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Gromadzka G, Bendykowska M, Przybyłkowski A. Wilson’s Disease—Genetic Puzzles with Diagnostic Implications. Diagnostics (Basel) 2023; 13:diagnostics13071287. [PMID: 37046505 PMCID: PMC10093728 DOI: 10.3390/diagnostics13071287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/12/2023] [Accepted: 03/18/2023] [Indexed: 03/30/2023] Open
Abstract
(1) Introduction: Wilson’s disease (WND) is an autosomal recessive disorder of copper metabolism. The WND gene is ATP7B, located on chromosome 13. WND is characterized by high clinical variability, which causes diagnostic difficulties. (2) Methods: The PubMed, Science Direct, and Wiley Online Library medical databases were reviewed using the following phrases: “Wilson’s disease”, “ATP7B genotype”, “genotype-phenotype”, “epigenetics”, “genetic modifiers”, and their combinations. Publications presenting the results of experimental and clinical studies, as well as review papers, were selected, which concerned: (i) the diversity of genetic strategies and tests used in WND diagnosis; (ii) the difficulties of genetic diagnosis, including uncertainty as to the pathogenicity of variants; (iii) genetic counseling; (iv) phenotypic effects of ATP7B variants in patients with WND and in heterozygous carriers (HzcWND); (v) genetic and epigenetics factors modifying the clinical picture of the disease. (3) Results and conclusions: The genetic diagnosis of WND is carried out using a variety of strategies and tests. Due to the large number of known variants in the ATP7B gene (>900), the usefulness of genetic tests in routine diagnostics is still relatively small and even analyses performed using the most advanced technologies, including next-generation sequencing, require additional tests, including biochemical evidence of abnormal copper metabolism, to confirm the diagnosis of WND. Pseudodominant inheritance, the presence of three various pathogenic variants in the same patient, genotypes indicating the possibility of segmental uniparental disomy, have been reported. Genotype–phenotype relationships in WND are complex. The ATP7B genotype, to some extent, determines the clinical picture of the disease, but other genetic and epigenetic modifiers are also relevant.
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Orädd F, Steffen JH, Gourdon P, Andersson M. Copper binding leads to increased dynamics in the regulatory N-terminal domain of full-length human copper transporter ATP7B. PLoS Comput Biol 2022; 18:e1010074. [PMID: 36070320 PMCID: PMC9484656 DOI: 10.1371/journal.pcbi.1010074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 09/19/2022] [Accepted: 08/17/2022] [Indexed: 11/25/2022] Open
Abstract
ATP7B is a human copper-transporting P1B-type ATPase that is involved in copper homeostasis and resistance to platinum drugs in cancer cells. ATP7B consists of a copper-transporting core and a regulatory N-terminal tail that contains six metal-binding domains (MBD1-6) connected by linker regions. The MBDs can bind copper, which changes the dynamics of the regulatory domain and activates the protein, but the underlying mechanism remains unknown. To identify possible copper-specific structural dynamics involved in transport regulation, we constructed a model of ATP7B spanning the N-terminal tail and core catalytic domains and performed molecular dynamics (MD) simulations with (holo) and without (apo) copper ions bound to the MBDs. In the holo protein, MBD2, MBD3 and MBD5 showed enhanced mobilities, which resulted in a more extended N-terminal regulatory region. The observed separation of MBD2 and MBD3 from the core protein supports a mechanism where copper binding activates the ATP7B protein by reducing interactions among MBD1-3 and between MBD1-3 and the core protein. We also observed an increased interaction between MBD5 and the core protein that brought the copper-binding site of MBD5 closer to the high-affinity internal copper-binding site in the core protein. The simulation results assign specific, mechanistic roles to the metal-binding domains involved in ATP7B regulation that are testable in experimental settings. Living organisms depend upon active transport against gradients across biological membranes for survival. Such transport can be accomplished by ATP-dependent membrane protein transporters for which the activity must be regulated to maintain optimal concentrations in the cellular compartments. The regulatory mechanisms often involve structural responses inherent to the protein structure, which because of their dynamic nature can be hard to assess experimentally. A prime example is regulation of cellular copper levels by a copper-binding tail in the human copper transporter ATP7B. Dysregulation can cause severe diseases, for example the copper metabolism disorder Wilson’s disease, which is caused by mutations in ATP7B regulation machinery. Due to the practical difficulties in working with membrane proteins, most studies of ATP7B have been conducted in the absence of the membrane-bound protein core. Here, we used computer simulations of full-length ATP7B to study how structural dynamics in the regulatory tail differ between copper-bound and copper-free states. Copper induced increased dynamics in the tail, resulting in an overall movement towards the ion-binding site in the protein core. The simulations identified several, hitherto not reported, interactions between the regulatory tail and the protein core that can be targeted experimentally to enhance our understanding of this medically relevant regulatory mechanism.
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Affiliation(s)
- Fredrik Orädd
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Jonas Hyld Steffen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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3
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Clinical and genetic characterization of a large cohort of patients with Wilson’s disease in China. Transl Neurodegener 2022; 11:13. [PMID: 35220961 PMCID: PMC8883683 DOI: 10.1186/s40035-022-00287-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 02/03/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Wilson’s disease (WD) is an autosomal recessive disorder of copper metabolism caused by ATP7B (encoding a copper-transporting P-type ATPase) variants that shows various characteristics according to race and geographical region. This study was aimed to provide a comprehensive analysis of ATP7B variants in China and to investigate a plausible role of common variants in WD manifestations.
Methods
A total of 1366 patients (1302 index patients and 64 siblings) clinically diagnosed with WD (Leipzig score ≥ 4) were recruited. They underwent ATP7B gene sequencing and information of age and symptoms at onset was collected. The genotype–phenotype correlation was assessed in the index patients who were examined with two pathogenic variants and onset with hepatic (n = 276) or neurologic (n = 665) symptoms.
Results
We identified 294 potentially pathogenic ATP7B variants (112 truncating, 174 missense, 8 in-frame) in the 1302 index patients, including 116 novel variants. The most frequent variant was c.2333G>T (R778L, allele frequency: 28.96%), followed by c.2975C>T (P992L, 13.82%), c.2621C>T (A874V, 5.99%), c.2755C>G (R919G, 2.46%), and c.3646G>A (V1216M, 1.92%). In 1167 patients, both pathogentic variants were identified, of which 532 different variant combinations were found. By binary logistic regression analysis, the factor associated with neurological presentation was high age-at-onset, but not sex, protein-truncating variant (PTV), or the common missense variants (R778L, P992L, and A874V). In the neurological group, low age-at-onset was a factor associated with dystonia, gait abnormality, and salivation; high age-at-onset was a factor associated with tremor; and the sex, low age-at-onset and A874V were independent factors associated with dysarthria. In addition, PTV, R778L, and P992L were predominant in early-onset patients, whereas A874V was predominant in late-onset patients, and patients with R778L/A874V genotype displayed a higher age-at-onset than patients with R778L/R778L or R778L/P992L genotype.
Conclusions
Our work expanded the ATP7B variant spectrum and highlighted the differences among patients with WD in age-at-onset and ATP7B variants, which may provide some valuable insights into the diagnosis, counseling, and treatment of patients with WD.
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Soczewka P, Tribouillard-Tanvier D, di Rago JP, Zoladek T, Kaminska J. Targeting Copper Homeostasis Improves Functioning of vps13Δ Yeast Mutant Cells, a Model of VPS13-Related Diseases. Int J Mol Sci 2021; 22:2248. [PMID: 33668157 PMCID: PMC7956333 DOI: 10.3390/ijms22052248] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/12/2021] [Accepted: 02/19/2021] [Indexed: 01/01/2023] Open
Abstract
Ion homeostasis is crucial for organism functioning, and its alterations may cause diseases. For example, copper insufficiency and overload are associated with Menkes and Wilson's diseases, respectively, and iron imbalance is observed in Parkinson's and Alzheimer's diseases. To better understand human diseases, Saccharomyces cerevisiae yeast are used as a model organism. In our studies, we used the vps13Δ yeast strain as a model of rare neurological diseases caused by mutations in VPS13A-D genes. In this work, we show that overexpression of genes encoding copper transporters, CTR1, CTR3, and CCC2, or the addition of copper salt to the medium, improved functioning of the vps13Δ mutant. We show that their mechanism of action, at least partially, depends on increasing iron content in the cells by the copper-dependent iron uptake system. Finally, we present that treatment with copper ionophores, disulfiram, elesclomol, and sodium pyrithione, also resulted in alleviation of the defects observed in vps13Δ cells. Our study points at copper and iron homeostasis as a potential therapeutic target for further investigation in higher eukaryotic models of VPS13-related diseases.
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Affiliation(s)
- Piotr Soczewka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland;
| | - Déborah Tribouillard-Tanvier
- IBGC, UMR 5095, CNRS, Université de Bordeaux, F-33000 Bordeaux, France; (D.T.-T.); (J.-P.d.R.)
- Institut National de la Santé et de la Recherche Médicale (INSERM), F-33077 Bordeaux, France
| | - Jean-Paul di Rago
- IBGC, UMR 5095, CNRS, Université de Bordeaux, F-33000 Bordeaux, France; (D.T.-T.); (J.-P.d.R.)
| | - Teresa Zoladek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland;
| | - Joanna Kaminska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland;
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Penon-Portmann M, Lotz-Esquivel S, Chavez Carrera A, Jiménez-Hernández M, Alvarado-Romero D, Segura-Cordero S, Rimolo-Donadio F, Hevia-Urrutia F, Mora-Guevara A, Saborío-Rocafort M, Jiménez-Arguedas G, Badilla-Porras R. Wilson disease in Costa Rica: Pediatric phenotype and genotype characterization. JIMD Rep 2020; 52:55-62. [PMID: 32154060 PMCID: PMC7052697 DOI: 10.1002/jmd2.12098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/14/2020] [Accepted: 01/17/2020] [Indexed: 12/20/2022] Open
Abstract
Introduction The prevalence of Wilson disease (WD) in Costa Rica is among the highest reported in the world, 4.9:100 000. Previous investigators have also described a burden of autosomal recessive conditions in this country. Genetic testing for WD began in 2010 as a strategy for earlier detection due to the country's high prevalence. Here we describe what we have learned about the genotype and phenotype of the Costa Rican pediatric population with WD. Methods We completed a retrospective review of medical records from pediatric individuals (<18 years of age) with molecular testing for ATP7B between 2010 and 2015. We documented phenotype and genotype for cases with WD as defined by the international scoring system. Results Thirty-four WD cases from 28 families were included, 15 female and 19 male patients. The most frequent pathogenic variant in ATP7B was NM_000053:c.3809A>G, p.Asn1270Ser, with 58.8% of affected individuals homozygous for this variant. Age of diagnosis ranged from 1 to 17 years, with an average of 8.8 ± 3.6 years. All individuals who presented with acute liver failure (n = 6) were homozygous for the p.Asn1270Ser variant (Chi-squared, P < .05). Discussion Molecular testing has facilitated the detection of presymptomatic patients with WD in Costa Rica. We hope that ongoing efforts in the delivery of clinical services lead to optimized molecular screening for WD and other genetic conditions in Costa Rica.
