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Dluhosch D, Kersten LS, Schott-Verdugo S, Hoppen C, Schwarten M, Willbold D, Gohlke H, Groth G. Structure and dimerization properties of the plant-specific copper chaperone CCH. Sci Rep 2024; 14:19099. [PMID: 39154065 PMCID: PMC11330527 DOI: 10.1038/s41598-024-69532-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: 05/02/2024] [Accepted: 08/06/2024] [Indexed: 08/19/2024] Open
Abstract
Copper chaperones of the ATX1 family are found in a wide range of organisms where these essential soluble carriers strictly control the transport of monovalent copper across the cytoplasm to various targets in diverse cellular compartments thereby preventing detrimental radical formation catalyzed by the free metal ion. Notably, the ATX1 family in plants contains two distinct forms of the cellular copper carrier. In addition to ATX1 having orthologs in other species, they also contain the copper chaperone CCH. The latter features an extra C-terminal extension whose function is still unknown. The secondary structure of this extension was predicted to be disordered in previous studies, although this has not been experimentally confirmed. Solution NMR studies on purified CCH presented in this study disclose that this region is intrinsically disordered regardless of the chaperone's copper loading state. Further biophysical analyses of the purified metallochaperone provide evidence that the C-terminal extension stabilizes chaperone dimerization in the copper-free and copper-bound states. A variant of CCH lacking the C-terminal extension, termed CCHΔ, shows weaker dimerization but similar copper binding. Computational studies further corroborate the stabilizing role of the C-terminal extension in chaperone dimerization and identify key residues that are vital to maintaining dimer stability.
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Affiliation(s)
- Dominik Dluhosch
- Institute of Biochemical Plant Physiology, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Lisa Sophie Kersten
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Stephan Schott-Verdugo
- Institute of Bio- and Geosciences: Bioinformatics (IBG-4), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Claudia Hoppen
- Institute of Biochemical Plant Physiology, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Melanie Schwarten
- Institute of Biological Information Processing: Structural Biochemistry (IBI-7), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Dieter Willbold
- Institute of Biological Information Processing: Structural Biochemistry (IBI-7), Forschungszentrum Jülich, 52425, Jülich, Germany
- Institut Für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
- Institute of Bio- and Geosciences: Bioinformatics (IBG-4), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Georg Groth
- Institute of Biochemical Plant Physiology, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany.
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2
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Choi W, Cha S, Kim K. Navigating the CRISPR/Cas Landscape for Enhanced Diagnosis and Treatment of Wilson's Disease. Cells 2024; 13:1214. [PMID: 39056796 PMCID: PMC11274827 DOI: 10.3390/cells13141214] [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: 05/27/2024] [Revised: 07/15/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024] Open
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) system continues to evolve, thereby enabling more precise detection and repair of mutagenesis. The development of CRISPR/Cas-based diagnosis holds promise for high-throughput, cost-effective, and portable nucleic acid screening and genetic disease diagnosis. In addition, advancements in transportation strategies such as adeno-associated virus (AAV), lentiviral vectors, nanoparticles, and virus-like vectors (VLPs) offer synergistic insights for gene therapeutics in vivo. Wilson's disease (WD), a copper metabolism disorder, is primarily caused by mutations in the ATPase copper transporting beta (ATP7B) gene. The condition is associated with the accumulation of copper in the body, leading to irreversible damage to various organs, including the liver, nervous system, kidneys, and eyes. However, the heterogeneous nature and individualized presentation of physical and neurological symptoms in WD patients pose significant challenges to accurate diagnosis. Furthermore, patients must consume copper-chelating medication throughout their lifetime. Herein, we provide a detailed description of WD and review the application of novel CRISPR-based strategies for its diagnosis and treatment, along with the challenges that need to be overcome.
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Affiliation(s)
- Woong Choi
- Department of Physiology, Korea University College of Medicine, Seoul 02841, Republic of Korea;
| | - Seongkwang Cha
- Department of Physiology, Korea University College of Medicine, Seoul 02841, Republic of Korea;
- Neuroscience Research Institute, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Kyoungmi Kim
- Department of Physiology, Korea University College of Medicine, Seoul 02841, Republic of Korea;
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 02841, Republic of Korea
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3
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Sharma PK, Aram A, Pandian V, Polaka Y. Wilson's Disease in an Early Adolescent: Classic Magnetic Resonance Imaging Findings. Cureus 2024; 16:e58092. [PMID: 38738008 PMCID: PMC11088745 DOI: 10.7759/cureus.58092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/10/2024] [Indexed: 05/14/2024] Open
Abstract
Wilson's disease (WD), alternatively termed hepatolenticular degeneration, represents a rare autosomal recessive disorder typified by disrupted copper metabolism, culminating in copper accumulation across various organs. WD commonly manifests with early-onset liver cirrhosis, with notable involvement of the central nervous system, particularly impacting the midbrain and basal ganglia. This case report delineates the clinical presentation of an early adolescent female with WD, accentuating classical magnetic resonance imaging (MRI) findings. These MRI findings, which include the "face of a giant panda sign" and the "Face of a miniature panda sign," are pivotal for expeditious diagnosis. Recognition of these classical signs underscores the indispensable role of MRI in elucidating the neurological dimensions of WD.
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Affiliation(s)
- Praveen K Sharma
- Department of Radiology, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - Arun Aram
- Department of Radiology, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - Vinoth Pandian
- Department of Radiology, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - Yashaswinii Polaka
- Department of Radiology, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
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4
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Dmitriev OY, Patry J. Structure and mechanism of the human copper transporting ATPases: Fitting the pieces into a moving puzzle. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184306. [PMID: 38408697 DOI: 10.1016/j.bbamem.2024.184306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/07/2024] [Accepted: 02/18/2024] [Indexed: 02/28/2024]
Abstract
Human copper transporters ATP7B and ATP7A deliver copper to biosynthetic pathways and maintain copper homeostasis in the cell. These enzymes combine several challenges for structural biology because they are large low abundance membrane proteins with many highly mobile domains and long disordered loops. No method has yet succeeded in solving the structure of the complete fully functional protein. Still, X-ray crystallography, Cryo-EM and NMR helped to piece together a structure based model of the enzyme activity and regulation by copper. We review the structures of ATP7B and ATP7A with an emphasis on the mechanistic insights into the unique aspects of the transport function and regulation of the human copper ATPases that have emerged from more than twenty years of research.
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Affiliation(s)
- Oleg Y Dmitriev
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada.
| | - Jaala Patry
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
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5
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Stalke A, Behrendt A, Hennig F, Gohlke H, Buhl N, Reinkens T, Baumann U, Schlegelberger B, Illig T, Pfister ED, Skawran B. Functional characterization of novel or yet uncharacterized ATP7B missense variants detected in patients with clinical Wilson's disease. Clin Genet 2023. [PMID: 37157876 DOI: 10.1111/cge.14352] [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: 01/19/2023] [Revised: 04/14/2023] [Accepted: 04/20/2023] [Indexed: 05/10/2023]
Abstract
Wilson's disease (WD, MIM#277900) is an autosomal recessive disorder resulting in copper excess caused by biallelic variants in the ATP7B gene (MIM#606882) encoding a copper transporting P-type ATPase. ATP7B variants of unknown significance (VUS) are detected frequently, sometimes impeding a clear diagnosis. Functional analyses can help to classify these variants as benign or pathogenic. Additionally, variants already classified as (likely) pathogenic benefit from functional analyses to understand their pathomechanism, thus contribute to the development of personalized treatment approaches in the future. We described clinical features of six WD patients and functionally characterized five ATP7B missense variants (two VUS, three yet uncharacterized likely pathogenic variants), detected in these patients. We determined the protein level, copper export capacity, and cellular localization in an in vitro model and potential structural consequences using an ATP7B protein model based on AlphaFold. Our analyses give insight into the pathomechanism and allowed reclassification for the two VUS to likely pathogenic and for two of the three likely pathogenic variants to pathogenic.
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Affiliation(s)
- Amelie Stalke
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
- Department of Pediatric Gastroenterology and Hepatology, Division of Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Annika Behrendt
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Finja Hennig
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Nicole Buhl
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
- Department of Pediatric Gastroenterology and Hepatology, Division of Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Thea Reinkens
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Ulrich Baumann
- Department of Pediatric Gastroenterology and Hepatology, Division of Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | | | - Thomas Illig
- Hannover Unified Bank, Hannover Medical School, Hannover, Germany
| | - Eva-Doreen Pfister
- Department of Pediatric Gastroenterology and Hepatology, Division of Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Britta Skawran
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
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6
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Li J, Wang X, Zou J, Yang K, Wang X, Wang Y, Zhang H, Huang H, Su X, Yao B, Luo H, Qin X. Identification and Characterization of the Determinants of Copper Resistance in the Acidophilic Fungus Acidomyces richmondensis MEY-1 Using the CRISPR/Cas9 System. Appl Environ Microbiol 2023; 89:e0210722. [PMID: 36912653 PMCID: PMC10056952 DOI: 10.1128/aem.02107-22] [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: 12/23/2022] [Accepted: 02/14/2023] [Indexed: 03/14/2023] Open
Abstract
Copper (Cu) homeostasis has not been well documented in filamentous fungi, especially extremophiles. One of the main obstacles impeding their characterization is the lack of a powerful genome-editing tool. In this study, we applied a CRISPR/Cas9 system for efficient targeted gene disruption in the acidophilic fungus Acidomyces richmondensis MEY-1, formerly known as Bispora sp. strain MEY-1. Using this system, we investigated the basis of Cu tolerance in strain MEY-1. This strain has extremely high Cu tolerance among filamentous fungi, and the transcription factor ArAceA (A. richmondensis AceA) has been shown to be involved in this process. The ArAceA deletion mutant (ΔArAceA) exhibits specific growth defects at Cu concentrations of ≥10 mM and is transcriptionally more sensitive to Cu than the wild-type strain. In addition, the putative metallothionein ArCrdA was involved in Cu tolerance only under high Cu concentrations. MEY-1 has no Aspergillus nidulans CrpA homologs, which are targets of AceA-like transcription factors and play a role in Cu tolerance. Instead, we identified the Cu-transporting P-type ATPase ArYgA, homologous to A. nidulans YgA, which was involved in pigmentation rather than Cu tolerance. When the ΔArYgA mutant was grown on medium supplemented with Cu ions, the black color was completely restored. The lack of CrpA homologs in A. richmondensis MEY-1 and its high tolerance to Cu suggest that a novel Cu detoxification mechanism differing from the AceA-CrpA axis exists. IMPORTANCE Filamentous fungi are widely distributed worldwide and play an important ecological role as decomposers. However, the mechanisms of their adaptability to various environments are not fully understood. Various extremely acidophilic filamentous fungi have been isolated from acidic mine drainage (AMD) with extremely low pH and high heavy metal and sulfate concentrations, including A. richmondensis. The lack of genetic engineering tools, particularly genome-editing tools, hinders the study of these acidophilic and heavy metal-resistant fungi at the molecular level. Here, we first applied a CRISPR/Cas9-mediated gene-editing system to A. richmondensis MEY-1. Using this system, we identified and characterized the determinants of Cu resistance in A. richmondensis MEY-1. The conserved roles of the Cu-binding transcription factor ArAceA in Cu tolerance and the Cu-transporting P-type ATPase ArYgA in the Cu-dependent production of pigment were confirmed. Our findings provide insights into the molecular basis of Cu tolerance in the acidophilic fungus A. richmondensis MEY-1. Furthermore, the CRISPR/Cas9 system used here would be a powerful tool for studies of the mechanisms of adaptability of acidophilic fungi to extreme environments.
