1
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Cembran A, Fernandez-Funez P. Intrinsic determinants of prion protein neurotoxicity in Drosophila: from sequence to (dys)function. Front Mol Neurosci 2023; 16:1231079. [PMID: 37645703 PMCID: PMC10461008 DOI: 10.3389/fnmol.2023.1231079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 08/02/2023] [Indexed: 08/31/2023] Open
Abstract
Prion diseases are fatal brain disorders characterized by deposition of insoluble isoforms of the prion protein (PrP). The normal and pathogenic structures of PrP are relatively well known after decades of studies. Yet our current understanding of the intrinsic determinants regulating PrP misfolding are largely missing. A 3D subdomain of PrP comprising the β2-α2 loop and helix 3 contains high sequence and structural variability among animals and has been proposed as a key domain regulating PrP misfolding. We combined in vivo work in Drosophila with molecular dynamics (MD) simulations, which provide additional insight to assess the impact of candidate substitutions in PrP from conformational dynamics. MD simulations revealed that in human PrP WT the β2-α2 loop explores multiple β-turn conformations, whereas the Y225A (rabbit PrP-like) substitution strongly favors a 310-turn conformation, a short right-handed helix. This shift in conformational diversity correlates with lower neurotoxicity in flies. We have identified additional conformational features and candidate amino acids regulating the high toxicity of human PrP and propose a new strategy for testing candidate modifiers first in MD simulations followed by functional experiments in flies. In this review we expand on these new results to provide additional insight into the structural and functional biology of PrP through the prism of the conformational dynamics of a 3D domain in the C-terminus. We propose that the conformational dynamics of this domain is a sensitive measure of the propensity of PrP to misfold and cause toxicity. This provides renewed opportunities to identify the intrinsic determinants of PrP misfolding through the contribution of key amino acids to different conformational states by MD simulations followed by experimental validation in transgenic flies.
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Affiliation(s)
- Alessandro Cembran
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN, United States
| | - Pedro Fernandez-Funez
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN, United States
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2
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Gabrielli F, Antinucci M, Tofanelli S. Gene Structure Evolution of the Short-Chain Dehydrogenase/Reductase (SDR) Family. Genes (Basel) 2022; 14:110. [PMID: 36672851 PMCID: PMC9859523 DOI: 10.3390/genes14010110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/12/2022] [Accepted: 12/22/2022] [Indexed: 12/31/2022] Open
Abstract
SDR (Short-chain Dehydrogenases/Reductases) are one of the oldest and heterogeneous superfamily of proteins, whose classification is problematic because of the low percent identity, even within families. To get clearer insights into SDR molecular evolution, we explored the splicing site organization of the 75 human SDR genes across their vertebrate and invertebrate orthologs. We found anomalous gene structures in members of the human SDR7C and SDR42E families that provide clues of retrogene properties and independent evolutionary trajectories from a common invertebrate ancestor. The same analyses revealed that the identity value between human and invertebrate non-allelic variants is not necessarily associated with the homologous gene structure. Accordingly, a revision of the SDR nomenclature is proposed by including the human SDR40C1 and SDR7C gene in the same family.
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Affiliation(s)
- Franco Gabrielli
- Department of Biology, University of Pisa, Via Ghini, 13-56126 Pisa, Italy
| | - Marco Antinucci
- Department of Medicine and Life Sciences, Institute of Evolutionary Biology (UPF-CSIC), Universitat Pompeu Fabra, 08002 Barcelona, Spain
| | - Sergio Tofanelli
- Department of Biology, University of Pisa, Via Ghini, 13-56126 Pisa, Italy
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3
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Liu Z, Hu Z, Cai X, Liu S. SLC39A5 promotes lung adenocarcinoma cell proliferation by activating PI3K/AKT signaling. Pathol Res Pract 2021; 224:153541. [PMID: 34252710 DOI: 10.1016/j.prp.2021.153541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/01/2021] [Accepted: 07/01/2021] [Indexed: 12/13/2022]
Abstract
Lung cancer is the most common cancer and the primary cause of cancer-related deaths worldwide. Solute carrier family 39 member 5 (SLC39A5) regulates cellular zinc homeostasis and plays a vital role in several human cancers. However, the clinical significance and biological function of SLC39A5 in lung adenocarcinoma (LUAD) remain unclear. Hence, we sought to elucidate the role of SLC39A5 in LUAD pathophysiology in this study. The expression and clinical significance of SLC39A5 were evaluated using The Cancer Genome Atlas, the Gene Expression Omnibus, and tissue microarray data. We used the Cell Counting Kit-8, flow cytometry, western blotting, and quantitative reverse transcriptase-polymerase chain reaction analyses to determine the function of SLC39A5 in vitro. We also used a mouse xenograft model to evaluate the function of SLC39A5 in vivo. Our results indicate that SLC39A5 was upregulated in LUAD tissues compared with that in adjacent non-tumor lung tissues. SLC39A5 overexpression correlated with poor survival in patients with LUAD. SLC39A5 promoted LUAD cell proliferation by accelerating the G1-to-S phase transition and inhibiting apoptosis. SLC39A5 knockdown inhibited the tumorigenesis of LUAD cells in a nude mouse model of xenograft tumors. SLC39A5 promoted LUAD cell proliferation by activating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling. SLC39A5 played an oncogenic role in LUAD by activating the PI3K/AKT signaling. Hence, SLC39A5 may serve as a novel prognostic biomarker and potential therapeutic target for LUAD.
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Affiliation(s)
- Zhaohui Liu
- Department of Respiratory Medicine, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Respiratory Medicine, Chenzhou No.1 People's Hospital, Chenzhou 423000, China
| | - Zheng Hu
- Translational Medicine Institute, the First People's Hospital of Chenzhou Affiliated to University of South China, Chenzhou 432000, China
| | - Xingdong Cai
- Department of Respiratory Medicine, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Shengming Liu
- Department of Respiratory Medicine, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
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4
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Schmitt-Ulms G, Mehrabian M, Williams D, Ehsani S. The IDIP framework for assessing protein function and its application to the prion protein. Biol Rev Camb Philos Soc 2021; 96:1907-1932. [PMID: 33960099 DOI: 10.1111/brv.12731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 01/06/2023]
Abstract
The quest to determine the function of a protein can represent a profound challenge. Although this task is the mandate of countless research groups, a general framework for how it can be approached is conspicuously lacking. Moreover, even expectations for when the function of a protein can be considered to be 'known' are not well defined. In this review, we begin by introducing concepts pertinent to the challenge of protein function assignments. We then propose a framework for inferring a protein's function from four data categories: 'inheritance', 'distribution', 'interactions' and 'phenotypes' (IDIP). We document that the functions of proteins emerge at the intersection of inferences drawn from these data categories and emphasise the benefit of considering them in an evolutionary context. We then apply this approach to the cellular prion protein (PrPC ), well known for its central role in prion diseases, whose function continues to be considered elusive by many investigators. We document that available data converge on the conclusion that the function of the prion protein is to control a critical post-translational modification of the neural cell adhesion molecule in the context of epithelial-to-mesenchymal transition and related plasticity programmes. Finally, we argue that this proposed function of PrPC has already passed the test of time and is concordant with the IDIP framework in a way that other functions considered for this protein fail to achieve. We anticipate that the IDIP framework and the concepts analysed herein will aid the investigation of other proteins whose primary functional assignments have thus far been intractable.