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Affiliation(s)
- Monica Penon-Portmann
- Servicio de Genética y Enfermedades Metabólicas, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera", Caja Costarricense de Seguro Social & Sistema de Estudios de Posgrado Universidad de Costa Rica San José Costa Rica.,Division of Medical Genetics, Department of Pediatrics & Institute for Human Genetics University of California San Francisco San Francisco California
| | - Stephanie Lotz-Esquivel
- Clínica Multidisciplinaria de Enfermedades Raras y Huérfanas & Unidad de Investigación, Departamento de Medicina Interna, Hospital San Juan de Dios Caja Costarricense de Seguro Social San José Costa Rica
| | - Alejandra Chavez Carrera
- Division of Medical Genetics, Department of Pediatrics & Institute for Human Genetics University of California San Francisco San Francisco California.,Escuela de Medicina, Colegio de Ciencias de la Salud Universidad San Francisco de Quito Quito Ecuador
| | - Mildred Jiménez-Hernández
- Programa Nacional de Tamizaje Neonatal Caja Costarricense de Seguro Social San José Costa Rica.,Laboratorio Nacional de Tamizaje Neonatal y Alto Riesgo Caja Costarricense de Seguro Social San José Costa Rica
| | - Danny Alvarado-Romero
- Programa Nacional de Tamizaje Neonatal Caja Costarricense de Seguro Social San José Costa Rica.,Laboratorio Nacional de Tamizaje Neonatal y Alto Riesgo Caja Costarricense de Seguro Social San José Costa Rica
| | - Sharon Segura-Cordero
- Clínica Multidisciplinaria de Enfermedades Raras y Huérfanas & Unidad de Investigación, Departamento de Medicina Interna, Hospital San Juan de Dios Caja Costarricense de Seguro Social San José Costa Rica
| | - Fiorella Rimolo-Donadio
- Unidad de Trasplante, Departamento de Cirugía, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera" Caja Costarricense de Seguro Social San José Costa Rica
| | - Francisco Hevia-Urrutia
- Servicio de Gastroenterología, Sección de Medicina, Hospital San Juan de Dios Caja Costarricense de Seguro Social San José Costa Rica
| | - Alfredo Mora-Guevara
- Servicio de Gastroenterología, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera" Caja Costarricense de Seguro Social San José Costa Rica
| | - Manuel Saborío-Rocafort
- Servicio de Genética y Enfermedades Metabólicas, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera", Caja Costarricense de Seguro Social & Sistema de Estudios de Posgrado Universidad de Costa Rica San José Costa Rica.,Programa Nacional de Tamizaje Neonatal Caja Costarricense de Seguro Social San José Costa Rica
| | - Gabriela Jiménez-Arguedas
- Servicio de Gastroenterología, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera" Caja Costarricense de Seguro Social San José Costa Rica
| | - Ramsés Badilla-Porras
- Servicio de Genética y Enfermedades Metabólicas, Departamento de Pediatría, Hospital Nacional de Niños, "Dr. Carlos Sáenz Herrera", Caja Costarricense de Seguro Social & Sistema de Estudios de Posgrado Universidad de Costa Rica San José Costa Rica.,Programa Nacional de Tamizaje Neonatal Caja Costarricense de Seguro Social San José Costa Rica
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Shanmugavel KP, Wittung-Stafshede P. Copper relay path through the N-terminus of Wilson disease protein, ATP7B. Metallomics 2019; 11:1472-1480. [PMID: 31321400 DOI: 10.1039/c9mt00147f] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In human cells, copper (Cu) ions are transported by the cytoplasmic Cu chaperone Atox1 to the Wilson disease protein (ATP7B) in the Golgi for loading of Cu-dependent enzymes. ATP7B is a membrane-spanning protein which, in contrast to non-mammalian homologs, has six cytoplasmic metal-binding domains (MBDs). To address the reason for multiple MBDs, we introduced strategic mutations in which one, two or three MBDs had been blocked for Cu binding via cysteine-to-serine mutations (but all six MBDs are present in all) in a yeast system that probes Cu flow through Atox1 and ATP7B. The results, combined with earlier work, support a mechanistic model in which MBD1-3 forms a regulatory unit of ATP7B Cu transport. Cu delivery via Atox1 to this unit, followed by loading of Cu in MBD3, promotes release of inhibitory interactions. Whereas the Cu site in MBD4 can be mutated without a large effect, an intact Cu site in either MBD5 or MBD6 is required for Cu transport. All MBDs, expressed as single-domain proteins, can replace Atox1 and deliver Cu to full-length ATP7B. However, only MBD6 can deliver Cu to truncated ATP7B where all six MBDs are removed, suggesting a docking role for this structural unit.
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Affiliation(s)
| | - Pernilla Wittung-Stafshede
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden.
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Allocca S, Ciano M, Ciardulli MC, D'Ambrosio C, Scaloni A, Sarnataro D, Caporaso MG, D'Agostino M, Bonatti S. An αB-Crystallin Peptide Rescues Compartmentalization and Trafficking Response to Cu Overload of ATP7B-H1069Q, the Most Frequent Cause of Wilson Disease in the Caucasian Population. Int J Mol Sci 2018; 19:ijms19071892. [PMID: 29954118 PMCID: PMC6073935 DOI: 10.3390/ijms19071892] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/20/2018] [Accepted: 06/22/2018] [Indexed: 12/14/2022] Open
Abstract
The H1069Q substitution is the most frequent mutation of the Cu transporter ATP7B that causes Wilson disease in the Caucasian population. ATP7B localizes to the Golgi complex in hepatocytes, but, in the presence of excessive Cu, it relocates to the endo-lysosomal compartment to excrete Cu via bile canaliculi. In contrast, ATP7B-H1069Q is strongly retained in the ER, does not reach the Golgi complex and fails to move to the endo-lysosomal compartment in the presence of excessive Cu, thus causing toxic Cu accumulation. We have previously shown that, in transfected cells, the small heat-shock protein αB-crystallin is able to correct the mislocalization of ATP7B-H1069Q and its trafficking in the presence of Cu overload. Here, we first show that the α-crystallin domain of αB-crystallin mimics the effect of the full-length protein, whereas the N- and C-terminal domains have no such effect. Next, and most importantly, we demonstrate that a twenty-residue peptide derived from the α-crystallin domain of αB-crystallin fully rescues Golgi localization and the trafficking response of ATP7B-H1069Q in the presence of Cu overload. In addition, we show that this peptide interacts with the mutant transporter in the live cell. These results open the way to attempt developing a pharmacologically active peptide to specifically contrast the Wilson disease form caused by the ATP7B-H1069Q mutant.
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Affiliation(s)
- Simona Allocca
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via S. Pansini 5, 80131 Naples, Italy.
| | - Michela Ciano
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via S. Pansini 5, 80131 Naples, Italy.
| | - Maria Camilla Ciardulli
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via S. Pansini 5, 80131 Naples, Italy.
| | - Chiara D'Ambrosio
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Via Argine 1085, 80147 Naples, Italy.
| | - Andrea Scaloni
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Via Argine 1085, 80147 Naples, Italy.
| | - Daniela Sarnataro
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via S. Pansini 5, 80131 Naples, Italy.
- Ceinge Biotecnologie avanzate scarl, via G. Salvatore 486, 80145 Naples, Italy.
| | - Maria Gabriella Caporaso
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via S. Pansini 5, 80131 Naples, Italy.
| | - Massimo D'Agostino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via S. Pansini 5, 80131 Naples, Italy.
| | - Stefano Bonatti
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via S. Pansini 5, 80131 Naples, Italy.
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Ponnandai Shanmugavel K, Petranovic D, Wittung-Stafshede P. Probing functional roles of Wilson disease protein (ATP7B) copper-binding domains in yeast. Metallomics 2018; 9:981-988. [PMID: 28653724 DOI: 10.1039/c7mt00101k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
After Ctr1-mediated uptake into human cells, copper (Cu) ions are transported by the cytoplasmic Cu chaperone Atox1 to the Wilson disease protein (ATP7B) in the Golgi network. Cu transfer occurs via direct protein-protein interactions and leads to incorporation of Cu into Cu-dependent enzymes. ATP7B is a large multi-domain membrane-spanning protein which, in contrast to homologs, has six cytoplasmic metal-binding domains (MBDs). The reason for multiple MBDs is proposed to be indirect modulation of activity but mechanistic studies of full-length ATP7B are limited. We here developed a system that probes Cu flow through human Atox1 and ATP7B proteins when expressed in yeast. Using this assay, we assessed the roles of the different MBDs in ATP7B and found that the presence of the most N-terminal MBD increased, whereas the third MBD decreased, overall ATP7B-mediated Cu transport activity. Upon removal of all MBDs in ATP7B, the ability to transport Cu disappeared. The designed system can be expanded to include other yeast viability parameters and will be a useful tool for further mechanistic insights on human Cu transport as well as diseases involving Cu imbalance.
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Affiliation(s)
| | - Dina Petranovic
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden. and Novo Nordisk Foundation, Center for Biosustainability, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Pernilla Wittung-Stafshede
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden.
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Parisi S, Polishchuk EV, Allocca S, Ciano M, Musto A, Gallo M, Perone L, Ranucci G, Iorio R, Polishchuk RS, Bonatti S. Characterization of the most frequent ATP7B mutation causing Wilson disease in hepatocytes from patient induced pluripotent stem cells. Sci Rep 2018; 8:6247. [PMID: 29674751 PMCID: PMC5908878 DOI: 10.1038/s41598-018-24717-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/09/2018] [Indexed: 12/27/2022] Open
Abstract
H1069Q substitution represents the most frequent mutation of the copper transporter ATP7B causing Wilson disease in Caucasian population. ATP7B localizes to the Golgi complex in hepatocytes but moves in response to copper overload to the endo-lysosomal compartment to support copper excretion via bile canaliculi. In heterologous or hepatoma-derived cell lines, overexpressed ATP7B-H1069Q is strongly retained in the ER and fails to move to the post-Golgi sites, resulting in toxic copper accumulation. However, this pathogenic mechanism has never been tested in patients’ hepatocytes, while animal models recapitulating this form of WD are still lacking. To reach this goal, we have reprogrammed skin fibroblasts of homozygous ATP7B-H1069Q patients into induced pluripotent stem cells and differentiated them into hepatocyte-like cells. Surprisingly, in HLCs we found one third of ATP7B-H1069Q localized in the Golgi complex and able to move to the endo-lysosomal compartment upon copper stimulation. However, despite normal mRNA levels, the expression of the mutant protein was only 20% compared to the control because of endoplasmic reticulum-associated degradation. These results pinpoint rapid degradation as the major cause for loss of ATP7B function in H1069Q patients, and thus as the primary target for designing therapeutic strategies to rescue ATP7B-H1069Q function.