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Affiliation(s)
- Jinyang Li
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiao Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiahuan Zou
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Kun Yang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaolu Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuan Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Honglian Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huoqing Huang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoyun Su
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xing Qin
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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7
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Roy S, McCann CJ, Ralle M, Ray K, Ray J, Lutsenko S, Jayakanthan S. Analysis of Wilson disease mutations revealed that interactions between different ATP7B mutants modify their properties. Sci Rep 2020; 10:13487. [PMID: 32778786 PMCID: PMC7418023 DOI: 10.1038/s41598-020-70366-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 06/16/2020] [Indexed: 01/05/2023] Open
Abstract
Wilson disease (WD) is an autosomal-recessive disorder caused by mutations in the copper (Cu)-transporter ATP7B. Thus far, studies of WD mutations have been limited to analysis of ATP7B mutants in the homozygous states. However, the majority of WD patients are compound-heterozygous, and how different mutations on two alleles impact ATP7B properties is unclear. We characterized five mutations identified in Indian WD patients, first by expressing each alone and then by co-expressing two mutants with dissimilar properties. Mutations located in the regulatory domains of ATP7B-A595T, S1362A, and S1426I-do not affect ATP7B targeting to the trans-Golgi network (TGN) but reduce its Cu-transport activity. The S1362A mutation also inhibits Cu-dependent trafficking from the TGN. The G1061E and G1101R mutations, which are located within the ATP-binding domain, cause ATP7B retention in the endoplasmic reticulum, inhibit Cu-transport, and lower ATP7B protein abundance. Co-expression of the A595T and G1061E mutations, which mimics the compound-heterozygous state of some WD patients, revealed an interaction between these mutants that altered their intracellular localization and trafficking under both low and high Cu conditions. These findings highlight the need to study WD variants in both the homozygous and compound-heterozygous states to better understand the genotype-phenotype correlations and incomplete penetrance observed in WD.
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Affiliation(s)
- Shubhrajit Roy
- Department of Physiology, Johns Hopkins Medical Institute, Baltimore, MD, USA. .,S. N. Pradhan Centre for Neurosciences, University of Calcutta, Kolkata, India.
| | - Courtney J McCann
- Department of Physiology, Johns Hopkins Medical Institute, Baltimore, MD, USA
| | - Martina Ralle
- Oregon Health and Science University, Portland, OR, USA
| | - Kunal Ray
- ATGC Diagnostics Private Ltd, Kolkata, India
| | - Jharna Ray
- S. N. Pradhan Centre for Neurosciences, University of Calcutta, Kolkata, India
| | - Svetlana Lutsenko
- Department of Physiology, Johns Hopkins Medical Institute, Baltimore, MD, USA.
| | - Samuel Jayakanthan
- Department of Physiology, Johns Hopkins Medical Institute, Baltimore, MD, USA
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8
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McCann CJ, Jayakanthan S, Siotto M, Yang N, Osipova M, Squitti R, Lutsenko S. Single nucleotide polymorphisms in the human ATP7B gene modify the properties of the ATP7B protein. Metallomics 2020; 11:1128-1139. [PMID: 31070637 DOI: 10.1039/c9mt00057g] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Single nucleotide polymorphisms (SNPs) are the largest source of sequence variation in the human genome. However, their functional significance is not well understood. We show that SNPs in the Wilson disease gene, ATP7B, that produce amino-acid substitutions K832R and R952K, modulate ATP7B properties in vitro and influence serum copper (Cu) status in vivo. The presence of R832 is associated with a lower ATP7B abundance and a diminished trafficking in response to elevated Cu. The K832R substitution alters surface exposure of amino acid residues in the actuator domain and increases its conformational flexibility. All SNP-related ATP7B variants (R832/R952, R832/K952, K832/K952, and K832/R952) have Cu-transport activity. However, the activity of ATP7B-K832/K952 is lower compared to other variants. In humans, the presence of K952 is associated with a higher fraction of exchangeable Cu in serum. Thus, SNPs may modulate the properties of ATP7B and the organism Cu status.
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Affiliation(s)
- Courtney J McCann
- Department of Physiology, Johns Hopkins University, Baltimore, MD, USA.
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9
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Adão-Novaes J, Valverde R, Landemberger M, Silveira M, Simões-Pires E, Lowe J, Linden R. Substrain-related dependence of Cu(I)-ATPase activity among prion protein-null mice. Brain Res 2020; 1727:146550. [DOI: 10.1016/j.brainres.2019.146550] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/08/2019] [Accepted: 11/09/2019] [Indexed: 01/20/2023]
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10
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Petruzzelli R, Polishchuk RS. Activity and Trafficking of Copper-Transporting ATPases in Tumor Development and Defense against Platinum-Based Drugs. Cells 2019; 8:E1080. [PMID: 31540259 PMCID: PMC6769697 DOI: 10.3390/cells8091080] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/10/2019] [Accepted: 09/12/2019] [Indexed: 02/06/2023] Open
Abstract
Membrane trafficking pathways emanating from the Golgi regulate a wide range of cellular processes. One of these is the maintenance of copper (Cu) homeostasis operated by the Golgi-localized Cu-transporting ATPases ATP7A and ATP7B. At the Golgi, these proteins supply Cu to newly synthesized enzymes which use this metal as a cofactor to catalyze a number of vitally important biochemical reactions. However, in response to elevated Cu, the Golgi exports ATP7A/B to post-Golgi sites where they promote sequestration and efflux of excess Cu to limit its potential toxicity. Growing tumors actively consume Cu and employ ATP7A/B to regulate the availability of this metal for oncogenic enzymes such as LOX and LOX-like proteins, which confer higher invasiveness to malignant cells. Furthermore, ATP7A/B activity and trafficking allow tumor cells to detoxify platinum (Pt)-based drugs (like cisplatin), which are used for the chemotherapy of different solid tumors. Despite these noted activities of ATP7A/B that favor oncogenic processes, the mechanisms that regulate the expression and trafficking of Cu ATPases in malignant cells are far from being completely understood. This review summarizes current data on the role of ATP7A/B in the regulation of Cu and Pt metabolism in malignant cells and outlines questions and challenges that should be addressed to understand how ATP7A and ATP7B trafficking mechanisms might be targeted to counteract tumor development.
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Affiliation(s)
- Raffaella Petruzzelli
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy.
| | - Roman S Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy.
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11
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Kwok ML, Chan KM. Functional characterization of copper transporters zCtr1, zAtox1, zAtp7a and zAtp7b in zebrafish liver cell line ZFL. Metallomics 2019; 11:1532-1546. [PMID: 31469368 DOI: 10.1039/c9mt00159j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Copper (Cu) is an essential element for all organisms, serving as an enzyme cofactor to maintain cellular activity and vitality. However, Cu homeostasis must be maintained at the physiological and cellular levels as Cu ions can be highly toxic. In mammals, ATP7A is expressed in most tissues, but relatively lower expression is found in the liver, and is responsible for the intestinal uptake of Cu, while ATP7B is highly expressed in the liver, kidneys and placenta, and is responsible for removal of Cu in the liver. CTR1 and ATOX1 are responsible for cellular Cu uptake and intracellular Cu transport, respectively. Here, using a zebrafish liver cell line (ZFL), we studied the cellular functions of four zebrafish Cu transporters. In zebrafish, zAtp7a is expressed mainly in the liver and zAtp7b is expressed mainly in the intestines, different from that of humans which have a high ATP7b level in the liver and high ATP7a level in the intestines. We here found that zctr1 or zatox1 overexpression increased Cu accumulation in ZFL cells. Moreover, zctr1 overexpression made ZFL cells more sensitive to Cu and Zn exposure, and overexpression of zatox1 or zatp7b increased Cu uptake and Cu tolerance in ZFL cells. Overexpression of zatp7a made ZFL cells more sensitive to Zn. Taken together, our findings suggest that zatp7b is responsible for Cu export despite its expression level being much lower than zatp7a in ZFL cells.
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Affiliation(s)
- Man Long Kwok
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong.
| | - King Ming Chan
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong.
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12
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Hermann W. Classification and differential diagnosis of Wilson's disease. ANNALS OF TRANSLATIONAL MEDICINE 2019; 7:S63. [PMID: 31179300 PMCID: PMC6531651 DOI: 10.21037/atm.2019.02.07] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 02/01/2019] [Indexed: 12/13/2022]
Abstract
Wilson's disease is characterized by hepatic and extrapyramidal movement disorders (EPS) with variable manifestation primarily between age 5 and 45. This variability often makes an early diagnosis difficult. A classification defines different clinical variants of Wilson's disease, which enables classifying the current clinical findings and making an early tentative diagnosis. Until the unequivocal proof or an autosomal recessive disorder of the hepatic copper transporter ATP7B has been ruled out, differential diagnoses have to be examined. Laboratory-chemical parameters of copper metabolism can both be deviations from the norm not related to the disease as well as other copper metabolism disorders besides Wilson's disease. In addition to known diseases such as Menkes disease, occipital horn syndrome (OHS), Indian childhood cirrhosis (ICC) and ceruloplasmin deficiency, recently discovered disorders are taken into account. These include MEDNIK syndrome, Huppke-Brendel syndrome and CCS chaperone deficiency. Another main focus is on differential diagnoses of childhood icterus correlated with age and anaemia as well as disorders of the extrapyramidal motor system. The Kayser-Fleischer ring (KFR) is qualified as classical ophthalmologic manifestation. The recently described manganese storage disease presents another rare metabolic disorder with symptoms similar to Wilson's disease. As this overview shows, Wilson's disease fits into a broad spectrum of internal and neurological disease patterns with icterus, anaemia and EPS.
