1
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Chen S, Pan X, Gao P, Wu F. Single-nucleus transcriptome analysis identifies a novel FKBP5+ endothelial cell subtype involved in endothelial-to-mesenchymal transition in adipose tissue during aging. Biochem Biophys Res Commun 2024; 722:150157. [PMID: 38805789 DOI: 10.1016/j.bbrc.2024.150157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 05/03/2024] [Accepted: 05/21/2024] [Indexed: 05/30/2024]
Abstract
Age-associated adipose tissue (AT) dysfunction is multifactorial and often leads to detrimental health consequences. AT is highly vascularized and endothelial cells (ECs) has been recently identified as a key regulator in the homeostasis of AT. However, the alteration of cell composition in AT during aging and the communication between endothelial cells and adipocytes remain poorly understood. In this study, we take advantage of single nucleus RNA sequencing analysis, and discovered a group of FKBP5+ ECs specifically resident in aged AT. Of interest, FKBP5+ ECs exhibited the potential for endothelial-to-mesenchymal transition (EndoMT) and exhibited a critical role in regulating adipocytes. Furthermore, lineage tracing experiments demonstrated that ECs in aged AT tend to express FKBP5 and undergo EndoMT with progressive loss of endothelial marker. This study may provide a basis for a new mechanism of microvascular ECs-induced AT dysfunction during aging.
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Affiliation(s)
- Siyuan Chen
- Department of Geriatrics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoxi Pan
- Department of Cardiovascular Medicine, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Department of Hypertension, Ruijin Hospital and Shanghai Institute of Hypertension, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Pingjin Gao
- Department of Cardiovascular Medicine, State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Hypertension, Department of Hypertension, Ruijin Hospital and Shanghai Institute of Hypertension, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fang Wu
- Department of Geriatrics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Clinical Research Center for Aging and Medicine, Shanghai, China.
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2
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Ściskalska M, Ołdakowska M, Milnerowicz H. Importance of Genetic Polymorphisms in MT1 and MT2 Genes in Metals Homeostasis and Their Relationship with the Risk of Acute Pancreatitis Occurrence in Smokers-Preliminary Findings. Int J Mol Sci 2021; 22:5725. [PMID: 34072023 PMCID: PMC8197913 DOI: 10.3390/ijms22115725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/13/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
This study was aimed at evaluating the changes in metallothionein (MT) concentration in the blood of patients with acute pancreatitis (AP) and healthy subjects, taking into account the extracellular (plasma) and intracellular (erythrocyte lysate) compartments. The impact of single-nucleotide polymorphisms (SNPs) in the MT1A (rs11640851), MT1B (rs964372) and MT2A (rs10636) genes on MT concentration and their association with the concentration of metals (Cu, Zn, Cd) and ceruloplasmin as Cu-related proteins were analyzed. The concentration of a high-sensitivity C-reactive protein (hs-CRP) and IL-6 as markers of inflammation, and malonyldialdehyde (MDA), superoxide dismutase (SODs) activity and the value of total antioxidant capacity (TAC) as parameters describing the pro/antioxidative balance were also assessed. In the AP patient groups, an increased MT concentration in erythrocyte lysate compared to healthy subjects was shown, especially in individuals with the GG genotype for rs964372 in the MT1B gene. A Zn concentration was especially decreased in the blood of smoking AP patients with the AA genotype for SNP rs11640851 in the MT1A gene and the GC genotype for SNP rs10636 in MT2A, compared to non-smokers with AP, which was accompanied by an increase in the value of the Cu/Zn ratio. The exposure to tobacco smoke xenobiotics increased the risk of AP occurrence in subjects with the CC genotype for SNP rs11640851 in the MT1A gene by more than fourfold. The investigated polymorphisms, rs11640851 in the MT1A gene, rs964372 in the MT1B gene and rs10636 in the MT2A gene, seem to be an important factor in maintaining homeostasis in an organism under oxidative stress conditions.
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Affiliation(s)
- Milena Ściskalska
- Department of Biomedical and Environmental Analyses, Faculty of Pharmacy, Wroclaw Medical University, 50-556 Wroclaw, Poland; (M.O.); (H.M.)
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3
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Melenbacher A, Korkola NC, Stillman MJ. The pathways and domain specificity of Cu(i) binding to human metallothionein 1A. Metallomics 2020; 12:1951-1964. [DOI: 10.1039/d0mt00215a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We describe the sequential formation of 3 key Cu(i)–thiolate clusters in human metallothionein 1A using a combination of ESI-MS and phosphorescence lifetime methods.
