19:17-27. [PMID: 24132751 PMCID: PMC3889686 DOI: 10.1007/s00775-013-1051-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 10/03/2013] [Indexed: 01/11/2023]
Abstract
Platinum-based antitumor agents have been the mainstay in cancer chemotherapy for many human malignancies. Drug resistance is an important obstacle to achieving the maximal therapeutic efficacy of these drugs. Understanding how platinum drugs enter cells is of great importance in improving therapeutic efficacy. It has been demonstrated that human high-affinity copper transporter 1 (hCtr1) is involved in transporting cisplatin into cells to elicit cytotoxic effects, although other mechanisms may exist. In this communication, we demonstrate that cisplatin transcriptionally induces the expression of hCtr1 in time- and concentration-dependent manners. Cisplatin functions as a competitor for hCtr1-mediated copper transport, resulting in reduced cellular copper levels and leading to upregulated expression of Sp1, which is a positive regulator for hCtr1 expression. Thus, regulation of hCtr1 expression by cisplatin is an integral part of the copper homeostasis regulation system. We also demonstrate that Ag(I) and Zn(II), which are known to suppress hCtr1-mediated copper transport, can also induce hCtr1/Sp1 expression. In contrast, Cd(II), another inhibitor of copper transport, downregulates hCtr1 expression by suppressing Sp1 expression. Collectively, our results demonstrate diverse mechanisms of regulating copper metabolism by these heavy metals.
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Affiliation(s)
- Zheng Dong Liang
- Department of Translational Molecular Pathology (Route 2951), The University of Texas MD Anderson Cancer Center, 2130 W. Holcombe Blvd., Houston, TX 77030 USA
| | - Yan Long
- Department of Translational Molecular Pathology (Route 2951), The University of Texas MD Anderson Cancer Center, 2130 W. Holcombe Blvd., Houston, TX 77030 USA
| | - Helen H. W. Chen
- Department of Radiation Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Niramol Savaraj
- Hematology-Oncology Section, VA Medical Center, Miami, FL 33125 USA
| | - Macus Tien Kuo
- Department of Translational Molecular Pathology (Route 2951), The University of Texas MD Anderson Cancer Center, 2130 W. Holcombe Blvd., Houston, TX 77030 USA
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41
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SLC31 (CTR) family of copper transporters in health and disease. Mol Aspects Med 2013; 34:561-70. [PMID: 23506889 DOI: 10.1016/j.mam.2012.07.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 05/31/2012] [Indexed: 12/19/2022]
Abstract
Copper is a vital mineral for many organisms, yet it is highly toxic as demonstrated by serious health concerns associated with its deficiency or excess accumulation. The SLC31 (CTR) family of copper transporters is a major gateway of copper acquisition in eukaryotes, ranging from yeast to humans. Characterization of the function, modes of action, and regulation of CTR and other molecular factors that functionally cooperate with CTR for copper transport, compartmentalization, incorporation into cuproproteins, and detoxification has revealed that organisms have evolved fascinating mechanisms for tight control of copper metabolism. This research progress further indicates the significance of copper in health and disease and opens avenues for therapeutic control of copper bioavailability and its metabolic pathways.
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42
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Barchi JJ. Mucin-Type Glycopeptide Structure in Solution: Past, Present, and Future. Biopolymers 2013; 99:713-23. [DOI: 10.1002/bip.22313] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 06/05/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Joseph J. Barchi
- Chemical Biology Laboratory; Center for Cancer Research, National Cancer Institute at Frederick; Frederick; MD; 21702
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43
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Landon CD, Benjamin SE, Ashcraft KA, Dewhirst MW. A role for the copper transporter Ctr1 in the synergistic interaction between hyperthermia and cisplatin treatment. Int J Hyperthermia 2013; 29:528-38. [PMID: 23879689 DOI: 10.3109/02656736.2013.790563] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
PURPOSE Hyperthermia enhances cytotoxic effects of chemotherapeutic agents such as cisplatin. However, the underlying molecular mechanisms remain unclear. We hypothesised that hyperthermia increases cisplatin accumulation and efficacy by modulating function of copper transport protein 1 (Ctr1), a major regulator of cellular cisplatin uptake. We examined the significance of Ctr1 in the synergistic interaction between hyperthermia and cisplatin. We assessed the importance of cisplatin- and hyperthermia-induced Ctr1 multimerisation in sensitising cells to cisplatin cytotoxicity. MATERIALS AND METHODS Ctr1 protein levels and cisplatin sensitivities were assessed in bladder cancer cell lines with immunoblotting and clonogenic survival assays. Using Myc-tagged-Ctr1 HEK293 cells, we assessed the effect of hyperthermia on Ctr1 multimerisation with immunoblotting. The effect of hyperthermia on cisplatin sensitivity and accumulation was assessed in wild-type (WT) and Ctr1 knockout (Ctr1-/-) mouse embryonic fibroblasts (MEFs) with clonogenic assays and inductively coupled plasma-mass spectrometry (ICP-MS). RESULTS Increased Ctr1 protein expression was observed for the most cisplatin-sensitive bladder cancer cell lines and MEFs. Heat-induced increase in Ctr1 multimerisation with cisplatin was observed in Myc-tagged Ctr1 cells. Hyperthermia enhanced cisplatin-mediated cytotoxicity in WT more than Ctr1-/- cells (dose modifying factors 1.75 versus 1.4, respectively). WT cells accumulated more platinum versus Ctr1-/- cells; this was further increased by hyperthermia in WT cells. CONCLUSIONS Hyperthermia enhanced cisplatin uptake and cytotoxicity in WT cells. Heat increased Ctr1 activity by increasing multimerisation, enhancing drug cytotoxicity. Furthermore, Ctr1 protein profiles of bladder tumours, as well as other tumour types, may predict their response to cisplatin and overall efficacy of treatment.
