1
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Melenbacher A, Stillman MJ. ESI-MS analysis of Cu(I) binding to apo and Zn7 human metallothionein 1A, 2, and 3 identifies the formation of a similar series of metallated species with no individual isoform optimization for Cu(I). Metallomics 2024; 16:mfae015. [PMID: 38503570 PMCID: PMC11004924 DOI: 10.1093/mtomcs/mfae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 03/09/2024] [Indexed: 03/21/2024]
Abstract
Metallothioneins (MTs) are cysteine-rich proteins involved in metal homeostasis, heavy metal detoxification, and protection against oxidative stress. Whether the four mammalian MT isoforms exhibit different metal binding properties is not clear. In this paper, the Cu(I) binding properties of the apo MT1A, apo MT2, and apo MT3 are compared and the relative Cu(I) binding affinities are reported. In all three isoforms, Cu4, Cu6, and Cu10 species form cooperatively, and MT1A and MT2 also form a Cu13 species. The Cu(I) binding properties of Zn7-MT1A, Zn7-MT2, and Zn7-MT3 are compared systematically using isotopically pure 63Cu(I) and 68Zn(II). The species formed in each MT isoform were detected through electrospray ionization-mass spectrometry and further characterized using room temperature phosphorescence spectroscopy. The mixed metal Cu, Zn species forming in MT1A, MT2, and MT3 have similar stoichiometries and their emission spectral properties indicate that analogous clusters form in the three isoforms. Three parallel metallation pathways have been proposed through analysis of the detailed Cu, Zn speciation in MT1A, MT2, and MT3. Pathway ① results in Cu5Zn5-MT and Cu9Zn3-MT. Pathway ② involves Cu6Zn4-MT and Cu10Zn2-MT. Pathway ③ includes Cu8Zn4-MT. Speciation analysis indicates that Pathway ② is the preferred pathway for MT2. This is also evident in the phosphorescence spectra with the 750 nm emission from Cu6Zn4-MT being most prominent in MT2. We see no evidence for different MT isoforms being optimized or exhibiting preferences for certain metals. We discuss the probable stoichiometry for MTs in vivo based on the in vitro determined binding constants.
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Affiliation(s)
- Adyn Melenbacher
- 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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2
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Chen B, Yu P, Chan WN, Xie F, Zhang Y, Liang L, Leung KT, Lo KW, Yu J, Tse GMK, Kang W, To KF. Cellular zinc metabolism and zinc signaling: from biological functions to diseases and therapeutic targets. Signal Transduct Target Ther 2024; 9:6. [PMID: 38169461 PMCID: PMC10761908 DOI: 10.1038/s41392-023-01679-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 09/15/2023] [Accepted: 10/10/2023] [Indexed: 01/05/2024] Open
Abstract
Zinc metabolism at the cellular level is critical for many biological processes in the body. A key observation is the disruption of cellular homeostasis, often coinciding with disease progression. As an essential factor in maintaining cellular equilibrium, cellular zinc has been increasingly spotlighted in the context of disease development. Extensive research suggests zinc's involvement in promoting malignancy and invasion in cancer cells, despite its low tissue concentration. This has led to a growing body of literature investigating zinc's cellular metabolism, particularly the functions of zinc transporters and storage mechanisms during cancer progression. Zinc transportation is under the control of two major transporter families: SLC30 (ZnT) for the excretion of zinc and SLC39 (ZIP) for the zinc intake. Additionally, the storage of this essential element is predominantly mediated by metallothioneins (MTs). This review consolidates knowledge on the critical functions of cellular zinc signaling and underscores potential molecular pathways linking zinc metabolism to disease progression, with a special focus on cancer. We also compile a summary of clinical trials involving zinc ions. Given the main localization of zinc transporters at the cell membrane, the potential for targeted therapies, including small molecules and monoclonal antibodies, offers promising avenues for future exploration.
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Affiliation(s)
- Bonan Chen
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China
- CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Peiyao Yu
- Department of Pathology, Nanfang Hospital and Basic Medical College, Southern Medical University, Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Wai Nok Chan
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China
- CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Fuda Xie
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China
- CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Yigan Zhang
- Institute of Biomedical Research, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Li Liang
- Department of Pathology, Nanfang Hospital and Basic Medical College, Southern Medical University, Guangdong Province Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Kam Tong Leung
- Department of Pediatrics, The Chinese University of Hong Kong, Hong Kong, China
| | - Kwok Wai Lo
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Jun Yu
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
| | - Gary M K Tse
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Wei Kang
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China.
- CUHK-Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
| | - Ka Fai To
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
- State Key Laboratory of Digestive Disease, Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China.
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3
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Jamrozik D, Dutczak R, Machowicz J, Wojtyniak A, Smędowski A, Pietrucha-Dutczak M. Metallothioneins, a Part of the Retinal Endogenous Protective System in Various Ocular Diseases. Antioxidants (Basel) 2023; 12:1251. [PMID: 37371981 DOI: 10.3390/antiox12061251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/01/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Metallothioneins are the metal-rich proteins that play important roles in metal homeostasis and detoxification. Moreover, these proteins protect cells against oxidative stress, inhibit proapoptotic mechanisms and enhance cell differentiation and survival. Furthermore, MTs, mainly MT-1/2 and MT-3, play a vital role in protecting the neuronal retinal cells in the eye. Expression disorders of these proteins may be responsible for the development of various age-related eye diseases, including glaucoma, age-related macular degeneration, diabetic retinopathy and retinitis pigmentosa. In this review, we focused on the literature reports suggesting that these proteins may be a key component of the endogenous protection system of the retinal neurons, and, when the expression of MTs is disrupted, this system becomes inefficient. Moreover, we described the location of different MT isoforms in ocular tissues. Then we discussed the changes in MT subtypes' expression in the context of the common eye diseases. Finally, we highlighted the possibility of the use of MTs as biomarkers for cancer diagnosis.
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Affiliation(s)
- Daniel Jamrozik
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland
| | - Radosław Dutczak
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland
| | - Joanna Machowicz
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland
| | - Alicja Wojtyniak
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland
| | - Adrian Smędowski
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland
- GlaucoTech Co., Gen., Władysława Sikorskiego 45/177, 40-282 Katowice, Poland
| | - Marita Pietrucha-Dutczak
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland
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4
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Hajdu B, Hunyadi-Gulyás É, Kato K, Kawaguchi A, Nagata K, Gyurcsik B. Zinc binding of a Cys2His2-type zinc finger protein is enhanced by the interaction with DNA. J Biol Inorg Chem 2023; 28:301-315. [PMID: 36820987 PMCID: PMC10036435 DOI: 10.1007/s00775-023-01988-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 01/10/2023] [Indexed: 02/24/2023]
Abstract
Zinc finger proteins specifically recognize DNA sequences and, therefore, play a crucial role in living organisms. In this study the Zn(II)-, and DNA-binding of 1MEY#, an artificial zinc finger protein consisting of three finger units was characterized by multiple methods. Fluorimetric, circular dichroism and isothermal calorimetric titrations were applied to determine the accurate stability constant of a zinc finger protein. Assuming that all three zinc finger subunits behave identically, the obtained thermodynamic data for the Zn(II) binding were ΔHbinding site = - (23.5 - 28.0) kcal/mol (depending on the applied protonation state of the cysteines) and logβ'pH 7.4 = 12.2 ± 0.1, being similar to those of the CP1 consensus zinc finger peptide. The specific DNA binding of the protein can be characterized by logβ'pH 7.4 = 8.20 ± 0.08, which is comparable to the affinity of the natural zinc finger proteins (Sp1, WT1, TFIIIA) toward DNA. This value is ~ 1.9 logβ' unit higher than those determined for semi- or nonspecific DNA binding. Competitive circular dichroism and electrophoretic mobility shift measurements revealed that the conditional stability constant characteristic for Zn(II) binding of 1MEY# protein increased by 3.4 orders of magnitude in the presence of its target DNA sequence.
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Affiliation(s)
- Bálint Hajdu
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm Tér 7, 6720, Szeged, Hungary
| | - Éva Hunyadi-Gulyás
- Laboratory of Proteomics Research, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Temesvári Krt. 62, 6726, Szeged, Hungary
| | - Kohsuke Kato
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan
| | - Atsushi Kawaguchi
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan
| | - Kyosuke Nagata
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan
| | - Béla Gyurcsik
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm Tér 7, 6720, Szeged, Hungary.
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5
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Goldberg JM, Lippard SJ. Mobile zinc as a modulator of sensory perception. FEBS Lett 2023; 597:151-165. [PMID: 36416529 PMCID: PMC10108044 DOI: 10.1002/1873-3468.14544] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/24/2022]
Abstract
Mobile zinc is an abundant transition metal ion in the central nervous system, with pools of divalent zinc accumulating in regions of the brain engaged in sensory perception and memory formation. Here, we present essential tools that we developed to interrogate the role(s) of mobile zinc in these processes. Most important are (a) fluorescent sensors that report the presence of mobile zinc and (b) fast, Zn-selective chelating agents for measuring zinc flux in animal tissue and live animals. The results of our studies, conducted in collaboration with neuroscientist experts, are presented for sensory organs involved in hearing, smell, vision, and learning and memory. A general principle emerging from these studies is that the function of mobile zinc in all cases appears to be downregulation of the amplitude of the response following overstimulation of the respective sensory organs. Possible consequences affecting human behavior are presented for future investigations in collaboration with interested behavioral scientists.
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Affiliation(s)
| | - Stephen J Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
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6
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Rozenberg JM, Kamynina M, Sorokin M, Zolotovskaia M, Koroleva E, Kremenchutckaya K, Gudkov A, Buzdin A, Borisov N. The Role of the Metabolism of Zinc and Manganese Ions in Human Cancerogenesis. Biomedicines 2022; 10:biomedicines10051072. [PMID: 35625809 PMCID: PMC9139143 DOI: 10.3390/biomedicines10051072] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 04/30/2022] [Accepted: 05/03/2022] [Indexed: 12/14/2022] Open
Abstract
Metal ion homeostasis is fundamental for life. Specifically, transition metals iron, manganese and zinc play a pivotal role in mitochondrial metabolism and energy generation, anti-oxidation defense, transcriptional regulation and the immune response. The misregulation of expression or mutations in ion carriers and the corresponding changes in Mn2+ and Zn2+ levels suggest that these ions play a pivotal role in cancer progression. Moreover, coordinated changes in Mn2+ and Zn2+ ion carriers have been detected, suggesting that particular mechanisms influenced by both ions might be required for the growth of cancer cells, metastasis and immune evasion. Here, we present a review of zinc and manganese pathophysiology suggesting that these ions might cooperatively regulate cancerogenesis. Zn and Mn effects converge on mitochondria-induced apoptosis, transcriptional regulation and the cGAS-STING signaling pathway, mediating the immune response. Both Zn and Mn influence cancer progression and impact treatment efficacy in animal models and clinical trials. We predict that novel strategies targeting the regulation of both Zn and Mn in cancer will complement current therapeutic strategies.
