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Nishito Y, Kamimura Y, Nagamatsu S, Yamamoto N, Yasui H, Kambe T. Zinc and manganese homeostasis closely interact in mammalian cells. FASEB J 2024; 38:e23605. [PMID: 38597508 DOI: 10.1096/fj.202400181r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/13/2024] [Accepted: 03/28/2024] [Indexed: 04/11/2024]
Abstract
Understanding the homeostatic interactions among essential trace metals is important for explaining their roles in cellular systems. Recent studies in vertebrates suggest that cellular Mn metabolism is related to Zn metabolism in multifarious cellular processes. However, the underlying mechanism remains unclear. In this study, we examined the changes in the expression of proteins involved in cellular Zn and/or Mn homeostatic control and measured the Mn as well as Zn contents and Zn enzyme activities to elucidate the effects of Mn and Zn homeostasis on each other. Mn treatment decreased the expression of the Zn homeostatic proteins metallothionein (MT) and ZNT1 and reduced Zn enzyme activities, which were attributed to the decreased Zn content. Moreover, loss of Mn efflux transport protein decreased MT and ZNT1 expression and Zn enzyme activity without changing extracellular Mn content. This reduction was not observed when supplementing with the same Cu concentrations and in cells lacking Cu efflux proteins. Furthermore, cellular Zn homeostasis was oppositely regulated in cells expressing Zn and Mn importer ZIP8, depending on whether Zn or Mn concentration was elevated in the extracellular milieu. Our results provide novel insights into the intricate interactions between Mn and Zn homeostasis in mammalian cells and facilitate our understanding of the physiopathology of Mn, which may lead to the development of treatment strategies for Mn-related diseases in the future.
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Affiliation(s)
- Yukina Nishito
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Yoshiki Kamimura
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Shino Nagamatsu
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Nao Yamamoto
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Hiroyuki Yasui
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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Mizuno A, Toyama T, Ichikawa A, Sakai N, Yoshioka Y, Nishito Y, Toga R, Amesaka H, Kaneko T, Arisawa K, Tsutsumi R, Mita Y, Tanaka SI, Noguchi N, Saito Y. An efficient selenium transport pathway of selenoprotein P utilizing a high-affinity ApoER2 receptor variant and being independent of selenocysteine lyase. J Biol Chem 2023; 299:105009. [PMID: 37406814 PMCID: PMC10407282 DOI: 10.1016/j.jbc.2023.105009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 07/07/2023] Open
Abstract
Selenoprotein P (SeP, encoded by the SELENOP gene) is a plasma protein that contains selenium in the form of selenocysteine residues (Sec, a cysteine analog containing selenium instead of sulfur). SeP functions for the transport of selenium to specific tissues in a receptor-dependent manner. Apolipoprotein E receptor 2 (ApoER2) has been identified as a SeP receptor. However, diverse variants of ApoER2 have been reported, and the details of its tissue specificity and the molecular mechanism of its efficiency remain unclear. In the present study, we found that human T lymphoma Jurkat cells have a high ability to utilize selenium via SeP, while this ability was low in human rhabdomyosarcoma cells. We identified an ApoER2 variant with a high affinity for SeP in Jurkat cells. This variant had a dissociation constant value of 0.67 nM and a highly glycosylated O-linked sugar domain. Moreover, the acidification of intracellular vesicles was necessary for selenium transport via SeP in both cell types. In rhabdomyosarcoma cells, SeP underwent proteolytic degradation in lysosomes and transported selenium in a Sec lyase-dependent manner. However, in Jurkat cells, SeP transported selenium in Sec lyase-independent manner. These findings indicate a preferential selenium transport pathway involving SeP and high-affinity ApoER2 in a Sec lyase-independent manner. Herein, we provide a novel dynamic transport pathway for selenium via SeP.
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Affiliation(s)
- Ayako Mizuno
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Takashi Toyama
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Atsuya Ichikawa
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Naoko Sakai
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Yuya Yoshioka
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Yukina Nishito
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Renya Toga
- Laboratory of Biostructural Chemistry, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Hiroshi Amesaka
- Laboratory of Biostructural Chemistry, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Takayuki Kaneko
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Kotoko Arisawa
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Ryouhei Tsutsumi
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yuichiro Mita
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Shun-Ichi Tanaka
- Laboratory of Biostructural Chemistry, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan; Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Shiga, Japan
| | - Noriko Noguchi
- The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Yoshiro Saito
- Laboratory of Molecular Biology and Metabolism, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan; The Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan.
