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Maung MT, Carlson A, Olea-Flores M, Elkhadragy L, Schachtschneider KM, Navarro-Tito N, Padilla-Benavides T. The molecular and cellular basis of copper dysregulation and its relationship with human pathologies. FASEB J 2021; 35:e21810. [PMID: 34390520 DOI: 10.1096/fj.202100273rr] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 06/23/2021] [Accepted: 07/07/2021] [Indexed: 12/16/2022]
Abstract
Copper (Cu) is an essential micronutrient required for the activity of redox-active enzymes involved in critical metabolic reactions, signaling pathways, and biological functions. Transporters and chaperones control Cu ion levels and bioavailability to ensure proper subcellular and systemic Cu distribution. Intensive research has focused on understanding how mammalian cells maintain Cu homeostasis, and how molecular signals coordinate Cu acquisition and storage within organs. In humans, mutations of genes that regulate Cu homeostasis or facilitate interactions with Cu ions lead to numerous pathologic conditions. Malfunctions of the Cu+ -transporting ATPases ATP7A and ATP7B cause Menkes disease and Wilson disease, respectively. Additionally, defects in the mitochondrial and cellular distributions and homeostasis of Cu lead to severe neurodegenerative conditions, mitochondrial myopathies, and metabolic diseases. Cu has a dual nature in carcinogenesis as a promotor of tumor growth and an inducer of redox stress in cancer cells. Cu also plays role in cancer treatment as a component of drugs and a regulator of drug sensitivity and uptake. In this review, we provide an overview of the current knowledge of Cu metabolism and transport and its relation to various human pathologies.
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Affiliation(s)
- May T Maung
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
| | - Alyssa Carlson
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
| | - Monserrat Olea-Flores
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Guerrero, Mexico
| | - Lobna Elkhadragy
- Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA
| | - Kyle M Schachtschneider
- Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA.,Department of Biochemistry & Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA.,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Napoleon Navarro-Tito
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Guerrero, Mexico
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2
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Das S, Maji S, Ruturaj, Bhattacharya I, Saha T, Naskar N, Gupta A. Retromer retrieves the Wilson disease protein ATP7B from endolysosomes in a copper-dependent manner. J Cell Sci 2020; 133:jcs246819. [PMID: 33268466 PMCID: PMC7611186 DOI: 10.1242/jcs.246819] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 11/19/2020] [Indexed: 12/31/2022] Open
Abstract
The Wilson disease protein, ATP7B maintains copper (herein referring to the Cu+ ion) homeostasis in the liver. ATP7B traffics from trans-Golgi network to endolysosomes to export excess copper. Regulation of ATP7B trafficking to and from endolysosomes is not well understood. We investigated the fate of ATP7B after copper export. At high copper levels, ATP7B traffics primarily to acidic, active hydrolase (cathepsin-B)-positive endolysosomes and, upon subsequent copper chelation, returns to the trans-Golgi network (TGN). At high copper, ATP7B colocalizes with endolysosomal markers and with a core member of retromer complex, VPS35. Knocking down VPS35 did not abrogate the copper export function of ATP7B or its copper-responsive anterograde trafficking to vesicles; rather upon subsequent copper chelation, ATP7B failed to relocalize to the TGN, which was rescued by overexpressing wild-type VPS35. Overexpressing mutants of the retromer complex-associated proteins Rab7A and COMMD1 yielded a similar non-recycling phenotype of ATP7B. At high copper, VPS35 and ATP7B are juxtaposed on the same endolysosome and form a large complex that is stabilized by in vivo photoamino acid labeling and UV-crosslinking. We demonstrate that retromer regulates endolysosome to TGN trafficking of copper transporter ATP7B in a manner that is dependent upon intracellular copper.