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Affiliation(s)
- Julian Markovich Rozenberg
- Moscow Institute of Physics and Technology, National Research University, 141700 Moscow, Russia; (M.S.); (M.Z.); (E.K.); (K.K.); (A.B.); (N.B.)
- Correspondence:
| | - Margarita Kamynina
- Group of Experimental Biotherapy and Diagnostic, Institute for Regenerative Medicine, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (M.K.); (A.G.)
| | - Maksim Sorokin
- Moscow Institute of Physics and Technology, National Research University, 141700 Moscow, Russia; (M.S.); (M.Z.); (E.K.); (K.K.); (A.B.); (N.B.)
- Group of Experimental Biotherapy and Diagnostic, Institute for Regenerative Medicine, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (M.K.); (A.G.)
| | - Marianna Zolotovskaia
- Moscow Institute of Physics and Technology, National Research University, 141700 Moscow, Russia; (M.S.); (M.Z.); (E.K.); (K.K.); (A.B.); (N.B.)
- OmicsWay Corporation, Walnut, CA 91789, USA
| | - Elena Koroleva
- Moscow Institute of Physics and Technology, National Research University, 141700 Moscow, Russia; (M.S.); (M.Z.); (E.K.); (K.K.); (A.B.); (N.B.)
| | - Kristina Kremenchutckaya
- Moscow Institute of Physics and Technology, National Research University, 141700 Moscow, Russia; (M.S.); (M.Z.); (E.K.); (K.K.); (A.B.); (N.B.)
| | - Alexander Gudkov
- Group of Experimental Biotherapy and Diagnostic, Institute for Regenerative Medicine, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (M.K.); (A.G.)
| | - Anton Buzdin
- Moscow Institute of Physics and Technology, National Research University, 141700 Moscow, Russia; (M.S.); (M.Z.); (E.K.); (K.K.); (A.B.); (N.B.)
- Group of Experimental Biotherapy and Diagnostic, Institute for Regenerative Medicine, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (M.K.); (A.G.)
- OmicsWay Corporation, Walnut, CA 91789, USA
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Oncobox Ltd., 121205 Moscow, Russia
| | - Nicolas Borisov
- Moscow Institute of Physics and Technology, National Research University, 141700 Moscow, Russia; (M.S.); (M.Z.); (E.K.); (K.K.); (A.B.); (N.B.)
- OmicsWay Corporation, Walnut, CA 91789, USA
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7
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Zinc ionophores: chemistry and biological applications. J Inorg Biochem 2021; 228:111691. [PMID: 34929542 DOI: 10.1016/j.jinorgbio.2021.111691] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 02/06/2023]
Abstract
Zinc can play a pathophysiological role in several diseases and can interfere in key processes of microbial growth. This evidence justifies the efforts in applying Zinc ionophores to restore Zinc homeostasis and treat bacterial/viral infections such as coronavirus diseases. Zinc ionophores increase the intracellular concentration of Zinc ions causing significant biological effects. This review provides, for the first time, an overview of the applications of the main Zinc ionophores in Zinc deficiency, infectious diseases, and in cancer, discussing the pharmacological and coordination properties of the Zinc ionophores.
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8
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Mahim A, Karim M, Petering DH. Zinc trafficking 1. Probing the roles of proteome, metallothionein, and glutathione. Metallomics 2021; 13:6362609. [PMID: 34472617 DOI: 10.1093/mtomcs/mfab055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/18/2021] [Indexed: 11/13/2022]
Abstract
The cellular trafficking pathways that conduct zinc to its sites of binding in functional proteins remain largely unspecified. In this study, the hypothesis was investigated that nonspecific proteomic binding sites serve as intermediates in zinc trafficking. Proteome from pig kidney LLC-PK1 cells contains a large concentration of such sites, displaying an average conditional stability constant of 1010-11, that are dependent on sulfhydryl ligands to achieve high-affinity binding of zinc. As a result, the proteome competes effectively with induced metallothionein for Zn2+ upon exposure of cells to extracellular Zn2+ or during in vitro direct competition. The reaction of added Zn2+ bound to proteome with apo-carbonic anhydrase was examined as a potential model for intracellular zinc trafficking. The extent of this reaction was inversely dependent upon proteome concentration and under cellular conditions thought to be negligible. The rate of reaction was strictly first order in both Zn2+ and apo-carbonic anhydrase, and also considered to be insignificant in cells. Adding the low molecular weight fraction of cell supernatant to the proteome markedly enhanced the speed of this reaction, a phenomenon dependent on the presence of glutathione (GSH). In agreement, inclusion of GSH accelerated the reaction in a concentration-dependent manner. The implications of abundant high-affinity binding sites for Zn2+ within the proteome are considered in relation to their interaction with GSH in the efficient delivery of Zn2+ to functional binding sites and in the operation of fluorescent zinc sensors as a tool to observe zinc trafficking.
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Affiliation(s)
- Afsana Mahim
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Mohammad Karim
- Department of Cell and Gene Therapy, PPD, Middleton, WI, USA
| | - David H Petering
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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9
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Bahr G, González LJ, Vila AJ. Metallo-β-lactamases in the Age of Multidrug Resistance: From Structure and Mechanism to Evolution, Dissemination, and Inhibitor Design. Chem Rev 2021; 121:7957-8094. [PMID: 34129337 PMCID: PMC9062786 DOI: 10.1021/acs.chemrev.1c00138] [Citation(s) in RCA: 96] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Antimicrobial resistance is one of the major problems in current practical medicine. The spread of genes coding for resistance determinants among bacteria challenges the use of approved antibiotics, narrowing the options for treatment. Resistance to carbapenems, last resort antibiotics, is a major concern. Metallo-β-lactamases (MBLs) hydrolyze carbapenems, penicillins, and cephalosporins, becoming central to this problem. These enzymes diverge with respect to serine-β-lactamases by exhibiting a different fold, active site, and catalytic features. Elucidating their catalytic mechanism has been a big challenge in the field that has limited the development of useful inhibitors. This review covers exhaustively the details of the active-site chemistries, the diversity of MBL alleles, the catalytic mechanism against different substrates, and how this information has helped developing inhibitors. We also discuss here different aspects critical to understand the success of MBLs in conferring resistance: the molecular determinants of their dissemination, their cell physiology, from the biogenesis to the processing involved in the transit to the periplasm, and the uptake of the Zn(II) ions upon metal starvation conditions, such as those encountered during an infection. In this regard, the chemical, biochemical and microbiological aspects provide an integrative view of the current knowledge of MBLs.
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Affiliation(s)
- Guillermo Bahr
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
| | - Lisandro J. González
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
| | - Alejandro J. Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
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10
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Zlobin IE, Kartashov AV, Nosov AV, Fomenkov AA, Kuznetsov VV. The labile zinc pool in plant cells. FUNCTIONAL PLANT BIOLOGY : FPB 2019; 46:796-805. [PMID: 31072451 DOI: 10.1071/fp19064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/18/2019] [Indexed: 06/09/2023]
Abstract
Zinc is the most abundant and important transition metal in plants; however, the dynamic aspects of zinc homeostasis in plant cells are poorly understood. In this study we explored the pool of labile exchangeable zinc complexes in plant cells, and the potential influence of changes in intracellular zinc availability on cellular physiology. Work was performed on cultivated cell extracts of Arabidopsis thaliana (L.) Heynh. and Thellungiella salsuginea (Pall.) O.E. Schulz grown under control (3.48 µM Zn2+), 10-fold Zn excess or Zn starvation conditions. The free and labile Zn contents in the extracts were then determined by fluorimetric titration. We observed for the first time that plant cells contain micromolar concentrations of labile zinc complexes that account for a low percentage of the total zinc content. Labile zinc is mainly protein bound. Zn starvation inhibits cell proliferation and leads to the disappearance of the labile zinc pool, whereas Zn excess drastically increases the labile zinc pool. Free Zn2+ is buffered at picomolar concentrations in the intracellular milieu, and the increase in free Zn2+ concentrations to low nanomolar values clearly modulates enzyme activity by direct reversible binding. Such increases in free Zn2+ can be achieved by the substantial influx of additional zinc or by the oxidation of zinc-binding thiols. The observed features of the labile zinc pool in plant cells suggest it has a role in intracellular zinc trafficking and zinc signalling.
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Affiliation(s)
- Ilya E Zlobin
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; and Corresponding author.
| | - Alexander V Kartashov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia
| | - Alexander V Nosov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia
| | - Artem A Fomenkov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia
| | - Vladimir V Kuznetsov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia
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11
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Ren L, Dowlatshahi Pour M, Malmberg P, Ewing AG. Altered Lipid Composition of Secretory Cells Following Exposure to Zinc Can Be Correlated to Changes in Exocytosis. Chemistry 2019; 25:5406-5411. [PMID: 30762272 DOI: 10.1002/chem.201900010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Indexed: 12/20/2022]
Abstract
A micromolar concentration of zinc has been shown to significantly change the dynamics of exocytosis as well as the vesicle contents in a model cell line, providing direct evidence that zinc regulates neurotransmitter release. To provide insight into how zinc modulates these exocytotic processes, neurotransmitter release and vesicle content were compared with single cell amperometry and intracellular impact vesicle cytometry with a range of zinc concentrations. Additionally, time-of-flight secondary ion mass spectrometry (ToF-SIMS) images of lipid distributions in the cell membrane after zinc treatment correlate to changes in exocytosis. By combining electrochemical techniques and mass spectrometry imaging, we proposed a mechanism by which zinc changes the fusion pore and the rate of neurotransmitter release by changing lipid distributions and results in the modulation of synaptic strength and plasticity.