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Affiliation(s)
- Adyn Melenbacher
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
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4
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Scheller JS, Irvine GW, Stillman MJ. Unravelling the mechanistic details of metal binding to mammalian metallothioneins from stoichiometric, kinetic, and binding affinity data. Dalton Trans 2018; 47:3613-3637. [PMID: 29431781 DOI: 10.1039/c7dt03319b] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Metallothioneins (MTs) are small, cysteine-rich proteins, found throughout Nature. Their ability to bind a number of different metals with a range of stoichiometric ratios means that this protein family is critically important for essential metal (Zn2+ and Cu+) homeostasis, metal storage, metal donation to nascent metalloenzymes as well as heavy metal detoxification. With its 20 cysteines, metallothionein is also considered to protect cells against oxidative stress. MT has been studied by a large number of researchers over the last 6 decades using a variety of spectroscopic techniques. The lack of distinguishing chromophores for the multitude of binding sites has made the evaluation of stoichiometric properties for different metals challenging. Initially, only 113Cd-NMR spectroscopy could provide strong evidence for the proposed cluster formation of Cd-MT. The extraordinary development of electrospray ionization mass spectrometry (ESI-MS), where all coexisting species in solution are observed, revolutionized MT research. Prior to the use of ESI-MS data, a range of "magic numbers" representing metal-to-MT molar ratios were reported from optical spectroscopic studies. The availability of ESI mass spectral data led to (i) the confirmation of cluster formation, (ii) a conceptual understanding of the cooperativity involved in multiple metal binding events, (iii) the presence of domain specificity between regions of the protein and (iv) mechanistic details involving both binding affinities and rate constants. The kinetic experiments identified the presence of multiple individual binding sites, each with a unique rate constant and an analogous binding affinity. The almost linear trend in rate constants as a function of bound As3+ provided a unique insight that became a critical step in the complete understanding of the mechanistic details of the metalation of MT. To fully define the biological function of this sulfur-rich protein it is necessary to determine kinetic rate constants and binding affinities for the essential metals. Recently, Zn2+ competition experiments between both of the isolated fragments (α and β) and the full-length protein (βα-MT 1a) as well as Zn2+ competition between βα-MT 1a and carbonic anhydrase were reported. From these data, the trend in binding affinities and the values of the Kf of the 7 bimolecular reactions involved in metalation were determined. From the analysis of ESI-MS data for Cu+ binding to βα-MT 1a at different pH-values, a trend in the 20 binding affinities for the complete metalation mechanism was reported. This review details a personal view of the historical development of the determination of stoichiometry for metal binding, the structure of the binding sites, the rates of the metalation reactions and the underlying binding affinities for each metalation step. We have attempted to summarize the experimental developments that led to the publication in May 2017 of the experimental determination of the 20 binding constants for the 20 sequential bimolecular reactions for Cu+ binding to the 20 Cys of apoMT as a function of pH that show the appearance and disappearance of clusters. We report both published data and in a series of tables an assembly of stoichiometries, and equilibrium constants for Zn2+ and Cu+ for many different metallothioneins.
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Affiliation(s)
- Judith S Scheller
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada.
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5
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Park Y, Zhang J, Cai L. Reappraisal of metallothionein: Clinical implications for patients with diabetes mellitus. J Diabetes 2018; 10:213-231. [PMID: 29072367 DOI: 10.1111/1753-0407.12620] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 08/29/2017] [Accepted: 10/20/2017] [Indexed: 12/22/2022] Open
Abstract
Reactive oxygen and nitrogen species (ROS and RNS, respectively) are byproducts of cellular physiological processes of the metabolism of intermediary nutrients. Although physiological defense mechanisms readily convert these species into water or urea, an improper balance between their production and removal leads to oxidative stress (OS), which is harmful to cellular components. This OS may result in uncontrolled growth or, ultimately, cell death. In addition, ROS and RNS are closely related to the development of diabetes and its complications. Therefore, numerous researchers have proposed the development of strategies for the removal of ROS/RNS to prevent or treat diabetes and its complications. Some molecules that are synthesized in the body or obtained from food participate in the removal and neutralization of ROS and RNS. Metallothionein, a cysteine-rich protein, is a metal-binding protein that has a wide range of functions in cellular homeostasis and immunity. Metallothionein can be induced by a variety of conditions, including zinc supplementation, and plays a crucial role in mediating anti-OS, anti-apoptotic, detoxification, and anti-inflammatory effects. Metallothionein can modulate various stress-induced signaling pathways (mitogen-activated protein kinase, Wnt, nuclear factor-κB, phosphatidylinositol 3-kinase, sirtuin 1/AMP-activated protein kinase and fibroblast growth factor 21) to alleviate diabetes and diabetic complications. However, a deeper understanding of the functional, biochemical, and molecular characteristics of metallothionein is needed to bring about new opportunities for OS therapy. This review focuses on newly proposed functions of a metallothionein and their implications relevant to diabetes and its complications.