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Nishito Y, Hashimoto A, Kambe T. Simple in vitro method to evaluate ZIP zinc transport ability through zinc transporter 1 and metallothionein expression measurements. Methods Enzymol 2023; 687:207-239. [PMID: 37666633 DOI: 10.1016/bs.mie.2023.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Measuring the cellular zinc content and examining the alteration of zinc status are critical for investigating the cellular homeostasis and dynamics of zinc and its involvement in patho-physiological functions. Many Zrt- and Irt-related protein (ZIP) transporters uptake zinc from the extracellular space. Among Zn transporters (ZNTs), ZNT1 effluxes cytosolic zinc. As cytosolic zinc-binding proteins, metallothioneins (MTs) also contribute to the control of cellular zinc homeostasis. Systemic and cellular zinc homeostasis is considered to be maintained by balancing expression and functional activities of these proteins. The zinc transport ability of ZIPs is typically measured by evaluating cellular zinc content with various zinc-detection methods and systems. Many small-molecule fluorescent probes and fluorescence resonance energy transfer-based protein sensors have been exploited for this purpose. Although powerful analytical methods using special instruments have been developed to quantify zinc, they are often not easily accessible. Here, we present a simplified and inexpensive method to estimate the zinc transport ability of ZIP transporters using the expression responses of ZNT1 and MT. This protocol should be effective in several applications because ZNT1 and MT expression are easily evaluated by immunoblotting and immunofluorescence staining as basic biochemical techniques available in most laboratories. This method is advantageous for examining the relative zinc status or alterations mediated by expression changes of ZIPs in cells cultured in normal medium without zinc supplementation. As zinc is an essential micronutrient, extensive research is necessary to improve dietary zinc absorption to promote health. Therefore, we also propose a simple screening method of foods to improve zinc absorption as an application of measuring ZIP-mediated MT expression.
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Affiliation(s)
- Yukina Nishito
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Ayako Hashimoto
- Department of Food and Nutrition, Faculty of Home Economics, Kyoto Women's University, Kyoto, Japan
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
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Wagatsuma T, Suzuki E, Shiotsu M, Sogo A, Nishito Y, Ando H, Hashimoto H, Petris MJ, Kinoshita M, Kambe T. Pigmentation and TYRP1 expression are mediated by zinc through the early secretory pathway-resident ZNT proteins. Commun Biol 2023; 6:403. [PMID: 37072620 PMCID: PMC10113262 DOI: 10.1038/s42003-023-04640-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 02/28/2023] [Indexed: 04/20/2023] Open
Abstract
Tyrosinase (TYR) and tyrosinase-related proteins 1 and 2 (TYRP1 and TYRP2) are essential for pigmentation. They are generally classified as type-3 copper proteins, with binuclear copper active sites. Although there is experimental evidence for a copper cofactor in TYR, delivered via the copper transporter, ATP7A, the presence of copper in TYRP1 and TYRP2 has not been demonstrated. Here, we report that the expression and function of TYRP1 requires zinc, mediated by ZNT5-ZNT6 heterodimers (ZNT5-6) or ZNT7-ZNT7 homodimers (ZNT7). Loss of ZNT5-6 and ZNT7 function results in hypopigmentation in medaka fish and human melanoma cells, and is accompanied by immature melanosomes and reduced melanin content, as observed in TYRP1 dysfunction. The requirement of ZNT5-6 and ZNT7 for TYRP1 expression is conserved in human, mouse, and chicken orthologs. Our results provide novel insights into the pigmentation process and address questions regarding metalation in tyrosinase protein family.
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Affiliation(s)
- Takumi Wagatsuma
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
| | - Eisuke Suzuki
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
| | - Miku Shiotsu
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
| | - Akiko Sogo
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Yukina Nishito
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
| | - Hideya Ando
- Department of Applied Chemistry and Biotechnology, Okayama University of Science, Okayama, 700-0005, Japan
| | - Hisashi Hashimoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, 464-8602, Japan
| | - Michael J Petris
- Departments of Ophthalmology, University of Missouri, Columbia, MO, 65211, USA
- Biochemistry, University of Missouri, Columbia, MO, 65211, USA
- Bond Life Sciences Center, Columbia, MO, 65211, USA
| | - Masato Kinoshita
- Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.