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Affiliation(s)
- Silvia Parisi
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy.
| | | | - Simona Allocca
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Michela Ciano
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Anna Musto
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Maria Gallo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Lucia Perone
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Giusy Ranucci
- Department of Translational Medical Science, Section of Pediatric, University of Naples Federico II, Naples, Italy
| | - Raffaele Iorio
- Department of Translational Medical Science, Section of Pediatric, University of Naples Federico II, Naples, Italy
| | | | - Stefano Bonatti
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy.
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10
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Daneshjoo O, Garshasbi M. Novel compound heterozygote mutations in the ATP7B gene in an Iranian family with Wilson disease: a case report. J Med Case Rep 2018; 12:68. [PMID: 29540233 PMCID: PMC5853083 DOI: 10.1186/s13256-018-1608-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/10/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Wilson disease is an autosomal recessive disorder of copper transport and is characterized by excessive accumulation of cellular copper in the liver and other tissues because of impaired biliary copper excretion and disturbed incorporation of copper into ceruloplasmin. Hepatic failure and neuronal degeneration are the major symptoms of Wilson disease. Mutations in the ATP7B gene are the major cause of Wilson disease. CASE PRESENTATION In this study we have screened one pedigree with several affected members, including a 24-year-old Iranian woman and a 20-year-old Iranian man, who showed psychiatric and neurological symptoms of varying severity, by amplifying the coding regions including exon-intron boundaries with polymerase chain reaction and sequencing. We identified c.1924G>C and c.3809A>G mutations in affected members as compound heterozygote state. These mutations segregated with the disease in the family and they were absent in a cohort of 100 Iranian ethnicity-matched healthy controls. CONCLUSIONS No homozygote state has been reported for these two variants in public databases. In silico predicting tools consider these two variants to be damaging. So this study introduces the novel combination of c.1924G>C and c.3809A>G variants as a cause for Wilson disease.
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Affiliation(s)
- Omid Daneshjoo
- Department of Molecular and Cell Biology, Nano and Biotechnology Research Group, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Iran
- Medical Genetics Department, DeNA laboratory, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
- Medical Genetics Department, DeNA laboratory, Tehran, Iran
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11
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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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12
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Moinuddin FM, Shinsato Y, Komatsu M, Mitsuo R, Minami K, Yamamoto M, Kawahara K, Hirano H, Arita K, Furukawa T. ATP7B expression confers multidrug resistance through drug sequestration. Oncotarget 2017; 7:22779-90. [PMID: 26988911 PMCID: PMC5008400 DOI: 10.18632/oncotarget.8059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/23/2016] [Indexed: 11/30/2022] Open
Abstract
We previously reported that ATP7B is involved in cisplatin resistance and ATP7A confers multidrug resistance (MDR) in cancer cells. In this study, we show that ATP7B expressing cells also are resistant to doxorubicin, SN-38, etoposide, and paclitaxel as well as cisplatin. In ATP7B expressing cells, doxorubicin relocated from the nuclei to the late-endosome at 4 hours after doxorubicin exposure. EGFP-ATP7B mainly colocalized with doxorubicin. ATP7B has six metal binding sites (MBSs) in the N-terminal cytoplasmic region. To investigate the role of the MBSs of ATP7B in doxorubicin resistance, we used three mutant ATP7B (Cu0, Cu6 and M6C/S) expressing cells. Cu0 has no MBSs, Cu6 has only the sixth MBS and M6C/S carries CXXC to SXXS mutation in the sixth MBS. Cu6 expressing cells were less resistance to the anticancer agents than wild type ATP7B expressing cells, and had doxorubicin sequestration in the late-endosome. Cu0- and M6C/S-expressing cells were sensitive to doxorubicin. In these cells, doxorubicin did not relocalize to the late-endosome. EGFP-M6C/S mainly localized to the trans-Golgi network (TGN) even in the presence of copper. Thus the cysteine residues in the sixth MBS of ATP7B are essential for MDR phenotype. Finally, we found that ammonium chloride and tamoxifen suppressed late endosomal sequestration of doxorubicin, thereby attenuating drug resistance. These results suggest that the sequestration depends on the acidity of the vesicles partly. We here demonstrate that ATP7B confers MDR by facilitating nuclear drug efflux and late endosomal drug sequestration.
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Affiliation(s)
- F M Moinuddin
- Department of Neurosurgery, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.,Department of Molecular Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Yoshinari Shinsato
- Department of Molecular Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.,Center for the Research of Advanced Diagnosis and Therapy of Cancer, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Masaharu Komatsu
- Division of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 4-50-20, Shimoarata, Kagoshima 890-0056, Japan
| | - Ryoichi Mitsuo
- Department of Molecular Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Kentaro Minami
- Department of Molecular Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.,Center for the Research of Advanced Diagnosis and Therapy of Cancer, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Masatatsu Yamamoto
- Department of Molecular Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.,Center for the Research of Advanced Diagnosis and Therapy of Cancer, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Kohich Kawahara
- Department of Molecular Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.,Center for the Research of Advanced Diagnosis and Therapy of Cancer, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Hirofumi Hirano
- Department of Neurosurgery, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Kazunori Arita
- Department of Neurosurgery, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Tatsuhiko Furukawa
- Department of Molecular Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.,Center for the Research of Advanced Diagnosis and Therapy of Cancer, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
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13
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Concilli M, Iacobacci S, Chesi G, Carissimo A, Polishchuk R. A systems biology approach reveals new endoplasmic reticulum-associated targets for the correction of the ATP7B mutant causing Wilson disease. Metallomics 2017; 8:920-930. [PMID: 27714068 DOI: 10.1039/c6mt00148c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Copper (Cu) is an important trace element required for the activity of essential enzymes. However, excess Cu compromises the redox balance in cells and tissues causing serious toxicity. The process of disposal of excess Cu from organisms relies on the activity of Cu-transporting ATPase ATP7B. ATP7B is mainly expressed in liver hepatocytes where it sequesters the potentially toxic metal and mediates its excretion into the bile. Mutations in the ATP7B gene cause Wilson disease (WD), which is characterized by the accumulation of toxic Cu in the liver due to the scarce expression of ATP7B as well as the failure of ATP7B mutants to pump Cu and/or traffic to the Cu-excretion sites. The most frequent ATP7B mutant, H1069Q, still presents a significant Cu-transporting activity, but undergoes retention within the endoplasmic reticulum (ER) where the mutant is rapidly degraded. Expression of this ATP7B mutant has been recently reported to activate the p38 and JNK stress kinase pathways, which, in turn, trigger quality control mechanisms leading to the arrest of ATP7B-H1069Q in the ER and to the acceleration of its degradation. However, the main molecular players operating in these p38/JNK-dependent ER quality control pathways remain to be discovered. By using a combination of RNAseq, bioinformatics and RNAi approaches, we found a cluster of ER quality control genes whose expression is controlled by p38 and JNK and is required for the efficient retention of the ATP7B-H1069Q mutant in the ER. Silencing these genes reduced the accumulation of the ATP7B mutant in the ER and facilitated the mutant sorting and export to the Golgi and post-Golgi copper excretion sites. In sum, our findings reveal the ER-associated genes that could be utilized for the correction of ATP7B mutants and, hence, for the normalization of Cu homeostasis in Wilson disease.
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Affiliation(s)
- Mafalda Concilli
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, NA 80078, Italy.
| | - Simona Iacobacci
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, NA 80078, Italy.
| | - Giancarlo Chesi
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, NA 80078, Italy.
| | - Annamaria Carissimo
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, NA 80078, Italy.
| | - Roman Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, NA 80078, Italy.
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14
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Ariöz C, Li Y, Wittung-Stafshede P. The six metal binding domains in human copper transporter, ATP7B: molecular biophysics and disease-causing mutations. Biometals 2017; 30:823-840. [PMID: 29063292 PMCID: PMC5684295 DOI: 10.1007/s10534-017-0058-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/05/2017] [Indexed: 12/16/2022]
Abstract
Wilson Disease (WD) is a hereditary genetic disorder, which coincides with a dysfunctional copper (Cu) metabolism caused by mutations in ATP7B, a membrane-bound P1B-type ATPase responsible for Cu export from hepatic cells. The N-terminal part (~ 600 residues) of the multi-domain 1400-residue ATP7B constitutes six metal binding domains (MBDs), each of which can bind a copper ion, interact with other ATP7B domains as well as with different proteins. Although the ATP7B's MBDs have been investigated in vitro and in vivo intensively, it remains unclear how these domains modulate overall structure, dynamics, stability and function of ATP7B. The presence of six MBDs is unique to mammalian ATP7B homologs, and many WD causing missense mutations are found in these domains. Here, we have summarized previously reported in vitro biophysical data on the MBDs of ATP7B and WD point mutations located in these domains. Besides the demonstration of where the research field stands today, this review showcasts the need for further biophysical investigation about the roles of MBDs in ATP7B function. Molecular mechanisms of ATP7B are important not only in the development of new WD treatment but also for other aspects of human physiology where Cu transport plays a role.
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Affiliation(s)
- Candan Ariöz
- Department of Biology and Biological Engineering, Division of Chemical Biology, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg, Sweden
| | - Yaozong Li
- Department of Chemistry, Umeå University, Kemihuset A, Linnaeus väg 10, 901 87 Umeå, Sweden
| | - Pernilla Wittung-Stafshede
- Department of Biology and Biological Engineering, Division of Chemical Biology, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg, Sweden
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15
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Lv T, Li X, Zhang W, Zhao X, Ou X, Huang J. Recent advance in the molecular genetics of Wilson disease and hereditary hemochromatosis. Eur J Med Genet 2016; 59:532-9. [PMID: 27592149 DOI: 10.1016/j.ejmg.2016.08.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 07/12/2016] [Accepted: 08/31/2016] [Indexed: 02/07/2023]
Abstract
Metabolic liver diseases such as Wilson disease (WD) and hereditary hemochromatosis (HH) possess complicated pathogenesis and typical hereditary characteristics with the hallmarks of a deficiency in metal metabolism. Mutations in genes encoding ATPase, Cu + transporting, beta polypeptide (ATP7B) and hemochromatosis (HFE) or several non-HFE genes are considered to be causative for WD and HH, respectively. Although the identification of novel mutations in ATP7B for WD and HFE or the non-HFE genes for HH has increased, especially with the application of whole genome sequencing technology in recent years, the biological function of the identified mutations, as well as genotype-phenotype correlations remain to be explored. Further analysis of the causative gene mutation would be critical to clarify the mechanisms underlying specific disease phenotypes. In this review, we therefore summarize the recent advances in the molecular genetics of WD and HH including the updated mutation spectrums and the correlation between genotype and phenotype, with an emphasis on biological functional studies of the individual mutations identified in WD and HH. The weakness of the current functional studies and analysis for the clinical association of the individual mutation was also discussed. These works are essential for the understanding of the association between genotypes and phenotypes of these inherited metabolic liver diseases.