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Affiliation(s)
- Lin Ren
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | - Masoumeh Dowlatshahi Pour
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- Chemical Imaging Infrastructure, CII, University of Gothenburg and Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | - Per Malmberg
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- Chemical Imaging Infrastructure, CII, University of Gothenburg and Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | - Andrew G Ewing
- Chemical Imaging Infrastructure, CII, University of Gothenburg and Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 41296, Gothenburg, Sweden
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12
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Uh K, Ryu J, Zhang L, Errington J, Machaty Z, Lee K. Development of novel oocyte activation approaches using Zn2+ chelators in pigs. Theriogenology 2019; 125:259-267. [DOI: 10.1016/j.theriogenology.2018.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/31/2018] [Accepted: 11/14/2018] [Indexed: 10/27/2022]
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13
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Macias-Contreras M, He H, Zhu L. Beyond O6-Benzylguanine: O6-(5-Pyridylmethyl)guanine as a Substrate for the Self-Labeling Enzyme SNAP-Tag. Bioconjug Chem 2018; 29:4104-4109. [DOI: 10.1021/acs.bioconjchem.8b00703] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Miguel Macias-Contreras
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Huan He
- College of Medicine, Florida State University, Tallahassee, Florida 32306-4300, United States
| | - Lei Zhu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
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14
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Gaál A, Orgován G, Mihucz VG, Pape I, Ingerle D, Streli C, Szoboszlai N. Metal transport capabilities of anticancer copper chelators. J Trace Elem Med Biol 2018; 47:79-88. [PMID: 29544811 DOI: 10.1016/j.jtemb.2018.01.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/19/2018] [Accepted: 01/23/2018] [Indexed: 12/31/2022]
Abstract
In the present study, several Cu chelators [2,2'-biquinoline, 8-hydroxiquinoline (oxine), ammonium pyrrolidinedithiocarbamate (APDTC), Dp44mT, dithizone, neocuproine] were used to study Cu uptake, depletion and localization in different cancer cell lines. To better understand the concentration dependent fluctuations in the Cu intracellular metal content and Cu-dependent in vitro antiproliferative data, the conditional stability constants of the Cu complex species of the investigated ligands were calculated. Each investigated chelator increased the intracellular Cu content on HT-29 cells causing Cu accumulation depending on the amount of the free Cu(II). Copper accumulation was 159 times higher for Dp44mT compared to the control. Investigating a number of other transition metals, intracellular accumulation of Cd was observed only for two chelators. Intracellular Zn content slightly decreased (cca. 10%) for MCF-7 cells, while a dramatic decrease was observed on MDA-MB-231 ones (cca. 50%). A similar decrease was observed for HCT-116, while Zn depletion for HT-29 corresponded to cca. 20%. The IC50 values were registered for the investigated four cell lines at increasing external Cu(II) concentration, namely, MDA-MB-231 cells had the lowest IC50 values for Dp44mT ranging between 7 and 35 nM. Thus, Zn depletion could be associated with lower IC50 values. Copper depletion was observed for all ligands being less pronounced for Dp44mT and neocuproine. Copper localization and its colocalization with Zn were determined by μ-XRF imaging. Loose correlation (0.57) was observed for the MCF-7 cells independently of the applied chelator. Similarly, a weak correlation (0.47) was observed for HT-29 cells treated with Cu(II) and oxine. Colocalization of Cu and Zn in the nucleus of HT-29 cells was observed for Dp44mT (correlation coefficient of 0.85).
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Affiliation(s)
- Anikó Gaál
- Laboratory for Environmental Chemistry and Bioanalytics, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter stny. 1/A, Hungary
| | - Gábor Orgován
- Department of Pharmaceutical Chemistry, Semmelweis University, H-1092 Budapest, Hőgyes Endre u. 9, Hungary; Research Group of Drugs of Abuse and Doping Agents, Hungarian Academy of Sciences, H-1092 Budapest, Hőgyes Endre u. 9, Hungary
| | - Victor G Mihucz
- Laboratory for Environmental Chemistry and Bioanalytics, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter stny. 1/A, Hungary; Hungarian Satellite Trace Elements Institute to UNESCO, H-1117 Budapest, Pázmány Péter stny. 1/A, Hungary
| | - Ian Pape
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE, United Kingdom
| | - Dieter Ingerle
- Atominstitut, Technische Universitaet Wien, A-1020 Vienna, Stadionallee 2, Austria
| | - Christina Streli
- Atominstitut, Technische Universitaet Wien, A-1020 Vienna, Stadionallee 2, Austria
| | - Norbert Szoboszlai
- Laboratory for Environmental Chemistry and Bioanalytics, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter stny. 1/A, Hungary.
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15
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Imam HT, Blindauer CA. Differential reactivity of closely related zinc(II)-binding metallothioneins from the plant Arabidopsis thaliana. J Biol Inorg Chem 2018; 23:137-154. [PMID: 29218630 PMCID: PMC5756572 DOI: 10.1007/s00775-017-1516-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 11/12/2017] [Indexed: 12/04/2022]
Abstract
The dynamics of metal binding to and transfer from metalloproteins involved in metal homeostasis are important for understanding cellular distribution of metal ions. The dicotyledonous plant Arabidopsis thaliana has two type 4 seed-specific metallothionein homologues, MT4a and MT4b, with likely roles in zinc(II) homeostasis. These two metallothioneins are 84% identical, with full conservation of all metal-binding cysteine and histidine residues. Yet, differences in their spatial and temporal expression patterns suggested divergence in their biological roles. To investigate whether biological functions are reflected in molecular properties, we compare aspects of zinc(II)-binding dynamics of full-length MT4a and MT4b, namely the pH dependence of zinc(II) binding and protein folding, and zinc(II) transfer to the chelator EDTA. UV-Vis and NMR spectroscopies as well as native electrospray ionisation mass spectrometry consistently showed that transfer from Zn6MT4a is considerably faster than from Zn6MT4b, with pseudo-first-order rate constants for the fastest observed step of k obs = 2.8 × 10-4 s-1 (MT4b) and k obs = 7.5 × 10-4 s-1 (MT4a) (5 µM protein, 500 µM EDTA, 25 mM Tris buffer, pH 7.33, 298 K). 2D heteronuclear NMR experiments allowed locating the most labile zinc(II) ions in domain II for both proteins. 3D homology models suggest that reactivity of this domain is governed by the local environment around the mononuclear Cys2His2 site that is unique to type 4 MTs. Non-conservative amino acid substitutions in this region affect local electrostatics as well as whole-domain dynamics, with both effects rendering zinc(II) ions bound to MT4a more reactive in metal transfer reactions. Therefore, domain II of MT4a is well suited to rapidly release its bound zinc(II) ions, in broad agreement with a previously suggested role of MT4a in zinc(II) transport and delivery to other proteins.
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Affiliation(s)
- Hasan T Imam
- Department of Chemistry, The University of Warwick, Coventry, CV4 7AL, UK
- School of Chemistry, University of St. Andrews, St. Andrews, KY16 9ST, UK
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Reiber C, Brieger A, Engelhardt G, Hebel S, Rink L, Haase H. Zinc chelation decreases IFN-β-induced STAT1 upregulation and iNOS expression in RAW 264.7 macrophages. J Trace Elem Med Biol 2017; 44:76-82. [PMID: 28965604 DOI: 10.1016/j.jtemb.2017.05.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/11/2017] [Accepted: 05/30/2017] [Indexed: 12/24/2022]
Abstract
One consequence of lipopolysaccharide (LPS)-induced stimulation of macrophages is the release of Interferon (IFN)-β, and subsequently the activation of the JAK-STAT1 pathway, resulting in the expression of inducible nitric oxide synthase (iNOS). Free intracellular zinc ions (Zn2+) have a profound impact as a second messenger in LPS-dependent gene expression. Previous work had indicated a Zn2+-dependent upregulation of STAT1 mRNA in response to LPS and IFN-β, potentially affecting STAT1-dependent downstream signaling upon pre-incubation with these agents. The aim of the present study was to investigate the long-term influence of Zn2+ chelation on cellular STAT1 levels and their effect on protein levels and activity of iNOS. The LPS- and IFN-β-mediated increase of STAT1 mRNA and protein levels was abrogated by chelation of Zn2+ with the membrane permeable chelator N,N,N',N'-Tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) in RAW 264.7 macrophages. After 48h pre-incubation together with IFN-β, TPEN also led to reduced nitric monoxide formation in response to a second stimulation with LPS. Nonetheless, the latter was observed regardless of any pre-incubation with IFN-β, suggesting that the effect of treatment with TPEN negatively affects iNOS induction independently from cellular STAT1 levels. In conclusion, long term Zn2+ chelation does affect STAT1 protein expression, but interferes with NO production by a different, yet unknown pathway not involving STAT1. However, as there are many additional STAT1-dependent genes, there might still be effects on targets other than iNOS.
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Affiliation(s)
- Cathleen Reiber
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Anne Brieger
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Gabriela Engelhardt
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Silke Hebel
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Lothar Rink
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Hajo Haase
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany; Department of Food Chemistry and Toxicology, Berlin Institute of Technology, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany.
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17
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Zlobin IE, Kartashov AV, Shpakovski GV. Different roles of glutathione in copper and zinc chelation in Brassica napus roots. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 118:333-341. [PMID: 28683402 DOI: 10.1016/j.plaphy.2017.06.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
We investigated the specific features of copper and zinc excess action on the roots of canola (Brassica napus L.) plants. Copper rapidly accumulated in canola root cells and reached saturation during several hours of treatment, whereas the root zinc content increased relatively slowly. Excessive copper and zinc entry inside the cell resulted in significant cell damage, as evidenced by alterations in plasmalemma permeability and decreases in cellular enzymatic activity. Zinc excess specifically damaged root hair cells, which correlated with a pronounced elevation of their labile zinc level. In vitro, we showed that reduced glutathione (GSH) readily reacted with copper ions to form complexes with blocked sulfhydryl groups. In contrast, zinc ions were ineffective as glutathione blockers, and glutathione molecules did not lose their specific chemical activity in the presence of Zn2+ ions. The effect of copper and zinc excess on the glutathione pool in canola root cells was analysed by a combination of biochemical determination of total and oxidized glutathione contents and fluorescent staining of free reduced glutathione with monochlorobimane dye. Excess copper led to dose-dependent diminution of free reduced glutathione contents in the root cells, which could not be explained by the loss of total cellular glutathione or its oxidation. In contrast, we observed little effect of much higher intracellular zinc concentrations on the free reduced glutathione content. We concluded that GSH plays an important role in copper excess, but not zinc excess chelation, in canola root cells.
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Affiliation(s)
- Ilya E Zlobin
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, 127276 Moscow, Russia
| | - Alexander V Kartashov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, 127276 Moscow, Russia.
| | - George V Shpakovski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
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18
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Abstract
The cellular constitution of Zn-proteins and Zn-dependent signaling depend on the capacity of Zn2+ to find specific binding sites in the face of a plethora of other high affinity ligands. The most prominent of these is metallothionein (MT). It serves as a storage site for Zn2+ under various conditions, and has chemical properties that support a dynamic role for MT in zinc trafficking. Consistent with these characteristics, changing the availability of zinc for cells and tissues causes rapid alteration of zinc bound to MT. Nevertheless, zinc trafficking occurs in metallothionein-null animals and cells, hypothetically making use of proteomic binding sites to mediate the intracellular movements of zinc. Like metallothionein, the proteome contains a large concentration of proteins that strongly coordinate zinc. In this environment, free Zn2+ may be of little significance. Instead, this review sets forth the basis for the hypothesis that components of the proteome and MT jointly provide the platform for zinc trafficking.
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Affiliation(s)
- David H Petering
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53217, USA.
| | - Afsana Mahim
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53217, USA.