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Suzuki E, Ogawa N, Takeda TA, Nishito Y, Tanaka YK, Fujiwara T, Matsunaga M, Ueda S, Kubo N, Tsuji T, Fukunaka A, Yamazaki T, Taylor KM, Ogra Y, Kambe T. Detailed analyses of the crucial functions of Zn transporter proteins in alkaline phosphatase activation. J Biol Chem 2020; 295:5669-5684. [PMID: 32179649 PMCID: PMC7186172 DOI: 10.1074/jbc.ra120.012610] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/04/2020] [Indexed: 11/06/2022] Open
Abstract
Numerous zinc ectoenzymes are metalated by zinc and activated in the compartments of the early secretory pathway before reaching their destination. Zn transporter (ZNT) proteins located in these compartments are essential for ectoenzyme activation. We have previously reported that ZNT proteins, specifically ZNT5-ZNT6 heterodimers and ZNT7 homodimers, play critical roles in the activation of zinc ectoenzymes, such as alkaline phosphatases (ALPs), by mobilizing cytosolic zinc into these compartments. However, this process remains incompletely understood. Here, using genetically-engineered chicken DT40 cells, we first determined that Zrt/Irt-like protein (ZIP) transporters that are localized to the compartments of the early secretory pathway play only a minor role in the ALP activation process. These transporters included ZIP7, ZIP9, and ZIP13, performing pivotal functions in maintaining cellular homeostasis by effluxing zinc out of the compartments. Next, using purified ALP proteins, we showed that zinc metalation on ALP produced in DT40 cells lacking ZNT5-ZNT6 heterodimers and ZNT7 homodimers is impaired. Finally, by genetically disrupting both ZNT5 and ZNT7 in human HAP1 cells, we directly demonstrated that the tissue-nonspecific ALP-activating functions of both ZNT complexes are conserved in human cells. Furthermore, using mutant HAP1 cells, we uncovered a previously-unrecognized and unique spatial regulation of ZNT5-ZNT6 heterodimer formation, wherein ZNT5 recruits ZNT6 to the Golgi apparatus to form the heterodimeric complex. These findings fill in major gaps in our understanding of the molecular mechanisms underlying zinc ectoenzyme activation in the compartments of the early secretory pathway.
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Affiliation(s)
- Eisuke Suzuki
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Namino Ogawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Taka-Aki Takeda
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Yukina Nishito
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Yu-Ki Tanaka
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Takashi Fujiwara
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Mayu Matsunaga
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Sachiko Ueda
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Naoya Kubo
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Tokuji Tsuji
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Ayako Fukunaka
- Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan
| | - Tomohiro Yamazaki
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan
| | - Kathryn M Taylor
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, King Edward VIIth Avenue, Cardiff CF10 3NB, United Kingdom
| | - Yasumitsu Ogra
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Taiho Kambe
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
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Nishito Y, Kambe T. Zinc transporter 1 (ZNT1) expression on the cell surface is elaborately controlled by cellular zinc levels. J Biol Chem 2019; 294:15686-15697. [PMID: 31471319 DOI: 10.1074/jbc.ra119.010227] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/20/2019] [Indexed: 12/11/2022] Open
Abstract
Zinc transporter 1 (ZNT1) is the only zinc transporter predominantly located on the plasma membrane, where it plays a pivotal role exporting cytosolic zinc to the extracellular space. Numerous studies have focused on the physiological and pathological functions of ZNT1. However, its biochemical features remain poorly understood. Here, we investigated the regulation of ZNT1 expression in human and vertebrate cells, and found that ZNT1 expression is posttranslationally regulated by cellular zinc status. We observed that under zinc-sufficient conditions, ZNT1 accumulates on the plasma membrane, consistent with its zinc efflux function. In contrast, under zinc-deficient conditions, ZNT1 molecules on the plasma membrane were endocytosed and degraded through both the proteasomal and lysosomal pathways. Zinc-responsive ZNT1 expression corresponded with that of metallothionein, supporting the idea that ZNT1 and metallothionein cooperatively regulate cellular zinc homeostasis. ZNT1 is N-glycosylated on Asn299 in the extracellular loop between transmembrane domains V and VI, and this appears to be involved in the regulation of ZNT1 stability, as nonglycosylated ZNT1 is more stable. However, this posttranslational modification had no effect on ZNT1's ability to confer cellular resistance against high zinc levels or its subcellular localization. Our results provide molecular insights into ZNT1-mediated regulation of cellular zinc homeostasis, and indicate that the control of cellular and systemic zinc homeostasis via dynamic regulation of ZNT1 expression is more sophisticated than previously thought.