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Affiliation(s)
- Santanu Das
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Saptarshi Maji
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Ruturaj
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Indira Bhattacharya
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Tanusree Saha
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Nabanita Naskar
- Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Arnab Gupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
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3
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Lalioti V, Peiró R, Pérez-Berlanga M, Tsuchiya Y, Muñoz A, Villalba T, Sanchez C, Sandoval IV. Basolateral sorting and transcytosis define the Cu+-regulated translocation of ATP7B to the bile canaliculus. J Cell Sci 2016; 129:2190-201. [DOI: 10.1242/jcs.184663] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/28/2016] [Indexed: 01/22/2023] Open
Abstract
The Cu+ pump ATP7B plays an irreplaceable role in the elimination of excess Cu+ by the hepatocyte into the bile. The traffic and site of ATP7B action is a subject of controversy. One current proposal is that an increase in intracellular Cu+ results in the translocation of ATP7B to the lysosomes and excretion of excess Cu+ by lysosomal mediated exocytosis at the bile canaliculus. Here we show that ATP7B is transported from the trans-Golgi network to the bile canaliculus by basolateral sorting and endocytosis, and microtubule mediated transcytosis through the subapical compartment. Trafficking ATP7B is not incorporated into lysosomes and addition of Cu+ does not cause relocalization of lysosomes and the appearance of lysosome markers in the bile canaliculus. Our data describes the pathway of the Cu+-mediated transport of ATP7B from the TGN to the bile canaliculus and indicates that the bile canaliculus is the prime site of ATP7B action in the elimination of excess Cu+.
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Affiliation(s)
- Vasiliki Lalioti
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Cantoblanco, 28049 Madrid, Spain
| | - Ramón Peiró
- Genomics and Massive Sequencing, Centro de Biología Molecular Severo Ochoa, Cantoblanco, 28049 Madrid, Spain
| | - Manuela Pérez-Berlanga
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Cantoblanco, 28049 Madrid, Spain
| | - Yo Tsuchiya
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Cantoblanco, 28049 Madrid, Spain
| | - Angeles Muñoz
- Optical and Confocal Microscopy, Centro de Biología Molecular Severo Ochoa, Cantoblanco, 28049 Madrid, Spain
| | - Teresa Villalba
- Optical and Confocal Microscopy, Centro de Biología Molecular Severo Ochoa, Cantoblanco, 28049 Madrid, Spain
| | - Carlos Sanchez
- Optical and Confocal Microscopy, Centro de Biología Molecular Severo Ochoa, Cantoblanco, 28049 Madrid, Spain
| | - Ignacio V. Sandoval
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Cantoblanco, 28049 Madrid, Spain
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4
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Polishchuk EV, Concilli M, Iacobacci S, Chesi G, Pastore N, Piccolo P, Paladino S, Baldantoni D, van IJzendoorn SCD, Chan J, Chang CJ, Amoresano A, Pane F, Pucci P, Tarallo A, Parenti G, Brunetti-Pierri N, Settembre C, Ballabio A, Polishchuk RS. Wilson disease protein ATP7B utilizes lysosomal exocytosis to maintain copper homeostasis. Dev Cell 2014; 29:686-700. [PMID: 24909901 PMCID: PMC4070386 DOI: 10.1016/j.devcel.2014.04.033] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 03/15/2014] [Accepted: 04/29/2014] [Indexed: 12/24/2022]
Abstract
Copper is an essential yet toxic metal and its overload causes Wilson disease, a disorder due to mutations in copper transporter ATP7B. To remove excess copper into the bile, ATP7B traffics toward canalicular area of hepatocytes. However, the trafficking mechanisms of ATP7B remain elusive. Here, we show that, in response to elevated copper, ATP7B moves from the Golgi to lysosomes and imports metal into their lumen. ATP7B enables lysosomes to undergo exocytosis through the interaction with p62 subunit of dynactin that allows lysosome translocation toward the canalicular pole of hepatocytes. Activation of lysosomal exocytosis stimulates copper clearance from the hepatocytes and rescues the most frequent Wilson-disease-causing ATP7B mutant to the appropriate functional site. Our findings indicate that lysosomes serve as an important intermediate in ATP7B trafficking, whereas lysosomal exocytosis operates as an integral process in copper excretion and hence can be targeted for therapeutic approaches to combat Wilson disease.