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Affiliation(s)
- Yongsoo Park
- Department of Pediatrics, Pediatrics Research Institute, University of Louisville, Louisville, Kentucky, USA
- Hanyang University, College of Medicine and Engineering, Seoul, South Korea
| | - Jian Zhang
- Department of Pediatrics, Pediatrics Research Institute, University of Louisville, Louisville, Kentucky, USA
- The Center of Cardiovascular Disorders, The First Hospital of Jilin University, Changchun, China
| | - Lu Cai
- Department of Pediatrics, Pediatrics Research Institute, University of Louisville, Louisville, Kentucky, USA
- Department of Radiation Oncology, University of Louisville, Louisville, Kentucky, USA
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
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6
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Scheller JS, Irvine GW, Wong DL, Hartwig A, Stillman MJ. Stepwise copper(i) binding to metallothionein: a mixed cooperative and non-cooperative mechanism for all 20 copper ions. Metallomics 2017; 9:447-462. [DOI: 10.1039/c7mt00041c] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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7
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Irvine GW, Pinter TBJ, Stillman MJ. Defining the metal binding pathways of human metallothionein 1a: balancing zinc availability and cadmium seclusion. Metallomics 2016; 8:71-81. [PMID: 26583802 DOI: 10.1039/c5mt00225g] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Metallothioneins (MTs) are cysteine-rich, metal-binding proteins that are found throughout Nature. This ubiquity highlights their importance in essential metal regulation, heavy metal detoxification and cellular redox chemistry. Missing from the current description of MT function is the underlying mechanism by which MTs achieve their proposed biological functions. To date, there have been conflicting reports on the mechanism of metal binding and the structures of the metal binding intermediates formed during metalation of apoMTs. The form of the metal-bound intermediates dictates the metal sequestering and metal-donating properties of the protein. Through a detailed analysis of spectral data from electrospray ionization mass spectromeric and circular dichroism methods we report that Zn(ii) and Cd(ii) metalation of the human MT1a takes place through two distinct pathways. The first pathway involves formation of beaded structures with up to five metals bound terminally to the 20 cysteines of the protein via a noncooperative mechanism. The second pathway is dominated by the formation of the four-metal domain cluster structure M4SCYS11via a cooperative mechanism. We report that there are different pathway preferences for Zn(ii) and Cd(ii) metalation of apo-hMT1a. Cd(ii) binding follows the beaded pathway above pH 7.1 but beginning below pH 7.1 the clustered (Cd4Scys11) pathway begins to dominate. In contrast, Zn(ii) binding follows the terminal, "beaded", pathway at all physiologically relevant pH (pH ≥ 5.2) only following the clustered pathway below pH 5.1. The results presented here allow us to reconcile the conflicting reports concerning the presence of different metalation intermediates of MTs. The conflict regarding cooperative versus noncooperative binding mechanisms is also reconciled with the experimental results described here. These two metal-specific pathways and the presence of radically different intermediate structures provide insight into the multi-functional nature of MT: binding Zn(ii) terminally for donation to metalloenzymes and sequestering toxic Cd(ii) in a cluster structure.
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Affiliation(s)
- Gordon W Irvine
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada.
| | - Tyler B J Pinter
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada.
| | - Martin J Stillman
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada.
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8
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Mammalian Metallothionein-2A and Oxidative Stress. Int J Mol Sci 2016; 17:ijms17091483. [PMID: 27608012 PMCID: PMC5037761 DOI: 10.3390/ijms17091483] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 08/19/2016] [Accepted: 08/24/2016] [Indexed: 01/01/2023] Open
Abstract
Mammalian metallothionein-2A (MT2A) has received considerable attention in recent years due to its crucial pathophysiological role in anti-oxidant, anti-apoptosis, detoxification and anti-inflammation. For many years, most studies evaluating the effects of MT2A have focused on reactive oxygen species (ROS), as second messengers that lead to oxidative stress injury of cells and tissues. Recent studies have highlighted that oxidative stress could activate mitogen-activated protein kinases (MAPKs), and MT2A, as a mediator of MAPKs, to regulate the pathogenesis of various diseases. However, the molecule mechanism of MT2A remains elusive. A deeper understanding of the functional, biochemical and molecular characteristics of MT2A would be identified, in order to bring new opportunities for oxidative stress therapy.