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Affiliation(s)
- Yukina Nishito
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
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Abstract
Essential trace elements play pivotal roles in numerous structural and catalytic functions of proteins. Adequate intake of essential trace elements from the daily diet is indispensable to the maintenance of health, and their deficiency leads to a variety of conditions. However, excessive amounts of these trace elements may be highly toxic, and in some cases, may cause damage by the production of harmful reactive oxygen species. Homeostatic dysregulation of their metabolism increases the risk of developing diseases. Specific transport proteins that facilitate influx or efflux of trace elements play key roles in maintaining the homeostasis. Recent elucidation of their crucial functions significantly facilitated our understanding of the molecular mechanisms of iron (Fe), copper (Cu), and zinc (Zn) absorption in the small intestine. This paper summarizes their absorption mechanisms, with a focus on indispensable functions of the molecules involved in it, and briefly discusses the mechanisms of homeostatic control of each element at the cellular and systemic levels.
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Affiliation(s)
- Yukina Nishito
- The Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University
| | - Taiho Kambe
- The Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University
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Nishito Y, Tsuji N, Fujishiro H, Takeda TA, Yamazaki T, Teranishi F, Okazaki F, Matsunaga A, Tuschl K, Rao R, Kono S, Miyajima H, Narita H, Himeno S, Kambe T. Direct Comparison of Manganese Detoxification/Efflux Proteins and Molecular Characterization of ZnT10 Protein as a Manganese Transporter. J Biol Chem 2016; 291:14773-87. [PMID: 27226609 DOI: 10.1074/jbc.m116.728014] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Indexed: 12/14/2022] Open
Abstract
Manganese homeostasis involves coordinated regulation of specific proteins involved in manganese influx and efflux. However, the proteins that are involved in detoxification/efflux have not been completely resolved nor has the basis by which they select their metal substrate. Here, we compared six proteins, which were reported to be involved in manganese detoxification/efflux, by evaluating their ability to reduce manganese toxicity in chicken DT40 cells, finding that human ZnT10 (hZnT10) was the most significant contributor. A domain swapping and substitution analysis between hZnT10 and the zinc-specific transporter hZnT1 showed that residue Asn(43), which corresponds to the His residue constituting the potential intramembranous zinc coordination site in other ZnT transporters, is necessary to impart hZnT10's unique manganese mobilization activity; residues Cys(52) and Leu(242) in transmembrane domains II and V play a subtler role in controlling the metal specificity of hZnT10. Interestingly, the His → Asn reversion mutant in hZnT1 conferred manganese transport activity and loss of zinc transport activity. These results provide important information about manganese detoxification/efflux mechanisms in vertebrate cells as well as the molecular characterization of hZnT10 as a manganese transporter.
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Affiliation(s)
- Yukina Nishito
- From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Natsuko Tsuji
- From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Hitomi Fujishiro
- the Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan
| | - Taka-Aki Takeda
- From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Tomohiro Yamazaki
- From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Fumie Teranishi
- From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Fumiko Okazaki
- the Department of Food Science, Kyoto Women's University, Kyoto 605-8501, Japan
| | - Ayu Matsunaga
- the Department of Food Science, Kyoto Women's University, Kyoto 605-8501, Japan
| | - Karin Tuschl
- the Clinical and Molecular Genetics Unit, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Rajini Rao
- the Department of Physiology, School of Medicine, The Johns Hopkins University, Baltimore, Maryland 21205, and
| | - Satoshi Kono
- the First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Hiroaki Miyajima
- the First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Hiroshi Narita
- the Department of Food Science, Kyoto Women's University, Kyoto 605-8501, Japan
| | - Seiichiro Himeno
- the Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan
| | - Taiho Kambe
- From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan,
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Kambe T, Takeda TA, Nishito Y. Activation of zinc-requiring ectoenzymes by ZnT transporters during the secretory process: Biochemical and molecular aspects. Arch Biochem Biophys 2016; 611:37-42. [PMID: 27046342 DOI: 10.1016/j.abb.2016.03.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/21/2016] [Accepted: 03/30/2016] [Indexed: 01/11/2023]
Abstract