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Affiliation(s)
- Wieland Hermann
- Department of Neurology, SRO AG Spital Langenthal, Langenthal, Switzerland
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13
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Guttmann S, Bernick F, Naorniakowska M, Michgehl U, Groba SR, Socha P, Zibert A, Schmidt HH. Functional Characterization of Novel ATP7B Variants for Diagnosis of Wilson Disease. Front Pediatr 2018; 6:106. [PMID: 29761093 PMCID: PMC5937294 DOI: 10.3389/fped.2018.00106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 04/03/2018] [Indexed: 12/14/2022] Open
Abstract
Background: Diagnosis of rare Wilson disease (WD) in pediatric patients is difficult, in particular when hepatic manifestation is absent. Genetic analysis of ATP7B represents the single major determinant of the diagnostic scoring system in WD children having mild symptoms. Objectives: To assess the impact of molecularly expressed ATP7B gene products in order to assist diagnosis of Wilson disease in pediatric patients having a novel mutation and subtle neuropsychiatric disease. Methods: The medical history, clinical presentation, biochemical parameters, and the genetic analysis of ATP7B were determined. Due to ambiguous clinical and biochemical findings and identification of a novel compound ATP7B mutation with unknown disease-causing status, a molecular analysis of the ATP7B gene products in a previously well characterized cell model was performed. Results: The ATP7B variants were transgenically expressed and the respective gene function molecularly characterized. Despite normal mRNA expression, low ATP7B protein expression of the mutants p.L168P and p.S1423N was observed (34.3 ± 8% and 66.0 ± 8%, respectively). Copper exposure did not result in decreased viability of transgenic cells as compared to wild type. Intracellular copper accumulation was reduced (≤47.9 ± 8%) and intracellular protein trafficking was impaired. Conclusion: Our report suggests that functional characterization of novel ATP7B mutants can assist diagnosis; however mild functional impairments of ATP7B variants may hamper the value of such approaches.
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Affiliation(s)
- Sarah Guttmann
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Münster, Germany
| | - Friedrich Bernick
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Münster, Germany
| | - Magdalena Naorniakowska
- Department of Gastroenterology, Hepatology, Nutritional Disorders and Pediatrics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Ulf Michgehl
- Internal Medicine D, Molecular Nephrology, University Hospital of Münster, Münster, Germany
| | - Sara Reinartz Groba
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Münster, Germany
| | - Piotr Socha
- Internal Medicine D, Molecular Nephrology, University Hospital of Münster, Münster, Germany
| | - Andree Zibert
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Münster, Germany
| | - Hartmut H Schmidt
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Münster, Germany
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14
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Jayakanthan S, Braiterman LT, Hasan NM, Unger VM, Lutsenko S. Human copper transporter ATP7B (Wilson disease protein) forms stable dimers in vitro and in cells. J Biol Chem 2017; 292:18760-18774. [PMID: 28842499 DOI: 10.1074/jbc.m117.807263] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/21/2017] [Indexed: 11/06/2022] Open
Abstract
ATP7B is a copper-transporting P1B-type ATPase (Cu-ATPase) with an essential role in human physiology. Mutations in ATP7B cause the potentially fatal Wilson disease, and changes in ATP7B expression are observed in several cancers. Despite its physiologic importance, the biochemical information about ATP7B remains limited because of a complex multidomain organization of the protein. By analogy with the better characterized prokaryotic Cu-ATPases, ATP7B is assumed to be a single-chain monomer. We show that in eukaryotic cells, human ATP7B forms dimers that can be purified following solubilization. Deletion of the four N-terminal metal-binding domains, characteristic for human ATP7B, does not disrupt dimerization, i.e. the dimer interface is formed by the domains that are conserved among Cu-ATPases. Unlike the full-length ATP7B, which is targeted to the trans-Golgi network, 1-4ΔMBD-7B is targeted primarily to vesicles. This result and the analysis of differentially tagged ATP7B variants indicate that the dimeric structure is retained during ATP7B trafficking between the intracellular compartments. Purified dimeric species of 1-4ΔMBD-7B were characterized by a negative stain electron microscopy in the presence of ADP/MgCl2 Single-particle analysis yielded a low-resolution 3D model that provides the first insight into an overall architecture of a human Cu-ATPase, positions of the main domains, and a dimer interface.
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Affiliation(s)
| | - Lelita T Braiterman
- Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205 and
| | | | - Vinzenz M Unger
- the Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
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15
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Tadini-Buoninsegni F, Smeazzetto S. Mechanisms of charge transfer in human copper ATPases ATP7A and ATP7B. IUBMB Life 2017; 69:218-225. [PMID: 28164426 DOI: 10.1002/iub.1603] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/26/2016] [Indexed: 12/30/2022]
Abstract
ATP7A and ATP7B are Cu+ -transporting ATPases of subclass IB and play a fundamental role in intracellular copper homeostasis. ATP7A/B transfer Cu+ ions across the membrane from delivery to acceptor proteins without establishing a free Cu+ gradient. Transfer of copper across the membrane is coupled to ATP hydrolysis. Current measurements on solid supported membranes (SSM) were performed to investigate the mechanism of copper-related charge transfer across ATP7A and ATP7B. SSM measurements demonstrated that electrogenic copper displacement occurs within ATP7A/B following addition of ATP and formation of the phosphorylated intermediate. Comparison of the time constants for cation displacement in ATP7A/B and sarcoplasmic reticulum Ca2+ -ATPase is consistent with the slower phosphoenzyme formation in copper ATPases. Moreover, ATP-dependent copper transfer in ATP7A/B is not affected by varying the pH, suggesting that net proton counter-transport may not occur in copper ATPases. Platinum anticancer drugs activate ATP7A/B and are subjected to ATP-dependent vectorial displacement with a mechanism analogous to that of copper. © 2016 IUBMB Life, 69(4):218-225, 2017.
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Affiliation(s)
| | - Serena Smeazzetto
- Department of Chemistry "Ugo Schiff,", University of Florence, Sesto Fiorentino, Italy
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16
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Sautron E, Mayerhofer H, Giustini C, Pro D, Crouzy S, Ravaud S, Pebay-Peyroula E, Rolland N, Catty P, Seigneurin-Berny D. HMA6 and HMA8 are two chloroplast Cu+-ATPases with different enzymatic properties. Biosci Rep 2015; 35:e00201. [PMID: 26182363 PMCID: PMC4613667 DOI: 10.1042/bsr20150065] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/01/2015] [Accepted: 04/14/2015] [Indexed: 12/16/2022] Open
Abstract
Copper (Cu) plays a key role in the photosynthetic process as cofactor of the plastocyanin (PC), an essential component of the chloroplast photosynthetic electron transfer chain. Encoded by the nuclear genome, PC is translocated in its apo-form into the chloroplast and the lumen of thylakoids where it is processed to its mature form and acquires Cu. In Arabidopsis, Cu delivery into the thylakoids involves two transporters of the PIB-1 ATPases family, heavy metal associated protein 6 (HMA6) located at the chloroplast envelope and HMA8 at the thylakoid membrane. To gain further insight into the way Cu is delivered to PC, we analysed the enzymatic properties of HMA8 and compared them with HMA6 ones using in vitro phosphorylation assays and phenotypic tests in yeast. These experiments reveal that HMA6 and HMA8 display different enzymatic properties: HMA8 has a higher apparent affinity for Cu(+) but a slower dephosphorylation kinetics than HMA6. Modelling experiments suggest that these differences could be explained by the electrostatic properties of the Cu(+) releasing cavities of the two transporters and/or by the different nature of their cognate Cu(+) acceptors (metallochaperone/PC).
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Affiliation(s)
- Emeline Sautron
- CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, iRTSV, F-38054 Grenoble, France
- INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France
| | - Hubert Mayerhofer
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, Institut de Biologie Structurale, F-38044 Grenoble, France
- CNRS, Institut de Biologie Structurale, UMR5075, 71, avenue des Martyrs, F-38044 Grenoble, France
| | - Cécile Giustini
- CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, iRTSV, F-38054 Grenoble, France
- INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France
| | - Danièle Pro
- CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, iRTSV, F-38054 Grenoble, France
- INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France
| | - Serge Crouzy
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, iRTSV, F-38054 Grenoble, France
- *CNRS, Laboratoire de Chimie et Biologie des Métaux, UMR 5249, 17 rue des Martyrs, F-38054 Grenoble, France
| | - Stéphanie Ravaud
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, Institut de Biologie Structurale, F-38044 Grenoble, France
- CNRS, Institut de Biologie Structurale, UMR5075, 71, avenue des Martyrs, F-38044 Grenoble, France
| | - Eva Pebay-Peyroula
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, Institut de Biologie Structurale, F-38044 Grenoble, France
- CNRS, Institut de Biologie Structurale, UMR5075, 71, avenue des Martyrs, F-38044 Grenoble, France
| | - Norbert Rolland
- CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, iRTSV, F-38054 Grenoble, France
- INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France
| | - Patrice Catty
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, iRTSV, F-38054 Grenoble, France
- *CNRS, Laboratoire de Chimie et Biologie des Métaux, UMR 5249, 17 rue des Martyrs, F-38054 Grenoble, France
| | - Daphné Seigneurin-Berny
- CNRS, Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, 17 rue des Martyrs, F-38054 Grenoble, France
- Univ. Grenoble Alpes, F-38054 Grenoble, France
- CEA, DSV, iRTSV, F-38054 Grenoble, France
- INRA, LPCV, USC1359, 17 rue des Martyrs, F-38054 Grenoble, France
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17
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Abstract
Copper ATPases, in analogy with other members of the P-ATPase superfamily, contain a catalytic headpiece including an aspartate residue reacting with ATP to form a phosphoenzyme intermediate, and transmembrane helices containing cation-binding sites [TMBS (transmembrane metal-binding sites)] for catalytic activation and cation translocation. Following phosphoenzyme formation by utilization of ATP, bound copper undergoes displacement from the TMBS to the lumenal membrane surface, with no H+ exchange. Although PII-type ATPases sustain active transport of alkali/alkali-earth ions (i.e. Na+, Ca2+) against electrochemical gradients across defined membranes, PIB-type ATPases transfer transition metal ions (i.e. Cu+) from delivery to acceptor proteins and, prominently in mammalian cells, undergo trafficking from/to various membrane compartments. A specific component of copper ATPases is the NMBD (N-terminal metal-binding domain), containing up to six copper-binding sites in mammalian (ATP7A and ATP7B) enzymes. Copper occupancy of NMBD sites and interaction with the ATPase headpiece are required for catalytic activation. Furthermore, in the presence of copper, the NMBD allows interaction with protein kinase D, yielding phosphorylation of serine residues, ATP7B trafficking and protection from proteasome degradation. A specific feature of ATP7A is glycosylation and stabilization on plasma membranes. Cisplatin, a platinum-containing anti-cancer drug, binds to copper sites of ATP7A and ATP7B, and undergoes vectorial displacement in analogy with copper.