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9
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Irvine GW, Stillman MJ. Cadmium binding mechanisms of isolated domains of human MT isoform 1a: Non-cooperative terminal sites and cooperative cluster sites. J Inorg Biochem 2016; 158:115-121. [DOI: 10.1016/j.jinorgbio.2016.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 03/05/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
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10
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Jacobs AD, Chang FMJ, Morrison L, Dilger JM, Wysocki VH, Clemmer DE, Giedroc DP. Resolution of Stepwise Cooperativities of Copper Binding by the Homotetrameric Copper-Sensitive Operon Repressor (CsoR): Impact on Structure and Stability. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201506349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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11
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Putting the pieces into place: Properties of intact zinc metallothionein 1A determined from interaction of its isolated domains with carbonic anhydrase. Biochem J 2015; 471:347-56. [DOI: 10.1042/bj20150676] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 08/20/2015] [Indexed: 12/25/2022]
Abstract
Competitive metallation reactions between the isolated domain fragments and apo-carbonic anhydrase [CA; metal-free CA (apo-CA)] provided the binding affinities for each of the eight sites and showed that CA competed more efficiently for added zinc with the β-domain fragment. The combined effects of the number of sites, chain length and cysteine accessibility modulate the zinc-binding properties of mammalian metallothionein (MT).
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12
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Jacobs AD, Chang FMJ, Morrison L, Dilger JM, Wysocki VH, Clemmer DE, Giedroc DP. Resolution of Stepwise Cooperativities of Copper Binding by the Homotetrameric Copper-Sensitive Operon Repressor (CsoR): Impact on Structure and Stability. Angew Chem Int Ed Engl 2015; 54:12795-9. [PMID: 26332992 DOI: 10.1002/anie.201506349] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/06/2015] [Indexed: 12/11/2022]
Abstract
The cooperativity of ligand binding is central to biological regulation and new approaches are needed to quantify these allosteric relationships. Herein, we exploit a suite of mass spectrometry (MS) experiments to provide novel insights into homotropic Cu-binding cooperativity, gas-phase stabilities and conformational ensembles of the D2 -symmetric, homotetrameric copper-sensitive operon repressor (CsoR) as a function of Cu(I) ligation state. Cu(I) binding is overall positively cooperative, but is characterized by distinct ligation state-specific cooperativities. Structural transitions occur upon binding the first and fourth Cu(I) , with the latter occurring with significantly higher cooperativity than previous steps; this results in the formation of a holo-tetramer that is markedly more resistant than apo-, and partially ligated CsoR tetramers toward surface-induced dissociation (SID).
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Affiliation(s)
- Alexander D Jacobs
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102 (USA)
| | | | - Lindsay Morrison
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 (USA)
| | - Jonathan M Dilger
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102 (USA)
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 (USA)
| | - David E Clemmer
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102 (USA)
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102 (USA).
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13
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Pinter TBJ, Irvine GW, Stillman MJ. Domain Selection in Metallothionein 1A: Affinity-Controlled Mechanisms of Zinc Binding and Cadmium Exchange. Biochemistry 2015; 54:5006-16. [DOI: 10.1021/acs.biochem.5b00452] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tyler B. J. Pinter
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Gordon W. Irvine
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Martin J. Stillman
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
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14
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Dong G, Chen H, Qi M, Dou Y, Wang Q. Balance between metallothionein and metal response element binding transcription factor 1 is mediated by zinc ions (review). Mol Med Rep 2015; 11:1582-6. [PMID: 25405524 DOI: 10.3892/mmr.2014.2969] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 10/24/2014] [Indexed: 11/06/2022] Open
Abstract
Metal ion homeostasis and heavy metal detoxification systems are regulated by certain genes associated with metal ion transport. Metallothionein (MT) and metal response element binding transcription factor 1 (MTF‑1) are important regulatory proteins involved in the mediation of intracellular metal ion balance. Differences in the zinc‑binding affinities of the zinc fingers of MTF‑1 and the α‑ and β‑domains of MT facilitate their regulation of Zn2+ concentration. Alterations in the intracellular concentration of Zn2+ influence the MTF‑1 zinc finger number, and MTF‑1 containing certain zinc finger numbers regulates the expression of corresponding target genes. The present review evaluates the association between zinc finger number in MTF‑1 protein, MTF‑1 target genes and the mechanism underlying MT regulation of the zinc finger number in MTF‑1.