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Affiliation(s)
- Tingxia Lv
- Liver Research Center, Experimental Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xuan-wu District, Beijing, 100050, China.
| | - Xiaojin Li
- Liver Research Center, Experimental Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xuan-wu District, Beijing, 100050, China.
| | - Wei Zhang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xuan-wu District, Beijing, 100050, China.
| | - Xinyan Zhao
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xuan-wu District, Beijing, 100050, China.
| | - Xiaojuan Ou
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xuan-wu District, Beijing, 100050, China.
| | - Jian Huang
- Liver Research Center, Experimental Center, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xuan-wu District, Beijing, 100050, China.
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16
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Chesi G, Hegde RN, Iacobacci S, Concilli M, Parashuraman S, Festa BP, Polishchuk EV, Di Tullio G, Carissimo A, Montefusco S, Canetti D, Monti M, Amoresano A, Pucci P, van de Sluis B, Lutsenko S, Luini A, Polishchuk RS. Identification of p38 MAPK and JNK as new targets for correction of Wilson disease-causing ATP7B mutants. Hepatology 2016; 63:1842-59. [PMID: 26660341 PMCID: PMC5066671 DOI: 10.1002/hep.28398] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 11/23/2015] [Accepted: 12/01/2015] [Indexed: 12/11/2022]
Abstract
UNLABELLED Wilson disease (WD) is an autosomal recessive disorder that is caused by the toxic accumulation of copper (Cu) in the liver. The ATP7B gene, which is mutated in WD, encodes a multitransmembrane domain adenosine triphosphatase that traffics from the trans-Golgi network to the canalicular area of hepatocytes, where it facilitates excretion of excess Cu into the bile. Several ATP7B mutations, including H1069Q and R778L that are two of the most frequent variants, result in protein products, which, although still functional, remain in the endoplasmic reticulum. Thus, they fail to reach Cu excretion sites, resulting in the toxic buildup of Cu in the liver of WD patients. Therefore, correcting the location of these mutants by leading them to the appropriate functional sites in the cell should restore Cu excretion and would be beneficial to help large cohorts of WD patients. However, molecular targets for correction of endoplasmic reticulum-retained ATP7B mutants remain elusive. Here, we show that expression of the most frequent ATP7B mutant, H1069Q, activates p38 and c-Jun N-terminal kinase signaling pathways, which favor the rapid degradation of the mutant. Suppression of these pathways with RNA interference or specific chemical inhibitors results in the substantial rescue of ATP7B(H1069Q) (as well as that of several other WD-causing mutants) from the endoplasmic reticulum to the trans-Golgi network compartment, in recovery of its Cu-dependent trafficking, and in reduction of intracellular Cu levels. CONCLUSION Our findings indicate p38 and c-Jun N-terminal kinase as intriguing targets for correction of WD-causing mutants and, hence, as potential candidates, which could be evaluated for the development of novel therapeutic strategies to combat WD. (Hepatology 2016;63:1842-1859).
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Affiliation(s)
| | - Ramanath N. Hegde
- Institute of Protein BiochemistryNational Research CouncilNaplesItaly
| | | | | | | | | | | | | | | | | | - Diana Canetti
- CEINGE and Department of Chemical SciencesFederico II UniversityNaplesItaly
| | - Maria Monti
- CEINGE and Department of Chemical SciencesFederico II UniversityNaplesItaly
| | - Angela Amoresano
- CEINGE and Department of Chemical SciencesFederico II UniversityNaplesItaly
| | - Piero Pucci
- CEINGE and Department of Chemical SciencesFederico II UniversityNaplesItaly
| | - Bart van de Sluis
- Molecular Genetics Section of Department of Pediatrics, University of GroningenUniversity Medical Center GroningenGroningenThe Netherlands
| | | | - Alberto Luini
- Institute of Protein BiochemistryNational Research CouncilNaplesItaly,Istituto di Ricovero e Cura a Carattere Scientifico SDNNaplesItaly
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Spincemaille P, Cammue BP, Thevissen K. Sphingolipids and mitochondrial function, lessons learned from yeast. MICROBIAL CELL (GRAZ, AUSTRIA) 2014; 1:210-224. [PMID: 28357246 PMCID: PMC5349154 DOI: 10.15698/mic2014.07.156] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 06/10/2014] [Indexed: 01/22/2023]
Abstract
Mitochondrial dysfunction is a hallmark of several neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, but also of cancer, diabetes and rare diseases such as Wilson's disease (WD) and Niemann Pick type C1 (NPC). Mitochondrial dysfunction underlying human pathologies has often been associated with an aberrant cellular sphingolipid metabolism. Sphingolipids (SLs) are important membrane constituents that also act as signaling molecules. The yeast Saccharomyces cerevisiae has been pivotal in unraveling mammalian SL metabolism, mainly due to the high degree of conservation of SL metabolic pathways. In this review we will first provide a brief overview of the major differences in SL metabolism between yeast and mammalian cells and the use of SL biosynthetic inhibitors to elucidate the contribution of specific parts of the SL metabolic pathway in response to for instance stress. Next, we will discuss recent findings in yeast SL research concerning a crucial signaling role for SLs in orchestrating mitochondrial function, and translate these findings to relevant disease settings such as WD and NPC. In summary, recent research shows that S. cerevisiae is an invaluable model to investigate SLs as signaling molecules in modulating mitochondrial function, but can also be used as a tool to further enhance our current knowledge on SLs and mitochondria in mammalian cells.
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Affiliation(s)
- Pieter Spincemaille
- Centre of Microbial and Plant Genetics (CMPG), KU Leuven,
Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
| | - Bruno P. Cammue
- Centre of Microbial and Plant Genetics (CMPG), KU Leuven,
Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052,
Ghent, Belgium
| | - Karin Thevissen
- Centre of Microbial and Plant Genetics (CMPG), KU Leuven,
Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
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18
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Safaei R, Adams PL, Mathews RA, Manorek G, Howell SB. The role of metal binding and phosphorylation domains in the regulation of cisplatin-induced trafficking of ATP7B. Metallomics 2014; 5:964-72. [PMID: 23803742 DOI: 10.1039/c3mt00131h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The copper (Cu) exporter ATP7B mediates cellular resistance to cisplatin (cDDP) by increasing drug efflux. ATP7B binds and sequesters cDDP in into secretory vesicles. Upon cDDP exposure ATP7B traffics from the trans-Golgi network (TGN) to the periphery of the cell in a manner that requires the cysteine residues in its metal binding domains (MBD). To elucidate the role of the various domains of ATP7B in its cDDP-induced trafficking we expressed a series of mCherry-tagged variants of ATP7B in HEK293T cells and analyzed their subcellular localization in basal media and after a 1 h exposure to 30 μM cDDP. The wild type ATP7B and a variant in which the cysteines in the CXXC motifs of MBD 1-5 were converted to serines trafficked out of the trans-Golgi (TGN) when exposed to cDDP. Conversion of the cysteines in all 6 of the CXXC motifs to serines, or in only the sixth MBD, rendered ATP7B incapable of trafficking on exposure to cDDP. Truncation of MBD1-5 or MBD1-6 resulted in the loss of TGN localization. Addition of the first 63 amino acids of ATP7B to these variants restored TGN localization to a great extent and enabled the MBD1-5 variant to undergo cDDP-induced trafficking. A variant of ATP7B in which the aspartate 1027 residue in the phosphorylation domain was converted to glutamine localized to the TGN but was incapable of cDDP-induced trafficking. These results demonstrate that the CXXC motif in the sixth MBD and the catalytic activity of ATP7B are required for cDDP-induced trafficking as they are for Cu-induced redistribution of ATP7B; this provides further evidence that cDDP mimics Cu with respect to the molecular mechanisms by they control the subcellular distribution of ATP7B.
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Affiliation(s)
- Roohangiz Safaei
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, USA
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19
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Liaw SH, Chuang LM. Cu2+-ATPases: Sequence Analyses and Implications in the Wilson Disease. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.199900099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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20
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D'Agostino M, Lemma V, Chesi G, Stornaiuolo M, Cannata Serio M, D'Ambrosio C, Scaloni A, Polishchuk R, Bonatti S. The cytosolic chaperone α-crystallin B rescues folding and compartmentalization of misfolded multispan transmembrane proteins. J Cell Sci 2013; 126:4160-72. [PMID: 23843626 DOI: 10.1242/jcs.125443] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The α-crystallin B chain (CRYAB or HspB5) is a cytosolic chaperone belonging to the small heat shock protein family, which is known to help in the folding of cytosolic proteins. Here we show that CRYAB binds the mutant form of at least two multispan transmembrane proteins (TMPs), exerting an anti-aggregation activity. It rescues the folding of mutant Frizzled4, which is responsible for a rare autosomal dominant form of familial exudative vitreoretinopathy (Fz4-FEVR), and the mutant ATP7B Cu transporter (ATP7B-H1069Q) associated with a common form of Wilson's disease. In the case of Fz4-FEVR, CRYAB prevents the formation of inter-chain disulfide bridges between the lumenal ectodomains of the aggregated mutant chains, which enables correct folding and promotes appropriate compartmentalization on the plasma membrane. ATP7B-H1069Q, with help from CRYAB, folds into the proper conformation, moves to the Golgi complex, and responds to copper overload in the same manner as wild-type ATP7B. These findings strongly suggest that CRYAB plays a pivotal role, previously undetected, in the folding of multispan TMPs and, from the cytosol, is able to orchestrate folding events that take place in the lumen of the ER. Our results contribute to the explanation of the complex scenario behind multispan TMP folding; additionally, they serve to expose interesting avenues for novel therapeutic approaches.