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18
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Huang Y, Nokhrin S, Hassanzadeh-Ghassabeh G, Yu CH, Yang H, Barry AN, Tonelli M, Markley JL, Muyldermans S, Dmitriev OY, Lutsenko S. Interactions between metal-binding domains modulate intracellular targeting of Cu(I)-ATPase ATP7B, as revealed by nanobody binding. J Biol Chem 2014; 289:32682-93. [PMID: 25253690 DOI: 10.1074/jbc.m114.580845] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The biologically and clinically important membrane transporters are challenging proteins to study because of their low level of expression, multidomain structure, and complex molecular dynamics that underlies their activity. ATP7B is a copper transporter that traffics between the intracellular compartments in response to copper elevation. The N-terminal domain of ATP7B (N-ATP7B) is involved in binding copper, but the role of this domain in trafficking is controversial. To clarify the role of N-ATP7B, we generated nanobodies that interact with ATP7B in vitro and in cells. In solution NMR studies, nanobodies revealed the spatial organization of N-ATP7B by detecting transient functionally relevant interactions between metal-binding domains 1-3. Modulation of these interactions by nanobodies in cells enhanced relocalization of the endogenous ATP7B toward the plasma membrane linking molecular and cellular dynamics of the transporter. Stimulation of ATP7B trafficking by nanobodies in the absence of elevated copper provides direct evidence for the important role of N-ATP7B structural dynamics in regulation of ATP7B localization in a cell.
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Affiliation(s)
- Yiping Huang
- From the Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Sergiy Nokhrin
- the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Gholamreza Hassanzadeh-Ghassabeh
- the Vrije Universiteit Brussel, Structural Biology Research Center, and Nanobody Service Facility, VIB, 1050 Brussels, Belgium, and
| | - Corey H Yu
- the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Haojun Yang
- From the Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Amanda N Barry
- From the Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Marco Tonelli
- the Department of Biochemistry, National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - John L Markley
- the Department of Biochemistry, National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Serge Muyldermans
- the Vrije Universiteit Brussel, Structural Biology Research Center, and
| | - Oleg Y Dmitriev
- the Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada,
| | - Svetlana Lutsenko
- From the Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205,
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19
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Chandhok G, Schmitt N, Sauer V, Aggarwal A, Bhatt M, Schmidt HHJ. The effect of zinc and D-penicillamine in a stable human hepatoma ATP7B knockout cell line. PLoS One 2014; 9:e98809. [PMID: 24892424 PMCID: PMC4044041 DOI: 10.1371/journal.pone.0098809] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/07/2014] [Indexed: 12/27/2022] Open
Abstract
Mutations in the copper (Cu) transporter gene ATP7B, the primary cause of Wilson disease (WD), result in high liver Cu and death of hepatocytes. Cu chelators and zinc salts are the two most important drugs used in the treatment of WD patients; however, the molecular mechanisms of the drugs with regard to ATP7B expression have not been determined. A targeted knockout of ATP7B (KO) was established in the most widely used human hepatoma cell line, HepG2 for molecular studies of the pathogenesis and treatment of the disease. KO cells showed similar growth, Cu uptake, release, and gene expression as compared to parental cells. However, in the presence of Cu, morphological changes, oxidative stress, apoptosis, and loss of viability were observed. Induction of metallothionein (MT1X) after Cu exposure was significantly reduced in KO cells. Following zinc treatment, MT1X expression was strongly induced and a high percentage of KO cells could be rescued from Cu induced toxicity. D-penicillamine treatment had a minor effect on the viability of KO cells whereas the parental cell line showed a pronounced improvement. Combined treatment displayed a highly synergistic effect in KO cells. The data suggest that zinc has a previously unrecognized effect on the viability of hepatocytes that lack ATP7B due to a high induction of MT1X expression that compensates low gene expression after Cu exposure. A combination therapy that simultaneously targets at MT1X induction and Cu chelation improves the overall survival of hepatocytes for most efficient therapy of patients having WD.
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Affiliation(s)
- Gursimran Chandhok
- Clinic for Transplantation Medicine, Münster University Hospital, Münster, Germany
- Wilson Disease Clinic, Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai, India
| | - Nadine Schmitt
- Clinic for Transplantation Medicine, Münster University Hospital, Münster, Germany
| | - Vanessa Sauer
- Clinic for Transplantation Medicine, Münster University Hospital, Münster, Germany
| | - Annu Aggarwal
- Wilson Disease Clinic, Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai, India
| | - Mohit Bhatt
- Wilson Disease Clinic, Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai, India
| | - Hartmut H. J. Schmidt
- Clinic for Transplantation Medicine, Münster University Hospital, Münster, Germany
- * E-mail:
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20
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Öhrvik H, Thiele DJ. The role of Ctr1 and Ctr2 in mammalian copper homeostasis and platinum-based chemotherapy. J Trace Elem Med Biol 2014; 31:178-82. [PMID: 24703712 PMCID: PMC4175275 DOI: 10.1016/j.jtemb.2014.03.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/13/2014] [Indexed: 12/31/2022]
Abstract
Copper (Cu) is an essential metal for growth and development that has the potential to be toxic if levels accumulate beyond the ability of cells to homeostatically balance uptake with detoxification. One system for Cu acquisition is the integral membrane Cu(+) transporter, Ctr1, which has been quite well characterized in terms of its function and physiology. The mammalian Ctr2 protein has been a conundrum for the copper field, as it is structurally closely related to the high affinity Cu transporter Ctr1, sharing important motifs for Cu transport activity. However, in contrast to mammalian Ctr1, Ctr2 fails to suppress the Cu-dependent growth phenotype of yeast cells defective in Cu(+) import, nor does it appreciably stimulate Cu acquisition when over-expressed in mammalian cells, underscoring important functional dissimilarities between the two proteins. Several roles for the mammalian Ctr2 have been suggested both in vitro and in vivo. Here, we summarize and discuss current insights into the Ctr2 protein and its interaction with Ctr1, its functions in mammalian Cu homeostasis and platinum-based chemotherapy.
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Affiliation(s)
- Helena Öhrvik
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
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21
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Telianidis J, Hung YH, Materia S, Fontaine SL. Role of the P-Type ATPases, ATP7A and ATP7B in brain copper homeostasis. Front Aging Neurosci 2013; 5:44. [PMID: 23986700 PMCID: PMC3750203 DOI: 10.3389/fnagi.2013.00044] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/05/2013] [Indexed: 12/21/2022] Open
Abstract
Over the past two decades there have been significant advances in our understanding of copper homeostasis and the pathological consequences of copper dysregulation. Cumulative evidence is revealing a complex regulatory network of proteins and pathways that maintain copper homeostasis. The recognition of copper dysregulation as a key pathological feature in prominent neurodegenerative disorders such as Alzheimer's, Parkinson's, and prion diseases has led to increased research focus on the mechanisms controlling copper homeostasis in the brain. The copper-transporting P-type ATPases (copper-ATPases), ATP7A and ATP7B, are critical components of the copper regulatory network. Our understanding of the biochemistry and cell biology of these complex proteins has grown significantly since their discovery in 1993. They are large polytopic transmembrane proteins with six copper-binding motifs within the cytoplasmic N-terminal domain, eight transmembrane domains, and highly conserved catalytic domains. These proteins catalyze ATP-dependent copper transport across cell membranes for the metallation of many essential cuproenzymes, as well as for the removal of excess cellular copper to prevent copper toxicity. A key functional aspect of these copper transporters is their copper-responsive trafficking between the trans-Golgi network and the cell periphery. ATP7A- and ATP7B-deficiency, due to genetic mutation, underlie the inherited copper transport disorders, Menkes and Wilson diseases, respectively. Their importance in maintaining brain copper homeostasis is underscored by the severe neuropathological deficits in these disorders. Herein we will review and update our current knowledge of these copper transporters in the brain and the central nervous system, their distribution and regulation, their role in normal brain copper homeostasis, and how their absence or dysfunction contributes to disturbances in copper homeostasis and neurodegeneration.
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Affiliation(s)
- Jonathon Telianidis
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
| | - Ya Hui Hung
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia
- Centre for Neuroscience Research, The University of MelbourneParkville, VIC, Australia
| | - Stephanie Materia
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
| | - Sharon La Fontaine
- Strategic Research Centre for Molecular and Medical Research, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin UniversityBurwood, VIC, Australia
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22
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Hung YH, Bush AI, La Fontaine S. Links between copper and cholesterol in Alzheimer's disease. Front Physiol 2013; 4:111. [PMID: 23720634 PMCID: PMC3655288 DOI: 10.3389/fphys.2013.00111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/30/2013] [Indexed: 01/01/2023] Open
Abstract
Altered copper homeostasis and hypercholesterolemia have been identified independently as risk factors for Alzheimer's disease (AD). Abnormal copper and cholesterol metabolism are implicated in the genesis of amyloid plaques and neurofibrillary tangles (NFT), which are two key pathological signatures of AD. Amyloidogenic processing of a sub-population of amyloid precursor protein (APP) that produces Aβ occurs in cholesterol-rich lipid rafts in copper deficient AD brains. Co-localization of Aβ and a paradoxical high concentration of copper in lipid rafts fosters the formation of neurotoxic Aβ:copper complexes. These complexes can catalytically oxidize cholesterol to generate H2O2, oxysterols and other lipid peroxidation products that accumulate in brains of AD cases and transgenic mouse models. Tau, the core protein component of NFTs, is sensitive to interactions with copper and cholesterol, which trigger a cascade of hyperphosphorylation and aggregation preceding the generation of NFTs. Here we present an overview of copper and cholesterol metabolism in the brain, and how their integrated failure contributes to development of AD.
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Affiliation(s)
- Ya Hui Hung
- Oxidation Biology Laboratory, Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia ; Centre for Neuroscience Research, The University of Melbourne Parkville, VIC, Australia
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23
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Gupta A, Lutsenko S. Evolution of copper transporting ATPases in eukaryotic organisms. Curr Genomics 2012; 13:124-33. [PMID: 23024604 PMCID: PMC3308323 DOI: 10.2174/138920212799860661] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 09/22/2011] [Accepted: 09/29/2011] [Indexed: 11/22/2022] Open
Abstract
Copper is an essential nutrient for most life forms, however in excess it can be harmful. The ATP-driven copper pumps (Copper-ATPases) play critical role in living organisms by maintaining appropriate copper levels in cells and tissues. These evolutionary conserved polytopic membrane proteins are present in all phyla from simplest life forms (bacteria) to highly evolved eukaryotes (Homo sapiens). The presumed early function in metal detoxification remains the main function of Copper-ATPases in prokaryotic kingdom. In eukaryotes, in addition to removing excess copper from the cell, Copper-ATPases have another equally important function - to supply copper to copper dependent enzymes within the secretory pathway. This review focuses on the origin and diversification of Copper ATPases in eukaryotic organisms. From a single Copper ATPase in protozoans, a divergence into two functionally distinct ATPases is observed with the evolutionary appearance of chordates. Among the key functional domains of Copper-ATPases, the metal-binding N-terminal domain could be responsible for functional diversification of the copper ATPases during the course of evolution.