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Affiliation(s)
- Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, M5T 0S8, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | | | - Declan Williams
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, M5T 0S8, Canada
| | - Sepehr Ehsani
- Theoretical and Philosophical Biology, Department of Philosophy, University College London, Bloomsbury, London, WC1E 6BT, U.K.,Ronin Institute for Independent Scholarship, Montclair, NJ, 07043, U.S.A
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5
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Colomar-Carando N, Meseguer A, Company-Garrido I, Jutz S, Herrera-Fernández V, Olvera A, Kiefer K, Brander C, Steinberger P, Vicente R. Zip6 Transporter Is an Essential Component of the Lymphocyte Activation Machinery. THE JOURNAL OF IMMUNOLOGY 2018; 202:441-450. [PMID: 30552163 DOI: 10.4049/jimmunol.1800689] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/13/2018] [Indexed: 11/19/2022]
Abstract
Zinc deficiency causes immune dysfunction. In T lymphocytes, hypozincemia promotes thymus atrophy, polarization imbalance, and altered cytokine production. Zinc supplementation is commonly used to boost immune function to prevent infectious diseases in at-risk populations. However, the molecular players involved in zinc homeostasis in lymphocytes are poorly understood. In this paper, we wanted to determine the identity of the transporter responsible for zinc entry into lymphocytes. First, in human Jurkat cells, we characterized the effect of zinc on proliferation and activation and found that zinc supplementation enhances activation when T lymphocytes are stimulated using anti-CD3/anti-CD28 Abs. We show that zinc entry depends on specific pathways to correctly tune the NFAT, NF-κB, and AP-1 activation cascades. Second, we used various human and murine models to characterize the zinc transporter family, Zip, during T cell activation and found that Zip6 was strongly upregulated early during activation. Therefore, we generated a Jurkat Zip6 knockout (KO) line to study how the absence of this transporter affects lymphocyte physiology. We found that although Zip6KO cells showed no altered zinc transport or proliferation under basal conditions, under activation, these KO cells showed deficient zinc transport and a drastically impaired activation program. Our work shows that zinc entry into activated lymphocytes depends on Zip6 and that this transporter is essential for the correct function of the cellular activation machinery.
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Affiliation(s)
- Natalia Colomar-Carando
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Pompeu Fabra University, 08003 Barcelona, Spain
| | - Alberto Meseguer
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Pompeu Fabra University, 08003 Barcelona, Spain
| | - Iván Company-Garrido
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Pompeu Fabra University, 08003 Barcelona, Spain
| | - Sabrina Jutz
- Division of Immune Receptors and T Cell Activation, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Víctor Herrera-Fernández
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Pompeu Fabra University, 08003 Barcelona, Spain
| | - Alex Olvera
- HIVACAT, IrsiCaixa AIDS Research Institute, Germans Trias i Pujol University Hospital, 08916 Badalona, Spain.,University of Vic and Central Catalonia, 08500 Vic, Spain; and
| | - Kerstin Kiefer
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Pompeu Fabra University, 08003 Barcelona, Spain
| | - Christian Brander
- HIVACAT, IrsiCaixa AIDS Research Institute, Germans Trias i Pujol University Hospital, 08916 Badalona, Spain.,University of Vic and Central Catalonia, 08500 Vic, Spain; and.,Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Peter Steinberger
- Division of Immune Receptors and T Cell Activation, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Rubén Vicente
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Pompeu Fabra University, 08003 Barcelona, Spain;
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6
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Bowers K, Srai SKS. The trafficking of metal ion transporters of the Zrt- and Irt-like protein family. Traffic 2018; 19:813-822. [PMID: 29952128 DOI: 10.1111/tra.12602] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/25/2018] [Accepted: 06/25/2018] [Indexed: 12/28/2022]
Abstract
Metal ion transporters of the Zrt- and Irt-like protein (ZIP, or SLC39A) family transport zinc, iron, manganese and/or cadmium across cellular membranes and into the cytosol. The 14 human ZIP family proteins are expressed in a wide variety of tissues and function in many different cellular processes. Many of these proteins (including ZIP1, 2, 3, 4, 5, 6/10, 8, 9, 11, 12, 14) are situated, at least some of the time, on the plasma membrane, where they mediate metal ion uptake into cells. Their level on the cell surface can be controlled rapidly via protein trafficking in response to the ions they transport. For example, the cell surface level of many ZIPs (including ZIP1, 3, 4, 8 and 12) is mediated by the available concentration of zinc. Zinc depletion causes a decrease in endocytosis and degradation, resulting in more ZIP on the surface to take up the essential ion. ZIP levels on the cell surface are a balance between endocytosis, recycling and degradation. We review the trafficking mechanisms of human ZIP proteins, highlighting possible targeting motifs and suggesting a model of zinc-mediated endocytic trafficking. We also provide two possible models for ZIP14 trafficking and degradation.