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Affiliation(s)
- Massimo D'Agostino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy
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22
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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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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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24
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Keller AM, Benítez JJ, Klarin D, Zhong L, Goldfogel M, Yang F, Chen TY, Chen P. Dynamic multibody protein interactions suggest versatile pathways for copper trafficking. J Am Chem Soc 2012; 134:8934-43. [PMID: 22578168 DOI: 10.1021/ja3018835] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As part of intracellular copper trafficking pathways, the human copper chaperone Hah1 delivers Cu(+) to the Wilson's Disease Protein (WDP) via weak and dynamic protein-protein interactions. WDP contains six homologous metal binding domains (MBDs) connected by flexible linkers, and these MBDs all can receive Cu(+) from Hah1. The functional roles of the MBD multiplicity in Cu(+) trafficking are not well understood. Building on our previous study of the dynamic interactions between Hah1 and the isolated fourth MBD of WDP, here we study how Hah1 interacts with MBD34, a double-domain WDP construct, using single-molecule fluorescence resonance energy transfer (smFRET) combined with vesicle trapping. By alternating the positions of the smFRET donor and acceptor, we systematically probed Hah1-MBD3, Hah1-MBD4, and MBD3-MBD4 interaction dynamics within the multidomain system. We found that the two interconverting interaction geometries were conserved in both intermolecular Hah1-MBD and intramolecular MBD-MBD interactions. The Hah1-MBD interactions within MBD34 are stabilized by an order of magnitude relative to the isolated single-MBDs, and thermodynamic and kinetic evidence suggest that Hah1 can interact with both MBDs simultaneously. The enhanced interaction stability of Hah1 with the multi-MBD system, the dynamic intramolecular MBD-MBD interactions, and the ability of Hah1 to interact with multiple MBDs simultaneously suggest an efficient and versatile mechanism for the Hah1-to-WDP pathway to transport Cu(+).
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Affiliation(s)
- Aaron M Keller
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
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25
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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: 90] [Impact Index Per Article: 7.5] [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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26
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Safaei R, Adams PL, Maktabi MH, Mathews RA, Howell SB. The CXXC motifs in the metal binding domains are required for ATP7B to mediate resistance to cisplatin. J Inorg Biochem 2012; 110:8-17. [PMID: 22459168 DOI: 10.1016/j.jinorgbio.2012.02.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/01/2012] [Accepted: 02/20/2012] [Indexed: 01/01/2023]
Abstract
The copper (Cu) exporter ATP7B mediates resistance to cisplatin (cDDP) but details of the mechanism are unknown. We explored the role of the CXXC motifs in the metal binding domains (MBDs) of ATP7B by investigating binding of cDDP to the sixth metal binding domain (MBD6) or a variant in which the CXXC motif was converted to SXXS. Platinum measurement showed that cDDP bound to wild type MBD6 but not to the SXXS variant. Wild type ATP7B rendered ovarian 2008 cells resistant to cDDP. In 2008 and in HEK293T cells, wild type ATP7B trafficked from TGN to peripheral locations in response to Cu or cDDP. A variant in which the CXXC motifs in all 6 MBDs were converted to SXXS localized correctly to the TGN but failed to traffic when exposed to either Cu or cDDP. Deletion of either the first 5 MBDs or all 6 MBDs resulted in failure to localize to the TGN. Neither the SXXS variant nor the deletion variant was able to mediate resistance to cDDP. We conclude that cDDP binds to the CXXC motifs of ATP7B and that this interaction is essential to the trafficking of ATP7B and to its ability to mediate resistance to cDDP.
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Affiliation(s)
- Roohangiz Safaei
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0819, USA.
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27
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Braiterman L, Nyasae L, Leves F, Hubbard AL. Critical roles for the COOH terminus of the Cu-ATPase ATP7B in protein stability, trans-Golgi network retention, copper sensing, and retrograde trafficking. Am J Physiol Gastrointest Liver Physiol 2011; 301:G69-81. [PMID: 21454443 PMCID: PMC3129927 DOI: 10.1152/ajpgi.00038.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
ATP7A and ATP7B are copper-transporting P-type ATPases that are essential to eukaryotic copper homeostasis and must traffic between intracellular compartments to carry out their functions. Previously, we identified a nine-amino acid sequence (F37-E45) in the NH(2) terminus of ATP7B that is required to retain the protein in the Golgi when copper levels are low and target it apically in polarized hepatic cells when copper levels rise. To understand further the mechanisms regulating the intracellular dynamics of ATP7B, using multiple functional assays, we characterized the protein phenotypes of 10 engineered and Wilson disease-associated mutations in the ATP7B COOH terminus in polarized hepatic cells and fibroblasts. We also examined the behavior of a chimera between ATP7B and ATP7A. Our results clearly demonstrate the importance of the COOH terminus of ATP7B in the protein's copper-responsive apical trafficking. L1373 at the end of transmembrane domain 8 is required for protein stability and Golgi retention in low copper, the trileucine motif (L1454-L1456) is required for retrograde trafficking, and the COOH terminus of ATP7B exhibits a higher sensitivity to copper than does ATP7A. Importantly, our results demonstrating that four Wilson disease-associated missense mutations behaved in a wild-type manner in all our assays, together with current information in the literature, raise the possibility that several may not be disease-causing mutations.
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Affiliation(s)
- L. Braiterman
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - L. Nyasae
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - F. Leves
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - A. L. Hubbard
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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28
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Lee BH, Kim JH, Lee SY, Jin HY, Kim KJ, Lee JJ, Park JY, Kim GH, Choi JH, Kim KM, Yoo HW. Distinct clinical courses according to presenting phenotypes and their correlations to ATP7B mutations in a large Wilson's disease cohort. Liver Int 2011; 31:831-9. [PMID: 21645214 DOI: 10.1111/j.1478-3231.2011.02503.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION AND AIMS Wide phenotypic and genotypic heterogeneities in Wilson's disease (WD) have been reported, hampering the study of their correlations. The goal of this study was to identify the factors related to these diversities. METHODS Clinical courses and molecular genetic characteristics were analysed in 237 unrelated Korean WD families. The average follow-up period was 8.2 ± 5.8 years. RESULTS Presenting phenotypes were classified as H1 (12.2%), H2 (42.4%), N1 (21.6%), N2 (0.4%), NX (0.4%), presymptomatic (22.4%) and other (0.4%), modifying the guidelines by Ferenci and colleagues. Age at presentation was youngest and cirrhosis was rarest in the presymptomatic group. Decompensated cirrhosis was the highest in the H1 group. Favourable outcome was rarest in the N1 group. Forty-seven (11 novel) ATP7B mutations were identified in 85% of the 474 alleles. Multiplex ligation-dependent probe amplification assays in ATP7B and analyses of ATOX1 and COMMD1 genes identified no additional mutations. Yeast complementation assays demonstrated functional perturbation of the seven novel missense mutants. Five major mutations, p.Arg778Leu, p.Ala874Val, p.Asn1270Ser, p.Lys838SerfsX35 and p.Leu1083Phe, accounted for 63% of the alleles. H1 was more common, age at presentation was younger and N1+N2+NX tended to be less common in patients with nonsense, frame shifting or splicing mutations than in those with missense mutations alone. Patients with both mutations in the transduction (Td) or the ATP hinge domain showed presymptomatic or hepatic manifestations but no neurological manifestation. CONCLUSIONS The presenting phenotype strongly affects the clinical outcome of WD, and is related to the ATP7B mutation type and location, providing an evidence for genotype-phenotype correlations in WD.
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Affiliation(s)
- Beom H Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
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29
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Li XH, Lu Y, Ling Y, Fu QC, Xu J, Zang GQ, Zhou F, De-Min Y, Han Y, Zhang DH, Gong QM, Lu ZM, Kong XF, Wang JS, Zhang XX. Clinical and molecular characterization of Wilson's disease in China: identification of 14 novel mutations. BMC MEDICAL GENETICS 2011; 12:6. [PMID: 21219664 PMCID: PMC3025937 DOI: 10.1186/1471-2350-12-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 01/11/2011] [Indexed: 02/07/2023]
Abstract
BACKGROUND Wilson's disease (WND) is a rare autosomal recessive disorder. Here we have evaluated 62 WND cases (58 probands) from the Chinese Han population to expand our knowledge of ATP7B mutations and to more completely characterize WND in China. METHODS the coding and promoter regions of the ATP7B gene were analyzed by direct sequencing in 62 Chinese patients (58 probands) with WND (male, n = 37; female, n = 25; age range, 2 ~ 61 years old). RESULTS neurologic manifestations were associated with older age at diagnosis (p < 0.0001) and longer diagnostic delay (p < 0.0001). Age at diagnosis was also correlated with urinary copper concentration (r = 0.58, p < 0.001). Forty different mutations, including 14 novel mutations, were identified in these patients. Common mutations included p.Arg778Leu (31.9%) and p.Pro992Leu (11.2%). Homozygous p.Arg778Leu and nonsense mutation/frameshift mutations were more often associated with primary hepatic manifestations (p = 0.0286 and p = 0.0383, respectively) and higher alanine transaminase levels at diagnosis (p = 0.0361 and p = 0.0047, respectively). Nonsense mutation/frameshift mutations were also associated with lower serum ceruloplasmin (p = 0.0065). CONCLUSIONS we identified 14 novel mutations and found that the spectrum of mutations of ATP7B in China is quite distinct from that of Western countries. The mutation type plays a role in predicting clinical manifestations. Genetic testing is a valuable tool to detect WND in young children, especially in patients younger than 8 years old. Four exons (8, 12, 13, and 16) and two mutations (p.Arg778Leu, p.Pro992Leu) should be considered high priority for cost-effective testing in China.
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Affiliation(s)
- Xin-Hua Li
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yi Lu
- The Center for Pediatric Liver Diseases, Children's Hospital of Fudan University
- Department of Pediatrics, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yun Ling
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qing-Chun Fu
- Liver Disease Research Center, Nanjing Military Command, Shanghai, China
| | - Jie Xu
- Department of Infectious Diseases, No. 3 People's Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai China
| | - Guo-Qing Zang
- Department of Infectious Diseases, No. 6 People's Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, China
| | - Feng Zhou
- Liver Disease Research Center, Nanjing Military Command, Shanghai, China
| | - Yu De-Min
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yue Han
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Dong-Hua Zhang
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qi-Ming Gong
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zhi-Meng Lu
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiao-Fei Kong
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jian-She Wang
- The Center for Pediatric Liver Diseases, Children's Hospital of Fudan University
- Department of Pediatrics, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xin-Xin Zhang
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Infectious and Respiratory Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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30
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Luoma LM, Deeb TM, Macintyre G, Cox DW. Functional analysis of mutations in the ATP loop of the Wilson disease copper transporter, ATP7B. Hum Mutat 2010; 31:569-77. [DOI: 10.1002/humu.21228] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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31
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Rodriguez-Granillo A, Crespo A, Wittung-Stafshede P. Conformational Dynamics of Metal-Binding Domains in Wilson Disease Protein: Molecular Insights into Selective Copper Transfer. Biochemistry 2009; 48:5849-63. [DOI: 10.1021/bi900235g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | - Alejandro Crespo
- Department of Bioengineering, Rice University, Houston, 77005 Texas
| | - Pernilla Wittung-Stafshede
- Department of Biochemistry and Cell Biology, Rice University, Houston, 77251 Texas
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
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32
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Young MJ, Court DA. Effects of the S288c genetic background and common auxotrophic markers on mitochondrial DNA function in Saccharomyces cerevisiae. Yeast 2009; 25:903-12. [PMID: 19160453 DOI: 10.1002/yea.1644] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Saccharomyces cerevisiae is a valuable model organism for the study of eukaryotic processes. Throughout its development as a research tool, several strain backgrounds have been utilized and different combinations of auxotrophic marker genes have been introduced into them, creating a useful but non-homogeneous set of strains. The ade2 allele was used as an auxotrophic marker, and for 'red-white' screening for respiratory competence. his3 alleles that influence the expression of MRM1 have been used as selectable markers, and the MIP1[S] allele, found in the commonly used S228c strain, is associated with mitochondrial DNA defects. The focus of the current work was to examine the effects of these alleles, singly and in combination, on the maintenance of mitochondrial function. The combination of the ade2 and MIP1[S] alleles is associated with a slight increase in point mutations in mitochondrial DNA. The deletion in the his3Delta200 allele, which removes the promoter for MRM1, is associated with loss of respiratory competence at 37 degrees C in the presence of either MIP1 allele. Thus, multiple factors can contribute to the maintenance of mitochondrial function, reinforcing the concept that strain background is an important consideration in both designing experiments and comparing results obtained by different research groups.