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Affiliation(s)
- Elena V Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Mafalda Concilli
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Simona Iacobacci
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Giancarlo Chesi
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Nunzia Pastore
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA
| | - Pasquale Piccolo
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, Federico II University, Naples 80125, Italy
| | | | - Sven C D van IJzendoorn
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen 9713, the Netherlands
| | - Jefferson Chan
- Department of Chemistry and Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Christopher J Chang
- Department of Chemistry and Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Angela Amoresano
- Department of Chemical Sciences, University of Naples Federico II, Napoli 80126, Italy
| | - Francesca Pane
- Department of Chemical Sciences, University of Naples Federico II, Napoli 80126, Italy
| | - Piero Pucci
- Department of Chemical Sciences, University of Naples Federico II, Napoli 80126, Italy
| | - Antonietta Tarallo
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy
| | - Giancarlo Parenti
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Medical Genetics, Department of Translational and Medical Sciences, Federico II University, Naples 80125, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Medical Genetics, Department of Translational and Medical Sciences, Federico II University, Naples 80125, Italy
| | - Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA; Medical Genetics, Department of Translational and Medical Sciences, Federico II University, Naples 80125, Italy; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Dulbecco Telethon Institute, TIGEM, Naples 80131, Italy
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy; Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA; Medical Genetics, Department of Translational and Medical Sciences, Federico II University, Naples 80125, Italy; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Roman S Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Naples 80131, Italy.
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5
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Harada M. Pathogenesis and management of Wilson disease. Hepatol Res 2014; 44:395-402. [PMID: 24450973 DOI: 10.1111/hepr.12301] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/09/2014] [Accepted: 01/14/2014] [Indexed: 02/08/2023]
Abstract
Hepatolenticular degeneration, commonly known as Wilson disease, is an autosomal recessive inherited disease of abnormal copper metabolism, characterized by the accumulation of copper in the body due to decreased biliary excretion of copper from hepatocytes. Wilson disease protein, ATP7B, functions in copper excretion into bile and in copper secretion to the bloodstream coupled with ceruloplasmin synthesis. Various kinds of mutations of ATP7B cause Wilson disease. Wilson disease is a rare genetic disease that can be treated pharmacologically. Recognition and prompt diagnosis are very important, because Wilson disease is fatal if left untreated. In this review, I summarize the pathogenesis and management of Wilson disease.
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Affiliation(s)
- Masaru Harada
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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Yanagimoto C, Harada M, Kumemura H, Abe M, Koga H, Sakata M, Kawaguchi T, Terada K, Hanada S, Taniguchi E, Ninomiya H, Ueno T, Sugiyama T, Sata M. Copper incorporation into ceruloplasmin is regulated by Niemann-Pick C1 protein. Hepatol Res 2011; 41:484-91. [PMID: 21518405 DOI: 10.1111/j.1872-034x.2011.00788.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
AIM Wilson disease is a genetic disorder of copper metabolism characterized by impaired biliary copper excretion. Wilson disease gene product (ATP7B) functions in copper incorporation to ceruloplasmin (Cp) and biliary copper excretion. Our previous study showed the late endosome localization of ATP7B and described the copper transport pathway from the late endosome to trans-Golgi network (TGN). However, the cellular localization of ATP7B and copper metabolism in hepatocytes remains controversial. The present study was performed to evaluate the role of Niemann-Pick type C (NPC) gene product NPC1 on intracellular copper transport in hepatocytes. METHODS We induced the NPC phenotype using U18666A to modulate the vesicle traffic from the late endosome to TGN. Then, we examined the effect of NPC1 overexpression on the localization of ATP7B and secretion of holo-Cp, a copper-binding mature form of Cp. RESULTS Overexpression of NPC1 increased holo-Cp secretion to culture medium of U18666A-treated cells, but did not affect the secretion of albumin. Manipulation of NPC1 function affected the localization of ATP7B and late endosome markers, but did not change the localization of a TGN marker. ATP7B co-localized with the late endosome markers, but not with the TGN marker. CONCLUSION These findings suggest that ATP7B localizes in the late endosomes and that copper in the late endosomes is transported to the secretory compartment via an NPC1-dependent pathway and incorporated into Cp.