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44
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Maryon EB, Molloy SA, Ivy K, Yu H, Kaplan JH. Rate and regulation of copper transport by human copper transporter 1 (hCTR1). J Biol Chem 2013; 288:18035-46. [PMID: 23658018 DOI: 10.1074/jbc.m112.442426] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Human copper transporter 1 (hCTR1) is a homotrimer of a 190-amino acid monomer having three transmembrane domains believed to form a pore for copper permeation through the plasma membrane. The hCTR1-mediated copper transport mechanism is not well understood, nor has any measurement been made of the rate at which copper ions are transported by hCTR1. In this study, we estimated the rate of copper transport by the hCTR1 trimer in cultured cells using (64)Cu uptake assays and quantification of plasma membrane hCTR1. For endogenous hCTR1, we estimated a turnover number of about 10 ions/trimer/s. When overexpressed in HEK293 cells, a second transmembrane domain mutant of hCTR1 (H139R) had a 3-fold higher Km value and a 4-fold higher turnover number than WT. Truncations of the intracellular C-terminal tail and an AAA substitution of the putative metal-binding HCH C-terminal tripeptide (thought to be required for transport) also exhibited elevated transport rates and Km values when compared with WT hCTR1. Unlike WT hCTR1, H139R and the C-terminal mutants did not undergo regulatory endocytosis in elevated copper. hCTR1 mutants combining methionine substitutions that block transport (M150L,M154L) on the extracellular side of the pore and the high transport H139R or AAA intracellular side mutations exhibited the blocked transport of M150L,M154L, confirming that Cu(+) first interacts with the methionines during permeation. Our results show that hCTR1 elements on the intracellular side of the hCTR1 pore, including the carboxyl tail, are not essential for permeation, but serve to regulate the rate of copper entry.
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Affiliation(s)
- Edward B Maryon
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, IL 60607, USA
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45
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Wee NK, Weinstein DC, Fraser ST, Assinder SJ. The mammalian copper transporters CTR1 and CTR2 and their roles in development and disease. Int J Biochem Cell Biol 2013; 45:960-3. [DOI: 10.1016/j.biocel.2013.01.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 01/14/2013] [Accepted: 01/25/2013] [Indexed: 12/26/2022]
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46
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Ivy KD, Kaplan JH. A re-evaluation of the role of hCTR1, the human high-affinity copper transporter, in platinum-drug entry into human cells. Mol Pharmacol 2013; 83:1237-46. [PMID: 23543413 DOI: 10.1124/mol.113.085068] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Cisplatin (cDDP) is an anticancer drug used in a number of malignancies, including testicular, ovarian, cervical, bladder, lung, head, and neck cancers. Its use is limited by the development of resistance, often rationalized via effects on cellular uptake. It has been claimed that human copper transporter 1 (hCTR1), the human high-affinity copper transporter, is the major entry pathway for cDDP and related drugs via a mechanism that mimics copper. This is an unexpected property of hCTR1, a highly selective copper (I) transporter. We compared the uptake rates of copper with cDDP (and several analogs) into human embryonic kidney 293 cells overexpressing wild-type or mutant hCTR1, mouse embryonic fibroblasts that do or do not express CTR1, and human ovarian tumor cells that are sensitive or resistant to cDDP. We have also compared the effects of extracellular copper, which causes regulatory endocytosis of hCTR1, to those of cDDP. We confirm the correlation between higher hCTR1 levels and higher platinum drug uptake in tumor cells sensitive to the drug. However, we show that hCTR1 is not the major entry route of platinum drugs, and that the copper transporter is not internalized in response to extracellular drug. Our data suggest the major entry pathway for platinum drugs is not saturable at relevant concentrations and not protein-mediated. Clinical trials have been initiated that depend upon regulating membrane levels of hCTR1. If reduced drug uptake is a major factor in resistance, hCTR1 is unlikely to be a productive target in attempts to enhance efficacy, although the proteins involved in copper homeostasis may play a role.