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19
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Petering DH. Reactions of the Zn Proteome with Cd2+ and Other Xenobiotics: Trafficking and Toxicity. Chem Res Toxicol 2016; 30:189-202. [DOI: 10.1021/acs.chemrestox.6b00328] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- David H. Petering
- Department of Chemistry and
Biochemistry, University of Wisconsin−Milwaukee, Milwaukee, Wisconsin 53201, United States
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20
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TPEN, a Specific Zn 2+ Chelator, Inhibits Sodium Dithionite and Glucose Deprivation (SDGD)-Induced Neuronal Death by Modulating Apoptosis, Glutamate Signaling, and Voltage-Gated K + and Na + Channels. Cell Mol Neurobiol 2016; 37:235-250. [PMID: 26983717 DOI: 10.1007/s10571-016-0364-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/08/2016] [Indexed: 02/06/2023]
Abstract
Hypoxia-ischemia-induced neuronal death is an important pathophysiological process that accompanies ischemic stroke and represents a major challenge in preventing ischemic stroke. To elucidate factors related to and a potential preventative mechanism of hypoxia-ischemia-induced neuronal death, primary neurons were exposed to sodium dithionite and glucose deprivation (SDGD) to mimic hypoxic-ischemic conditions. The effects of N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), a specific Zn2+-chelating agent, on SDGD-induced neuronal death, glutamate signaling (including the free glutamate concentration and expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor (GluR2) and N-methyl-D-aspartate (NMDA) receptor subunits (NR2B), and voltage-dependent K+ and Na+ channel currents were also investigated. Our results demonstrated that TPEN significantly suppressed increases in cell death, apoptosis, neuronal glutamate release into the culture medium, NR2B protein expression, and I K as well as decreased GluR2 protein expression and Na+ channel activity in primary cultured neurons exposed to SDGD. These results suggest that TPEN could inhibit SDGD-induced neuronal death by modulating apoptosis, glutamate signaling (via ligand-gated channels such as AMPA and NMDA receptors), and voltage-gated K+ and Na+ channels in neurons. Hence, Zn2+ chelation might be a promising approach for counteracting the neuronal loss caused by transient global ischemia. Moreover, TPEN could represent a potential cell-targeted therapy.
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21
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Dziegiel P, Pula B, Kobierzycki C, Stasiolek M, Podhorska-Okolow M. Metallothioneins: Structure and Functions. METALLOTHIONEINS IN NORMAL AND CANCER CELLS 2016. [DOI: 10.1007/978-3-319-27472-0_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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22
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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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23
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Liu Z, Huang YY, Wang YX, Wang HG, Deng F, Heng B, Xie LH, Liu YQ. Prevention of cell death by the zinc ion chelating agent TPEN in cultured PC12 cells exposed to Oxygen-Glucose Deprivation (OGD). J Trace Elem Med Biol 2015; 31:45-52. [PMID: 26004891 DOI: 10.1016/j.jtemb.2015.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 03/07/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
To elucidate the role of Zn(2+)-associated glutamate signaling pathway and voltage-dependent outward potassium ion currents in neuronal death induced by hypoxia-ischemia, PC12 cells were exposed to Oxygen-Glucose Deprivation (OGD) solution mimicking the hypoxic-ischemic condition in neuron, and the effect of N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), a specific Zn(2+) chelating agent on OGD-induced neuronal death was assessed in the present study. The cell survival rate, apoptosis status, potassium channel currents, intracellular free glutamate concentration and GluR2 expression in PC12 cells exposed to OGD in the absence or presence of TPEN for different time were investigated. The results showed that OGD exposure increased apoptosis, reduced the cell viability (P < 0.01 at 3h, 6h and 24h, respectively compared to control), changed the voltage-dependent outward potassium ion current (increase at 1h, but decrease at 3h) and decreased the concentration of intracellular glutamate (P < 0.05 at 3h and 6h, P < 0.01 at 24h respectively compared to control) and GluR2 expression (P < 0.05 at 3h, 6h and 24h, respectively compared to control) in PC12 cells. TPEN partially reversed the influence resulted from OGD. These results suggest that OGD-induced cell apoptosis and/or death is mediated by the alteration in glutamate signaling pathway and the voltage-dependent outward potassium ion currents, while TPEN effectively prevent cell apoptosis and/or death under hypoxic-ischemic condition.
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Affiliation(s)
- Zhao Liu
- College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Yue-yang Huang
- College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Yu-xiang Wang
- College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Hong-gang Wang
- College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Fei Deng
- College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Bin Heng
- College of Life Sciences, Nankai University, Tianjin 300071, PR China
| | - Lai-hua Xie
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, USA
| | - Yan-qiang Liu
- College of Life Sciences, Nankai University, Tianjin 300071, PR China.
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24
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Nowakowski AB, Wobig WJ, Petering DH. Native SDS-PAGE: high resolution electrophoretic separation of proteins with retention of native properties including bound metal ions. Metallomics 2014; 6:1068-78. [PMID: 24686569 PMCID: PMC4517606 DOI: 10.1039/c4mt00033a] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) is commonly used to obtain high resolution separation of complex mixtures of proteins. The method initially denatures the proteins that will undergo electrophoresis. Although covalent structural features of resolved proteins can be determined with SDS-PAGE, functional properties are destroyed, including the presence of non-covalently bound metal ions. To address this shortcoming, blue-native (BN)-PAGE has been introduced. This method retains functional properties but at the cost of protein resolving power. To address the need for a high resolution PAGE method that results in the separation of native proteins, experiments tested the impact of changing the conditions of SDS-PAGE on the quality of protein separation and retention of functional properties. Removal of SDS and EDTA from the sample buffer together with omission of a heating step had no effect on the results of PAGE. Reduction of SDS in the running buffer from 0.1% to 0.0375% together with deletion of EDTA also made little impact on the quality of the electrophoretograms of fractions of pig kidney (LLC-PK1) cell proteome in comparison with that achieved with the SDS-PAGE method. The modified conditions were called native (N)SDS-PAGE. Retention of Zn(2+) bound in proteomic samples increased from 26 to 98% upon shifting from standard to modified conditions. Moreover, seven of nine model enzymes, including four Zn(2+) proteins that were subjected to NSDS-PAGE retained activity. All nine were active in BN-PAGE, whereas all underwent denaturation during SDS-PAGE. Metal retention after electrophoresis was additionally confirmed using laser ablation-inductively coupled plasma-mass spectrometry and in-gel Zn-protein staining using the fluorophore TSQ.
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Affiliation(s)
- Andrew B Nowakowski
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 N Cramer Street, Milwaukee, WI 53201, USA.
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25
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Kiedrowski L. Proton-dependent zinc release from intracellular ligands. J Neurochem 2014; 130:87-96. [PMID: 24606401 DOI: 10.1111/jnc.12712] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/01/2014] [Accepted: 03/06/2014] [Indexed: 11/30/2022]
Abstract
In cultured cortical and hippocampal neurons when intracellular pH drops from 6.6 to 6.1, yet unclear intracellular stores release micromolar amounts of Zn(2+) into the cytosol. Mitochondria, acidic organelles, and/or intracellular ligands could release this Zn(2+) . Although exposure to the protonophore FCCP precludes reloading of the mitochondria and acidic organelles with Zn(2+) , FCCP failed to compromise the ability of the intracellular stores to repeatedly release Zn(2+) . Therefore, Zn(2+) -releasing stores were not mitochondria or acidic organelles but rather intracellular Zn(2+) ligands. To test which ligands might be involved, the rate of acid-induced Zn(2+) release from complexes with cysteine, glutathione, histidine, aspartate, glutamate, glycine, and carnosine was investigated; [Zn(2+) ] was monitored in vitro using the ratiometric Zn(2+) -sensitive fluorescent probe FuraZin-1. Carnosine failed to chelate Zn(2+) but did chelate Cu(2+) ; the remaining ligands chelated Zn(2+) and upon acidification were releasing it into the medium. However, when pH was decreasing from 6.6 to 6.1, only zinc-cysteine complexes rapidly accelerated the rate of Zn(2+) release. The zinc-cysteine complexes also released Zn(2+) when a histidine-modifying agent, diethylpyrocarbonate, was applied at pH 7.2. Since the cytosolic zinc-cysteine complexes can contain micromolar amounts of Zn(2+) , these complexes may represent the stores responsible for an acid-induced intracellular Zn(2+) release. This study aimed at identifying intracellular stores which release Zn(2+) when pHi drops from 6.6 to 6.1. It was found that these stores are not mitochondria or acidic organelles, but rather intracellular Zn(2+) ligands. When the pH was decreasing from 6.6 to 6.1, only zinc-cysteine complexes showed a rapid acceleration in the rate of Zn(2+) release. Therefore, the stores responsible for an acid-induced intracellular Zn(2+) release in neurons may be the cytosolic zinc-cysteine complexes.
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Affiliation(s)
- Lech Kiedrowski
- Departments of Psychiatry and Pharmacology, The Psychiatric Institute, The University of Illinois at Chicago, Chicago, Illinois, USA
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26
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Namdarghanbari MA, Bertling J, Krezoski S, Petering DH. Toxic metal proteomics: reaction of the mammalian zinc proteome with Cd²⁺. J Inorg Biochem 2014; 136:115-21. [PMID: 24529759 DOI: 10.1016/j.jinorgbio.2014.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 01/15/2014] [Accepted: 01/16/2014] [Indexed: 10/25/2022]
Abstract
The hypothesis was tested that Cd(2+) undergoes measureable reaction with the Zn-proteome through metal ion exchange chemistry. The Zn-proteome of pig kidney LLC-PK1 cells is relatively inert to reaction with competing ligands, including Zinquin acid, EDTA, and apo-metallothionein. Upon reaction of Cd(2+) with the Zn-proteome, Cd(2+) associates with the proteome and near stoichiometric amounts of Zn(2+) become reactive with these chelating agents. The results strongly support the hypothesis that Cd(2+) displaces Zn(2+) from native proteomic binding sites resulting in the formation of a Cd-proteome. Mobilized Zn(2+) becomes adventitiously bound to proteome and available for reaction with added metal binding ligands. Cd-proteome and Zn-metallothionein readily exchange metal ions, raising the possibility that this reaction restores functionality to Cd-proteins. In a parallel experiment, cells were exposed to Cd(2+) and pyrithione briefly to generate substantial proteome-bound Cd(2+). Upon transition to a Cd(2+) free medium, the cells generated new metallothionein protein over time that bound most of the proteomic Cd(2+) as well as additional Zn(2+).
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Affiliation(s)
| | - Joseph Bertling
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
| | - Susan Krezoski
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
| | - David H Petering
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.