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Affiliation(s)
- Chikatoshi Yanagimoto
- Division of Gastroenterology, Department of Medicine and Research Center for Innovative Cancer Therapy of the 21st Century COE Program for Medical Science, Kurume University School of Medicine, Kurume Yanagimoto-naika, Itoshima The Third Department of Internal Medicine, University of Occupational and Environmental Health, Japan School of Medicine, Kitakyushu Department of Medicine, Onoba Hospital Biochemistry, Akita University School of Medicine, Akita Department of Neurobiology, Tottori University Faculty of Medicine, Yonago, Japan
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7
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Yanagimoto C, Harada M, Kumemura H, Koga H, Kawaguchi T, Terada K, Hanada S, Taniguchi E, Koizumi Y, Koyota S, Ninomiya H, Ueno T, Sugiyama T, Sata M. Niemann-Pick C1 protein transports copper to the secretory compartment from late endosomes where ATP7B resides. Exp Cell Res 2009; 315:119-26. [PMID: 19007772 DOI: 10.1016/j.yexcr.2008.10.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 08/28/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
Abstract
Wilson disease is a genetic disorder characterized by the accumulation of copper in the body by defective biliary copper excretion. Wilson disease gene product (ATP7B) functions in copper incorporation to ceruloplasmin (Cp) and biliary copper excretion. However, copper metabolism in hepatocytes has been still unclear. Niemann-Pick disease type C (NPC) is a lipid storage disorder and the most commonly mutated gene is NPC1 and its gene product NPC1 is a late endosome protein and regulates intracellular vesicle traffic. In the present study, we induced NPC phenotype and examined the localization of ATP7B and secretion of holo-Cp, a copper-binding mature form of Cp. The vesicle traffic was modulated using U18666A, which induces NPC phenotype, and knock down of NPC1 by RNA interference. ATP7B colocalized with the late endosome markers, but not with the trans-Golgi network markers. U18666A and NPC1 knock down decreased holo-Cp secretion to culture medium, but did not affect the secretion of other secretory proteins. Copper accumulated in the cells after the treatment with U18666A. These findings suggest that ATP7B localizes in the late endosomes and that copper in the late endosomes is transported to the secretory compartment via NPC1-dependent pathway and incorporated into apo-Cp to form holo-Cp.
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Affiliation(s)
- Chikatoshi Yanagimoto
- Division of Gastroenterology, Department of Medicine and Research Center for Innovative Cancer Therapy of the 21st Century COE Program for Medical Science, Kurume University School of Medicine, Kurume, Japan.
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Hubbard AL, Braiterman LT. Could ATP7B export Cu(I) at the tight junctions and the apical membrane? Gastroenterology 2008; 134:1255-7. [PMID: 18395105 DOI: 10.1053/j.gastro.2008.02.073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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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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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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Guo Y, Nyasae L, Braiterman LT, Hubbard AL. NH2-terminal signals in ATP7B Cu-ATPase mediate its Cu-dependent anterograde traffic in polarized hepatic cells. Am J Physiol Gastrointest Liver Physiol 2005; 289:G904-16. [PMID: 15994426 DOI: 10.1152/ajpgi.00262.2005] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cu is an essential cofactor of cellular proteins but is toxic in its free state. The hepatic Cu-ATPase ATP7B has two functions in Cu homeostasis: it loads Cu+ onto newly synthesized apoceruloplasmin in the secretory pathway, thereby activating the plasma protein; and it participates in the excretion of excess Cu+ into the bile. To carry out these two functions, the membrane protein responds to changes in intracellular Cu levels by cycling between the Golgi and apical region. We used polarized hepatic WIF-B cells and high-resolution confocal microscopy to map the itinerary of endogenous and exogenous ATP7B under different Cu conditions. In Cu-depleted cells, ATP7B resided in a post-trans-Golgi network compartment that also contained syntaxin 6, whereas in Cu-loaded cells, the protein relocated to unique vesicles very near to the apical plasma membrane as well as the membrane itself. To determine the role of ATP7B's cytoplasmic NH2 terminus in regulating its intracellular movements, we generated seven mutations/deletions in this large [approximately 650 amino acid (AA)] domain and analyzed the Cu-dependent behavior of the mutant ATP7B proteins in WIF-B cells. Truncation of the ATP7B NH2 terminus up to the fifth copper-binding domain (CBD5) yielded an active ATPase that was insensitive to cellular Cu levels and constitutively trafficked to the opposite (basolateral) plasma membrane domain. Fusion of the NH2-terminal 63 AA of ATP7B to the truncated protein restored both its Cu responsiveness and correct intracellular targeting. These results indicate that important targeting information is contained in this relatively short sequence, which is absent from the related CuATPase, ATP7A.