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Affiliation(s)
- Arnab Gupta
- Department of Physiology, Johns Hopkins University, Baltimore, MD 21205, USA
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24
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León-García G, Santana A, Villegas-Sepúlveda N, Pérez-González C, Henrríquez-Esquíroz JM, de León-García C, Wong C, Baeza I. The T1048I mutation in ATP7A gene causes an unusual Menkes disease presentation. BMC Pediatr 2012; 12:150. [PMID: 22992316 PMCID: PMC3489546 DOI: 10.1186/1471-2431-12-150] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Accepted: 08/17/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The ATP7A gene encodes the ATP7A protein, which is a trans-Golgi network copper transporter expressed in the brain and other organs. Mutations in this gene cause disorders of copper metabolism, such as Menkes disease. Here we describe the novel and unusual mutation (p.T1048I) in the ATP7A gene of a child with Menkes disease. The mutation affects a conserved DKTGT1048 phosphorylation motif that is involved in the catalytic activity of ATP7A. We also describe the clinical course and the response to copper treatment in this patient. CASE PRESENTATION An 11-month-old male Caucasian infant was studied because of hypotonia, ataxia and global developmental delay. The patient presented low levels of serum copper and ceruloplasmin, and was shown to be hemizygous for the p.T1048I mutation in ATP7A. The diagnosis was confirmed when the patient was 18 months old, and treatment with copper-histidinate (Cu-His) was started immediately. The patient showed some neurological improvement and he is currently 8 years old. Because the p.T1048I mutation affects its catalytic site, we expected a complete loss of functional ATP7A and a classical Menkes disease presentation. However, the clinical course of the patient was mild, and he responded to Cu-His treatment, which suggests that this mutation leads to partial conservation of the activity of ATP7A. CONCLUSION This case emphasizes the important correlation between genotype and phenotype in patients with Menkes disease. The prognosis in Menkes disease is associated with early detection, early initiation of treatment and with the preservation of some ATP7A activity, which is necessary for Cu-His treatment response. The description of this new mutation and the response of the patient to Cu-His treatment will contribute to the growing body of knowledge about treatment response in Menkes disease.
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Affiliation(s)
- Gregorio León-García
- Department of Biochemistry, National School of Biological Sciences, National Polytechnic Institute (IPN), Mexico City, 11340, Mexico
| | - Alfredo Santana
- Centre for Biomedical Research on Rare Disease (CIBERER), Canarias University Hospital, Institute of Biomedical Technologies, University of La Laguna, Tenerife, Spain
| | - Nicolás Villegas-Sepúlveda
- Department of Molecular Biology, Centre for Research and Advanced Studies, IPN, Mexico City, 07360, Mexico
| | | | | | | | - Carlos Wong
- Department of Biochemistry, National School of Biological Sciences, National Polytechnic Institute (IPN), Mexico City, 11340, Mexico
| | - Isabel Baeza
- Department of Biochemistry, National School of Biological Sciences, National Polytechnic Institute (IPN), Mexico City, 11340, Mexico
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Kodama H, Fujisawa C, Bhadhprasit W. Inherited copper transport disorders: biochemical mechanisms, diagnosis, and treatment. Curr Drug Metab 2012; 13:237-50. [PMID: 21838703 PMCID: PMC3290776 DOI: 10.2174/138920012799320455] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/07/2011] [Accepted: 05/16/2011] [Indexed: 12/14/2022]
Abstract
Copper is an essential trace element required by all living organisms. Excess amounts of copper, however, results in cellular damage. Disruptions to normal copper homeostasis are hallmarks of three genetic disorders: Menkes disease, occipital horn syndrome, and Wilson's disease. Menkes disease and occipital horn syndrome are characterized by copper deficiency. Typical features of Menkes disease result from low copper-dependent enzyme activity. Standard treatment involves parenteral administration of copper-histidine. If treatment is initiated before 2 months of age, neurodegeneration can be prevented, while delayed treatment is utterly ineffective. Thus, neonatal mass screening should be implemented. Meanwhile, connective tissue disorders cannot be improved by copper-histidine treatment. Combination therapy with copper-histidine injections and oral administration of disulfiram is being investigated. Occipital horn syndrome characterized by connective tissue abnormalities is the mildest form of Menkes disease. Treatment has not been conducted for this syndrome. Wilson's disease is characterized by copper toxicity that typically affects the hepatic and nervous systems severely. Various other symptoms are observed as well, yet its early diagnosis is sometimes difficult. Chelating agents and zinc are effective treatments, but are inefficient in most patients with fulminant hepatic failure. In addition, some patients with neurological Wilson's disease worsen or show poor response to chelating agents. Since early treatment is critical, a screening system for Wilson's disease should be implemented in infants. Patients with Wilson's disease may be at risk of developing hepatocellular carcinoma. Understanding the link between Wilson's disease and hepatocellular carcinoma will be beneficial for disease treatment and prevention.
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Affiliation(s)
- Hiroko Kodama
- Department of health Dietetics, Teikyo Heisei University, Toshima-ku, Tokyo.
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26
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Schushan M, Bhattacharjee A, Ben-Tal N, Lutsenko S. A structural model of the copper ATPase ATP7B to facilitate analysis of Wilson disease-causing mutations and studies of the transport mechanism. Metallomics 2012; 4:669-78. [PMID: 22692182 DOI: 10.1039/c2mt20025b] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The copper-transporting ATPase ATP7B has an essential role in human physiology, particularly for the liver and brain function. Inactivation of ATP7B is associated with a severe hepato-neurologic disorder, Wilson disease (WD). Hundreds of WD related mutations have been identified in ATP7B to date. The low frequency and the compound-heterozygous nature of causative mutations complicate the analysis of individual mutants and the establishment of genotype-phenotype correlations. To facilitate studies of disease-causing mutations and mechanistic understanding of WD, we have homology-modelled the ATP7B core (residues 643-1377) using the recent structure of the bacterial copper-ATPase LCopA as a template. The model, supported by evolutionary conservation and hydrophobicity analysis, as well as existing and new mutagenesis data, allows molecular interpretations of experimentally characterized clinical mutations. We also illustrate that structure and conservation can be used to grade potential deleterious effects for many WD mutations, which were clinically detected but have not yet been experimentally characterized. Finally, we compare the structural features of ATP7B and LCopA and discuss specific features of the eukaryotic copper pump.
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Affiliation(s)
- Maya Schushan
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv 69978, Israel.
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27
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Abstract
P(IB)-type ATPases transport heavy metals (Cu(2+), Cu(+), Ag(+), Zn(2+), Cd(2+), Co(2+)) across biomembranes, playing a key role in homeostasis and in the mechanisms of biotolerance of these metals. Three genes coding for putative P(IB)-type ATPases are present in the genome of Thermus thermophilus (HB8 and HB27): the TTC1358, TTC1371, and TTC0354 genes; these genes are annotated, respectively, as two copper transporter (CopA and CopB) genes and a zinc-cadmium transporter (Zn(2+)/Cd(2+)-ATPase) gene. We cloned and expressed the three proteins with 8His tags using a T. thermophilus expression system. After purification, each of the proteins was shown to have phosphodiesterase activity at 65°C with ATP and p-nitrophenyl phosphate (pNPP) as substrates. CopA was found to have greater activity in the presence of Cu(+), while CopB was found to have greater activity in the presence of Cu(2+). The putative Zn(2+)/Cd(2+)-ATPase was truncated at the N terminus and was, surprisingly, activated in vitro by copper but not by zinc or cadmium. When expressed in Escherichia coli, however, the putative Zn(2+)/Cd(2+)-ATPase could be isolated as a full-length protein and the ATPase activity was increased by the addition of Zn(2+) and Cd(2+) as well as by Cu(+). Mutant strains in which each of the three P-type ATPases was deleted singly were constructed. In each case, the deletion increased the sensitivity of the strain to growth in the presence of copper in the medium, indicating that each of the three can pump copper out of the cells and play a role in copper detoxification.
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28
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Raimunda D, Long JE, Sassetti CM, Argüello JM. Role in metal homeostasis of CtpD, a Co²⁺ transporting P(1B4)-ATPase of Mycobacterium smegmatis. Mol Microbiol 2012; 84:1139-49. [PMID: 22591178 DOI: 10.1111/j.1365-2958.2012.08082.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Genetic studies in the tuberculosis mouse model have suggested that mycobacterial metal efflux systems, such as the P(1B4)-ATPase CtpD, are important for pathogenesis. The specificity for substrate metals largely determines the function of these ATPases; however, various substrates have been reported for bacterial and plant P(1B4)-ATPases leaving their function uncertain. Here we describe the functional role of the CtpD protein of Mycobacterium smegmatis. An M. smegmatis mutant strain lacking the ctpD gene was hypersensitive to Co²⁺ and Ni²⁺ and accumulated these metals in the cytoplasm. ctpD transcription was induced by both Co²⁺ and superoxide stress. Biochemical characterization of heterologously expressed, affinity-purified CtpD showed that this ATPase is activated by Co²⁺, Ni²⁺ and to a lesser extend Zn²⁺ (20% of maximum activity). The protein was also able to bind one Co²⁺, Ni²⁺ or Zn²⁺ to its transmembrane transport site. These observations indicate that CtpD is important for Co²⁺ and Ni²⁺ homeostasis in M. smegmatis, and that M. tuberculosis CtpD orthologue could be involved in metal detoxification and resisting cellular oxidative stress by modulating the intracellular concentration of these metals.