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27
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Stotz HU, Findling S, Nukarinen E, Weckwerth W, Mueller MJ, Berger S. A tandem affinity purification tag of TGA2 for isolation of interacting proteins in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2014; 9:e972794. [PMID: 25482810 PMCID: PMC4622720 DOI: 10.4161/15592316.2014.972794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Tandem affinity purification (TAP) tagging provides a powerful tool for isolating interacting proteins in vivo. TAP-tag purification offers particular advantages for the identification of stimulus-induced protein interactions. Type II bZIP transcription factors (TGA2, TGA5 and TGA6) play key roles in pathways that control salicylic acid, ethylene, xenobiotic and reactive oxylipin signaling. Although proteins interacting with these transcription factors have been identified through genetic and yeast 2-hybrid screening, others are still elusive. We have therefore generated a C-terminal TAP-tag of TGA2 to isolate additional proteins that interact with this transcription factor. Three lines most highly expressing TAP-tagged TGA2 were functional in that they partially complemented reactive oxylipin-responsive gene expression in a tga2 tga5 tga6 triple mutant. TAP-tagged TGA2 in the most strongly overexpressing line was proteolytically less stable than in the other 2 lines. Only this overexpressing line could be used in a 2-step purification process, resulting in isolation of co-purifying bands of larger molecular weight than TGA2. TAP-tagged TGA2 was used to pull down NPR1, a protein known to interact with this transcription factor. Mass spectrometry was used to identify peptides that co-purified with TAP-tagged TGA2. Having generated this TGA2 TAP-tag line will therefore be an asset to researchers interested in stimulus-induced signal transduction processes.
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Key Words
- 12-oxo-phytodienoic acid
- CBB, calmodulin binding buffer
- CBP, calmodulin-binding peptide
- CaMV, cauliflower mosaic virus
- FDR, false discovery rate
- MS, mass spectrometry
- OPDA, 12-oxo-phytodienoic acid
- PGA1, prostaglandin A1
- PPA1, phytoprostane A1
- RubisCo, ribulose-1,5-bisphosphate carboxylase
- SA, salicylic acid
- SAR, systemic acquired resistance
- TAP, tandem affinity purification
- TEV, tobacco etch virus
- Y2H, yeast 2-hybrid
- bZIP, basic region/leucine zipper motif
- glutathione-S-transferase
- lipid stress
- protein complex
- thale cress
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Affiliation(s)
- Henrik U Stotz
- Julius-von-Sachs-Institute für Biowissenschaften; Pharmazeutische Biologie; Universität Würzburg; Würzburg, Germany
- School of Life and Medical Sciences; University of Hertfordshire; Hatfield, U.K
- Correspondence to: Henrik U Stotz;
| | - Simone Findling
- Julius-von-Sachs-Institute für Biowissenschaften; Pharmazeutische Biologie; Universität Würzburg; Würzburg, Germany
| | - Ella Nukarinen
- Molecular Systems Biology; Faculty of Life Sciences; University of Vienna; Vienna, Austria
| | - Wolfram Weckwerth
- Molecular Systems Biology; Faculty of Life Sciences; University of Vienna; Vienna, Austria
| | - Martin J Mueller
- Julius-von-Sachs-Institute für Biowissenschaften; Pharmazeutische Biologie; Universität Würzburg; Würzburg, Germany
| | - Susanne Berger
- Julius-von-Sachs-Institute für Biowissenschaften; Pharmazeutische Biologie; Universität Würzburg; Würzburg, Germany
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Haase H, Rink L. Zinc signals and immune function. Biofactors 2014; 40:27-40. [PMID: 23804522 DOI: 10.1002/biof.1114] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/23/2013] [Accepted: 04/25/2013] [Indexed: 12/21/2022]
Abstract
For more than 50 years, it has been known that zinc deficiency compromises immune function. During this time, knowledge about the biochemistry of zinc has continued to grow, but only recent years have provided in-depth molecular insights into the multiple aspects of zinc as a regulator of immunity. A network based on ZnT and ZIP proteins for transport and metallothionein for storage tightly regulates zinc availability, and virtually all aspects of innate and adaptive immunity are affected by zinc. In vivo, zinc deficiency alters the number and function of neutrophil granulocytes, monocytes, natural killer (NK)-, T-, and B-cells. T cell functions and balance between the different subsets are particularly susceptible to changes in zinc status. This article focuses in particular on the main mechanisms by which zinc ions exert essential functions in the immune system. On the one hand, this includes tightly protein bound zinc ions serving catalytic or structural functions in a multitude of different proteins, in particular enzymes and transcription factors. On the other hand, increasing evidence arises for a regulatory role of free zinc ions in signal transduction, especially in cells of the immune system. Identification of several molecular targets, including phosphatases, phosphodiesterases, caspases, and kinases suggest that zinc ions are a second messenger regulating signal transduction in various kinds of immune cells.
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Affiliation(s)
- Hajo Haase
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Pauwelsstrasse 30, Aachen, Germany
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Huang Z, Zhang XA, Bosch M, Smith SJ, Lippard SJ. Tris(2-pyridylmethyl)amine (TPA) as a membrane-permeable chelator for interception of biological mobile zinc. Metallomics 2013; 5:648-55. [PMID: 23715510 DOI: 10.1039/c3mt00103b] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We report the characterization of tris(2-pyridylmethyl)amine (TPA) as a membrane-permeable zinc chelator for intercepting biological mobile zinc. Compared to N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), TPA chelates zinc with faster kinetics in cuvettes, live cells, and brain slices. TPA also is generally less toxic than TPEN in cell culture. Mechanistic analysis indicates that these improvements arise from both the electronic and steric properties of TPA including weaker metal-binding affinity, lower pKa, and smaller size. These results demonstrate that TPA chelation is a valuable addition to the methodologies available for investigating mobile zinc in biology.
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Affiliation(s)
- Zhen Huang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Heterologous expression and metal-binding characterization of a type 1 metallothionein isoform (OsMTI-1b) from rice (Oryza sativa). Protein J 2013; 32:131-7. [PMID: 23385446 DOI: 10.1007/s10930-013-9469-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Metallothioneins (MTs) are ubiquitous, low molecular mass and cysteine-rich proteins that play important roles in maintaining intracellular metal homeostasis, eliminating metal toxification and protecting the cells against oxidative damages. MTs are able to bind metal ions through the thiol groups of their cysteine residues. Plants have several MT isoforms which are classified into four types based on the arrangement of cysteine residues. In the present study, a rice (Oryza sativa) gene encoding type 1 MT isoform, OsMTI-1b, was inserted in vector pET41a and overexpressed in Escherichia coli as carboxy-terminal extensions of glutathione-S-transferase (GST). The recombinant protein GST-OsMTI-1b was purified using affinity chromatography and its ability to bind with Ni(2+), Cd(2+), Zn(2+) and Cu(2+) ions was analyzed. The results demonstrated that this isoform has ability to bind Ni(2+), Cd(2+) and Zn(2+) ions in vitro, whereas it has no substantial ability to bind Cu(2+) ions. From competitive reaction with 5,5'-dithiobis(2-nitrobenzoic acid), DTNB, the affinity of metal ions for recombinant form of GST-OsMTI-1b was as follows: Ni(2+)/Cd(2+) > Zn(2+) > Cu(2+).
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31
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Southern PJ. Missing out on the biology of heterosexual HIV-1 transmission. Trends Microbiol 2013; 21:245-52. [DOI: 10.1016/j.tim.2013.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 02/03/2013] [Accepted: 02/06/2013] [Indexed: 11/16/2022]
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Simmons JT, Allen JR, Morris DR, Clark RJ, Levenson CW, Davidson MW, Zhu L. Integrated and passive 1,2,3-triazolyl groups in fluorescent indicators for zinc(II) ions: thermodynamic and kinetic evaluations. Inorg Chem 2013; 52:5838-50. [PMID: 23621758 DOI: 10.1021/ic302798u] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In addition to being a covalent linker in molecular conjugation chemistry, the function of a 1,2,3-triazolyl moiety resulting from the copper(I)-catalyzed azide-alkyne cycloaddition reaction as a ligand for metal ions is receiving considerable attention. In this work, we characterize the thermodynamic and kinetic effects of incorporating a 1,2,3-triazolyl group in a multidentate ligand scaffold on metal coordination in the context of fluorescent zinc(II) indicator development. Ligands L14, BrL14, and FL14 (1,4-isomers) contain the 1,4-disubstituted-1,2,3-triazolyl group that is capable of binding with zinc(II) in conjunction with a di(2-picolylamino) (DPA) moiety within a multidentate ligand scaffold. Therefore, the 1,2,3-triazolyl in the 1,4-isomers is "integrated" in chelation. The 1,5-isomers L15, BrL15, and FL15 contain 1,2,3-triazolyls that are excluded from participating in zinc(II) coordination. These 1,2,3-triazolyls are "passive linkers". Zinc(II) complexes of 2:1 (ligand/metal) stoichiometry are identified in solution using (1)H NMR spectroscopy and isothermal titration calorimetry (ITC) and, in one case, characterized in the solid state. The 1:1 ligand/zinc(II) affinity ratio of L14 over L15, which is attributed to the affinity enhancement of a 1,2,3-triazolyl group to zinc(II) over that of the solvent acetonitrile, is quantified at 18 (-1.7 kcal/mol at 298 K) using an ITC experiment. Fluorescent ligands FL14 and FL15 are evaluated for their potential in zinc(II) sensing applications under pH neutral aqueous conditions. The 1,4-isomer FL14 binds zinc(II) both stronger and faster than the 1,5-isomer FL15. Visualization of free zinc(II) ion distribution in live HeLa cells is achieved using both FL14 and FL15. The superiority of FL14 in staining endogenous zinc(II) ions in live rat hippocampal slices is evident. In summation, this work is a fundamental study of 1,2,3-triazole coordination chemistry, with a demonstration of its utility in developing fluorescent indicators.
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Affiliation(s)
- J Tyler Simmons
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306-4390, United States
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Hasan R, Rink L, Haase H. Zinc signals in neutrophil granulocytes are required for the formation of neutrophil extracellular traps. Innate Immun 2012; 19:253-64. [DOI: 10.1177/1753425912458815] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Zinc signals, i.e. changes in the free intracellular Zn2+concentration, are an integral component of signal transduction in several immune cells. The aim of the present study was to investigate if this is also the case in neutrophil granulocytes. One neutrophil function is NETosis, the release of a matrix composed of DNA, chromatin and granule proteins to capture extracellular bacteria within so-called neutrophil extracellular traps (NET). NETosis can be induced by the protein kinase C (PKC) activator 12-myristate 13-acetate (PMA). PMA treatment led to a zinc signal in neutrophil granulocytes. NETosis was inhibited when the zinc signal was sequestered by the membrane permeable high affinity chelator N, N, N′, N′,-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN). PKC-mediated NET formation depends on the production of reactive oxygen species (ROS) by NADPH oxidase. Inhibition of NADPH oxidase with diphenyleneiodonium chloride blocked ROS formation and NETosis, as well as the zinc signal. TPEN, however, had no effect on PKC activity and ROS production, indicating that Zn2+ is not required for activation of PKC, but for signals downstream of ROS production. In conclusion, zinc signals are an essential component of the ROS-dependent signal transduction leading to NETosis.