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Affiliation(s)
- Katherine Bowers
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
| | - Surjit K S Srai
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
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7
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Leighton PLA, Kanyo R, Neil GJ, Pollock NM, Allison WT. Prion gene paralogs are dispensable for early zebrafish development and have nonadditive roles in seizure susceptibility. J Biol Chem 2018; 293:12576-12592. [PMID: 29903907 DOI: 10.1074/jbc.ra117.001171] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 06/07/2018] [Indexed: 11/06/2022] Open
Abstract
Normally folded prion protein (PrPC) and its functions in healthy brains remain underappreciated compared with the intense study of its misfolded forms ("prions," PrPSc) during the pathobiology of prion diseases. This impedes the development of therapeutic strategies in Alzheimer's and prion diseases. Disrupting the zebrafish homologs of PrPC has provided novel insights; however, mutagenesis of the zebrafish paralog prp2 did not recapitulate previous dramatic developmental phenotypes, suggesting redundancy with the prp1 paralog. Here, we generated zebrafish prp1 loss-of-function mutant alleles and dual prp1-/-;prp2-/- mutants. Zebrafish prp1-/- and dual prp1-/-;prp2-/- mutants resemble mammalian Prnp knockouts insofar as they lack overt phenotypes, which surprisingly contrasts with reports of severe developmental phenotypes when either prp1 or prp2 is knocked down acutely. Previous studies suggest that PrPC participates in neural cell development/adhesion, including in zebrafish where loss of prp2 affects adhesion and deposition patterns of lateral line neuromasts. In contrast with the expectation that prp1's functions would be redundant to prp2, they appear to have opposing functions in lateral line neurodevelopment. Similarly, loss of prp1 blunted the seizure susceptibility phenotypes observed in prp2 mutants, contrasting the expected exacerbation of phenotypes if these prion gene paralogs were serving redundant roles. In summary, prion mutant fish lack the overt phenotypes previously predicted, and instead they have subtle phenotypes similar to mammals. No evidence was found for functional redundancy in the zebrafish prion gene paralogs, and the phenotypes observed when each gene is disrupted individually are consistent with ancient functions of prion proteins in neurodevelopment and modulation of neural activity.
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Affiliation(s)
- Patricia L A Leighton
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Richard Kanyo
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Gavin J Neil
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Niall M Pollock
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - W Ted Allison
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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8
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The function of the cellular prion protein in health and disease. Acta Neuropathol 2018; 135:159-178. [PMID: 29151170 DOI: 10.1007/s00401-017-1790-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 12/11/2022]
Abstract
The essential role of the cellular prion protein (PrPC) in prion disorders such as Creutzfeldt-Jakob disease is well documented. Moreover, evidence is accumulating that PrPC may act as a receptor for protein aggregates and transduce neurotoxic signals in more common neurodegenerative disorders, such as Alzheimer's disease. Although the pathological roles of PrPC have been thoroughly characterized, a general consensus on its physiological function within the brain has not yet been established. Knockout studies in various organisms, ranging from zebrafish to mice, have implicated PrPC in a diverse range of nervous system-related activities that include a key role in the maintenance of peripheral nerve myelination as well as a general ability to protect against neurotoxic stimuli. Thus, the function of PrPC may be multifaceted, with different cell types taking advantage of unique aspects of its biology. Deciphering the cellular function(s) of PrPC and the consequences of its absence is not simply an academic curiosity, since lowering PrPC levels in the brain is predicted to be a powerful therapeutic strategy for the treatment of prion disease. In this review, we outline the various approaches that have been employed in an effort to uncover the physiological and pathological functions of PrPC. While these studies have revealed important clues about the biology of the prion protein, the precise reason for PrPC's existence remains enigmatic.
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9
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Kambe T, Matsunaga M, Takeda TA. Understanding the Contribution of Zinc Transporters in the Function of the Early Secretory Pathway. Int J Mol Sci 2017; 18:ijms18102179. [PMID: 29048339 PMCID: PMC5666860 DOI: 10.3390/ijms18102179] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/12/2017] [Accepted: 10/15/2017] [Indexed: 01/07/2023] Open
Abstract
More than one-third of newly synthesized proteins are targeted to the early secretory pathway, which is comprised of the endoplasmic reticulum (ER), Golgi apparatus, and other intermediate compartments. The early secretory pathway plays a key role in controlling the folding, assembly, maturation, modification, trafficking, and degradation of such proteins. A considerable proportion of the secretome requires zinc as an essential factor for its structural and catalytic functions, and recent findings reveal that zinc plays a pivotal role in the function of the early secretory pathway. Hence, a disruption of zinc homeostasis and metabolism involving the early secretory pathway will lead to pathway dysregulation, resulting in various defects, including an exacerbation of homeostatic ER stress. The accumulated evidence indicates that specific members of the family of Zn transporters (ZNTs) and Zrt- and Irt-like proteins (ZIPs), which operate in the early secretory pathway, play indispensable roles in maintaining zinc homeostasis by regulating the influx and efflux of zinc. In this review, the biological functions of these transporters are discussed, focusing on recent aspects of their roles. In particular, we discuss in depth how specific ZNT transporters are employed in the activation of zinc-requiring ectoenzymes. The means by which early secretory pathway functions are controlled by zinc, mediated by specific ZNT and ZIP transporters, are also subjects of this review.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
| | - Mayu Matsunaga
- 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.
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10
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Castle AR, Gill AC. Physiological Functions of the Cellular Prion Protein. Front Mol Biosci 2017; 4:19. [PMID: 28428956 PMCID: PMC5382174 DOI: 10.3389/fmolb.2017.00019] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/22/2017] [Indexed: 01/09/2023] Open
Abstract
The prion protein, PrPC, is a small, cell-surface glycoprotein notable primarily for its critical role in pathogenesis of the neurodegenerative disorders known as prion diseases. A hallmark of prion diseases is the conversion of PrPC into an abnormally folded isoform, which provides a template for further pathogenic conversion of PrPC, allowing disease to spread from cell to cell and, in some circumstances, to transfer to a new host. In addition to the putative neurotoxicity caused by the misfolded form(s), loss of normal PrPC function could be an integral part of the neurodegenerative processes and, consequently, significant research efforts have been directed toward determining the physiological functions of PrPC. In this review, we first summarise important aspects of the biochemistry of PrPC before moving on to address the current understanding of the various proposed functions of the protein, including details of the underlying molecular mechanisms potentially involved in these functions. Over years of study, PrPC has been associated with a wide array of different cellular processes and many interacting partners have been suggested. However, recent studies have cast doubt on the previously well-established links between PrPC and processes such as stress-protection, copper homeostasis and neuronal excitability. Instead, the functions best-supported by the current literature include regulation of myelin maintenance and of processes linked to cellular differentiation, including proliferation, adhesion, and control of cell morphology. Intriguing connections have also been made between PrPC and the modulation of circadian rhythm, glucose homeostasis, immune function and cellular iron uptake, all of which warrant further investigation.