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Affiliation(s)
- Y Guo
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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12
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Harada M, Kawaguchi T, Kumemura H, Terada K, Ninomiya H, Taniguchi E, Hanada S, Baba S, Maeyama M, Koga H, Ueno T, Furuta K, Suganuma T, Sugiyama T, Sata M. The Wilson disease protein ATP7B resides in the late endosomes with Rab7 and the Niemann-Pick C1 protein. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 166:499-510. [PMID: 15681833 PMCID: PMC1602322 DOI: 10.1016/s0002-9440(10)62272-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Wilson disease is a genetic disorder characterized by the accumulation of copper in the body due to a defect of biliary copper excretion. Although the Wilson disease gene has been cloned, the cellular localization of the gene product (ATP7B) has not been fully clarified. Therefore, the precise physiological action of ATP7B is still unknown. We examined the distribution of ATP7B using an anti-ATP7B antibody, green fluorescent protein (GFP)-ATP7B (GFP-ATP7B) and ATP7B-DsRed in various cultured cells. Intracellular organelles were visualized by fluorescence microscopy. The distribution of ATP7B was compared with that of Rab7 and Niemann-Pick C1 (NPC1), proteins that localize in the late endosomes. U18666A, which induces the NPC phenotype, was used to modulate the intracellular vesicle traffic. GFP-ATP7B colocalized with various late endosome markers including Rab7 and NPC1 but not with Golgi or lysosome markers. U18666A induced the formation of late endosome-lysosome hybrid organelles, with GFP-ATP7B localized with NPC1 in these structures. We have confirmed that ATP7B is a late endosome-associated membrane protein. ATP7B appears to translocate copper from the cytosol to the late endosomal lumen, thus participating in biliary copper excretion via lysosomes. Thus, defective copper ATPase activity of ATP7B in the late endosomes appears to be the main defect of Wilson disease.
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Affiliation(s)
- Masaru Harada
- Second Department of Medicine, Kurume University School of Medicine, 67 Asahi-Machi, Kurume 830-0011, Japan.
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13
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Katano K, Safaei R, Samimi G, Holzer A, Tomioka M, Goodman M, Howell SB. Confocal microscopic analysis of the interaction between cisplatin and the copper transporter ATP7B in human ovarian carcinoma cells. Clin Cancer Res 2005; 10:4578-88. [PMID: 15240550 DOI: 10.1158/1078-0432.ccr-03-0689] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Some cisplatin (DDP)-resistant cells overexpress the copper export transporter ATP7B, and cells molecularly engineered to overexpress ATP7B are resistant to DDP. The interaction of Cu with ATP7B normally triggers its relocalization from the perinuclear region to more peripheral vesicles. To investigate the interaction of DDP with ATP7B, we examined the effect of DDP on the subcellular localization of ATP7B using human ovarian carcinoma cells expressing a cyan fluorescent protein (ECFP)-tagged ATP7B (2008/ECFP-ATP7B). ATP7B expression was confirmed in 2008/ECFP-ATP7B cells by Western blotting, and its functionality was documented by showing that it rendered the cells 1.9-fold resistant to CuSO(4) and 4.1-fold resistant to DDP and also reduced the accumulation of both drugs. There was greater sequestration of Pt into intracellular vesicles in the 2008/ECFP-ATP7B cells than in the 2008/ECFP cells. Confocal digital microscopy revealed that ECFP-ATP7B localized in the perinuclear region in absence of drug exposure and that both Cu and DDP triggered relocalization to more peripheral vesicular structures. A fluorescein-labeled form of DDP that retained cytotoxicity and was subject to the same mechanisms of resistance as DDP colocalized with ECFP-ATP7B in the 2008/ECFP-ATP7B cells, whereas the same fluorochrome lacking the DDP moiety did not. These results provide evidence that DDP directly interacts with ATP7B to trigger its relocalization and that ATP7B mediates resistance to DDP by sequestering it into vesicles of the secretory pathway for export from the cell.