In humans, about 1000 enzymes are estimated to bind zinc. In most of these enzymes, zinc is present at the active site; thus, these enzymes are functional as "zinc-requiring enzymes". Of these zinc-requiring enzymes, zinc-requiring ectoenzymes (defined as secretory, membrane-bound, and organelle-resident enzymes) have received much attention because of their important physiological functions, involvement in a number of diseases, and potential applications as therapeutic targets for diseases. Zinc-requiring ectoenzymes may become active by coordinating zinc at their active site during the secretory process, which requires elaborate control of zinc mobilization from the extracellular milieu to the cytosol and then lumen in the early secretory pathway. Therefore, zinc transporters should properly maintain the process at systemic, cellular, and subcellular levels by mobilizing zinc across biological membranes. However, few studies have examined the mechanisms underlying this process. In this review, current knowledge of the activation process of zinc-requiring ectoenzymes by ZnT zinc transporters in the early secretory pathway is briefly reviewed at the molecular level, with a focus on tissue-nonspecific alkaline phosphatase. Moreover, we also discuss whether zinc-chaperone proteins function during the activation of these enzymes.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
| | - Taka-Aki Takeda
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Yukina Nishito
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
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Tanabe O, Hirata D, Usui H, Nishito Y, Miyakawa T, Igarashi K, Takeda M. Fission yeast homologues of the B' subunit of protein phosphatase 2A: multiple roles in mitotic cell division and functional interaction with calcineurin. Genes Cells 2001; 6:455-73. [PMID: 11380623 DOI: 10.1046/j.1365-2443.2001.00429.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase distributed in eukaryotes from yeast to human, and plays pivotal roles in diverse cellular functions such as metabolism, cell cycle progression, gene expression and development. PP2A holoenzyme is a heterodimer of a catalytic subunit C and a regulatory subunit A, or a heterotrimer of C, A and a variable regulatory subunit consisting of three families; B, B', and PR72. Specific functions for each variable subunit are not well understood. RESULTS Two fission yeast genes pbp1+ and pbp2+ homologous to the regulatory subunit B' were isolated. Physical in vivo interaction of the gene products with the catalytic subunit was demonstrated. A double disruption haploid mutant (Deltapbp1Deltapbp2) showed growth defect, cell shape and size abnormality, multiseptation and anucleated cell formation due to abnormality in septum positioning. These phenotypes were suppressed by human B' cDNA, indicating the striking conservation of the B' function from yeast to human. Over-expression of fission yeast B' led to growth defects, a loss of cell shape polarity, septal abnormality and anucleated cell formation. Deltapbp1Deltapbp2 and pbp1 null haploids were hypersensitive to calcineurin inhibitors, cyclosporin A and FK506, with which the mutants underwent arrest at post-anaphase and cell lysis. Double disruption of calcineurin and pbp1+, but not pbp2+, genes led to synthetic lethality. CONCLUSION The fission yeast B' subunit of PP2A plays critical roles in cell shape control and septum formation, and shares essential functions with calcineurin for viability, possibly through their roles in cytokinesis and cell wall integrity.
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Affiliation(s)
- O Tanabe
- Department of Biochemistry, Hiroshima University School of Medicine, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan.
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Inoue R, Usui H, Tanabe O, Nishito Y, Shimizu M, Takeda M. Studies on functions of the 63-kDa A- and 74-kDa B'(delta)-regulatory subunits in human erythrocyte protein phosphatase 2A: dissociation and reassociation of the subunits. J Biochem 1999; 126:1127-35. [PMID: 10578065 DOI: 10.1093/oxfordjournals.jbchem.a022558] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A heterodimeric form, CA, of protein-serine/threonine phosphatase (PP) 2A purified from human erythrocytes was dissociated into a 34-kDa catalytic subunit C and 63-kDa inactive subunit A by Sephacryl S-200 gel filtration in the presence of 6 M urea. Reassociation of the C- and A-subunits in the absence of urea suppressed the PP activity of the C subunit toward phosphorylase a, P-H2B histone, and P-H1 histone in the presence or absence of 20 mM MnCl(2) or 50 mM Mg(CH(3)COO)(2), but stimulated the PP activity toward P-H1 histone in the presence of 200 mM NaCl and the Mn(2+)-dependent protein-tyrosine phosphatase (PTP) activity toward P-Tyr-Glu copolymers. The 74-kDa inactive B'(delta) subunit was isolated from a heterotrimeric form, CAB'(delta), of PP2A partially purified from human erythrocytes, by heparin-Sepharose column chromatography. The B'(delta) subunit reassociated with CA and suppressed the PP- and PTP-activities of CA. The B'(delta) subunit did not associate with the isolated C subunit directly, and had no effect on the activities of the C subunit, indicating that the A subunit is essential for the association of the B'(delta) subunit with CA and the resulting suppression of the PP- and PTP-activities.