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11
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Hara T, Takeda TA, Takagishi T, Fukue K, Kambe T, Fukada T. Physiological roles of zinc transporters: molecular and genetic importance in zinc homeostasis. J Physiol Sci 2017; 67:283-301. [PMID: 28130681 PMCID: PMC10717645 DOI: 10.1007/s12576-017-0521-4] [Citation(s) in RCA: 247] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/04/2017] [Indexed: 02/07/2023]
Abstract
Zinc (Zn) is an essential trace mineral that regulates the expression and activation of biological molecules such as transcription factors, enzymes, adapters, channels, and growth factors, along with their receptors. Zn deficiency or excessive Zn absorption disrupts Zn homeostasis and affects growth, morphogenesis, and immune response, as well as neurosensory and endocrine functions. Zn levels must be adjusted properly to maintain the cellular processes and biological responses necessary for life. Zn transporters regulate Zn levels by controlling Zn influx and efflux between extracellular and intracellular compartments, thus, modulating the Zn concentration and distribution. Although the physiological functions of the Zn transporters remain to be clarified, there is growing evidence that Zn transporters are related to human diseases, and that Zn transporter-mediated Zn ion acts as a signaling factor, called "Zinc signal". Here we describe critical roles of Zn transporters in the body and their contribution at the molecular, biochemical, and genetic levels, and review recently reported disease-related mutations in the Zn transporter genes.
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Affiliation(s)
- Takafumi Hara
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
| | - Taka-Aki Takeda
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Teruhisa Takagishi
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
| | - Kazuhisa Fukue
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
| | - Toshiyuki Fukada
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan.
- Division of Pathology, Department of Oral Diagnostic Sciences, School of Dentistry, Showa University, Tokyo, Japan.
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, Japan.
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12
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Brethour D, Mehrabian M, Williams D, Wang X, Ghodrati F, Ehsani S, Rubie EA, Woodgett JR, Sevalle J, Xi Z, Rogaeva E, Schmitt-Ulms G. A ZIP6-ZIP10 heteromer controls NCAM1 phosphorylation and integration into focal adhesion complexes during epithelial-to-mesenchymal transition. Sci Rep 2017; 7:40313. [PMID: 28098160 PMCID: PMC5241876 DOI: 10.1038/srep40313] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 12/02/2016] [Indexed: 01/06/2023] Open
Abstract
The prion protein (PrP) evolved from the subbranch of ZIP metal ion transporters comprising ZIPs 5, 6 and 10, raising the prospect that the study of these ZIPs may reveal insights relevant for understanding the function of PrP. Building on data which suggested PrP and ZIP6 are critical during epithelial-to-mesenchymal transition (EMT), we investigated ZIP6 in an EMT paradigm using ZIP6 knockout cells, mass spectrometry and bioinformatic methods. Reminiscent of PrP, ZIP6 levels are five-fold upregulated during EMT and the protein forms a complex with NCAM1. ZIP6 also interacts with ZIP10 and the two ZIP transporters exhibit interdependency during their expression. ZIP6 contributes to the integration of NCAM1 in focal adhesion complexes but, unlike cells lacking PrP, ZIP6 deficiency does not abolish polysialylation of NCAM1. Instead, ZIP6 mediates phosphorylation of NCAM1 on a cluster of cytosolic acceptor sites. Substrate consensus motif features and in vitro phosphorylation data point toward GSK3 as the kinase responsible, and interface mapping experiments identified histidine-rich cytoplasmic loops within the ZIP6/ZIP10 heteromer as a novel scaffold for GSK3 binding. Our data suggests that PrP and ZIP6 inherited the ability to interact with NCAM1 from their common ZIP ancestors but have since diverged to control distinct posttranslational modifications of NCAM1.
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Affiliation(s)
- Dylan Brethour
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada.,Department of Laboratory Medicine &Pathobiology, University of Toronto, Ontario, Canada
| | - Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada.,Department of Laboratory Medicine &Pathobiology, University of Toronto, Ontario, Canada
| | - Declan Williams
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada
| | - Xinzhu Wang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada.,Department of Laboratory Medicine &Pathobiology, University of Toronto, Ontario, Canada
| | - Farinaz Ghodrati
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada.,Department of Laboratory Medicine &Pathobiology, University of Toronto, Ontario, Canada
| | - Sepehr Ehsani
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada.,Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Elizabeth A Rubie
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - James R Woodgett
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Jean Sevalle
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada
| | - Zhengrui Xi
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada
| | - Ekaterina Rogaeva
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada.,Department of Neurology, University of Toronto, Ontario, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Ontario, Canada.,Department of Laboratory Medicine &Pathobiology, University of Toronto, Ontario, Canada
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13
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Mehrabian M, Hildebrandt H, Schmitt-Ulms G. NCAM1 Polysialylation: The Prion Protein's Elusive Reason for Being? ASN Neuro 2016; 8:8/6/1759091416679074. [PMID: 27879349 PMCID: PMC5122176 DOI: 10.1177/1759091416679074] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 09/08/2016] [Accepted: 10/02/2016] [Indexed: 01/06/2023] Open
Abstract
Much confusion surrounds the physiological function of the cellular prion protein (PrPC). It is, however, anticipated that knowledge of its function will shed light on its contribution to neurodegenerative diseases and suggest ways to interfere with the cellular toxicity central to them. Consequently, efforts to elucidate its function have been all but exhaustive. Building on earlier work that uncovered the evolutionary descent of the prion founder gene from an ancestral ZIP zinc transporter, we recently investigated a possible role of PrPC in a morphogenetic program referred to as epithelial-to-mesenchymal transition (EMT). By capitalizing on PrPC knockout cell clones in a mammalian cell model of EMT and using a comparative proteomics discovery strategy, neural cell adhesion molecule-1 emerged as a protein whose upregulation during EMT was perturbed in PrPC knockout cells. Follow-up work led us to observe that PrPC regulates the polysialylation of the neural cell adhesion molecule NCAM1 in cells undergoing morphogenetic reprogramming. In addition to governing cellular migration, polysialylation modulates several other cellular plasticity programs PrPC has been phenotypically linked to. These include neurogenesis in the subventricular zone, controlled mossy fiber sprouting and trimming in the hippocampal formation, hematopoietic stem cell renewal, myelin repair and maintenance, integrity of the circadian rhythm, and glutamatergic signaling. This review revisits this body of literature and attempts to present it in light of this novel contextual framework. When approached in this manner, a coherent model of PrPC acting as a regulator of polysialylation during specific cell and tissue morphogenesis events comes into focus.