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Affiliation(s)
- Gang Dong
- Department of Oral Medicine, Shandong Wanjie Medical College, Zibo, Shandong 255213, P.R. China
| | - Hong Chen
- Key Laboratory of Biomedical Engineering and Technology of Shandong High School, Shandong Wanjie Medical College, Zibo, Shandong 255213, P.R. China
| | - Meiyu Qi
- Cattle Research Department, Animal Husbandry Institute, Heilongjiang Academy of Agricultural Sciences, Harbin, Heilongjiang 150086, P.R. China
| | - Ye Dou
- Key Laboratory of Biomedical Engineering and Technology of Shandong High School, Shandong Wanjie Medical College, Zibo, Shandong 255213, P.R. China
| | - Qinglu Wang
- Key Laboratory of Biomedical Engineering and Technology of Shandong High School, Shandong Wanjie Medical College, Zibo, Shandong 255213, P.R. China
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15
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Blindauer CA. Advances in the molecular understanding of biological zinc transport. Chem Commun (Camb) 2015; 51:4544-63. [DOI: 10.1039/c4cc10174j] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recognition of the importance of zinc homeostasis for health has driven a surge in structural data on major zinc-transporting proteins.
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16
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Irvine GW, Duncan KER, Gullons M, Stillman MJ. Metalation Kinetics of the Human α-Metallothionein 1a Fragment Is Dependent on the Fluxional Structure of the apo-Protein. Chemistry 2014; 21:1269-79. [DOI: 10.1002/chem.201404283] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Indexed: 01/06/2023]
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17
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Pinter TBJ, Stillman MJ. The zinc balance: competitive zinc metalation of carbonic anhydrase and metallothionein 1A. Biochemistry 2014; 53:6276-85. [PMID: 25208334 DOI: 10.1021/bi5008673] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The small, cysteine-rich metallothionein family of proteins is currently considered to play a critical role in the provision of metals to metalloenzymes. However, there is limited information available on the mechanisms of these fundamentally important interactions. We report on the competitive zinc metalation of apocarbonic anhydrase in the presence of apometallothionein 1A using electrospray-ionization mass spectrometry. These experiments revealed the relative affinities of zinc to all species in solution. The carbonic anhydrase is shown to compete efficiently only against Zn5-7MT. The calculated equilibrium zinc binding constants of each of the 7 zinc metallothionein 1A species ranged from a high of (log(KF)) 12.5 to a low of 11.8. The 8 equilibrium constants connecting the 10 active species in competition for the zinc were modeled by fitting the KF values of the 8 competitive bimolecular reactions to the ESI-mass spectral data. These modeled K values are shown to be experimentally connected to the metalation efficiency of the carbonic anhydrase. The series of 7 metallothionein binding affinities for zinc highlight the buffering role of zinc metallothioneins that permit simultaneously zinc storage and zinc sensing. Finally, the significance of the multiple zinc binding affinities of zinc metallothionein is discussed in relation to zinc homeostasis.
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Affiliation(s)
- Tyler B J Pinter
- Department of Chemistry and ‡Department of Biology, The University of Western Ontario , London, Ontario, Canada N6A 5B7
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18
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Manzetti S, van der Spoel ER, van der Spoel D. Chemical Properties, Environmental Fate, and Degradation of Seven Classes of Pollutants. Chem Res Toxicol 2014; 27:713-37. [DOI: 10.1021/tx500014w] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Sergio Manzetti
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, University of Uppsala, Box 596, SE-75124 Uppsala, Sweden
- Fjordforsk A.S., Midtun, 6894 Vangsnes, Norway
| | - E. Roos van der Spoel
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, University of Uppsala, Box 596, SE-75124 Uppsala, Sweden
| | - David van der Spoel
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, University of Uppsala, Box 596, SE-75124 Uppsala, Sweden
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19
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Sutherland DEK, Stillman MJ. Challenging conventional wisdom: single domain metallothioneins. Metallomics 2014; 6:702-28. [DOI: 10.1039/c3mt00216k] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Metallation studies of human metallothioneins support the role of single metal-binding-domains as commonplace with the typical two-domain-cluster structure as exceptional.
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