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Abstract
T cell activation is initiated by the recognition of specific antigenic peptides and subsequently accomplished by complex signaling cascades. These aspects have been extensively studied for decades as pivotal factors in the establishment of adaptive immunity. However, how receptors or signaling molecules are organized in the resting state prior to encountering antigens has received less attention. Recent advancements in super-resolution microscopy techniques have revealed topographically controlled pre-formed organization of key molecules involved in antigen recognition and signal transduction on microvillar projections of T cells before activation and substantial effort has been dedicated to characterizing the topological structure of resting T cells over the past decade. This review will summarize our current understanding of how key surface receptors are pre-organized on the T-cell plasma membrane and discuss the potential role of these receptors, which are preassembled prior to ligand binding in the early activation events of T cells.
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Affiliation(s)
- Yunmin Jung
- Department of Nano-Biomedical Engineering, Advanced Science Institute, Yonsei University, Seoul, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science, Seoul, Republic of Korea
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2
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Tonks NK. Protein Tyrosine Phosphatases: Mighty oaks from little acorns grow. IUBMB Life 2023; 75:337-352. [PMID: 36971473 PMCID: PMC10254075 DOI: 10.1002/iub.2716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 02/23/2023] [Indexed: 03/29/2023]
Abstract
In October 2020, we were finally able to gather for a celebration of Eddy Fischer's 100th birthday. As with many other events, COVID had disrupted and restricted preparations for the gathering, which ultimately was held via ZOOM. Nevertheless, it was a wonderful opportunity to share a day with Eddy, an exceptional scientist and true renaissance man, and to appreciate his stellar contributions to science. Eddy Fischer, together with Ed Krebs, was responsible for the discovery of reversible protein phosphorylation, which launched the entire field of signal transduction. The importance of this seminal work is now being felt throughout the biotechnology industry with the development of drugs that target protein kinases, which have transformed the treatment of a wide array of cancers. I was privileged to have worked with Eddy both as a postdoc and a junior faculty member, during which time we laid the foundations for our current understanding of the protein tyrosine phosphatase (PTP) family of enzymes and their importance as critical regulators of signal transduction. This tribute to Eddy is based upon the talk I presented at the event, giving a personal perspective on Eddy's influence on my career, our early research efforts together in this area, and how the field has developed since then.
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Affiliation(s)
- Nicholas K Tonks
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
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3
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Cohen P. The scientific career and life of Edmond H. Fischer-A personal tribute. IUBMB Life 2023; 75:284-288. [PMID: 36480402 DOI: 10.1002/iub.2695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 11/14/2022] [Indexed: 12/13/2022]
Affiliation(s)
- Philip Cohen
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
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4
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Anmol K, Akanksha H, Zhengguo X. Are CD45RO+ and CD45RA- genuine markers for bovine memory T cells? ANIMAL DISEASES 2022. [DOI: 10.1186/s44149-022-00057-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
AbstractEffective vaccination induces memory T cells, which protect the host against pathogen re-infections. Therefore, detection of memory T cells is essential for evaluating vaccine efficacy, which was originally dependent on cytokine induction assays. Currently, two isoforms of CD45 tyrosine phosphatase, CD45RO expression and CD45RA exclusion (CD45RO+/ CD45RA-) are used extensively for detecting memory T cells in cattle. The CD45RO+/CD45RA- markers were first established in humans around three decades ago, and were adopted in cattle soon after. However, in the last two decades, some published data in humans have challenged the initial paradigm, and required multiple markers for identifying memory T cells. On the contrary, memory T cell detection in cattle still mostly relies on CD45RO+/CD45RA- despite some controversial evidence. In this review, we summarized the current literature to examine if CD45RO+/CD45RA- are valid markers for detecting memory T cells in cattle. It seems CD45RA and CD45RO (CD45RA/RO) as markers for identifying bovine memory T cells are questionable.