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Affiliation(s)
- Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Herbert Hildebrandt
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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14
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Singh N, Asthana A, Baksi S, Desai V, Haldar S, Hari S, Tripathi AK. The prion-ZIP connection: From cousins to partners in iron uptake. Prion 2016; 9:420-8. [PMID: 26689487 PMCID: PMC4964862 DOI: 10.1080/19336896.2015.1118602] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Converging observations from disparate lines of inquiry are beginning to clarify the cause of brain iron dyshomeostasis in sporadic Creutzfeldt-Jakob disease (sCJD), a neurodegenerative condition associated with the conversion of prion protein (PrPC), a plasma membrane glycoprotein, from α-helical to a β-sheet rich PrP-scrapie (PrPSc) isoform. Biochemical evidence indicates that PrPC facilitates cellular iron uptake by functioning as a membrane-bound ferrireductase (FR), an activity necessary for the transport of iron across biological membranes through metal transporters. An entirely different experimental approach reveals an evolutionary link between PrPC and the Zrt, Irt-like protein (ZIP) family, a group of proteins involved in the transport of zinc, iron, and manganese across the plasma membrane. Close physical proximity of PrPC with certain members of the ZIP family on the plasma membrane and increased uptake of extracellular iron by cells that co-express PrPC and ZIP14 suggest that PrPC functions as a FR partner for certain members of this family. The connection between PrPC and ZIP proteins therefore extends beyond common ancestry to that of functional cooperation. Here, we summarize evidence supporting the facilitative role of PrPC in cellular iron uptake, and implications of this activity on iron metabolism in sCJD brains.
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Affiliation(s)
- Neena Singh
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Abhishek Asthana
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Shounak Baksi
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Vilok Desai
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Swati Haldar
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Sahi Hari
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
| | - Ajai K Tripathi
- a Department of Pathology ; School of Medicine; Case Western Reserve University ; Cleveland , OH USA
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15
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Aydemir TB, Troche C, Kim J, Kim MH, Teran OY, Leeuwenburgh C, Cousins RJ. Aging amplifies multiple phenotypic defects in mice with zinc transporter Zip14 (Slc39a14) deletion. Exp Gerontol 2016; 85:88-94. [PMID: 27647172 DOI: 10.1016/j.exger.2016.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/15/2016] [Accepted: 09/14/2016] [Indexed: 12/17/2022]
Abstract
Inflammation and zinc dyshomeostasis are two common hallmarks of aging. A major zinc transporter ZIP14 (slc39a14) is upregulated by proinflammatory stimuli, e.g. interleukin-6. We have evaluated the influence of age on the Zip14 KO phenotype using wild-type (WT) and Zip14 knockout (KO) mice. Aging produced a major increase in serum IL-6 concentrations that was dramatically augmented in the Zip14 KO mice. In keeping with enhanced serum IL-6 concentrations, aging produced tissue-specific increases in zinc concentration of skeletal muscle and white adipose tissue. Metabolic endotoxemia produced by Zip14 ablation is maintained in aged KO mice. Muscle non-heme iron (NHI) was increased in aged WT mice but not in aged Zip14 KO mice demonstrating NHI uptake by muscle is ZIP14-dependent and increases with age. NF-κB and STAT3 activation was greater in aged mice, but was tissue specific and inversely related to tissue zinc. Micro-CT analysis revealed that Zip14 KO mice had markedly reduced trabecular bone that was greatly amplified with aging. These results demonstrate that the inflammation-responsive zinc transporter ZIP14 has phenotypic effects that are amplified with aging.
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Affiliation(s)
- Tolunay Beker Aydemir
- Food Science and Human Nutrition Department, Center for Nutritional Sciences, College of Agriculture and Life Sciences, University of Florida, Gainesville, FL, United States
| | - Catalina Troche
- Food Science and Human Nutrition Department, Center for Nutritional Sciences, College of Agriculture and Life Sciences, University of Florida, Gainesville, FL, United States
| | - Jinhee Kim
- Food Science and Human Nutrition Department, Center for Nutritional Sciences, College of Agriculture and Life Sciences, University of Florida, Gainesville, FL, United States
| | - Min-Hyun Kim
- Food Science and Human Nutrition Department, Center for Nutritional Sciences, College of Agriculture and Life Sciences, University of Florida, Gainesville, FL, United States
| | - Oriana Y Teran
- Food Science and Human Nutrition Department, Center for Nutritional Sciences, College of Agriculture and Life Sciences, University of Florida, Gainesville, FL, United States
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, FL, United States; Institute on Aging, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Robert J Cousins
- Food Science and Human Nutrition Department, Center for Nutritional Sciences, College of Agriculture and Life Sciences, University of Florida, Gainesville, FL, United States.
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16
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Mehrabian M, Brethour D, Williams D, Wang H, Arnould H, Schneider B, Schmitt-Ulms G. Prion Protein Deficiency Causes Diverse Proteome Shifts in Cell Models That Escape Detection in Brain Tissue. PLoS One 2016; 11:e0156779. [PMID: 27327609 PMCID: PMC4915660 DOI: 10.1371/journal.pone.0156779] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/19/2016] [Indexed: 12/13/2022] Open
Abstract
A popular method for studying the function of a given protein is to generate and characterize a suitable model deficient for its expression. For the prion protein (PrP), best known for its role in several invariably fatal neurodegenerative diseases, a natural choice, therefore, would be to undertake such studies with brain samples. We recently documented the surprising observation that PrP deficiency caused a loss or enhancement of NCAM1 polysialylation, dependent on the cell model used. To identify possible causes for this disparity, we set out to systematically investigate the consequence of PrP deficiency on the global proteome in brain tissue and in four distinct cell models. Here we report that PrP deficiency causes robust but surprisingly divergent changes to the global proteomes of cell models but has no discernible impact on the global brain proteome. Amongst >1,500 proteins whose levels were compared in wild-type and PrP-deficient models, members of the MARCKS protein family exhibited pronounced, yet cell model-dependent changes to their steady-state levels. Follow-up experiments revealed that PrP collaborates with members of the MARCKS protein family in its control of NCAM1 polysialylation. We conclude that the physiological function of PrP may be masked in analyses of complex brain samples but its cell-type specific influence on a lipid raft-based NCAM1-related cell biology comes to the fore in investigations of specific cell types.