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Affiliation(s)
- Rafah Hasan
- RWTH Aachen University Hospital, Medical Faculty, Institute of Immunology, Germany
| | - Lothar Rink
- RWTH Aachen University Hospital, Medical Faculty, Institute of Immunology, Germany
| | - Hajo Haase
- RWTH Aachen University Hospital, Medical Faculty, Institute of Immunology, Germany
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34
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Meeusen JW, Nowakowski A, Petering DH. Reaction of metal-binding ligands with the zinc proteome: zinc sensors and N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine. Inorg Chem 2012; 51:3625-32. [PMID: 22380934 PMCID: PMC3564517 DOI: 10.1021/ic2025236] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The commonly used Zn(2+) sensors 6-methoxy-8-p-toluenesulfonamidoquinoline (TSQ) and Zinquin have been shown to image zinc proteins as a result of the formation of sensor-zinc-protein ternary adducts not Zn(TSQ)(2) or Zn(Zinquin)(2) complexes. The powerful, cell-permeant chelating agent N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) is also used in conjunction with these and other Zn(2+) sensors to validate that the observed fluorescence enhancement seen with the sensors depends on intracellular interaction with Zn(2+). We demonstrated that the kinetics of the reaction of TPEN with cells pretreated with TSQ or Zinquin was not consistent with its reaction with Zn(TSQ)(2) or Zn(Zinquin)(2). Instead, TPEN and other chelating agents extract between 25 and 35% of the Zn(2+) bound to the proteome, including zinc(2+) from zinc metallothionein, and thereby quench some, but not all, of the sensor-zinc-protein fluorescence. Another mechanism in which TPEN exchanges with TSQ or Zinquin to form TPEN-zinc-protein adducts found support in the reactions of TPEN with Zinquin-zinc-alcohol dehydrogenase. TPEN also removed one of the two Zn(2+) ions per monomer from zinc-alcohol dehydrogenase and zinc-alkaline phosphatase, consistent with its ligand substitution reactivity with the zinc proteome.
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Affiliation(s)
- Jeffrey W. Meeusen
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201
| | - Andrew Nowakowski
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201
| | - David H. Petering
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201
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35
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Nowakowski AB, Petering DH. Reactions of the fluorescent sensor, Zinquin, with the zinc-proteome: adduct formation and ligand substitution. Inorg Chem 2011; 50:10124-33. [PMID: 21905645 DOI: 10.1021/ic201076w] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Zinquin (ZQ) is a commonly used sensor for cellular Zn(2+) status. It has been assumed that it measures accessible Zn(2+) concentrations in the nanomolar range. Instead, this report shows a consistent pattern across seven mammalian cell and tissue types that ZQ reacts with micromolar concentrations of Zn(2+) bound as Zn-proteins. The predominant class of products were ZQ-Zn-protein adducts that were characterized in vivo and in vitro by a fluorescence emission spectrum centered at about 470 nm, by their migration over Sephadex G-75 as protein not low molecular weight species, by the exclusion of reaction with lipid vesicles, and by their large aggregate concentration. In addition, variable, minor formation of Zn(ZQ)(2) with a fluorescence band at about 490 nm was observed in vivo in each case. Because incubation of isolated Zn-proteome with ZQ also generated similar amounts of Zn(ZQ)(2), it was concluded that this species had formed through direct ligand substitution in which ZQ had successfully competed for protein-bound Zn(2+). Parallel studies with the model Zn-proteins, alcohol dehydrogenase (ADH), and alkaline phosphatase (AP) revealed a similar picture of reactivity: ZQ(ACID) (Zinquin acid, (2-methyl-8-p-toluenesulfonamido-6-quinolyloxy)acetate)) able to bind to one Zn(2+) and extract the other in Zn(2)-ADH, whereas it removed one Zn(2+) from Zn(2)-AP and did not bind to the other. Zinquin ethyl ester (ethyl(2-methyl-8-p-toluenesulfonamido-6-quinolyloxy)acetate); ZQ(EE)) bound to both proteins without sequestering Zn(2+) from either one. In contrast to a closely related sensor, 6-methoxy-8-p-toluenesulfonamido-quinoline (TSQ), neither ZQ(ACID) nor ZQ(EE) associated with Zn-carbonic anhydrase. A survey of reactivity of these sensors with partially fractionated Zn-proteome confirmed that ZQ and TSQ bind to distinct, overlapping subsets of the Zn-proteome.
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Affiliation(s)
- Andrew B Nowakowski
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA
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36
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Mammalian metallothionein in toxicology, cancer, and cancer chemotherapy. J Biol Inorg Chem 2011; 16:1087-101. [PMID: 21822976 DOI: 10.1007/s00775-011-0823-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 07/20/2011] [Indexed: 12/16/2022]
Abstract
The present paper centers on mammalian metallothionein 1 and 2 in relationship to cell and tissue injury beginning with its reaction with Cd²⁺ and then considering its role in the toxicology and chemotherapy of both metals and non-metal electrophiles and oxidants. Intertwined is a consideration of MTs role in tumor cell Zn²⁺ metabolism. The paper updates and expands on our recent review by Petering et al. (Met Ions Life Sci 5:353-398, 2009).
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Meeusen JW, Tomasiewicz H, Nowakowski A, Petering DH. TSQ (6-methoxy-8-p-toluenesulfonamido-quinoline), a common fluorescent sensor for cellular zinc, images zinc proteins. Inorg Chem 2011; 50:7563-73. [PMID: 21774459 DOI: 10.1021/ic200478q] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Zn(2+) is a necessary cofactor for thousands of mammalian proteins. Research has suggested that transient fluxes of cellular Zn(2+) are also involved in processes such as apoptosis. Observations of Zn(2+) trafficking have been collected using Zn(2+) responsive fluorescent dyes. A commonly used Zn(2+) fluorophore is 6-methoxy-8-p-toluenesulfonamido-quinoline (TSQ). The chemical species responsible for TSQ's observed fluorescence in resting or activated cells have not been characterized. Parallel fluorescence microscopy and spectrofluorometry of LLC-PK(1) cells incubated with TSQ demonstrated punctate staining that concentrated around the nucleus and was characterized by an emission maximum near 470 nm. Addition of cell permeable Zn-pyrithione resulted in greatly increased, diffuse fluorescence that shifted the emission peak to 490 nm, indicative of the formation of Zn(TSQ)(2). TPEN (N,N,N'N'-tetrakis(-)[2-pyridylmethyl]-ethylenediamine), a cell permeant Zn(2+) chelator, largely quenched TSQ fluorescence returning the residual fluorescence to the 470 nm emission maximum. Gel filtration chromatography of cell supernatant from LLC-PK(1) cells treated with TSQ revealed that TSQ fluorescence (470 nm emission) eluted with the proteome fractions. Similarly, addition of TSQ to proteome prior to chromatography resulted in 470 nm fluorescence emission that was not observed in smaller molecular weight fractions. It is hypothesized that Zn-TSQ fluorescence, blue-shifted from the 490 nm emission maximum of Zn(TSQ)(2), results from ternary complex, TSQ-Zn-protein formation. As an example, Zn-carbonic anhydrase formed a ternary adduct with TSQ characterized by a fluorescence emission maximum of 470 nm and a dissociation constant of 1.55 × 10(-7) M. Quantification of TSQ-Zn-proteome fluorescence indicated that approximately 8% of cellular Zn(2+) was imaged by TSQ. These results were generalized to other cell types and model Zn-proteins.
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Affiliation(s)
- Jeffrey W Meeusen
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA
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Abstract
Metallothioneins (MT) are a family of small cysteine rich proteins, which since their discovery in 1957, have been implicated in a range of roles including toxic metal detoxification, protection against oxidative stress, and as a metallochaperone involved in the homeostasis of both zinc and copper. The most well studied member of the family is the mammalian metallothionein, which consists of two domains: a β-domain with 9 cysteine residues, which sequesters 3 Cd(2+) or Zn(2+) or 6 Cu(+) ions, and an α-domain with 11 cysteine residues and, which sequesters 4 Cd(2+) or Zn(2+) or 6 Cu(+) ions. Despite over half a century of research, the exact functions of MT are still unknown. Much of current research aims to elucidate the mechanism of metal binding, as well as to isolate intermediates in metal exchange reactions; reactions necessary to maintain homeostatic equilibrium. These studies further our understanding of the role(s) of this remarkable and ubiquitous protein. Recently, supermetallated forms of the protein, where supermetallation describes metallation in excess of traditional levels, have been reported. These species may potentially be the metal exchange intermediates necessary to maintain homeostatic equilibrium. This review focuses on recent advances in the understanding of the mechanistic properties of metal binding, the implications for the metal induced protein folding reactions proposed for metallothionein metallation, the value of "magic numbers", which we informally define as the commonly determined metal-to-protein stoichiometric ratios and the significance of the new supermetallated states of the protein and the possible interpretation of the structural properties of this new metallation status. Together we provide a commentary on current experimental and theoretical advances and frame our consideration in terms of the possible functions of MT.
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Tuncay E, Bilginoglu A, Sozmen NN, Zeydanli EN, Ugur M, Vassort G, Turan B. Intracellular free zinc during cardiac excitation-contraction cycle: calcium and redox dependencies. Cardiovasc Res 2010; 89:634-42. [PMID: 21062918 DOI: 10.1093/cvr/cvq352] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
AIMS Zinc exists in biological systems as bound and histochemically reactive free Zn(2+). It is an essential structural constituent of many proteins, including enzymes from cellular signalling pathways, in which it functions as a signalling molecule. In cardiomyocytes at rest, Zn(2+) concentration is in the nanomolar range. Very little is known about precise mechanisms controlling the intracellular distribution of Zn(2+) and its variations during cardiac function. METHODS AND RESULTS Live-cell detection of intracellular Zn(2+) has become feasible through the recent development of Zn(2+)-sensitive and -selective fluorophores able to distinguish Zn(2+) from Ca(2+). Here, in freshly isolated rat cardiomyocytes, we investigated the rapid changes in Zn(2+) homeostasis using the Zn(2+)-specific fluorescent dye, FluoZin-3, in comparison to Ca(2+)-dependent fluo-3 fluorescence. Zn(2+) sparks and Zn(2+) transients, in quiescent and electrically stimulated cardiomyocytes, respectively, were visualized in a similar manner to known rapid Ca(2+) changes. Both Zn(2+) sparks and Zn(2+) transients required Ca(2+) entry. Inhibiting the sarcoplasmic reticulum Ca(2+) release or increasing the Ca(2+) load in a low-Na(+) solution suppressed or increased Zn(2+) movements, respectively. Mitochondrial inhibitors slightly reduced both Zn(2+) sparks and Zn(2+) transients. Oxidation by H₂O₂ facilitated and acidic pH inhibited the Ca(2+)-dependent Zn(2+) release. CONCLUSION It is proposed that Zn(2+) release during the cardiac cycle results mostly from intracellular free Ca(2+) increase, triggering production of reactive oxygen species that induce changes in metal-binding properties of metallothioneins and other redox-active proteins, aside from ionic exchange on these proteins.