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Affiliation(s)
- Kuniyuki Katano
- Department of Medicine, Chemistry and the Cancer Center, University of California, San Diego, La Jolla, California, USA
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Katano K, Safaei R, Samimi G, Holzer A, Rochdi M, Howell SB. The copper export pump ATP7B modulates the cellular pharmacology of carboplatin in ovarian carcinoma cells. Mol Pharmacol 2003; 64:466-73. [PMID: 12869652 DOI: 10.1124/mol.64.2.466] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Human tumor cells lines with acquired resistance to cisplatin (DDP) and carboplatin (CBDCA) are often cross-resistant to copper and vice versa, and some DDP-resistant cells overexpress the copper export pump ATP7B. We sought to demonstrate that ATP7B directly mediates resistance to DDP and CBDCA by stably transfecting human carcinoma cells with a vector designed to express ATP7B. Increased expression of ATP7B rendered all three cell lines tested more resistant to a 1-h exposure to DDP (1.6-2.6-fold), CBDCA (1.5-1.6-fold), and copper (1.2-1.4-fold). The effect of ATP7B on the cellular pharmacology of 64Cu and [14C]CBDCA was investigated in more detail using one cell pair (2008 cells transfected with an empty vector or an ATP7B-expressing vector). In the 2008/ATP7B subline, steady-state copper levels were decreased under both basal and copper-supplemented conditions, as was steady-state CBDCA content upon exposure to 50 microM [14C]CBDCA. Over the first 5 min, the average rate of accumulation of copper and CBCDA in the 2008/ATP7B cells was reduced by 37 and 61%, respectively. Efflux was more rapid from 2008/ATP7B cells for both copper and CBDCA. Two-compartment modeling indicated that the second phase of efflux was increased by a factor of 3.9-fold for CBCDA and to an even greater extent for copper. We conclude that expression of ATP7B regulates sensitivity to CBDCA as well as to DDP and copper and that a transporter that normally mediates copper homeostasis modulates the cellular pharmacology of CBDCA.
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Affiliation(s)
- Kuniyuki Katano
- Department of Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0058, USA
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Lockhart PJ, La Fontaine S, Firth SD, Greenough M, Camakaris J, Mercer JFB. Correction of the copper transport defect of Menkes patient fibroblasts by expression of two forms of the sheep Wilson ATPase. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1588:189-94. [PMID: 12385784 DOI: 10.1016/s0925-4439(02)00164-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Wilson disease (WD) protein (ATP7B) is a copper-transporting P-type ATPase that is responsible for the efflux of hepatic copper into the bile, a process that is essential for copper homeostasis in mammals. Compared with other mammals, sheep have a variant copper phenotype and do not efficiently excrete copper via the bile, often resulting in excessive copper accumulation in the liver. To investigate the function of sheep ATP7B and its potential role in the copper-accumulation phenotype, cDNAs encoding the two forms of ovine ATP7B were transfected into immortalised fibroblast cell lines derived from a Menkes disease patient and a normal control. Both forms of ATP7B were able to correct the copper-retention phenotype of the Menkes cell line, demonstrating each to be functional copper-transporting molecules and suggesting that the accumulation of copper in the sheep liver is not due to a defect in the copper transport function of either form of sATP7B.
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Affiliation(s)
- Paul J Lockhart
- Center for Cellular and Molecular Biology, School of Biological and Chemical Sciences, Deakin University, Building L, Burwood Campus, 221 Burwood Highway, Victoria 3125, Australia
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Blackwell JM, Goswami T, Evans CA, Sibthorpe D, Papo N, White JK, Searle S, Miller EN, Peacock CS, Mohammed H, Ibrahim M. SLC11A1 (formerly NRAMP1) and disease resistance. Cell Microbiol 2001; 3:773-84. [PMID: 11736990 PMCID: PMC3025745 DOI: 10.1046/j.1462-5822.2001.00150.x] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- J M Blackwell
- Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2XY, UK.