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Affiliation(s)
- Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Departments of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Canada
| | - Dylan Brethour
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Departments of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Canada
| | - Declan Williams
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Departments of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Canada
| | - Hansen Wang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
| | - Hélène Arnould
- French Institute of Health and Medical Research (INSERM), Paris, France, and University Paris Descartes, Paris, France
| | - Benoit Schneider
- French Institute of Health and Medical Research (INSERM), Paris, France, and University Paris Descartes, Paris, France
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Canada
- Departments of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Canada
- * E-mail:
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17
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Zinc transporter ZIP10 forms a heteromer with ZIP6 which regulates embryonic development and cell migration. Biochem J 2016; 473:2531-44. [PMID: 27274087 PMCID: PMC4980808 DOI: 10.1042/bcj20160388] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 06/06/2016] [Indexed: 12/18/2022]
Abstract
Zinc is involved in cell migration during embryo development and in cancer. We show that a zinc transporter consisting of two proteins, ZIP6 and ZIP10, stimulates both cell migration and division in mammalian cells and in the zebrafish embryo. There is growing evidence that zinc and its transporters are involved in cell migration during development and in cancer. In the present study, we show that zinc transporter ZIP10 (SLC39A10) stimulates cell motility and proliferation, both in mammalian cells and in the zebrafish embryo. This is associated with inactivation of GSK (glycogen synthase kinase)-3α and -3β and down-regulation of E-cadherin (CDH1). Morpholino-mediated knockdown of zip10 causes delayed epiboly and deformities of the head, eye, heart and tail. Furthermore, zip10 deficiency results in overexpression of cdh1, zip6 and stat3, the latter gene product driving transcription of both zip6 and zip10. The non-redundant requirement of Zip6 and Zip10 for epithelial to mesenchymal transition (EMT) is consistent with our finding that they exist as a heteromer. We postulate that a subset of ZIPs carrying prion protein (PrP)-like ectodomains, including ZIP6 and ZIP10, are integral to cellular pathways and plasticity programmes, such as EMT.
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18
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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] [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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19
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Pass R, Frudd K, Barnett JP, Blindauer CA, Brown DR. Prion infection in cells is abolished by a mutated manganese transporter but shows no relation to zinc. Mol Cell Neurosci 2015; 68:186-93. [PMID: 26253862 DOI: 10.1016/j.mcn.2015.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 07/27/2015] [Accepted: 08/03/2015] [Indexed: 10/23/2022] Open
Abstract
The cellular prion protein has been identified as a metalloprotein that binds copper. There have been some suggestions that prion protein also influences zinc and manganese homeostasis. In this study we used a series of cell lines to study the levels of zinc and manganese under different conditions. We overexpressed either the prion protein or known transporters for zinc and manganese to determine relations between the prion protein and both manganese and zinc homeostasis. Our observations supported neither a link between the prion protein and zinc metabolism nor any effect of altered zinc levels on prion protein expression or cellular infection with prions. In contrast we found that a gain of function mutant of a manganese transporter caused reduction of manganese levels in prion infected cells, loss of observable PrP(Sc) in cells and resistance to prion infection. These studies strengthen the link between manganese and prion disease.
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Affiliation(s)
- Rachel Pass
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Karen Frudd
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - James P Barnett
- Department of Chemistry, University of Warwick, Coventry, UK
| | | | - David R Brown
- Department of Biology and Biochemistry, University of Bath, Bath, UK.
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20
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Kambe T, Tsuji T, Hashimoto A, Itsumura N. The Physiological, Biochemical, and Molecular Roles of Zinc Transporters in Zinc Homeostasis and Metabolism. Physiol Rev 2015; 95:749-84. [DOI: 10.1152/physrev.00035.2014] [Citation(s) in RCA: 556] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Zinc is involved in a variety of biological processes, as a structural, catalytic, and intracellular and intercellular signaling component. Thus zinc homeostasis is tightly controlled at the whole body, tissue, cellular, and subcellular levels by a number of proteins, with zinc transporters being particularly important. In metazoan, two zinc transporter families, Zn transporters (ZnT) and Zrt-, Irt-related proteins (ZIP) function in zinc mobilization of influx, efflux, and compartmentalization/sequestration across biological membranes. During the last two decades, significant progress has been made in understanding the molecular properties, expression, regulation, and cellular and physiological roles of ZnT and ZIP transporters, which underpin the multifarious functions of zinc. Moreover, growing evidence indicates that malfunctioning zinc homeostasis due to zinc transporter dysfunction results in the onset and progression of a variety of diseases. This review summarizes current progress in our understanding of each ZnT and ZIP transporter from the perspective of zinc physiology and pathogenesis, discussing challenging issues in their structure and zinc transport mechanisms.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tokuji Tsuji
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Ayako Hashimoto
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Naoya Itsumura
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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21
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Tripathi AK, Haldar S, Qian J, Beserra A, Suda S, Singh A, Hopfer U, Chen SG, Garrick MD, Turner JR, Knutson MD, Singh N. Prion protein functions as a ferrireductase partner for ZIP14 and DMT1. Free Radic Biol Med 2015; 84:322-330. [PMID: 25862412 PMCID: PMC4476631 DOI: 10.1016/j.freeradbiomed.2015.03.037] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 03/30/2015] [Accepted: 03/30/2015] [Indexed: 12/21/2022]
Abstract
Excess circulating iron is stored in the liver, and requires reduction of non-Tf-bound iron (NTBI) and transferrin (Tf) iron at the plasma membrane and endosomes, respectively, by ferrireductase (FR) proteins for transport across biological membranes through divalent metal transporters. Here, we report that prion protein (PrP(C)), a ubiquitously expressed glycoprotein most abundant on neuronal cells, functions as a FR partner for divalent-metal transporter-1 (DMT1) and ZIP14. Thus, absence of PrP(C) in PrP-knock-out (PrP(-/-)) mice resulted in markedly reduced liver iron stores, a deficiency that was not corrected by chronic or acute administration of iron by the oral or intraperitoneal routes. Likewise, preferential radiolabeling of circulating NTBI with (59)Fe revealed significantly reduced uptake and storage of NTBI by the liver of PrP(-/-) mice relative to matched PrP(+/+) controls. However, uptake, storage, and utilization of ferritin-bound iron that does not require reduction for uptake were increased in PrP(-/-) mice, indicating a compensatory response to the iron deficiency. Expression of exogenous PrP(C) in HepG2 cells increased uptake and storage of ferric iron (Fe(3+)), not ferrous iron (Fe(2+)), from the medium, supporting the function of PrP(C) as a plasma membrane FR. Coexpression of PrP(C) with ZIP14 and DMT1 in HepG2 cells increased uptake of Fe(3+) significantly, and surprisingly, increased the ratio of N-terminally truncated PrP(C) forms lacking the FR domain relative to full-length PrP(C). Together, these observations indicate that PrP(C) promotes, and possibly regulates, the uptake of NTBI through DMT1 and Zip14 via its FR activity. Implications of these observations for neuronal iron homeostasis under physiological and pathological conditions are discussed.
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Affiliation(s)
- Ajai K. Tripathi
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Swati Haldar
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Juan Qian
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Amber Beserra
- School of Arts and Sciences, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Srinivas Suda
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Ajay Singh
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Ulrich Hopfer
- Department of physiology and Biophysics, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | - Shu G. Chen
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
| | | | | | | | - Neena Singh
- Department of Pathology, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, Ohio, USA
- To whom correspondence should be addressed: Neena Singh, Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, Ohio 44106, USA. Tel: 216-368-2617;
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22
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Blindauer CA. Advances in the molecular understanding of biological zinc transport. Chem Commun (Camb) 2015; 51:4544-63. [DOI: 10.1039/c4cc10174j] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recognition of the importance of zinc homeostasis for health has driven a surge in structural data on major zinc-transporting proteins.