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Affiliation(s)
- R Inoue
- Department of Biochemistry, Hiroshima University School of Medicine, Minami-ku, Hiroshima, 734-8551, Japan
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Nishito Y, Usui H, Tanabe O, Shimizu M, Takeda M. Interconversion of Mn(2+)-dependent and -independent protein phosphatase 2A from human erythrocytes: role of Zn(2+) and Fe(2+) in protein phosphatase 2A. J Biochem 1999; 126:632-8. [PMID: 10467181 DOI: 10.1093/oxfordjournals.jbchem.a022495] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Human erythrocyte Mn(2+)-dependent (C'A') and -independent (CA) protein-serine/threonine phosphatase (PP) 2A are composed of 34-kDa catalytic C' and C subunits, in which the metal dependency resides, and 63-kDa regulatory A' and A subunits, respectively. Each catalytic and regulatory subunit gave the same V8- and papain-peptide maps, respectively. Stoichiometric zinc and substoichiometric iron were detected in CA but not in C'A' [Nishito et al. (1999) FEBS Lett. 447, 29-33]. The Mn(2+)-dependent protein-tyrosine phosphatase (PTP) activity of C'A' was about 70-fold higher than that of CA. Pre-incubation of CA with 25 mM NaF changed CA to a Mn(2+)-dependent form with higher PTP activity. The same NaF treatment had no effect on C'A'. Pre-incubation of C'A' with ZnCl(2), zinc-metallothionein, or FeCl(2) activated the Mn(2+)-independent PP activity, but pre-incubation with FeCl(3) did not. Ascorbate in the pre-incubation and assay mixture significantly stimulated the effect of FeCl(2). Pre-incubation of C'A' with 5 microM ZnCl(2) and 15 microM FeCl(2) in the presence of 1 mM ascorbate synergistically stimulated the Mn(2+)-independent PP activity, with concomitant suppression of the Mn(2+)-dependent PP and PTP activities. The PP and PTP activities of CA were unaffected by the same zinc and/or iron treatment. Micromolar concentrations of vanadate strongly inhibited the Mn(2+)-dependent PP activity of C'A' but only slightly inhibited the PP activity of CA. Using the distinct effect of vanadate as an indicator, the interconversion between CA and C'A' with the above mentioned treatments was proved. These results support the notion that Mn(2+)-independent CA is a Zn(2+)- and Fe(2+)-metalloenzyme, whose apoenzyme is Mn(2+)-dependent C'A'.
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Affiliation(s)
- Y Nishito
- Department of Biochemistry, Hiroshima University School of Medicine, Minami-ku, Hiroshima, 734-8551, Japan
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Nishito Y, Usui H, Shinzawa-Itoh K, Inoue R, Tanabe O, Nagase T, Murakami T, Takeda M. Direct metal analyses of Mn2+-dependent and -independent protein phosphatase 2A from human erythrocytes detect zinc and iron only in the Mn2+-independent one. FEBS Lett 1999; 447:29-33. [PMID: 10218576 DOI: 10.1016/s0014-5793(99)00256-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A Mn2+-dependent protein phosphatase 2A which is composed of a 34 kDa catalytic C' subunit and a 63 kDa regulatory A' subunit, was purified from human erythrocyte cytosol. C' and A' produced V8- and papain-peptide maps identical to those of the 34 kDa catalytic C and the 63 kDa regulatory A subunits of the Mn2+-independent conventional protein phosphatase in human erythrocyte cytosol, respectively. Reconstitution of C'A and CA' revealed that the metal dependency resided in C' and not in A'. In CA, 0.87 +/- 0.12 mol zinc and 0.35 +/- 0.18 mol iron per mol enzyme were detected by atomic absorption spectrophotometry, but manganese, magnesium and cobalt were not detected. None of these metals was detected in C'A'. Pre-incubation of C' with ZnCl2 and FeCl2, but not FeCl3, synergistically stimulated the Mn2+-independent protein phosphatase activity. The protein phosphatase activity of C was unaffected by the same zinc and/or iron treatment. These results suggest that C is a Zn2+- and Fe2+-metalloenzyme and that C' is the apoenzyme.