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Affiliation(s)
- Erkan Tuncay
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara 06100, Turkey
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40
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Electrophoretic mobility shift assay of zinc finger proteins: competition for Zn(2+) bound to Sp1 in protocols including EDTA. J Inorg Biochem 2010; 105:569-76. [PMID: 21396899 DOI: 10.1016/j.jinorgbio.2010.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 08/18/2010] [Accepted: 08/19/2010] [Indexed: 10/19/2022]
Abstract
The electrophoretic mobility shift assay (EMSA) offers a principal method to detect specific DNA-protein interactions. As commonly conducted, the reaction and electrophoresis running buffers contain large concentrations of EDTA. EDTA has large affinity for Zn(2+) and readily competes with zinc finger peptides for Zn(2+) resulting in protein unfolding. Nevertheless, EMSA is routinely used to detect zinc finger protein-DNA adducts. This paper examines the chemistry that permits the detection of zinc finger-DNA complexes in the presence of EDTA, using Zn(3)-Sp1 and a cognate DNA binding site, GC1. Twice as much adduct was detected when the reaction was conducted in the absence than in the presence of EDTA. The observation of Zn-Sp1-GC1 was shown to depend on three properties: the inertness of Zn-Sp1-GC1 to reaction with EDTA and the comparatively similar rates of reaction of EDTA and GC1 with Zn(3)-Sp1 under the conditions of the assay that permit some Zn(3)-Sp1-GC1 to form. Inquiring about the mechanism of stabilization of Zn(3)-Sp1 by GC1, EDTA readily reacted with Zn(3)-Sp1 bound to a non-specific DNA, (polydI-dC). Two structurally similar but oppositely charged chelators, nitrilotriacetate (NTA) and tris-(2-ethylaminoethyl) amine (TREN), that react with free Zn(3)-Sp1 failed to compete for zinc bound in the Zn(3)-Sp1-GC-1 adduct. On the basis of these, other results indicated that the stability of Zn(3)-Sp1-GC-1 has a thermodynamic, not a kinetic origin. It is concluded that the observation of zinc finger proteins in the EMSA rests on a fortuitous set of chemical properties that may vary depending on the structures involved.
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Lee SJ, Park MH, Kim HJ, Koh JY. Metallothionein-3 regulates lysosomal function in cultured astrocytes under both normal and oxidative conditions. Glia 2010; 58:1186-96. [PMID: 20544854 DOI: 10.1002/glia.20998] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular zinc plays a key role in lysosomal change and cell death in neurons and astrocytes under oxidative stress. Here, using astrocytes lacking metallothionein-3 (MT3), a potential source of labile zinc in the brain, we studied the role of MT3 in oxidative stress responses. H(2)O(2) induced a large increase in labile zinc in wild-type (WT) astrocytes, but stimulated only a modest rise in MT3-null astrocytes. In addition, H(2)O(2)-induced lysosomal membrane permeabilization (LMP) and cell death were comparably attenuated in MT3-null astrocytes. Expression and glycosylation of Lamp1 (lysosome-associated membrane protein 1) and Lamp2 were increased in MT3-null astrocytes, and the activities of several lysosomal enzymes were significantly reduced, indicating an effect of MT3 on lysosomal components. Consistent with lysosomal dysfunction in MT3-null cells, the level of LC3-II (microtubule-associated protein 1 light chain 3), a marker of early autophagy, was increased by oxidative stress in WT astrocytes, but not in MT3-null cells. Similar changes in Lamp1, LC3, and cathepsin-D were induced by the lysosomal inhibitors bafilomycin A1, chloroquine, and monensin, indicating that lysosomal dysfunction may lie upstream of changes observed in MT3-null astrocytes. Consistent with this idea, lysosomal accumulation of cholesterol and lipofuscin were augmented in MT3-null astrocytes. Similar to the results seen in MT3-null cells, MT3 knockdown by siRNA inhibited oxidative stress-induced increases in zinc and LMP. These results indicate that MT3 may play a key role in normal lysosomal function in cultured astrocytes.
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Affiliation(s)
- Sook-Jeong Lee
- Neural Injury Research Lab, University of Ulsan College of Medicine, Seoul, Korea
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Kaltenberg J, Plum LM, Ober-Blöbaum JL, Hönscheid A, Rink L, Haase H. Zinc signals promote IL-2-dependent proliferation of T cells. Eur J Immunol 2010; 40:1496-503. [PMID: 20201035 DOI: 10.1002/eji.200939574] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Zinc signals, i.e. a change of the intracellular concentration of free zinc ions in response to receptor stimulation, are involved in signal transduction in several immune cells. Here, the role of zinc signals in T-cell activation by IL-2 was investigated in the murine cytotoxic T-cell line CTLL-2 and in primary human T cells. Measurements with the fluorescent dyes FluoZin-3 and Zinquin showed that zinc is released from lysosomes into the cytosol in response to stimulation of the IL-2-receptor. Activation of the ERK-pathway was blocked by chelation of free zinc with N,N,N',N'-tetrakis-2(pyridyl-methyl)ethylenediamine, whereas zinc was not required for STAT5 phosphorylation. In addition, the key signaling molecules MEK and ERK were activated in response to elevated free intracellular zinc, induced by incubation with zinc and the ionophore pyrithione. Downstream of ERK activation, ERK-specific gene expression of c-fos and IL-2-induced proliferation was found to depend on zinc. Further experiments indicated that inhibition of MEK and ERK-dephosphorylating protein phosphatases is the molecular mechanism for the influence of zinc on this pathway. In conclusion, an increase of cytoplasmic free zinc is required for IL-2-induced ERK signaling and proliferation of T cells.
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Affiliation(s)
- Jennifer Kaltenberg
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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Kumar S, Sun X, Wiseman DA, Tian J, Umapathy NS, Verin AD, Black SM. Hydrogen peroxide decreases endothelial nitric oxide synthase promoter activity through the inhibition of Sp1 activity. DNA Cell Biol 2010; 28:119-29. [PMID: 19105596 DOI: 10.1089/dna.2008.0775] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We have previously shown that endothelial nitric oxide synthase (eNOS) promoter activity is decreased in endothelial cells in response to the addition of hydrogen peroxide (H(2)O(2)), and this involves, at least in part, the inhibition of AP-1 activity. Thus, the objective of this study was to determine if other cis-element(s) and transcription factor(s) are involved in the oxidant-mediated downregulation of eNOS. Our initial experiments indicated that although H(2)O(2) treatment increased eNOS mRNA levels in ovine pulmonary arterial endothelial cells (OPAECs), there was a significant decrease in the promoter activity of an eNOS promoter construct containing 840 bp of upstream sequence. However, a truncated promoter construct that lacked the AP-1 element (650 bp) was also inhibited by H(2)O(2). A similar effect was observed when the 650 bp human eNOS promoter construct was transfected into human PAECs. We also found that although exposure of the cells to PEG-catalase prevented the inhibitory effect on eNOS promoter activity, the hydroxyl radical scavenger, deferoxamine myslate, did not. Nor could we identify an increase in hydroxyl radical levels in cells exposed to H(2)O(2). Exposure of PAECs caused a significant increase in labile zinc levels in response to H(2)O(2). As the eNOS promoter has a cis-element for Sp1 binding, we evaluated the role of Sp1 in response to H(2)O(2). As previously reported, mutation of the Sp1 consensus lead to the complete loss of eNOS promoter activity, confirming the key role of Sp1 in regulating basal eNOS promoter activity. In addition, we found, using electrophoretic mobility and supershift assays, that H(2)O(2) decreased Sp1 binding. Finally, using chromatin immunoprecipitation analysis, we found a significant decrease in Sp1 binding to the eNOS promoter in vivo in response to treatment with H(2)O(2). Together, these data suggest that the inhibition of Sp1 activity, possibly through loss of zinc in the protein, plays a role in the H(2)O(2)-induced inhibition of eNOS promoter activity.
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Affiliation(s)
- Sanjiv Kumar
- Vascular Biology Center, Medical College of Georgia, Augusta, Georgia 30912, USA
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Zhu J, Meeusen J, Krezoski S, Petering DH. Reactivity of Zn-, Cd-, and apo-metallothionein with nitric oxide compounds: in vitro and cellular comparison. Chem Res Toxicol 2010; 23:422-31. [PMID: 20085313 DOI: 10.1021/tx900387k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reactivity of Zn(7)- and Cd(7)-metallothionein (MT) with S-nitrosopenicillamine (SNAP), S-nitrosoglutathione (GSNO), and 2-(N,N-diethylamino)-diazenolate-2-oxide (DEA/NO) was investigated to explore the hypothesis that metallothionein is a signficant site of cellular reaction of nitric oxide or NO compounds. Zn(7)-MT reacted with SNAP or GSNO only under aerobic conditions and in the presence of light, which stimulates the decomposition of S-nitrosothiolates to NO. Zn(2+) is released, and protein thiols are modified. DEA/NO, which degrades spontaneously to release NO, also reacted with Zn(7)-MT only when oxygen was present. Anaerobically, DEA/NO reacted with Zn(7)-MT in the presence of 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, which converts NO to NO(2). Glutathione competed effectively with Zn(7)-MT for reactive nitrogen oxide species in reaction mixtures. Reaction of Cd(7)-MT with SNAP also required oxygen and light to react. In this case, only a fraction of the Cd(2+) bound to Cd(7)-MT was displaced by SNAP. Apo-metallothionein was much more reactive with SNAP and DEA-NO than Zn(7)- or Cd(7)-MT. TE671 and LLC-PK(1) cell lines were incubated with DEA/NO to examine the role that MT might play in the cellular reactions of this NO donor compound. Incubation of cells with 0-80 microM Zn(2+) for 24 h resulted in progressively increasing concentrations of Zn-unsaturated MT. One hour of cellular exposure to a range of DEA/NO concentrations followed by 24 h of incubation caused no evident acute toxicity at less than 0.45 mM. Preinduction of MT did not alter this response. The effects of DEA/NO on proteomic, metallothionein, and low molecular weight (LMW) thiol pools, including glutathione (GSH), were measured. Substantial fractions of the proteomic and LMW thiol pools underwent reaction with little dislocation of Zn(2+). In addition, one-third of the MT thiol pool reacted without labilizing any of the bound Zn(2+). These results demonstrated that it was free thiols associated with MT that reacted with DEA/NO not those bound to Zn(2+). Moreover, under the conditions of the experiments, DEA/NO reacted with the spectrum of cellular thiols in proportion to their fraction in the cytosol and did not preferentially react with MT sulfhydryl groups.