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Affiliation(s)
- M J Young
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
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33
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Wong CKE, Jarvis RS, Sherson SM, Cobbett CS. Functional analysis of the heavy metal binding domains of the Zn/Cd-transporting ATPase, HMA2, in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2009; 181:79-88. [PMID: 19076719 DOI: 10.1111/j.1469-8137.2008.02637.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The Zn/Cd-transporting ATPase, HMA2, has N- and C-terminal domains that can bind Zn ions with high affinity. Mutant derivatives were generated to determine the significance of these domains to HMA2 function in planta. Mutant derivatives, with and without a C-terminal GFP tag, were expressed from the HMA2 promoter in transgenic hma2,hma4, Zn-deficient, plants to test for functionality. A deletion mutant lacking the C-terminal 244 amino acids rescued most of the hma2,hma4 Zn-deficiency phenotypes with the exception of embryo or seed development. Root-to-shoot Cd translocation was fully rescued. The GFP-tagged derivative was partially mis-localized in the root pericycle cells in which it was expressed. Deletion derivatives lacking the C-terminal 121 and 21 amino acids rescued all phenotypes and localized normally. N-terminal domain mutants localized normally but failed to complement the hma2,hma4 phenotypes. These observations suggest that the N-terminal domain of HMA2 is essential for function in planta while the C-terminal domain, although not essential for function, may contain a signal important for the subcellular localization of the protein.
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Affiliation(s)
| | - Renée S Jarvis
- Department of Genetics, The University of Melbourne, Parkville, Australia, 3010
| | - Sarah M Sherson
- Department of Genetics, The University of Melbourne, Parkville, Australia, 3010
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34
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Hsi G, Cullen LM, Macintyre G, Chen MM, Glerum DM, Cox DW. Sequence variation in the ATP-binding domain of the Wilson disease transporter, ATP7B, affects copper transport in a yeast model system. Hum Mutat 2008; 29:491-501. [PMID: 18203200 DOI: 10.1002/humu.20674] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
ATP7B is a copper transporting P-type ATPase defective in the autosomal recessive copper storage disorder, Wilson disease (WND). Functional assessment of variants helps to distinguish normal from disease-causing variants and provides information on important amino acid residues. A total of 11 missense variants of ATP7B, originally identified in WND patients, were examined for their capacity to functionally complement a yeast mutant strain in which the yeast gene ortholog, CCC2, was disrupted. Solution structures of ATP7B domains were used to predict the effects of each variant on ATP7B structure. Three variants lie within the copper-binding domain and eight within the ATP-binding domain of ATP7B. All three ATP7B variants within the copper-binding domain and four within the ATP-binding domain showed full complementation of the yeast ccc2 phenotype. For the remaining four located in the ATP-binding domain, p.Glu1064Lys and p.Val1106Asp were unable to complement the yeast ccc2 high-affinity iron uptake deficiency phenotype, apparently due to mislocalization and/or change in conformation of the variant protein. p.Leu1083Phe exhibited a temperature-sensitive phenotype with partial complementation at 30 degrees C and a severe deficit at 37 degrees C. p.Met1169Val only partially complemented the ccc2 phenotype at 30 degrees C and 37 degrees C. Therefore, four variant positions were identified as important for copper transport and as disease-causing changes. Since the yeast assay specifically evaluates copper transport function, variants with normal transport could be defective in some other aspect of ATP7B function, particularly trafficking in mammalian cells. Functional assessment is critical for reliable use of mutation analysis as an aid to diagnosis of this clinically variable condition.
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Affiliation(s)
- Gloria Hsi
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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35
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Kenney SM, Cox DW. Sequence variation database for the Wilson disease copper transporter, ATP7B. Hum Mutat 2008; 28:1171-7. [PMID: 17680703 DOI: 10.1002/humu.20586] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Wilson disease (WND) is a disorder of copper transport resulting in copper accumulation in liver, kidney, and brain. This recessive disorder expresses variable clinical symptoms affecting liver, brain, and/or kidney. The age of onset of symptoms varies from 3 to almost 70 years, so the diagnosis for this treatable disorder is easily missed. The defective gene is a membrane P-type ATPase, with similar structure to the other metal transporting ATPases. Most patients with Wilson disease are compound heterozygotes. This report describes the database we have developed for reporting of mutations in ATP7B, the gene defective in WND. The database includes more than 518 variants (379 probable disease-causing and the remainder possible normal variants) from populations worldwide (Available at: www.medicalgenetics.med.ualberta.ca/wilson/index.php; Last accessed: 20 June 2007). The tables in this database are a valuable resource for the study of population variation and the function of the transporter, and will assist in the identification of disease and non-disease-causing sequence variants.
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Affiliation(s)
- Susan M Kenney
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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36
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Park S, Park JY, Kim GH, Choi JH, Kim KM, Kim JB, Yoo HW. Identification of novelATP7Bgene mutations and their functional roles in Korean patients with Wilson disease. Hum Mutat 2007; 28:1108-13. [PMID: 17587212 DOI: 10.1002/humu.20574] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Wilson disease (WND), an autosomal recessive disorder of copper transport, is characterized by excessive accumulation of intracellular copper in liver and extrahepatic tissues because of impaired biliary copper excretion and disturbed incorporation of copper into ceruloplasmin. Hepatic cirrhosis and neuronal degeneration are the major symptoms of WND, and mutations in the ATP7B gene are associated with WND. We have identified 28 different mutations in the ATP7B gene, including six novel variations, in 120 unrelated Korean patients with WND. Molecular defects in ATP7B were present in only 75.0% of Korean WND patients, with the most common mutation, p.Arg778Leu, having an allele frequency of 39.2%. To evaluate the functional defects of ATP7B caused by novel mutations, we used a yeast complementation system, and we used confocal microscopy to localize each mutation after transient expression in mammalian cells. Six novel variations were cloned into a yeast expression vector and two into a mammalian expression vector for confocal analysis. We found that c.2785A>G (p.Ile929Val) and c.3316G>A (p.Val1106Ile) were rare polymorphisms, whereas the others were novel variations disturbing ATP7B function.
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Affiliation(s)
- Sangwook Park
- Genome Research Center for Birth Defects & Genetic Disorders, Asan Medical Center, Seoul, Korea
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Lutsenko S, Barnes NL, Bartee MY, Dmitriev OY. Function and regulation of human copper-transporting ATPases. Physiol Rev 2007; 87:1011-46. [PMID: 17615395 DOI: 10.1152/physrev.00004.2006] [Citation(s) in RCA: 554] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Copper-transporting ATPases (Cu-ATPases) ATP7A and ATP7B are evolutionarily conserved polytopic membrane proteins with essential roles in human physiology. The Cu-ATPases are expressed in most tissues, and their transport activity is crucial for central nervous system development, liver function, connective tissue formation, and many other physiological processes. The loss of ATP7A or ATP7B function is associated with severe metabolic disorders, Menkes disease, and Wilson disease. In cells, the Cu-ATPases maintain intracellular copper concentration by transporting copper from the cytosol across cellular membranes. They also contribute to protein biosynthesis by delivering copper into the lumen of the secretory pathway where metal ion is incorporated into copper-dependent enzymes. The biosynthetic and homeostatic functions of Cu-ATPases are performed in different cell compartments; targeting to these compartments and the functional activity of Cu-ATPase are both regulated by copper. In recent years, significant progress has been made in understanding the structure, function, and regulation of these essential transporters. These studies raised many new questions related to specific physiological roles of Cu-ATPases in various tissues and complex mechanisms that control the Cu-ATPase function. This review summarizes current data on the structural organization and functional properties of ATP7A and ATP7B as well as their localization and functions in various tissues, and discusses the current models of regulated trafficking of human Cu-ATPases.
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Affiliation(s)
- Svetlana Lutsenko
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon 97239, USA.
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de Bie P, Muller P, Wijmenga C, Klomp LWJ. Molecular pathogenesis of Wilson and Menkes disease: correlation of mutations with molecular defects and disease phenotypes. J Med Genet 2007; 44:673-88. [PMID: 17717039 PMCID: PMC2752173 DOI: 10.1136/jmg.2007.052746] [Citation(s) in RCA: 244] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The trace metal copper is essential for a variety of biological processes, but extremely toxic when present in excessive amounts. Therefore, concentrations of this metal in the body are kept under tight control. Central regulators of cellular copper metabolism are the copper-transporting P-type ATPases ATP7A and ATP7B. Mutations in ATP7A or ATP7B disrupt the homeostatic copper balance, resulting in copper deficiency (Menkes disease) or copper overload (Wilson disease), respectively. ATP7A and ATP7B exert their functions in copper transport through a variety of interdependent mechanisms and regulatory events, including their catalytic ATPase activity, copper-induced trafficking, post-translational modifications and protein-protein interactions. This paper reviews the extensive efforts that have been undertaken over the past few years to dissect and characterise these mechanisms, and how these are affected in Menkes and Wilson disease. As both disorders are characterised by an extensive clinical heterogeneity, we will discus how the underlying genetic defects correlate with the molecular functions of ATP7A and ATP7B and with the clinical expression of these disorders.