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23
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Acevedo-Morantes CY, Wille H. The structure of human prions: from biology to structural models-considerations and pitfalls. Viruses 2014; 6:3875-92. [PMID: 25333467 PMCID: PMC4213568 DOI: 10.3390/v6103875] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 12/27/2022] Open
Abstract
Prion diseases are a family of transmissible, progressive, and uniformly fatal neurodegenerative disorders that affect humans and animals. Although cross-species transmissions of prions are usually limited by an apparent “species barrier”, the spread ofa prion disease to humans by ingestion of contaminated food, or via other routes of exposure, indicates that animal prions can pose a significant public health risk. The infectious agent responsible for the transmission of prion diseases is a misfolded conformer of the prion protein, PrPSc, a pathogenic isoform of the host-encoded, cellular prion protein,PrPC. The detailed mechanisms of prion conversion and replication, as well as the high-resolution structure of PrPSc, are unknown. This review will discuss the general background related to prion biology and assess the structural models proposed to date,while highlighting the experimental challenges of elucidating the structure of PrPSc.
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Affiliation(s)
- Claudia Y Acevedo-Morantes
- Department of Biochemistry and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada.
| | - Holger Wille
- Department of Biochemistry and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2M8, Canada.
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24
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Abstract
Zinc, the most abundant trace metal in the brain, has numerous functions in health and disease. It is released into the synaptic cleft alongside glutamate and this connection between zinc and glutamatergic neurotransmission allows the ion to modulate overall excitability of the brain and influence synaptic plasticity. To maintain healthy synapses, extracellular zinc levels need to be tightly regulated. We recently reported that the cellular prion protein (PrP (C) ) can directly influence neuronal zinc concentrations by promoting zinc uptake via AMPA receptors. The octapeptide repeat region of PrP (C) is involved in zinc sensing or scavenging and the AMPA receptor provides the channel for transport of the metal across the membrane, facilitated by a direct interaction between the N-terminal polybasic region of PrP (C) and AMPA receptors. PrP (C) has been evolutionarily linked to the Zrt/Irt-like protein (ZIP) metal ion transport family with the C-terminus of PrP (C) sharing sequence similarities with the N-terminal extracellular domains of ZIP 5, 6 and 10. By incorporating the properties of ZIP transporters (both zinc sensing and zinc transport) into two existing neuronal proteins, (PrP (C) as zinc sensor, AMPA receptor as zinc transporter), neuronal cells are enhancing their biological efficiency and functionality.
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Affiliation(s)
- Nicole T Watt
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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25
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Fleisch VC, Leighton PLA, Wang H, Pillay LM, Ritzel RG, Bhinder G, Roy B, Tierney KB, Ali DW, Waskiewicz AJ, Allison WT. Targeted mutation of the gene encoding prion protein in zebrafish reveals a conserved role in neuron excitability. Neurobiol Dis 2013; 55:11-25. [PMID: 23523635 DOI: 10.1016/j.nbd.2013.03.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 02/08/2013] [Accepted: 03/13/2013] [Indexed: 01/09/2023] Open
Abstract
The function of the cellular prion protein (PrP(C)) in healthy brains remains poorly understood, in part because Prnp knockout mice are viable. On the other hand, transient knockdown of Prnp homologs in zebrafish (including two paralogs, prp1 and prp2) has suggested that PrP(C) is required for CNS development, cell adhesion, and neuroprotection. It has been argued that zebrafish Prp2 is most similar to mammalian PrP(C), yet it has remained intransigent to the most thorough confirmations of reagent specificity during knockdown. Thus we investigated the role of prp2 using targeted gene disruption via zinc finger nucleases. Prp2(-/-) zebrafish were viable and did not display overt developmental phenotypes. Back-crossing female prp2(-/-) fish ruled out a role for maternal mRNA contributions. Prp2(-/-) larvae were found to have increased seizure-like behavior following exposure to the convulsant pentylenetetrazol (PTZ), as compared to wild type fish. In situ recordings from intact hindbrains demonstrated that prp2 regulates closing of N-Methyl-d-aspartate (NMDA) receptors, concomitant with neuroprotection during glutamate excitotoxicity. Overall, the knockout of Prp2 function in zebrafish independently confirmed hypothesized roles for PrP, identifying deeply conserved functions in post-developmental regulation of neuron excitability that are consequential to the etiology of prion and Alzheimer diseases.
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Affiliation(s)
- Valerie C Fleisch
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
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26
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Abstract
The vast knowledge of the physiologic functions of zinc in at least 3000 proteins and the recent recognition of fundamental regulatory functions of zinc(II) ions released from cells or within cells links this nutritionally essential metal ion to numerous diseases. However, this knowledge so far has had remarkably limited impact on diagnosing, preventing, and treating human diseases. One major roadblock is a lack of suitable biomarkers that would detect changes in cellular zinc metabolism and relate them to specific disease outcomes. It is not only the right amount of zinc in the diet that maintains health. At least as important is the proper functioning of the dozens of proteins that control cellular zinc homeostasis, regulate intracellular traffic of zinc between the cytosol and vesicles/organelles, and determine the fluctuations of signaling zinc(II) ions. Cellular zinc deficiencies or overloads, a term referring to zinc concentrations exceeding the cellular zinc buffering capacity, compromise the redox balance. Zinc supplementation may not readily remedy zinc deficiency if other factors limit the capability of a cell to control zinc. The role of zinc in human diseases requires a general understanding of the wide spectrum of functions of zinc, how zinc is controlled, how it interacts with the metabolism of other metal ions, in particular copper and iron, and how perturbation of specific zinc-dependent molecular processes causes disease and influences the progression of disease.