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Affiliation(s)
- Y Nishito
- Department of Biochemistry, Hiroshima University School of Medicine, Japan
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Usui H, Inoue R, Tanabe O, Nishito Y, Shimizu M, Hayashi H, Kagamiyama H, Takeda M. Activation of protein phosphatase 2A by cAMP-dependent protein kinase-catalyzed phosphorylation of the 74-kDa B'' (delta) regulatory subunit in vitro and identification of the phosphorylation sites. FEBS Lett 1998; 430:312-6. [PMID: 9688562 DOI: 10.1016/s0014-5793(98)00684-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Human erythrocyte protein phosphatase 2A, which comprises a 34-kDa catalytic C subunit, a 63-kDa regulatory A subunit and a 74-kDa regulatory B'' (delta) subunit, was phosphorylated at serine residues of B'' in vitro by cAMP-dependent protein kinase (A-kinase). In the presence and absence of 0.5 microM okadaic acid (OA), A-kinase gave maximal incorporation of 1.7 and 1.0 mol of phosphate per mol of B'', respectively. The Km value of A-kinase for CAB'' was 0.17 +/- 0.01 microM in the presence of OA. The major in vitro phosphorylation sites of B'' were identified as Ser-60, -75 and -573 in the presence of OA, and Ser-75 and -573 in the absence of OA. Phosphorylation of B'' did not dissociate B'' from CA, and stimulated the molecular activity of CAB'' toward phosphorylated H1 and H2B histones, 3.8- and 1.4-fold, respectively, but not toward phosphorylase a.
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Affiliation(s)
- H Usui
- Department of Biochemistry, Hiroshima University School of Medicine, Japan
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Usui H, Nishito Y. [The structure and regulatory mechanisms of protein phosphatase 2A]. Tanpakushitsu Kakusan Koso 1998; 43:945-51. [PMID: 9655950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- H Usui
- Department of Biochemistry, Hiroshima University School of Medicine, Japan
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Nagase T, Murakami T, Nozaki H, Inoue R, Nishito Y, Tanabe O, Usui H, Takeda M. Tissue and subcellular distributions, and characterization of rat brain protein phosphatase 2A containing a 72-kDa delta/B" subunit. J Biochem 1997; 122:178-87. [PMID: 9276686 DOI: 10.1093/oxfordjournals.jbchem.a021726] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A 74-kDa delta/B" subunit was isolated by heparin-Sepharose column chromatography from human erythrocyte protein phosphatase 2A (PP2A) consisting of a 34-kDa catalytic subunit (alpha/C) and 63- and 74-kDa regulatory subunits (beta/A and delta/B") in a ratio of 1:1:1. The purified delta/B" was used as an immunogen in mice, to prepare specific antisera against delta/B". Immunoblot analyses with the antisera detected an immunoreactive 72-kDa protein in the cytosol from various rat tissues including erythrocytes, brain, lung, testis, adrenal gland, heart, spleen, kidney, and liver. The 72-kDa protein was highly abundant in brain and was distributed evenly in cerebral cortex, cerebellum, and brain stem. The 72-kDa protein was also detected in mitochondria and microsome fractions. An immunoreactive 68-kDa protein was detected mainly in nuclear and microsome fractions. The 72-kDa protein from rat brain cytosol copurified with phosphorylated H2B histone phosphatase activity during successive chromatographies on DEAE-Toyopearl, AH-Sepharose, Sephadex G-150, H1 histone-Toyopearl, TSK DEAE-5PW, protamine-Toyopearl, and TSK G3000SW columns. The purified enzyme migrated as a single protein band on nondenaturing PAGE and as three protein bands of 34, 63, and 72 kDa in a ratio of 1:1:1 on SDS-PAGE. The molecular weight of the enzyme was estimated to be 170,000 from the s20,W value of 7.2 +/- 0.3 S and the Stokes radius of 5.5 +/- 0.1 nm. The rat brain enzyme was classified as PP2A, based on the following properties; (1) an IC50 for okadaic acid of 10(-9) M; (2) its preferential dephosphorylation of the a subunit of phosphorylase kinase; (3) its insensitivity to protein inhibitor 2; and (4) its heterotrimeric subunit structure. The Km value and the molecular activity of the enzyme for phosphorylated H2B histone were 72.3 +/- 0.3 microM and 192 +/- 2 mol Pi released/min/mol enzyme, respectively, and were comparable to those of human erythrocyte PP2A (alpha1 beta1 delta1/ CAB"). The 72-kDa subunit in the purified rat brain PP2A was phosphorylated in vitro by cAMP-dependent protein kinase.