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Affiliation(s)
- P de Bie
- Laboratory of Metabolic and Endocrine Diseases, Room KC.02.069.1, Lundlaan 6, 3584 EA Utrecht, The Netherlands
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Lutsenko S, LeShane ES, Shinde U. Biochemical basis of regulation of human copper-transporting ATPases. Arch Biochem Biophys 2007; 463:134-48. [PMID: 17562324 PMCID: PMC2025638 DOI: 10.1016/j.abb.2007.04.013] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 04/10/2007] [Accepted: 04/13/2007] [Indexed: 12/11/2022]
Abstract
Copper is essential for cell metabolism as a cofactor of key metabolic enzymes. The biosynthetic incorporation of copper into secreted and plasma membrane-bound proteins requires activity of the copper-transporting ATPases (Cu-ATPases) ATP7A and ATP7B. The Cu-ATPases also export excess copper from the cell and thus critically contribute to the homeostatic control of copper. The trafficking of Cu-ATPases from the trans-Golgi network to endocytic vesicles in response to various signals allows for the balance between the biosynthetic and copper exporting functions of these transporters. Although significant progress has been made towards understanding the biochemical characteristics of human Cu-ATPase, the mechanisms that control their function and intracellular localization remain poorly understood. In this review, we summarize current information on structural features and functional properties of ATP7A and ATP7B. We also describe sequence motifs unique for each Cu-ATPase and speculate about their role in regulating ATP7A and ATP7B activity and trafficking.
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Affiliation(s)
- Svetlana Lutsenko
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239, USA.
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La Fontaine S, Mercer JFB. Trafficking of the copper-ATPases, ATP7A and ATP7B: Role in copper homeostasis. Arch Biochem Biophys 2007; 463:149-67. [PMID: 17531189 DOI: 10.1016/j.abb.2007.04.021] [Citation(s) in RCA: 300] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 04/18/2007] [Accepted: 04/18/2007] [Indexed: 01/05/2023]
Abstract
Copper is essential for human health and copper imbalance is a key factor in the aetiology and pathology of several neurodegenerative diseases. The copper-transporting P-type ATPases, ATP7A and ATP7B are key molecules required for the regulation and maintenance of mammalian copper homeostasis. Their absence or malfunction leads to the genetically inherited disorders, Menkes and Wilson diseases, respectively. These proteins have a dual role in cells, namely to provide copper to essential cuproenzymes and to mediate the excretion of excess intracellular copper. A unique feature of ATP7A and ATP7B that is integral to these functions is their ability to sense and respond to intracellular copper levels, the latter manifested through their copper-regulated trafficking from the transGolgi network to the appropriate cellular membrane domain (basolateral or apical, respectively) to eliminate excess copper from the cell. Research over the last decade has yielded significant insight into the enzymatic properties and cell biology of the copper-ATPases. With recent advances in elucidating their localization and trafficking in human and animal tissues in response to physiological stimuli, we are progressing rapidly towards an integrated understanding of their physiological significance at the level of the whole animal. This knowledge in turn is helping to clarify the biochemical and cellular basis not only for the phenotypes conferred by individual Menkes and Wilson disease patient mutations, but also for the clinical variability of phenotypes associated with each of these diseases. Importantly, this information is also providing a rational basis for the applicability and appropriateness of certain diagnostic markers and therapeutic regimes. This overview will provide an update on the current state of our understanding of the localization and trafficking properties of the copper-ATPases in cells and tissues, the molecular signals and posttranslational interactions that govern their trafficking activities, and the cellular basis for the clinical phenotypes associated with disease-causing mutations.
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Affiliation(s)
- Sharon La Fontaine
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, 221 Burwood Highway, Burwood, Vic. 3125, Australia.
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41
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Achila D, Banci L, Bertini I, Bunce J, Ciofi-Baffoni S, Huffman DL. Structure of human Wilson protein domains 5 and 6 and their interplay with domain 4 and the copper chaperone HAH1 in copper uptake. Proc Natl Acad Sci U S A 2006; 103:5729-34. [PMID: 16571664 PMCID: PMC1458641 DOI: 10.1073/pnas.0504472103] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Indexed: 12/16/2022] Open
Abstract
Human Wilson protein is a copper-transporting ATPase located in the secretory pathway possessing six N-terminal metal-binding domains. Here we focus on the function of the metal-binding domains closest to the vesicular portion of the copper pump, i.e., domain 4 (WLN4), and a construct of domains 5 and 6 (WLN5-6). For comparison purposes, some experiments were also performed with domain 2 (WLN2). The solution structure of apoWLN5-6 consists of two ferredoxin folds connected by a short linker, and (15)N relaxation rate measurements show that it behaves as a unit in solution. An NMR titration of apoWLN5-6 with the metallochaperone Cu(I)HAH1 reveals no complex formation and no copper exchange between the two proteins, whereas titration of Cu(I)HAH1 with WLN4 shows the formation of an adduct that is in fast exchange on the NMR time scale with the isolated protein species as confirmed by (15)N relaxation data. A similar interaction is also observed between Cu(I)HAH1 and WLN2; however, the relative amount of the adduct in the protein mixture is lower. An NMR titration of apoWLN5-6 with Cu(I)WLN4 shows copper transfer, first to WLN6 then to WLN5, without the formation of an adduct. Therefore, we suggest that WLN4 and WLN2 are two acceptors of Cu(I) from HAH1, which then somehow route copper to WLN5-6, before the ATP-driven transport of copper across the vesicular membrane.
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Affiliation(s)
- David Achila
- *Department of Chemistry, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5413; and
| | - Lucia Banci
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Florence, Italy
| | - Ivano Bertini
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Florence, Italy
| | - Jennifer Bunce
- *Department of Chemistry, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5413; and
| | - Simone Ciofi-Baffoni
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Florence, Italy
| | - David L. Huffman
- *Department of Chemistry, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5413; and
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Lim CM, Cater MA, Mercer JFB, La Fontaine S. Copper-dependent interaction of dynactin subunit p62 with the N terminus of ATP7B but not ATP7A. J Biol Chem 2006; 281:14006-14. [PMID: 16554302 DOI: 10.1074/jbc.m512745200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The P-type ATPase affected in Wilson disease, ATP7B, is a key liver protein required to regulate and maintain copper homeostasis. When hepatocytes are exposed to elevated copper levels, ATP7B traffics from the trans-Golgi network toward the biliary canalicular membrane to excrete excess copper into bile. The N-terminal region of ATP7B contains six metal-binding sites (MBS), each with the copper-binding motif MXCXXC. These sites are required for the activity and copper-regulated intracellular redistribution of ATP7B. Two proteins are known to interact with the ATP7B N-terminal region: the copper chaperone ATOX1 that delivers copper to ATP7B, and COMMD1 (MURR1) that is potentially involved in vesicular copper sequestration. To identify additional proteins that interact with ATP7B and hence are involved in copper homeostasis, a yeast two-hybrid approach was employed to screen a human liver cDNA library. The dynactin subunit p62 (dynactin 4; DCTN4) was identified as an interacting partner, and this interaction was confirmed by co-immunoprecipitation from mammalian cells. The dynactin complex binds cargo, such as vesicles and organelles, to cytoplasmic dynein for retrograde microtubule-mediated trafficking and could feasibly be involved in the copper-regulated trafficking of ATP7B. The ATP7B/p62 interaction required copper, the metal-binding CXXC motifs, and the region between MBS 4 and MBS 6 of ATP7B. The p62 subunit did not interact with the related copper ATPase, ATP7A. We propose that the ATP7B interaction with p62 is a key component of the copper-induced trafficking pathway that delivers ATP7B to subapical vesicles of hepatocytes for the removal of excess copper into bile.
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Affiliation(s)
- Chris M Lim
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3125, Australia
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Beaudoin J, Laliberté J, Labbé S. Functional dissection of Ctr4 and Ctr5 amino-terminal regions reveals motifs with redundant roles in copper transport. MICROBIOLOGY (READING, ENGLAND) 2006; 152:209-222. [PMID: 16385131 DOI: 10.1099/mic.0.28392-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Copper uptake in the fission yeast Schizosaccharomyces pombe is carried out by a heteromeric complex formed by two proteins, Ctr4 and Ctr5. In this study, a stable expression system using integrative plasmids was developed to investigate the respective roles of Ctr4 and Ctr5 in copper transport. It was shown that expression of full-length Ctr4 or truncated Ctr4 containing residues 106-289 was required for localization of Ctr5 to the plasma membrane. Likewise, when the full-length Ctr5 or truncated Ctr5 from residues 44-173 was co-expressed with Ctr4, this protein was visualized at the periphery of the cell. To determine the importance of the Mets motifs (consisting of five methionines arranged as Met-X2-Met-X-Met, where X is any amino acid) of Ctr4 and Ctr5 in the heteroprotein complex, we co-expressed Ctr5 lacking the Mets motif and Cys-X-Met-X-Met sequence with wild-type Ctr4 or its mutant derivatives. Conversely, Ctr4 lacking the Mets motif and Met(122) was expressed with wild-type Ctr5 or its mutant derivatives. These experiments revealed that the five Mets motifs of Ctr4 and the Ctr4 residue Met(122) have equally important roles in copper assimilation. Furthermore, the two partially overlapping Mets motifs and the Cys-X-Met-X-Met sequence in Ctr5 have redundant functions in copper transport, with the latter sequence making a greater contribution than the former. Together, the data reveal that co-expression of both Ctr4 and Ctr5 is necessary for the proper function and localization of the heteroprotein complex to the plasma membrane. Once on the cell surface, the N-terminal regions of Ctr4 and Ctr5 can function independently to transport copper; however, the greatest efficiency is achieved when both N termini are present.
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Affiliation(s)
- Jude Beaudoin
- Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, Canada J1H 5N4
| | - Julie Laliberté
- Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, Canada J1H 5N4
| | - Simon Labbé
- Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, Canada J1H 5N4
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Banci L, Bertini I, Cantini F, Chasapis CT, Hadjiliadis N, Rosato A. A NMR Study of the Interaction of a Three-domain Construct of ATP7A with Copper(I) and Copper(I)-HAH1. J Biol Chem 2005; 280:38259-63. [PMID: 16172131 DOI: 10.1074/jbc.m506219200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP7A is a P-type ATPase involved in copper(I) homeostasis in humans. It possesses a long N-terminal tail protruding into the cytosol and containing six copper(I)-binding domains, which are individually folded and capable of binding one copper(I) ion. ATP7A receives copper from a soluble protein, the metallochaperone HAH1. The exact role and interplay of the six soluble domains is still quite unclear, as it has been extensively demonstrated that they are strongly redundant with respect to copper(I) transport in vivo. In the present work, a three-domain (fourth to sixth, MNK456) construct has been investigated in solution by NMR, in the absence and presence of copper(I). In addition, the interaction of MNK456 with copper(I)-HAH1 has been studied. It is proposed that the fourth domain is the preferential site for the initial interaction with the partner. A significant dependence of the overall domain dynamics on the metallation state and on the presence of HAH1 is observed. This dependence could constitute the molecular mechanism to trigger copper(I) translocation and/or ATP7A relocalization from the trans-Golgi network to the plasmatic membrane.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
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Portmann R, Solioz M. Purification and functional reconstitution of the human Wilson copper ATPase, ATP7B. FEBS Lett 2005; 579:3589-95. [PMID: 15963506 DOI: 10.1016/j.febslet.2005.05.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 05/25/2005] [Accepted: 05/26/2005] [Indexed: 11/24/2022]
Abstract
Wilson disease is a disorder of copper metabolism, due to inherited mutations in the Wilson copper ATPase gene ATP7B. To purify and study the function of the ATPase, the enzyme was truncated by five of the six metal binding domains and endowed with an N-terminal histidine-tag for affinity purification. This construct, delta1-5WNDP, was able to functionally complement a yeast strain defective in its native copper ATPase CCC2. Delta1-5WNDP was purified by Ni-affinity chromatography and reconstituted into proteoliposomes. This allowed, for the first time, the functional study of the Wilson ATPase in a purified, reconstituted system.