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27
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Ehsani S, Salehzadeh A, Huo H, Reginold W, Pocanschi CL, Ren H, Wang H, So K, Sato C, Mehrabian M, Strome R, Trimble WS, Hazrati LN, Rogaeva E, Westaway D, Carlson GA, Schmitt-Ulms G. LIV-1 ZIP ectodomain shedding in prion-infected mice resembles cellular response to transition metal starvation. J Mol Biol 2012; 422:556-574. [PMID: 22687393 DOI: 10.1016/j.jmb.2012.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 05/22/2012] [Accepted: 06/01/2012] [Indexed: 10/28/2022]
Abstract
We recently documented the co-purification of members of the LIV-1 subfamily of ZIP (Zrt-, Irt-like Protein) zinc transporters (LZTs) with the cellular prion protein (PrP(C)) and, subsequently, established that the prion gene family descended from an ancestral LZT gene. Here, we begin to address whether the study of LZTs can shed light on the biology of prion proteins in health and disease. Starting from an observation of an abnormal LZT immunoreactive band in prion-infected mice, subsequent cell biological analyses uncovered a surprisingly coordinated biology of ZIP10 (an LZT member) and prion proteins that involves alterations to N-glycosylation and endoproteolysis in response to manipulations to the extracellular divalent cation milieu. Starving cells of manganese or zinc, but not copper, causes shedding of the N1 fragment of PrP(C) and of the ectodomain of ZIP10. For ZIP10, this posttranslational biology is influenced by an interaction between its PrP-like ectodomain and a conserved metal coordination site within its C-terminal multi-spanning transmembrane domain. The transition metal starvation-induced cleavage of ZIP10 can be differentiated by an immature N-glycosylation signature from a constitutive cleavage targeting the same site. Data from this work provide a first glimpse into a hitherto neglected molecular biology that ties PrP to its LZT cousins and suggest that manganese or zinc starvation may contribute to the etiology of prion disease in mice.
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Affiliation(s)
- Sepehr Ehsani
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Ashkan Salehzadeh
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Hairu Huo
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2
| | - William Reginold
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Cosmin L Pocanschi
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2
| | - Hezhen Ren
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Hansen Wang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2
| | - Kelvin So
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2
| | - Christine Sato
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2
| | - Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Robert Strome
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2
| | - William S Trimble
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON, Canada M5G 1X8
| | - Lili-Naz Hazrati
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Ekaterina Rogaeva
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2.,Department of Medicine, University of Toronto, Toronto, ON, Canada M5G 2C4
| | - David Westaway
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada T6G 2M8
| | | | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada M5S 3H2.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada M5S 1A8
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Abstract
The evolutionary origins of vertebrate prion genes had remained elusive until recently when multiple lines of evidence converged to the proposition that members of the prion gene family represent an ancient branch of a larger family of ZIP metal ion transporters. (1) A follow-up investigation which explored the mechanism of evolution in more detail led to the surprising conclusion that the emergence of the prion founder gene likely involved the reverse transcription of a spliced transcript of a LIV-1 ZIP predecessor gene. (2) The objective of this perspective is to discuss the possible significance of this reunion of ZIP and prion gene subfamilies for understanding the biology of the prion protein in health and disease. While a recent review article broadly introduced this area of research, (3) the emphasis here is to comment on some of the more pertinent concepts, experimental paradigms, ongoing developments and challenges.
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Affiliation(s)
- Sepehr Ehsani
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON Canada
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Ehsani S, Tao R, Pocanschi CL, Ren H, Harrison PM, Schmitt-Ulms G. Evidence for retrogene origins of the prion gene family. PLoS One 2011; 6:e26800. [PMID: 22046361 PMCID: PMC3203146 DOI: 10.1371/journal.pone.0026800] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/03/2011] [Indexed: 11/29/2022] Open
Abstract
The evolutionary origin of prion genes, only known to exist in the vertebrate lineage, had remained elusive until recently. Following a lead from interactome investigations of the murine prion protein, our previous bioinformatic analyses revealed the evolutionary descent of prion genes from an ancestral ZIP metal ion transporter. However, the molecular mechanism of evolution remained unexplored. Here we present a computational investigation of this question based on sequence, intron-exon, synteny and pseudogene analyses. Our data suggest that during the emergence of metazoa, a cysteine-flanked core domain was modularly inserted, or arose de novo, in a preexisting ZIP ancestor gene to generate a prion-like ectodomain in a subbranch of ZIP genes. Approximately a half-billion years later, a genomic insertion of a spliced transcript coding for such a prion-like ZIP ectodomain may have created the prion founder gene. We document that similar genomic insertions involving ZIP transcripts, and probably relying on retropositional elements, have indeed occurred more than once throughout evolution.
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Affiliation(s)
- Sepehr Ehsani
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Renzhu Tao
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Cosmin L. Pocanschi
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Hezhen Ren
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Paul M. Harrison
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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Lichten LA, Ryu MS, Guo L, Embury J, Cousins RJ. MTF-1-mediated repression of the zinc transporter Zip10 is alleviated by zinc restriction. PLoS One 2011; 6:e21526. [PMID: 21738690 PMCID: PMC3124522 DOI: 10.1371/journal.pone.0021526] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 06/01/2011] [Indexed: 12/11/2022] Open
Abstract
The regulation of cellular zinc uptake is a key process in the overall mechanism governing mammalian zinc homeostasis and how zinc participates in cellular functions. We analyzed the zinc transporters of the Zip family in both the brain and liver of zinc-deficient animals and found a large, significant increase in Zip10 expression. Additionally, Zip10 expression decreased in response to zinc repletion. Moreover, isolated mouse hepatocytes, AML12 hepatocytes, and Neuro 2A cells also respond differentially to zinc availability in vitro. Measurement of Zip10 hnRNA and actinomycin D inhibition studies indicate that Zip10 was transcriptionally regulated by zinc deficiency. Through luciferase promoter constructs and ChIP analysis, binding of MTF-1 to a metal response element located 17 bp downstream of the transcription start site was shown to be necessary for zinc-induced repression of Zip10. Furthermore, zinc-activated MTF-1 causes down-regulation of Zip10 transcription by physically blocking Pol II movement through the gene. Lastly, ZIP10 is localized to the plasma membrane of hepatocytes and neuro 2A cells. Collectively, these results reveal a novel repressive role for MTF-1 in the regulation of the Zip10 zinc transporter expression by pausing Pol II transcription. ZIP10 may have roles in control of zinc homeostasis in specific sites particularly those of the brain and liver. Within that context ZIP10 may act as an important survival mechanism during periods of zinc inadequacy.
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Affiliation(s)
- Louis A. Lichten
- Center for Nutritional Sciences, Food Science and Human Nutrition Department, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Moon-Suhn Ryu
- Center for Nutritional Sciences, Food Science and Human Nutrition Department, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Liang Guo
- Center for Nutritional Sciences, Food Science and Human Nutrition Department, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Jennifer Embury
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Robert J. Cousins
- Center for Nutritional Sciences, Food Science and Human Nutrition Department, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida, United States of America
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
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Westaway D, Daude N, Wohlgemuth S, Harrison P. The PrP-Like Proteins Shadoo and Doppel. Top Curr Chem (Cham) 2011; 305:225-56. [DOI: 10.1007/128_2011_190] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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