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Affiliation(s)
- Kristin D Ivy
- Department of Biochemistry & Molecular Genetics, University of Illinois College of Medicine, Chicago, IL 60607, USA
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47
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Maryon EB, Molloy SA, Kaplan JH. Cellular glutathione plays a key role in copper uptake mediated by human copper transporter 1. Am J Physiol Cell Physiol 2013; 304:C768-79. [PMID: 23426973 DOI: 10.1152/ajpcell.00417.2012] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Copper is an essential micronutrient. Following entry via the human copper transporter 1 (hCTR1), copper is delivered to several copper chaperones, which subsequently transfer the metal to specific targets via protein:protein interactions. It is has been assumed, but not demonstrated, that chaperones acquire copper directly from hCTR1. However, some reports have pointed to an intermediary role for glutathione (GSH), an abundant copper-binding tri-peptide. To address the issue of how transported copper is acquired by the copper chaperones in vivo, we measured the initial rate of (64)Cu uptake in cells in which the cellular levels of copper chaperones or GSH were substantially depleted or elevated. Knockdown or overexpression of copper chaperones ATOX1, CCS, or both had no effect on the initial rate of (64)Cu entry into HEK293 cells having endogenous or overexpressed hCTR1. In contrast, depleting cellular GSH using L-buthionine-sulfoximine (BSO) caused a 50% decrease in the initial rate of (64)Cu entry in HEK293 cells and other cell types. This decrease was reversed by washout of BSO or GSH replenishment with a permeable ester. BSO treatment under our experimental conditions had no significant effects on the viability, ATP levels, or metal content of the cells. Attenuated (64)Cu uptake in BSO was not due to oxidation of the cysteine in the putative metal-binding motif (HCH) at the intracellular hCTR1 COOH terminus, because a mutant lacking this motif was fully active, and (64)Cu uptake was still reduced by BSO treatment. Our data suggest that GSH plays an important role in copper handling at the entry step.
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Affiliation(s)
- Edward B Maryon
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, IL 60607, USA
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48
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Schjoldager KTBG, Clausen H. Site-specific protein O-glycosylation modulates proprotein processing - deciphering specific functions of the large polypeptide GalNAc-transferase gene family. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1820:2079-94. [PMID: 23022508 DOI: 10.1016/j.bbagen.2012.09.014] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 09/17/2012] [Accepted: 09/19/2012] [Indexed: 01/18/2023]
Abstract
BACKGROUND Posttranslational modifications (PTMs) greatly expand the function and regulation of proteins, and glycosylation is the most abundant and diverse PTM. Of the many different types of protein glycosylation, one is quite unique; GalNAc-type (or mucin-type) O-glycosylation, where biosynthesis is initiated in the Golgi by up to twenty distinct UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts). These GalNAc-Ts are differentially expressed in cells and have different (although partly overlapping) substrate specificities, which provide for both unique functions and considerable redundancy. Recently we have begun to uncover human diseases associated with deficiencies in GalNAc-T genes (GALNTs). Thus deficiencies in individual GALNTs produce cell and protein specific effects and subtle distinct phenotypes such as hyperphosphatemia with hyperostosis (GALNT3) and dysregulated lipid metabolism (GALNT2). These phenotypes appear to be caused by deficient site-specific O-glycosylation that co-regulates proprotein convertase (PC) processing of FGF23 and ANGPTL3, respectively. SCOPE OF REVIEW Here we summarize recent progress in uncovering the interplay between human O-glycosylation and protease regulated processing and describes other important functions of site-specific O-glycosylation in health and disease. MAJOR CONCLUSIONS Site-specific O-glycosylation modifies pro-protein processing and other proteolytic events such as ADAM processing and thus emerges as an important co-regulator of limited proteolytic processing events. GENERAL SIGNIFICANCE Our appreciation of this function may have been hampered by our sparse knowledge of the O-glycoproteome and in particular sites of O-glycosylation. New strategies for identification of O-glycoproteins have emerged and recently the concept of SimpleCells, i.e. human cell lines made deficient in O-glycan extension by zinc finger nuclease gene targeting, was introduced for broad O-glycoproteome analysis.