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Affiliation(s)
- T Nagase
- Department of Biochemistry, Hiroshima University School of Medicine
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Tanabe O, Gomez GA, Nishito Y, Usui H, Takeda M. Molecular heterogeneity of the cDNA encoding a 74-kDa regulatory subunit (B" or delta) of human protein phosphatase 2A. FEBS Lett 1997; 408:52-6. [PMID: 9180267 DOI: 10.1016/s0014-5793(97)00392-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Two cDNAs for possible splicing variants of a 74-kDa regulatory subunit (B" or delta) of human protein phosphatase 2A, were isolated. These variants were identified from human cerebral cortex by library screening and PCR, and designated delta1 and delta3 isoforms, while the previously reported isoform [Tanabe et al. (1996) FEBS Lett. 379, 107-1111 was designated delta2. Compared with the delta2 isoform, the delta1 isoform contained a 32-residue insertion beginning at residue 84, and consisted of 602 amino acids in all. The delta3 isoform lacked a 74-residue sequence corresponding to residues 1083 of the delta2 isoform, and consisted of 496 amino acids. Using isoform-specific antipeptide antisera, the 74-kDa subunit (B" or delta) originally purified from human erythrocytes was identified as the delta1 isoform.
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Affiliation(s)
- O Tanabe
- Department of Biochemistry, Hiroshima University School of Medicine, Minami-ku, Japan
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Ariki M, Tanabe O, Usui H, Hayashi H, Inoue R, Nishito Y, Kagamiyama H, Takeda M. Identification of autophosphorylation sites in c-Yes purified from rat liver plasma membranes. J Biochem 1997; 121:104-11. [PMID: 9058199 DOI: 10.1093/oxfordjournals.jbchem.a021551] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
c-Yes was purified 322-fold from a rat liver plasma membrane fraction to a single 60-kDa band on SDS-PAGE. The purified protein contained essentially no phosphotyrosine residues and was autophosphorylated with Mg2+. ATP exclusively at tyrosine residues with a concomitant increase in the protein-tyrosine kinase activity. The autophosphorylated c-Yes was extensively digested by trypsin and the resultant two major phosphopeptides, peptides I and II, were purified by HPLC on a reversed-phase C-18 column. The amino acid sequence of peptide I was determined to be LIEDNEYTAR, which is identical with the sequence from Leu-418 through Arg-427 of mouse c-Yes, indicating that one of the autophosphorylation sites corresponds to Tyr-424 of the mouse c-Yes. After partial determination of the N-terminal sequence of 10 amino acid residues of peptide II, the 230 bp sequence of rat cDNA that encodes the N-terminal 76 amino acid residues of c-Yes covering peptide II, was determined. From the predicted amino acid sequence, the sequence of peptide II was assumed to be from Tyr-16 through Lys-46, YTPENPTEPVNTSAGHYGVEHATAATTSSTK. The purified c-Yes phosphorylated the tyrosine residue of synthetic peptides covering Tyr-32 and its surrounding sequence but did not phosphorylate peptides covering Tyr-16 and its surrounding sequence, suggesting that the other autophosphorylation site is Tyr-32.
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Affiliation(s)
- M Ariki
- Department of Biochemistry, Hiroshima University School of Medicine
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Tanabe O, Nagase T, Murakami T, Nozaki H, Usui H, Nishito Y, Hayashi H, Kagamiyama H, Takeda M. Molecular cloning of a 74-kDa regulatory subunit (B" or delta) of human protein phosphatase 2A. FEBS Lett 1996; 379:107-11. [PMID: 8566219 DOI: 10.1016/0014-5793(95)01500-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Based on amino acid sequence data of a 74-kDa regulatory subunit (B" or delta) of a human heterotrimeric protein phosphatase 2A, a cDNA encoding the subunit was isolated from a human cerebral cortex library. The cDNA had an open reading frame encoding an M(r) 66,138 protein of 570 amino acids. Bacterial expression of the cDNA yielded a protein immunoreactive with antisera specific to the 74-kDa subunit. The predicted primary structure of the subunit had no similarity to already reported sequences of PP2A regulatory subunits including A, B, and PR72. Potential phosphorylation sites for protein kinases A and C, a bipartite motif of putative nuclear localization signal, and SH3 accessible proline-rich domain, and a unique PQ repeat were found in the sequence. The subunit mRNA of about 2.9 kb was ubiquitously expressed in rat tissues.
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Affiliation(s)
- O Tanabe
- Department of Biochemistry, Hiroshima University School of Medicine, Japan
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