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Lockhart PJ, Mercer JF. Functional analysis of the sheep Wilson disease protein (sATP7B) in CHO cells. Eur J Cell Biol 2001; 80:349-57. [PMID: 11432725 DOI: 10.1078/0171-9335-00165] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In this study we investigated the function of the sheep orthologue of ATP7B (sATP7B), the protein affected in the human copper toxicosis disorder Wilson disease. Two forms of sATP7B are found in the sheep, a 'normal' form and one with an alternate N terminus, both of which were expressed in CHO-K1 cells. Cells expressing either form of sATP7B were more resistant to copper than the parental CHO-K1 cells. Subcellular localisation studies showed that both forms of sATP7B were similarly located in the trans-Golgi network (TGN). When the extracellular copper concentration was increased, each form of sATP7B redistributed to a punctate, vesicular compartment that extended throughout the cytoplasm. Both forms of sATP7B recycled to the perinuclear location within one hour when the cells were subsequently incubated in basal medium. After treatment of cells with bafilomycin A1 sATP7B accumulated in cytoplasmic vesicles, implying that ATP7B continuously recycles via the endocytic pathway. These results suggest that both forms of sATP7B are functional copper-transport proteins and that the intracellular location and trafficking of the sheep protein within the cell also appears normal.
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Affiliation(s)
- P J Lockhart
- Centre for Cellular and Molecular Biology, School of Biological and Chemical Sciences, Deakin University, Burwood/Australia
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Abstract
The discovery of novel metabolic pathways and the genetic basis for diseases of the liver continues to yield new insights into the pathogenesis of inherited metabolic diseases of the liver, whereas the application of new technologies to their treatment continues to advance therapeutic options. This review of selected articles covers a wide range of subjects, from the identification of novel proteins and transport pathways to disease diagnosis and treatment of acute liver failure. Four selected topics, Wilson disease, hemochromatosis and iron overload disorders, alpha-1 antitrypsin disease, and exciting new therapeutic options for lysosomal storage diseases are the focus of this review.
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Affiliation(s)
- M L Schilsky
- Department of Medicine and Genetics, The Mount Sinai Medical Center, New York, New York 10029, USA.
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Abstract
Iron is vital for almost all living organisms by participating in a wide variety of metabolic processes, including oxygen transport, DNA synthesis, and electron transport. However, iron concentrations in body tissues must be tightly regulated because excessive iron leads to tissue damage, as a result of formation of free radicals. Disorders of iron metabolism are among the most common diseases of humans and encompass a broad spectrum of diseases with diverse clinical manifestations, ranging from anemia to iron overload and, possibly, to neurodegenerative diseases. The molecular understanding of iron regulation in the body is critical in identifying the underlying causes for each disease and in providing proper diagnosis and treatments. Recent advances in genetics, molecular biology and biochemistry of iron metabolism have assisted in elucidating the molecular mechanisms of iron homeostasis. The coordinate control of iron uptake and storage is tightly regulated by the feedback system of iron responsive element-containing gene products and iron regulatory proteins that modulate the expression levels of the genes involved in iron metabolism. Recent identification and characterization of the hemochromatosis protein HFE, the iron importer Nramp2, the iron exporter ferroportin1, and the second transferrin-binding and -transport protein transferrin receptor 2, have demonstrated their important roles in maintaining body's iron homeostasis. Functional studies of these gene products have expanded our knowledge at the molecular level about the pathways of iron metabolism and have provided valuable insight into the defects of iron metabolism disorders. In addition, a variety of animal models have implemented the identification of many genetic defects that lead to abnormal iron homeostasis and have provided crucial clinical information about the pathophysiology of iron disorders. In this review, we discuss the latest progress in studies of iron metabolism and our current understanding of the molecular mechanisms of iron absorption, transport, utilization, and storage. Finally, we will discuss the clinical presentations of iron metabolism disorders, including secondary iron disorders that are either associated with or the result of abnormal iron accumulation.
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Affiliation(s)
- P T Lieu
- The R.W. Johnson Pharmaceutical Research Institute, 3210 Merryfield Row, San Diego, CA 92121, USA
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