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49
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Bachert C, Linstedt AD. A sensor of protein O-glycosylation based on sequential processing in the Golgi apparatus. Traffic 2012; 14:47-56. [PMID: 23046148 DOI: 10.1111/tra.12019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 10/05/2012] [Accepted: 10/09/2012] [Indexed: 12/25/2022]
Abstract
Protein O-glycosylation is important in numerous processes including the regulation of proteolytic processing sites by O-glycan masking in select newly synthesized proteins. To investigate O-glycan-mediated masking using an assay amenable to large-scale screens, we generated a fluorescent biosensor with an O-glycosylation site situated to mask a furin cleavage site. The sensor is activated when O-glycosylation fails to occur because furin cleavage releases a blocking domain allowing dye binding to a fluorogen activating protein. Thus, by design, glycosylation should block furin from activating the sensor only if it occurs first, which is predicted by the conventional view of Golgi organization. Indeed, and in contrast to the recently proposed rapid partitioning model, the sensor was non-fluorescent under normal conditions but became fluorescent when the Golgi complex was decompartmentalized. To test the utility of the sensor as a screening tool, cells expressing the sensor were exposed to a known inhibitor of O-glycosylation extension or siRNAs targeting factors known to alter glycosylation efficiency. These conditions activated the sensor substantiating its potential in identifying new inhibitors and cellular factors related to protein O-glycosylation. In summary, these findings confirm sequential processing in the Golgi, establish a new tool for studying the regulation of proteolytic processing by O-glycosylation, and demonstrate the sensor's potential usefulness for future screening projects.
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Affiliation(s)
- Collin Bachert
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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50
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Gray LW, Peng F, Molloy SA, Pendyala VS, Muchenditsi A, Muzik O, Lee J, Kaplan JH, Lutsenko S. Urinary copper elevation in a mouse model of Wilson's disease is a regulated process to specifically decrease the hepatic copper load. PLoS One 2012; 7:e38327. [PMID: 22802922 PMCID: PMC3390108 DOI: 10.1371/journal.pone.0038327] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 05/03/2012] [Indexed: 12/19/2022] Open
Abstract
Body copper homeostasis is regulated by the liver, which removes excess copper
via bile. In Wilson's disease (WD), this function is disrupted due to
inactivation of the copper transporter ATP7B resulting in hepatic copper
overload. High urinary copper is a diagnostic feature of WD linked to liver
malfunction; the mechanism behind urinary copper elevation is not fully
understood. Using Positron Emission Tomography-Computed Tomography (PET-CT)
imaging of live Atp7b−/− mice at
different stages of disease, a longitudinal metal analysis, and characterization
of copper-binding molecules, we show that urinary copper elevation is a specific
regulatory process mediated by distinct molecules. PET-CT and atomic absorption
spectroscopy directly demonstrate an age-dependent decrease in the capacity of
Atp7b−/− livers to accumulate
copper, concomitant with an increase in urinary copper. This reciprocal
relationship is specific for copper, indicating that cell necrosis is not the
primary cause for the initial phase of metal elevation in the urine. Instead,
the urinary copper increase is associated with the down-regulation of the
copper-transporter Ctr1 in the liver and appearance of a 2 kDa Small Copper
Carrier, SCC, in the urine. SCC is also elevated in the urine of the
liver-specific Ctr1−/− knockouts, which
have normal ATP7B function, suggesting that SCC is a normal metabolite carrying
copper in the serum. In agreement with this hypothesis, partially purified
SCC-Cu competes with free copper for uptake by Ctr1. Thus, hepatic
down-regulation of Ctr1 allows switching to an SCC-mediated removal of copper
via kidney when liver function is impaired. These results demonstrate that the
body regulates copper export through more than one mechanism; better
understanding of urinary copper excretion may contribute to an improved
diagnosis and monitoring of WD.
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Affiliation(s)
- Lawrence W. Gray
- Department of Physiology, Johns Hopkins
University, School of Medicine, Baltimore, Maryland, United States of
America
| | - Fangyu Peng
- Department of Radiology, University of Texas
Southwestern Medical Center, Dallas, Texas, United States of America
| | - Shannon A. Molloy
- Department of Biochemistry and Molecular
Genetics, University of Illinois at Chicago, Chicago, Illinois, United States of
America
| | - Venkata S. Pendyala
- Department of Physiology, Johns Hopkins
University, School of Medicine, Baltimore, Maryland, United States of
America
| | - Abigael Muchenditsi
- Department of Physiology, Johns Hopkins
University, School of Medicine, Baltimore, Maryland, United States of
America
| | - Otto Muzik
- Carman and Ann Adams Department of Pediatrics
and Department of Radiology, Wayne State University, School of Medicine,
Detroit, Michigan, United States of America
| | - Jaekwon Lee
- Redox Biology Center, Department of
Biochemistry, University of Nebraska, Lincoln, Nebraska, United States of
America
| | - Jack H. Kaplan
- Department of Biochemistry and Molecular
Genetics, University of Illinois at Chicago, Chicago, Illinois, United States of
America
| | - Svetlana Lutsenko
- Department of Physiology, Johns Hopkins
University, School of Medicine, Baltimore, Maryland, United States of
America
- * E-mail:
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