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Affiliation(s)
- Daniel Raimunda
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA, USA
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29
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Huster D, Kühne A, Bhattacharjee A, Raines L, Jantsch V, Noe J, Schirrmeister W, Sommerer I, Sabri O, Berr F, Mössner J, Stieger B, Caca K, Lutsenko S. Diverse functional properties of Wilson disease ATP7B variants. Gastroenterology 2012; 142:947-956.e5. [PMID: 22240481 PMCID: PMC3461965 DOI: 10.1053/j.gastro.2011.12.048] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 12/19/2011] [Accepted: 12/26/2011] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Wilson disease is a severe disorder of copper metabolism caused by mutations in ATP7B, which encodes a copper-transporting adenosine triphosphatase. The disease presents with a variable phenotype that complicates the diagnostic process and treatment. Little is known about the mechanisms that contribute to the different phenotypes of the disease. METHODS We analyzed 28 variants of ATP7B from patients with Wilson disease that affected different functional domains; the gene products were expressed using the baculovirus expression system in Sf9 cells. Protein function was analyzed by measuring catalytic activity and copper ((64)Cu) transport into vesicles. We studied intracellular localization of variants of ATP7B that had measurable transport activities and were tagged with green fluorescent protein in mammalian cells using confocal laser scanning microscopy. RESULTS Properties of ATP7B variants with pathogenic amino-acid substitution varied greatly even if substitutions were in the same functional domain. Some variants had complete loss of catalytic and transport activity, whereas others lost transport activity but retained phosphor-intermediate formation or had partial losses of activity. In mammalian cells, transport-competent variants differed in stability and subcellular localization. CONCLUSIONS Variants in ATP7B associated with Wilson disease disrupt the protein's transport activity, result in its mislocalization, and reduce its stability. Single assays are insufficient to accurately predict the effects of ATP7B variants the function of its product and development of Wilson disease. These findings will contribute to our understanding of genotype-phenotype correlation and mechanisms of disease pathogenesis.
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Affiliation(s)
- Dominik Huster
- Department of Medicine, Dermatology and Neurology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany.
| | - Angelika Kühne
- Department of Medicine, Dermatology and Neurology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
| | | | - Lily Raines
- Department of Physiology, Johns Hopkins University, Baltimore, Maryland
| | - Vanessa Jantsch
- Department of Medicine, Dermatology and Neurology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
| | - Johannes Noe
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zurich, Switzerland
| | - Wiebke Schirrmeister
- Department of Gastroenterology, Hepatology and Infectious Diseases, Otto-von-Guericke-University, Magdeburg, Germany,Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | - Ines Sommerer
- Department of Medicine, Dermatology and Neurology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
| | - Frieder Berr
- Department of Medicine, Dermatology and Neurology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany,Department of Internal Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Joachim Mössner
- Department of Medicine, Dermatology and Neurology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zurich, Switzerland
| | - Karel Caca
- Department of Medicine, Dermatology and Neurology, Division of Gastroenterology and Rheumatology, University of Leipzig, Leipzig, Germany,Department of Gastroenterology, Medizinische Klinik I, Klinikum Ludwigsburg, Ludwigsburg, Germany
| | - Svetlana Lutsenko
- Department of Physiology, Johns Hopkins University, Baltimore, Maryland
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Hercend C, Bauvais C, Bollot G, Delacotte N, Chappuis P, Woimant F, Launay JM, Manivet P. Elucidation of the ATP7B N-domain Mg2+-ATP coordination site and its allosteric regulation. PLoS One 2011; 6:e26245. [PMID: 22046264 PMCID: PMC3203118 DOI: 10.1371/journal.pone.0026245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Accepted: 09/23/2011] [Indexed: 11/25/2022] Open
Abstract
The diagnostic of orphan genetic disease is often a puzzling task as less attention is paid to the elucidation of the pathophysiology of these rare disorders at the molecular level. We present here a multidisciplinary approach using molecular modeling tools and surface plasmonic resonance to study the function of the ATP7B protein, which is impaired in the Wilson disease. Experimentally validated in silico models allow the elucidation in the Nucleotide binding domain (N-domain) of the Mg2+-ATP coordination site and answer to the controversial role of the Mg2+ ion in the nucleotide binding process. The analysis of protein motions revealed a substantial effect on a long flexible loop branched to the N-domain protein core. We demonstrated the capacity of the loop to disrupt the interaction between Mg2+-ATP complex and the N-domain and propose a role for this loop in the allosteric regulation of the nucleotide binding process.
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Affiliation(s)
- Claude Hercend
- APHP, Hôpital Lariboisière, Service de Biochimie et de Biologie Moléculaire, Paris, France
- INSERM U942, Biomarqueurs et Insuffisance cardiaque, Hôpital Lariboisière, Paris, France
| | - Cyril Bauvais
- Division of Structural Biology, Bioquanta, Paris, France
| | | | | | - Philippe Chappuis
- APHP, Hôpital Lariboisière, Service de Biochimie et de Biologie Moléculaire, Paris, France
| | - France Woimant
- APHP, Hôpital Lariboisière, Service de Neurologie, Paris, France
| | - Jean-Marie Launay
- APHP, Hôpital Lariboisière, Service de Biochimie et de Biologie Moléculaire, Paris, France
- INSERM U942, Biomarqueurs et Insuffisance cardiaque, Hôpital Lariboisière, Paris, France
| | - Philippe Manivet
- APHP, Hôpital Lariboisière, Service de Biochimie et de Biologie Moléculaire, Paris, France
- INSERM U829, SABNP Laboratory, Evry, France
- Université Evry Val-d'Essonne, Evry, France
- * E-mail:
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31
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Dmitriev OY. Mechanism of tumor resistance to cisplatin mediated by the copper transporter ATP7B. Biochem Cell Biol 2011; 89:138-47. [PMID: 21455266 DOI: 10.1139/o10-150] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The Wilson disease protein (ATP7B) is a copper-transporting ATPase that is responsible for regulating copper homeostasis in human tissues. ATP7B is associated with cancer resistance to cisplatin, one of the most widely used anticancer drugs. This minireview discusses the possible mechanisms of tumor resistance to cisplatin mediated by ATP7B. Cisplatin binds to the N-terminal cytosolic domain of ATP7B, which contains multiple copper-binding sites. Active platinum efflux catalyzed by ATP7B is unlikely to significantly contribute to cisplatin resistance in vivo. Transient platinum sequestration in the metal-binding domain followed by transfer to an acceptor protein or a low molecular weight compound is proposed as an alternative mechanism of cisplatin detoxification in the cell.
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Affiliation(s)
- Oleg Y Dmitriev
- Department of Biochemistry, University of Saskatchewan, SK, Canada.
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32
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Inesi G. Calcium and copper transport ATPases: analogies and diversities in transduction and signaling mechanisms. J Cell Commun Signal 2011; 5:227-37. [PMID: 21656155 PMCID: PMC3145875 DOI: 10.1007/s12079-011-0136-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 04/28/2011] [Indexed: 12/17/2022] Open
Abstract
The calcium transport ATPase and the copper transport ATPase are members of the P-ATPase family and retain an analogous catalytic mechanism for ATP utilization, including intermediate phosphoryl transfer to a conserved aspartyl residue, vectorial displacement of bound cation, and final hydrolytic cleavage of Pi. Both ATPases undergo protein conformational changes concomitant with catalytic events. Yet, the two ATPases are prototypes of different features with regard to transduction and signaling mechanisms. The calcium ATPase resides stably on membranes delimiting cellular compartments, acquires free Ca2+ with high affinity on one side of the membrane, and releases the bound Ca2+ on the other side of the membrane to yield a high free Ca2+ gradient. These features are a basic requirement for cellular Ca2+ signaling mechanisms. On the other hand, the copper ATPase acquires copper through exchange with donor proteins, and undergoes intracellular trafficking to deliver copper to acceptor proteins. In addition to the cation transport site and the conserved aspartate undergoing catalytic phosphorylation, the copper ATPase has copper binding regulatory sites on a unique N-terminal protein extension, and has also serine residues undergoing kinase assisted phosphorylation. These additional features are involved in the mechanism of copper ATPase intracellular trafficking which is required to deliver copper to plasma membranes for extrusion, and to the trans-Golgi network for incorporation into metalloproteins. Isoform specific glyocosylation contributes to stabilization of ATP7A copper ATPase in plasma membranes.
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Affiliation(s)
- Giuseppe Inesi
- California Pacific Medical Center Research Institute, 475 Brannan Street, San Francisco, CA, 94107, USA,
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33
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Barry AN, Otoikhian A, Bhatt S, Shinde U, Tsivkovskii R, Blackburn NJ, Lutsenko S. The lumenal loop Met672-Pro707 of copper-transporting ATPase ATP7A binds metals and facilitates copper release from the intramembrane sites. J Biol Chem 2011; 286:26585-94. [PMID: 21646353 DOI: 10.1074/jbc.m111.229039] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The copper-transporting ATPase ATP7A has an essential role in human physiology. ATP7A transfers the copper cofactor to metalloenzymes within the secretory pathway; inactivation of ATP7A results in an untreatable neurodegenerative disorder, Menkes disease. Presently, the mechanism of ATP7A-mediated copper release into the secretory pathway is not understood. We demonstrate that the characteristic His/Met-rich segment Met(672)-Pro(707) (HM-loop) that connects the first two transmembrane segments of ATP7A is important for copper release. Mutations within this loop do not prevent the ability of ATP7A to form a phosphorylated intermediate during ATP hydrolysis but inhibit subsequent dephosphorylation, a step associated with copper release. The HM-loop inserted into a scaffold protein forms two structurally distinct binding sites and coordinates copper in a mixed His-Met environment with an ∼2:1 stoichiometry. Binding of either copper or silver, a Cu(I) analog, induces structural changes in the loop. Mutations of 4 Met residues to Ile or two His-His pairs to Ala-Gly decrease affinity for copper. Altogether, the data suggest a two-step process, where copper released from the transport sites binds to the first His(Met)(2) site, triggering a structural change and binding to a second 2-coordinate His-His or His-Met site. We also show that copper binding within the HM-loop stabilizes Cu(I) and protects it from oxidation, which may further aid the transfer of copper from ATP7A to acceptor proteins. The mechanism of copper entry into the secretory pathway is discussed.
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Affiliation(s)
- Amanda N Barry
- From the Department of Physiology, Johns Hopkins University, Baltimore, Maryland 21205, USA
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Cellular copper levels determine the phenotype of the Arg875 variant of ATP7B/Wilson disease protein. Proc Natl Acad Sci U S A 2011; 108:5390-5. [PMID: 21406592 DOI: 10.1073/pnas.1014959108] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In human disorders, the genotype-phenotype relationships are often complex and influenced by genetic and/or environmental factors. Wilson disease (WD) is a monogenic disorder caused by mutations in the copper-transporting P-type ATPase ATP7B. WD shows significant phenotypic diversity even in patients carrying identical mutations; the basis for such diverse manifestations is unknown. We demonstrate that the 2623A/G polymorphism (producing the Gly(875) → Arg substitution in the A-domain of ATP7B) drastically alters the intracellular properties of ATP7B, whereas copper reverses the effects. Under basal conditions, the common Gly(875) variant of ATP7B is targeted to the trans-Golgi network (TGN) and transports copper into the TGN lumen. In contrast, the Arg(875) variant is located in the endoplasmic reticulum (ER) and does not deliver copper to the TGN. Elevated copper corrects the ATP7B-Arg(875) phenotype. Addition of only 0.5-5 μM copper triggers the exit of ATP7B-Arg(875) from the ER and restores copper delivery to the TGN. Analysis of the recombinant A-domains by NMR suggests that the ER retention of ATP7B-Arg(875) is attributable to increased unfolding of the Arg(875)-containing A-domain. Copper is not required for the folding of ATP7B-Arg(875) during biosynthesis, but it stabilizes protein and stimulates its activity. A chemotherapeutical drug, cisplatin, that mimics a copper-bound state of ATP7B also corrects the "disease-like" phenotype of ATP7B-Arg(875) and promotes its TGN targeting and transport function. We conclude that in populations harboring the Arg(875) polymorphism, the levels of bioavailable copper may play a vital role in the manifestations of WD.