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Affiliation(s)
- Jianyu Zhu
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA
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Kothinti R, Blodgett A, Tabatabai NM, Petering DH. Zinc finger transcription factor Zn3-Sp1 reactions with Cd2+. Chem Res Toxicol 2010; 23:405-12. [PMID: 20073493 DOI: 10.1021/tx900370u] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cadmium is a major environmental pollutant that causes kidney failure including the inability to resorb nutrients such as glucose. In a mouse kidney cell culture model, Cd(2+) inhibits Na(+)-dependent glucose uptake mediated by SGLT transporters. This defect has been traced to the down-regulation of SGLT mRNA synthesis mediated by the zinc-finger transcription factor, Zn(3)-Sp1. Incubation of Cd(2+) with Zn(2+)-Sp1 inhibited its capacity to bind to GC1, its binding site in the SGLT1 promoter. The extent of reaction was reduced as increasing concentrations of Zn(2+) are simultaneously present in the reaction mixture. The results are consistent with a Cd(2+)-Zn(2+) exchange reaction that inactivates the DNA binding function of the protein. The equilibrium constant for this reaction was calculated as 14 +/- 3 and 7 +/- 4 for the reactions measured by the binding to GC1 and an analogous SGLT2 promoter site. Sequential addition of Cd(2+) and Zn(2+) to Zn(3)-Sp1 failed to inhibit the reduction in DNA binding seen with Cd(2+) alone, indicating that substitution of Zn(2+) by Cd(2+) was followed by a second reaction that failed to respond to Zn(2+). Buffers for the DNA binding reaction (electrophoretic mobility shift assay) contain EDTA and Cd-EDTA is active in the same concentration range as Cd(2+). During the standard 15 min incubation, Cd(2+) down-regulates Zn(3)-Sp1 but is inactive against the adduct, Zn(3)-Sp1.GC1. Kinetic studies demonstrated that with 5 muM Cd(2+), Zn(3)-Sp1 was about 75% inactivated in 15 min, whereas, Zn(3)-Sp1.GC1 was slowly dissociated with 50% still remaining after 60 min. In contrast, Zn(3)-Sp1 bound to a cognate consensus site resisted any reaction over 60 min. An adduct of Zn(3)-Sp1.(polydI-dC) was just as reactive with Cd(2+) as Zn(3)-Sp1. Reexamination of the NMR structure of Zn- and Cd-finger peptides related to Sp1 fingers has revealed subtle changes in conformation of the metalbinding site and DNA-binding helix that occur when Cd(2+) is substituted by Zn(2+).
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Affiliation(s)
- Rajendra Kothinti
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA
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Blindauer CA, Leszczyszyn OI. Metallothioneins: unparalleled diversity in structures and functions for metal ion homeostasis and more. Nat Prod Rep 2010; 27:720-41. [PMID: 20442962 DOI: 10.1039/b906685n] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Metallothioneins have been the subject of intense study for five decades, and have greatly inspired the development of bio-analytical methodologies including multi-dimensional and multi-nuclear NMR.With further advancements in molecular biology, protein science, and instrumental techniques, recent years have seen a renaissance of research into metallothioneins. The current report focuses on in vitro studies of so-called class II metallothioneins from a variety of phyla, highlighting the diversity of metallothioneins in terms of structure, biological functions, and molecular functions such as metal ion specificity, thermodynamic stabilities, and kinetic reactivity. We are still far from being able to predict any of these properties, and further efforts will be required to generate the knowledge that will enable a better understanding of what governs the biological and chemical properties of these unusual and intriguing small proteins.
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Dubben S, Hönscheid A, Winkler K, Rink L, Haase H. Cellular zinc homeostasis is a regulator in monocyte differentiation of HL-60 cells by 1 alpha,25-dihydroxyvitamin D3. J Leukoc Biol 2010; 87:833-44. [PMID: 20089671 DOI: 10.1189/jlb.0409241] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
It was reported previously that zinc-deficient mice show impaired lymphopoiesis. At the same time, monocyte numbers in these animals are increased, indicating a negative impact of zinc on monocyte development. Here, we investigate the role of zinc homeostasis in the differentiation of myeloid precursors into monocytes. Reduced gene expression of several zinc transporters, predominantly from the Zip family, was observed during 1 alpha, 25-dihydroxyvitamin D(3) (1,25D(3))-induced differentiation of HL-60 cells. This was accompanied by a reduction of intracellular-free zinc, measured by FluoZin-3. Amplifying this reduction with the zinc chelator TPEN or zinc-depleted cell-culture medium enhanced 1,25D(3)-induced expression of monocytic surface markers CD11b and CD14 on HL-60, THP-1, and NB4 cells. In contrast, differentiation of NB4 cells to granulocytes was not zinc-sensitive, pointing toward a specific effect of zinc on monocyte differentiation. Further, monocyte functions, such as TNF-alpha secretion, phagocytosis, and oxidative burst, were also augmented by differentiation in the presence of TPEN. The second messenger cAMP promotes monocyte differentiation. We could show that zinc inhibits the cAMP-synthesizing enzyme adenylate cyclase, and chelation of zinc by TPEN increases cAMP generation after stimulation with the adenylate cyclase activator forskolin. Based on our in vitro results and the in vivo observations from the literature, we suggest a model in which the intracellular-free zinc concentration limits AC activity, and the decrease of zinc after 1,25D(3) treatment promotes differentiation by relieving AC inhibition. Thus, cellular zinc homeostasis acts as an endogenous modulator of monocyte differentiation.
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Affiliation(s)
- Svenja Dubben
- Institute of Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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48
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Reaction of the zinc sensor FluoZin-3 with Zn(7)-metallothionein: Inquiry into the existence of a proposed weak binding site. J Inorg Biochem 2009; 104:224-31. [PMID: 20007001 DOI: 10.1016/j.jinorgbio.2009.11.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 11/05/2009] [Accepted: 11/06/2009] [Indexed: 11/21/2022]
Abstract
It has been reported that Zn(7)-metallothionein (MT), contains one weak binding site for Zn(2+). To test this conclusion, rabbit liver MT isolated at pH 7 was reacted with chelating agents of modest affinity for Zn(2+). Contrary to the previous study, no evidence was found for Zn(2+) stoichiometrically bound to the protein with an apparent stability constant of about 10(8). Indeed, stability constant measurements based upon competition between Zn(7)-MT and ligands of known stability with Zn(2+) showed that all of the protein bound Zn(2+) displayed the same stability constant at pH 7.4 and 25 degrees C of (1.7+/-0.6)x10(11). Brief reaction of Zn(7)-MT with strong acid converted it into MT(*) and upon reneutralization into Zn(7)-MT(*), which demonstrated reactivity of about 1 Zn(2+)/mol MT with competing ligands. Acid titration of Zn(7)-MT to pH 2 or below rapidly resulted in the formation of Zn(7)-MT(*) that displayed biphasic titration with base, revealing the rebinding of lower affinity Zn(2+) between pH 5 and 7. Since MT is commonly acidified during preparation, care must be taken to document which form of the protein is present in subsequent experiments at pH 7.
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Yamaguchi S, Miura C, Kikuchi K, Celino FT, Agusa T, Tanabe S, Miura T. Zinc is an essential trace element for spermatogenesis. Proc Natl Acad Sci U S A 2009; 106:10859-64. [PMID: 19541612 PMCID: PMC2705534 DOI: 10.1073/pnas.0900602106] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Indexed: 12/11/2022] Open
Abstract
Zinc (Zn) plays important roles in various biological activities but there is little available information regarding its functions in spermatogenesis. In our current study, we further examined the role of Zn during spermatogenesis in the Japanese eel (Anguilla japonica). Human CG (hCG) was injected into the animals to induce spermatogenesis, after which the concentration of Zn in the testis increased in tandem with the progression of spermatogenesis. Staining of testicular cells with a Zn-specific fluorescent probe revealed that Zn accumulates in germ cells, particularly in the mitochondria of spermatogonia and spermatozoa. Using an in vitro testicular organ culture system for the Japanese eel, production of a Zn deficiency by chelation with N,N,N',N'-tetrakis (2-pyridylemethyl)ethylenediamine (TPEN) caused apoptosis of the germ cells. However, this cell death was rescued by the addition of Zn to the cultures. Furthermore, an induced deficiency of Zn by TPEN chelation was found to inhibit the germ cell proliferation induced by 11-ketotestosterone (KT), a fish specific androgen, 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP), the initiator of meiosis in fish, and estradiol-17beta (E2), an inducer of spermatogonial stem-cell renewal. We also investigated the effects of Zn deficiency on sperm motility and observed that TPEN treatment of eel sperm suppressed the rate and duration of their motility but that co-treatment with Zn blocked the effects of TPEN. Our present results thus suggest that Zn is an essential trace element for the maintenance of germ cells, the progression spermatogenesis, and the regulation of sperm motility.
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Affiliation(s)
- Sonoko Yamaguchi
- Research Group for Reproductive Physiology, South Ehime Fisheries Research Center, Ehime University, 1289-1, Funakoshi, Ainan, Ehime 798-4131, Japan
| | - Chiemi Miura
- Research Group for Reproductive Physiology, South Ehime Fisheries Research Center, Ehime University, 1289-1, Funakoshi, Ainan, Ehime 798-4131, Japan
| | - Kazuya Kikuchi
- Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan; and
| | - Fritzie T. Celino
- Research Group for Reproductive Physiology, South Ehime Fisheries Research Center, Ehime University, 1289-1, Funakoshi, Ainan, Ehime 798-4131, Japan
| | - Tetsuro Agusa
- Center for Marine Environmental Science, Ehime University, Matsuyama 790-8577, Japan
| | - Shinsuke Tanabe
- Center for Marine Environmental Science, Ehime University, Matsuyama 790-8577, Japan
| | - Takeshi Miura
- Research Group for Reproductive Physiology, South Ehime Fisheries Research Center, Ehime University, 1289-1, Funakoshi, Ainan, Ehime 798-4131, Japan
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Zovo K, Palumaa P. Modulation of redox switches of copper chaperone Cox17 by Zn(II) ions determined by new ESI MS-based approach. Antioxid Redox Signal 2009; 11:985-95. [PMID: 19018666 DOI: 10.1089/ars.2008.2262] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cox17, a copper chaperone for cytochrome-c oxidase, contains six conserved Cys residues and exists in three oxidative states, linked with two thiol-based redox switches. The first switch leads to formation of two disulfides and occurs upon transport of Cox17 into mitochondrial intermembrane space (IMS). Cox17(2S-S) is retained in the IMS and is also a functional form of the protein, which can be further oxidized to Cox17(3S-S). According to the midpoint redox potential values, Cox17 can be partially oxidized in the cytosol, which might hinder its transport into IMS. We hypothesize that Zn(II) ions might protect cytosolic Cox17 from oxidation. In order to get quantitative information about the modulatory effect of Zn(II) ions on redox switches in Cox17, we have used ESI MS for determination of the midpoint potentials for redox couples of Cox17: Cox17(3S-S) <--> Cox17(2S-S) (E(m1)) and Cox17(2S-S) <--> Cox17(0S-S) (E(m2)) in the presence of Zn(II). 10 microM Zn(II) ions shift the E(m2) by 21 mV and E(m1) by 15 mV to more positive values. Apparent dissociation constants for Zn(II) complexes of Cox17(0S-S) and Cox17(2S-S), are 0.067 and 0.29 nM, respectively. The high affinity shows that metallation of Cox17(0S-S) by Zn(II) might be significant in cellular conditions, which might protect Cox17 from oxidation and enable its transport into IMS.
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Affiliation(s)
- Kairit Zovo
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia.
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