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Affiliation(s)
- Reto Portmann
- Department of Clinical Pharmacology, University of Berne, Murtenstrasse 35, 3010 Berne, Switzerland
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Verret F, Gravot A, Auroy P, Preveral S, Forestier C, Vavasseur A, Richaud P. Heavy metal transport by AtHMA4 involves the N-terminal degenerated metal binding domain and the C-terminal His11 stretch. FEBS Lett 2005; 579:1515-22. [PMID: 15733866 DOI: 10.1016/j.febslet.2005.01.065] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 01/26/2005] [Accepted: 01/27/2005] [Indexed: 10/25/2022]
Abstract
The Arabidopsis thaliana AtHMA4 is a P1B-type ATPase that clusters with the Zn/Cd/Pb/Co subgroup. It has been previously shown, by heterologous expression and the study of AtHMA4 knockout or overexpressing lines in Arabidopsis , that AtHMA4 is implicated in zinc homeostasis and cadmium tolerance. Here, we report the study of the heterologous expression of AtHMA4 in the yeast Saccharomyces cerevisiae. AtHMA4 expression resulted in an increased tolerance to Zn, Cd and Pb and to a phenotypic complementation of hypersensitive mutants. In contrast, an increased sensitivity towards Co was observed. An AtHMA4::GFP fusion protein was observed in endocytic vesicles and at the yeast plasma membrane. Mutagenesis of the cysteine and glutamate residues from the N-ter degenerated heavy metal binding domain impaired the function of AtHMA4. It was also the case when the C-ter His11 stretch was deleted, giving evidence that these amino acids are essential for the AtHMA4 binding/translocation of metals.
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Affiliation(s)
- Frédéric Verret
- CEA Cadarache, DSV/DEVM/Laboratoire des Echanges Membranaires et Signalisation, UMR 6191 CNRS-CEA-Aix-Marseille II - F-13108 St. Paul les Durance Cedex, France
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Nakayama K, Kanzaki A, Terada K, Mutoh M, Ogawa K, Sugiyama T, Takenoshita S, Itoh K, Yaegashi N, Miyazaki K, Neamati N, Takebayashi Y. Prognostic value of the Cu-transporting ATPase in ovarian carcinoma patients receiving cisplatin-based chemotherapy. Clin Cancer Res 2004; 10:2804-11. [PMID: 15102688 DOI: 10.1158/1078-0432.ccr-03-0454] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE A major obstacle in the treatment of ovarian carcinoma is the intrinsic/acquired resistance to cisplatin-based chemotherapy. Cu-transporting ATPase (ATP7B) has been reported to be associated with cisplatin resistance in vitro. However, the clinical significance of this transporter has not previously been addressed. Our goal was to investigate ATP7B expression in ovarian carcinoma and whether its expression correlates with prognosis and reduced responsiveness to cisplatin treatment. EXPERIMENTAL DESIGN We retrospectively examined the expression of ATP7B and p53 in primary ovarian carcinoma and its association with chemotherapeutic effect. Tissues were surgically removed from 104 ovarian carcinomas patients who received cisplatin-based chemotherapy. We performed immunohistochemical analysis of ATP7B and p53 using a monoclonal antibody against ATP7B and DO7 antibody against p53 protein in 104 ovarian carcinomas and adjacent nonneoplastic tissues. The significance of ATP7B and p53 in the prognosis of patients with ovarian carcinomas was also examined in the survival analysis of mortality follow-up data covering the period between 1988 and 2001. Furthermore, mutation analysis at the six Cu-binding domain and ATP-binding domain, which may be important for cisplatin transport, were performed using single-strand conformational polymorphism after reverse transcriptase-PCR. RESULTS A variable degree of cytoplasmic staining of ATP7B in tumor cells was observed in 34.6% (36 of 104 cases) of the analyzed carcinomas. ATP7B expression was not observed in adjacent nonneoplastic tissues. ATP7B positivity in poorly/moderately differentiated carcinoma was significantly higher than that in low malignant potential tumor/well-differentiated carcinoma (P = 0.0276). Patients with ATP7B-positive tumors had a significantly inferior response to chemotherapy compared with the patients with ATP7B-negative tumors (P = 0.025). The multivariate Cox regression analysis revealed that ATP7B expression (hazard ratio, 1.8; 95% confidence interval, 1.0-3.2, P = 0.048), as well as International Federation of Gynecologists and Obstetricians stage (hazard ratio, 2.0; 95% confidence interval, 1.1-3.6, P = 0.018), was prognostic for poor disease outcome after adjustment for p53 expression, grade, and residual tumor. p53 expression was detected in 31.5% (26/104 cases). No mutation was observed on the six Cu-binding domain or ATP-binding domain in human ovarian carcinomas expressing ATP7B gene. CONCLUSIONS This study demonstrates that overexpression of ATP7B in ovarian carcinoma is correlated with unfavorable clinical outcome in patients treated with cisplatin-based chemotherapy. Therefore, ATP7B expression may be considered as a predictive marker of chemoresistance for cisplatin-based chemotherapy in patients with ovarian carcinoma. We further predict that drugs targeting ATP7B might be useful in combination with cisplatin-based regimen for the improvement of patients with ovarian carcinoma.
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Affiliation(s)
- Kentaro Nakayama
- Department of Obstetrics, Shimane Medical University, Izumo, Japan
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Stapelbroek JM, Bollen CW, van Amstel JKP, van Erpecum KJ, van Hattum J, van den Berg LH, Klomp LWJ, Houwen RHJ. The H1069Q mutation in ATP7B is associated with late and neurologic presentation in Wilson disease: results of a meta-analysis. J Hepatol 2004; 41:758-63. [PMID: 15519648 DOI: 10.1016/j.jhep.2004.07.017] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Revised: 07/01/2004] [Accepted: 07/16/2004] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND AIMS Wilson disease is an hereditary disorder of copper metabolism, caused by mutations in the ATP7B gene, and leading to hepatic or neurologic disease. We examined whether H1069Q, the most common ATP7B mutation, is associated with a specific phenotype. METHODS Genotyping results in 70 Dutch patients were related to clinical presentation. Subsequently a meta-analysis for genotype-phenotype correlation was performed on all patients available from literature, combined with the current Dutch group, a total of 577 patients. RESULTS The Dutch patients homozygous or heterozygous for the H1069Q mutation presented more frequently with neurologic disease (63% and 43% vs. 15%), and at a later age (20.9 and 15.9 vs. 12.6 years) than patients without the H1069Q mutation. In the meta-analysis the odds-ratio for neurologic presentation in homozygous or heterozygous H1069Q vs. non-H1069Q patients was 3.50 (95% CI 2.01-6.09) and 2.13 (95% CI 1.18-3.83), respectively. Age at presentation was 21.1, 19.2 and 16.5 years, respectively, corresponding to a weighted mean difference (WMD) of 4.41 (95% CI 1.56-7.26) for homozygous H1069Q vs. heterozygous patients and 6.68 (95% CI 4.33-9.38) for homozygous H1069Q vs. non-H1069Q patients. CONCLUSIONS Our results indicate that the H1069Q mutation is associated with a late and neurologic presentation.
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Affiliation(s)
- Janneke M Stapelbroek
- Department of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center, P.O. Box 85090, 3508 AB Utrecht, The Netherlands
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Hsi G, Cullen LM, Moira Glerum D, Cox DW. Functional assessment of the carboxy-terminus of the Wilson disease copper-transporting ATPase, ATP7B. Genomics 2004; 83:473-81. [PMID: 14962673 DOI: 10.1016/j.ygeno.2003.08.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2003] [Accepted: 08/27/2003] [Indexed: 01/23/2023]
Abstract
The carboxy-terminus of ATP7B, the protein defective in the copper-transport disorder Wilson disease, was investigated with respect to its role in copper delivery to the ferroxidase ceruloplasmin. We use yeast as a model system to assess the functional capabilities of ATP7B variants. The yeast ferroxidase, Fet3p, acquires copper from Ccc2p and cannot function if Ccc2p is impaired; expression of wild-type ATP7B in ccc2 yeast complements the iron-deficient phenotype. Our results demonstrate that the C-terminus of ATP7B is necessary for protein stability, as removal of the nonmembranous terminus leads to reduced protein levels and cessation of growth in iron-limited medium. Growth is partially restored when an additional three amino acids are present and is near wild-type levels when only one-third of the C-terminus is present. Measurement of ferroxidase activity is a more sensitive indicator of copper transport function and allowed identification of impaired variants not detected with the growth assay.
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Affiliation(s)
- Gloria Hsi
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada T6G 2H7
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50
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Wernimont AK, Yatsunyk LA, Rosenzweig AC. Binding of copper(I) by the Wilson disease protein and its copper chaperone. J Biol Chem 2004; 279:12269-76. [PMID: 14709553 DOI: 10.1074/jbc.m311213200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Wilson disease protein (WND) is a transport ATPase involved in copper delivery to the secretory pathway. Mutations in WND and its homolog, the Menkes protein, lead to genetic disorders of copper metabolism. The WND and Menkes proteins are distinguished from other P-type ATPases by the presence of six soluble N-terminal metal-binding domains containing a conserved CXXC metal-binding motif. The exact roles of these domains are not well established, but possible functions include exchanging copper with the metallochaperone Atox1 and mediating copper-responsive cellular relocalization. Although all six domains can bind copper, genetic and biochemical studies indicate that the domains are not functionally equivalent. One way the domains could be tuned to perform different functions is by having different affinities for Cu(I). We have used isothermal titration calorimetry to measure the association constant (K(a)) and stoichiometry (n) values of Cu(I) binding to the WND metal-binding domains and to their metallochaperone Atox1. The association constants for both the chaperone and target domains are approximately 10(5) to 10(6) m(-1), suggesting that the handling of copper by Atox1 and copper transfer between Atox1 and WND are under kinetic rather than thermodynamic control. Although some differences in both n and K(a) values are observed for variant proteins containing less than the full complement of six metal-binding domains, the data for domains 1-6 were best fitted with a single site model. Thus, the individual functions of the six WND metal-binding domains are not conferred by different Cu(I) affinities but instead by fold and electrostatic surface properties.
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Affiliation(s)
- Amy K Wernimont
- Department of Biochemistry, Northwestern University, Evanston, IL 60208, USA
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