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35
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Valverde RHF, Britto-Borges T, Lowe J, Einicker-Lamas M, Mintz E, Cuillel M, Vieyra A. Two serine residues control sequential steps during catalysis of the yeast copper ATPase through different mechanisms that involve kinase-mediated phosphorylations. J Biol Chem 2010; 286:6879-89. [PMID: 21163943 DOI: 10.1074/jbc.m110.207704] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ccc2, the yeast copper-transporting ATPase, pumps copper from the cytosol to the Golgi lumen. During its catalytic cycle, Ccc2 undergoes auto-phosphorylation on Asp(627) and uses the energy gained to transport copper across the cell membrane. We previously demonstrated that cAMP-dependent protein kinase (PKA) controls the energy interconversion (Cu)E∼P → E-P + Cu when Ser(258) is phosphorylated. We now demonstrate that Ser(258) is essential in vivo for copper homeostasis in extremely low copper and iron concentrations. The S258A mutation abrogates all PKA-mediated phosphorylations of Ccc2, whereas the S971A mutation leads to a 100% increase in its global regulatory phosphorylation. With S258A, the first-order rate constant of catalytic phosphorylation by ATP decreases from 0.057 to 0.030 s(-1), with an 8-fold decrease in the burst of initial phosphorylation. With the S971A mutant, the rate constant decreases to 0.007 s(-1). PKAi(5-24) decreases the amount of the aspartylphosphate intermediate (EP) in Ccc2 wt by 50% within 1 min, but not in S258A, S971A, or S258A/S971A. The increase of the initial burst and the extremely slow phosphorylation when the "phosphomimetic" mutant S258D was assayed (k = 0.0036 s(-1)), indicate that electrostatic and conformational (non-electrostatic) mechanisms are involved in the regulatory role of Ser(258). Accumulation of an ADP-insensitive form in S971A demonstrates that Ser(971) is required to accelerate the hydrolysis of the E-P form during turnover. We propose that Ser(258) and Ser(971) are under long-range intramolecular, reciprocal and concerted control, in a sequential process that is crucial for catalysis and copper transport in the yeast copper ATPase.
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Affiliation(s)
- Rafael H F Valverde
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21949-900 Rio de Janeiro, Brazil
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36
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Liu Y, Pilankatta R, Hatori Y, Lewis D, Inesi G. Comparative features of copper ATPases ATP7A and ATP7B heterologously expressed in COS-1 cells. Biochemistry 2010; 49:10006-12. [PMID: 20964302 PMCID: PMC2982669 DOI: 10.1021/bi101423j] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 10/18/2010] [Indexed: 11/28/2022]
Abstract
ATP7A and ATP7B are P-type ATPases required for copper homeostasis and involved in the etiology of Menkes and Wilson diseases. We used heterologous expression of ATP7A or ATP7B in COS-1 cells infected with adenovirus vectors to characterize differential features pertinent to each protein expressed in the same mammalian cell type, rather than to extrinsic factors related to different cells sustaining expression. Electrophoretic analysis of the expressed protein, before and after purification, prior or subsequent to treatment with endoglycosidase, and evidenced by protein or glycoprotein staining as well as Western blotting, indicates that the ATP7A protein is glycosylated while ATP7B is not. This is consistent with the prevalence of glycosylation motifs in the ATP7A sequence, and not in ATP7B. ATP7A and ATP7B undergo copper-dependent phosphorylation by utilization of ATP, forming equal levels of an "alkali labile" phosphoenzyme intermediate that undergoes similar catalytic (P-type ATPase) turnover in both enzymes. In addition, incubation with ATP yields an "alkali stable" phosphoprotein fraction, attributed to phosphorylation of serines. Alkali stable phosphorylation occurs at lower levels in ATP7A, consistent with a different distribution of serines in the amino acid sequence. Immunostaining of COS-1 cells sustaining heterologous expression shows initial association of both ATP7A and ATP7B with Golgi and the trans-Golgi network. However, in the presence of added copper, ATP7A undergoes prevalent association with the plasma membrane while ATP7B exhibits intense trafficking with cytosolic vesicles. Glycosylation of ATP7A and phosphorylation of ATP7B apparently contribute to their different trafficking and membrane association when expressed in the same cell type.
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Affiliation(s)
- Yueyong Liu
- California Pacific Medical Center Research Institute, San Francisco, California 94107, United States
| | - Rajendra Pilankatta
- California Pacific Medical Center Research Institute, San Francisco, California 94107, United States
| | - Yuta Hatori
- California Pacific Medical Center Research Institute, San Francisco, California 94107, United States
| | - David Lewis
- California Pacific Medical Center Research Institute, San Francisco, California 94107, United States
| | - Giuseppe Inesi
- California Pacific Medical Center Research Institute, San Francisco, California 94107, United States
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37
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Hilário-Souza E, Valverde RHF, Britto-Borges T, Vieyra A, Lowe J. Golgi membranes from liver express an ATPase with femtomolar copper affinity, inhibited by cAMP-dependent protein kinase. Int J Biochem Cell Biol 2010; 43:358-62. [PMID: 21084060 DOI: 10.1016/j.biocel.2010.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 11/03/2010] [Accepted: 11/08/2010] [Indexed: 11/27/2022]
Abstract
Copper-stimulated P-type ATPases are essential in the fine-tuning of intracellular copper. In the present work we characterized a copper-dependent ATPase hydrolysis in a native Golgi-enriched preparation from liver and investigated its modulation by cyclic AMP-dependent protein kinase (PKA). The very high-affinity Atp7b copper pump presented here shows a K(0.5) for free copper of 2.5×10(-17) M in bathocuproine disulfonate/copper buffer and ATP hydrolysis was inhibited 50% upon stimulation of PKA pathway, using forskolin, cAMP or cholera toxin. Incubation with PKA inhibitor (PKAi(5-24) peptide) raises Cu(I)-ATPase activity by 50%. Addition of purified PKA α-catalytic subunit increases K(0.5) for free copper (6.2×10(-17) M) without modification in the affinity for ATP in the low-affinity range of the substrate curve (∼1 mM). The Hill coefficient for free copper activation also remains unchanged if exogenous PKA is added (2.7 and 2.3 in the absence and presence of PKA, respectively). The results demonstrate that this high-affinity copper pump in its natural environment is a target of the liver PKA pathway, being regulatory phosphorylation able to influence both turnover rate and ion affinity.
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Affiliation(s)
- Elaine Hilário-Souza
- Laboratório de Físico-Química Biológica Aída Hassón-Voloch, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal de Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil
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38
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Tadini-Buoninsegni F, Bartolommei G, Moncelli MR, Pilankatta R, Lewis D, Inesi G. ATP dependent charge movement in ATP7B Cu+-ATPase is demonstrated by pre-steady state electrical measurements. FEBS Lett 2010; 584:4619-22. [PMID: 20965182 DOI: 10.1016/j.febslet.2010.10.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 10/12/2010] [Accepted: 10/13/2010] [Indexed: 12/22/2022]
Abstract
ATP7B is a copper dependent P-type ATPase, required for copper homeostasis. Taking advantage of high yield heterologous expression of recombinant protein, we investigated charge transfer in ATP7B. We detected charge displacement within a single catalytic cycle upon ATP addition and formation of phosphoenzyme intermediate. We attribute this charge displacement to movement of bound copper within ATP7B. Based on specific mutations, we demonstrate that enzyme activation by copper requires occupancy of a site in the N-terminus extension which is not present in other transport ATPases, as well as of a transmembrane site corresponding to the cation binding site of other ATPases.
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39
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Abstract
Aerobic organisms are faced with a dilemma. Environmental iron is found primarily in the relatively inert Fe(III) form, whereas the more metabolically active ferrous form is a strong pro-oxidant. This conundrum is solved by the redox cycling of iron between Fe(III) and Fe(II) at every step in the iron metabolic pathway. As a transition metal ion, iron can be "metabolized" only by this redox cycling, which is catalyzed in aerobes by the coupled activities of ferric iron reductases (ferrireductases) and ferrous iron oxidases (ferroxidases).
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Affiliation(s)
- Daniel J Kosman
- Department of Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York 14214.
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Copper in the brain and Alzheimer’s disease. J Biol Inorg Chem 2009; 15:61-76. [DOI: 10.1007/s00775-009-0600-y] [Citation(s) in RCA: 313] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Accepted: 10/13/2009] [Indexed: 12/13/2022]
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42
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Bartee MY, Ralle M, Lutsenko S. The loop connecting metal-binding domains 3 and 4 of ATP7B is a target of a kinase-mediated phosphorylation. Biochemistry 2009; 48:5573-81. [PMID: 19405516 DOI: 10.1021/bi900325k] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cu-ATPase ATP7B (Wilson's disease protein) transports copper into the trans-Golgi network for biosynthetic incorporation into ceruloplasmin and sequesters excess copper to endocytic vesicles for further export out of the cell. The activity and intracellular location of ATP7B are regulated by copper levels; the trafficking of ATP7B between cellular compartments is coupled to changes in the level of protein phosphorylation. Neither the nature of the kinase(s) phosphorylating ATP7B nor the location of phosphorylation sites is known. We demonstrate that the membrane-bound ATP7B is phosphorylated by an ATP-dependent, GTP-independent kinase that can be either soluble or membrane-associated. Mg(2+) or Mn(2+) is necessary for kinase activity. We further show that the recombinant N-terminal domain of ATP7B (N-ATP7B) is a specific target for a kinase-mediated phosphorylation in vitro and in cells. Although exogenous addition of copper is not required for kinase activity, copper binding to N-ATP7B markedly alters the exposure of loops connecting the metal-binding subdomains (MBDs) to proteolysis and facilitates phosphorylation by 25-30%. MBD1-2 and MBD4-5 linkers become protected, while MBD2-3 and MBD3-4 regions remain exposed. A significant, 5-fold increase in the level of phosphorylation is also observed for the ATP7B variant that lacks the 29 kDa N-terminal fragment (mostly likely comprised of MBD1-3). Analysis of phosphorylated peptides by two-dimensional gel electrophoresis and mass spectrometry points to the loop connecting MBD3 and MBD4 as a region of phosphorylation. Altogether, the results suggest a mechanism in which kinase-mediated phosphorylation of ATP7B is controlled by a conformational state of N-ATP7B.
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Affiliation(s)
- Mee Y Bartee
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239-3098, USA
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43
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Morin I, Gudin S, Mintz E, Cuillel M. Dissecting the role of the N-terminal metal-binding domains in activating the yeast copper ATPasein vivo. FEBS J 2009; 276:4483-95. [DOI: 10.1111/j.1742-4658.2009.07155.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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44
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Pilankatta R, Lewis D, Adams CM, Inesi G. High yield heterologous expression of wild-type and mutant Cu+-ATPase (ATP7B, Wilson disease protein) for functional characterization of catalytic activity and serine residues undergoing copper-dependent phosphorylation. J Biol Chem 2009; 284:21307-16. [PMID: 19520855 PMCID: PMC2755855 DOI: 10.1074/jbc.m109.023341] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
ATP7B is a P-type ATPase required for copper homeostasis and related to Wilson disease of humans. In addition to various domains corresponding to other P-type ATPases, ATP7B includes an N terminus extension (NMBD) with six copper binding sites. We obtained high yield expression of WT and mutant ATP7B in COS1 cells infected with adenovirus vector. ATP7B, isolated with the microsomal fraction of cell homogenates, accounts for 10–20% of the total protein. Copper-dependent, steady-state ATPase yields 30 nmol of Pi/mg of protein/min at 37 °C, pH 6.0. ATP7B phosphorylation with ATP occurs with diphasic kinetics and is totally copper-dependent. Alkali labile phosphoenzyme (catalytic intermediate of P-ATPases) accounts for a small fraction of the total phosphoprotein and is prevented by D1027N (P domain) or C983A/C985A (CXC copper binding motif in TM6) mutations. Decay of [32P]phosphoenzyme following chase with non-radioactive ATP occurs with an initial burst involving alkali labile phosphoenzyme (absent in D1027N and C983A/C985A mutants) and continues at a slow rate involving alkali-resistant phosphoenzyme. If a copper chelator is added with the ATP chase, the initial burst is smaller, and further cleavage is totally inhibited. Analysis by proteolysis and mass spectrometry demonstrates that the alkali stable phosphoenzyme involves Ser478 and Ser481 (NMBD), Ser1121 (“N” domain) and Ser1453 (C terminus), and occurs with the same pattern ex vivo (COS-1) and in vitro (microsomes). The overall copper dependence of phosphorylation and hydrolytic cleavage suggests long range conformational effects, including interactions of NMBD and headpiece domains, with strong influence on catalytic turnover.
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Affiliation(s)
- Rajendra Pilankatta
- California Pacific Medical Center Research Institute, San Francisco, California 94107, USA
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Leonhardt K, Gebhardt R, Mössner J, Lutsenko S, Huster D. Functional interactions of Cu-ATPase ATP7B with cisplatin and the role of ATP7B in the resistance of cells to the drug. J Biol Chem 2009; 284:7793-802. [PMID: 19141620 DOI: 10.1074/jbc.m805145200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cisplatin is a widely used chemotherapeutic agent for treatment of ovarian, testicular, lung, and stomach cancers. The initial response to the drug is robust; however, tumor cells commonly develop resistance to cisplatin, which complicates treatment. Recently, overexpression of the Cu-ATPase ATP7B in ovary cells was linked to the increased cellular resistance to cisplatin; and the role for Cu-ATPases in the export of cisplatin from cells was proposed. Our results support functional interactions between cisplatin and ATP7B but argue against the active transport through the copper translocation pathway as a mechanism of drug resistance. In hepatocytes, we observed no correlation between the levels of endogenous ATP7B and the resistance of cells to cisplatin. Unlike copper, cisplatin does not induce trafficking of ATP7B in hepatoma cells, neither does it compete with copper in a transport assay. However, cisplatin binds to ATP7B and stimulates catalytic phosphorylation with EC(50) similar to that of copper. Mutations of the first five N-terminal copper-binding sites of ATP7B do not inhibit the cisplatin-induced phosphorylation of ATP7B. In contrast, the deletion of the first four copper-binding sites abolishes the effect of cisplatin on the ATP7B activity. Thus, cisplatin binding to ATP7B and/or general changes in cellular copper homeostasis are likely contributors to the increased resistance to the drug. The link between changes in copper homeostasis and cisplatin resistance was confirmed by treating the Huh7 cells with copper chelator and increasing their resistance to cisplatin.cisplatin.
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Affiliation(s)
- Karoline Leonhardt
- Department of Medicine II and Department of Biochemistry, University of Leipzig, 04103 Leipzig, Germany
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46
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Kodama H, Fujisawa C. Copper metabolism and inherited copper transport disorders: molecular mechanisms, screening, and treatment. Metallomics 2009. [DOI: 10.1039/b816011m] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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47
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Mechanism of Cu+-transporting ATPases: soluble Cu+ chaperones directly transfer Cu+ to transmembrane transport sites. Proc Natl Acad Sci U S A 2008; 105:5992-7. [PMID: 18417453 DOI: 10.1073/pnas.0711446105] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
As in other P-type ATPases, metal binding to transmembrane metal-binding sites (TM-MBS) in Cu(+)-ATPases is required for enzyme phosphorylation and subsequent transport. However, Cu(+) does not access Cu(+)-ATPases in a free (hydrated) form but is bound to a chaperone protein. Cu(+) transfer from Cu(+) chaperones to regulatory cytoplasmic metal-binding domains (MBDs) present in these ATPases has been described, but there is no evidence of a proposed subsequent Cu(+) movement from the MBDs to the TM-MBS. Alternatively, we postulate the parsimonious Cu(+) transfer by the chaperone directly to TM-MBS. Testing both models, the delivery of Cu(+) by Archaeoglobus fulgidus Cu(+) chaperone CopZ to the corresponding Cu(+)-ATPase, CopA, was studied. As expected, CopZ interacted with and delivered the metal to CopA MBDs. Cu(+)-loaded MBDs, acting as metal donors, were unable to activate CopA or a truncated CopA lacking MBDs. Conversely, Cu(+)-loaded CopZ activated the CopA ATPase and CopA constructs in which MBDs were rendered unable to bind Cu(+). Furthermore, under nonturnover conditions, CopZ transferred Cu(+) to the TM-MBS of a CopA lacking MBDs. These data are consistent with a model where MBDs serve a regulatory function without participating in metal transport and the chaperone delivers Cu(+) directly to transmembrane transport sites of Cu(+)-ATPases.
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Valverde RH, Morin I, Lowe J, Mintz E, Cuillel M, Vieyra A. Cyclic AMP-dependent protein kinase controls energy interconversion during the catalytic cycle of the yeast copper-ATPase. FEBS Lett 2008; 582:891-5. [DOI: 10.1016/j.febslet.2008.02.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 02/08/2008] [Indexed: 11/25/2022]
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49
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Lörinczi E, Tsivkovskii R, Haase W, Bamberg E, Lutsenko S, Friedrich T. Delivery of the Cu-transporting ATPase ATP7B to the plasma membrane in Xenopus oocytes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:896-906. [PMID: 18222167 DOI: 10.1016/j.bbamem.2007.12.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 12/11/2007] [Accepted: 12/27/2007] [Indexed: 10/22/2022]
Abstract
Cu-transporting ATPase ATP7B (Wilson disease protein) is essential for the maintenance of intracellular copper concentration. In hepatocytes, ATP7B is required for copper excretion, which is thought to occur via a transient delivery of the ATP7B- and copper-containing vesicles to the apical membrane. The currently available experimental systems do not allow analysis of ATP7B at the cell surface. Using epitope insertion, we identified an extracellular loop into which the HA-epitope can be introduced without inhibiting ATP7B activity. The HA-tagged ATP7B was expressed in Xenopus oocytes and the presence of ATP7B at the plasma membrane was demonstrated by electron microscopy, freeze-fracture experiments, and surface luminescence measurements in intact cells. Neither the deletion of the entire N-terminal copper-binding domain nor the inactivating mutation of catalytic Asp1027 affected delivery to the plasma membrane of oocytes. In contrast, surface targeting was decreased for the ATP7B variants with mutations in the ATP-binding site or the intra-membrane copper-binding site, suggesting that ligand-stabilized conformation(s) are important for ATP7B trafficking. The developed system provides significant advantages for studies that require access to both sides of ATP7B in the membrane.
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Affiliation(s)
- Eva Lörinczi
- Max-Planck-Institute of Biophysics, D-60438 Frankfurt am Main, Germany
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50
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Safaei R, Otani S, Larson BJ, Rasmussen ML, Howell SB. Transport of cisplatin by the copper efflux transporter ATP7B. Mol Pharmacol 2007; 73:461-8. [PMID: 17978167 DOI: 10.1124/mol.107.040980] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
ATP7B is a P-type ATPase that mediates the efflux of copper. Recent studies have demonstrated that ATP7B regulates the cellular efflux of cisplatin (DDP) and controls sensitivity to the cytotoxic effects of this drug. To determine whether DDP is a substrate for ATP7B, DDP transport was assayed in vesicles isolated from Sf9 cells infected with a baculovirus that expressed either the wild-type ATP7B or a mutant ATP7B that was unable to transport copper as a result of conversion of the transmembrane metal binding CPC motif to CPA. Only the wild-type ATP7B-expressing vesicles exhibited copper-dependent ATPase activity, copper-induced acyl-phosphate formation, and ATP-dependent transport of copper. The amount of DDP that became bound was higher for vesicles expressing either type of ATP7B than for those not expressing either form of ATP7B, but only the vesicles expressing wild-type ATP7B mediated ATP-dependent accumulation of the drug. At pH 4.6, the vesicles expressing the wild-type ATP7B exhibited ATP-dependent accumulation of DDP with an apparent K(m) of 1.2 +/- 0.5 (S.E.M.) muM and V(max) of 0.03 +/- 0.002 (S.E.M.) nmol/mg of protein/min. DDP also induced the acyl-phosphorylation of ATP7B but at a much slower rate than copper. Copper and DDP each inhibited the ATP-dependent transport of the other. These results establish that DDP is a substrate for ATP7B but is transported at a much slower rate than copper.
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Affiliation(s)
- Roohangiz Safaei
- Department of Medicine, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, USA.
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