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5
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Differential Expression of CD45RO and CD45RA in Bovine T Cells. Cells 2022; 11:cells11111844. [PMID: 35681539 PMCID: PMC9180881 DOI: 10.3390/cells11111844] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/28/2022] [Accepted: 06/02/2022] [Indexed: 01/06/2023] Open
Abstract
Effective vaccination induces immune memory to protect animals upon pathogen re-encounter. Despite contradictory reports, bovine memory T cells are identified based on two isoforms of CD45, expression of CD45RO plus exclusion of CD45RA. In this report, we contrasted CD45RA/RO expression on circulatory T cells with IFNγ and IL4 expression induced by a conventional method. To our surprise, 20% of cattle from an enclosed herd did not express CD45RO on T cells without any significant difference on CD45RA expression and IFNγ or IL4 induction. In CD45RO expressing cattle, CD45RA and CD45RO expressions excluded each other, with dominant CD45RO (>90%) expression on gamma delta (γδ) followed by CD4+ (60%) but significantly higher CD45RA expression on CD8+ T cells (about 80%). Importantly, more than 80% of CD45RO expressing CD4+ and CD8+ T cells failed to produce IFNγ and IL-4; however, within the cytokine inducing cells, CD4+ T cells highly expressed CD45RO but those within CD8+ T cells mostly expressed CD45RA. Hence, CD45RO is not ubiquitously expressed in cattle, and rather than with memory phenotype, CD45RA/RO expression are more associated with distinct T cell subtypes.
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6
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Protein tyrosine phosphatases in skeletal development and diseases. Bone Res 2022; 10:10. [PMID: 35091552 PMCID: PMC8799702 DOI: 10.1038/s41413-021-00181-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/29/2021] [Accepted: 09/14/2021] [Indexed: 12/24/2022] Open
Abstract
Skeletal development and homeostasis in mammals are modulated by finely coordinated processes of migration, proliferation, differentiation, and death of skeletogenic cells originating from the mesoderm and neural crest. Numerous molecular mechanisms are involved in these regulatory processes, one of which is protein posttranslational modifications, particularly protein tyrosine phosphorylation (PYP). PYP occurs mainly through the action of protein tyrosine kinases (PTKs), modifying protein enzymatic activity, changing its cellular localization, and aiding in the assembly or disassembly of protein signaling complexes. Under physiological conditions, PYP is balanced by the coordinated action of PTKs and protein tyrosine phosphatases (PTPs). Dysregulation of PYP can cause genetic, metabolic, developmental, and oncogenic skeletal diseases. Although PYP is a reversible biochemical process, in contrast to PTKs, little is known about how this equilibrium is modulated by PTPs in the skeletal system. Whole-genome sequencing has revealed a large and diverse superfamily of PTP genes (over 100 members) in humans, which can be further divided into cysteine (Cys)-, aspartic acid (Asp)-, and histidine (His)-based PTPs. Here, we review current knowledge about the functions and regulatory mechanisms of 28 PTPs involved in skeletal development and diseases; 27 of them belong to class I and II Cys-based PTPs, and the other is an Asp-based PTP. Recent progress in analyzing animal models that harbor various mutations in these PTPs and future research directions are also discussed. Our literature review indicates that PTPs are as crucial as PTKs in supporting skeletal development and homeostasis.
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7
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Jung Y, Wen L, Altman A, Ley K. CD45 pre-exclusion from the tips of T cell microvilli prior to antigen recognition. Nat Commun 2021; 12:3872. [PMID: 34162836 PMCID: PMC8222282 DOI: 10.1038/s41467-021-23792-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 05/11/2021] [Indexed: 12/18/2022] Open
Abstract
The tyrosine phosphatase CD45 is a major gatekeeper for restraining T cell activation. Its exclusion from the immunological synapse (IS) is crucial for T cell receptor (TCR) signal transduction. Here, we use expansion super-resolution microscopy to reveal that CD45 is mostly pre-excluded from the tips of microvilli (MV) on primary T cells prior to antigen encounter. This pre-exclusion is diminished by depleting cholesterol or by engineering the transmembrane domain of CD45 to increase its membrane integration length, but is independent of the CD45 extracellular domain. We further show that brief MV-mediated contacts can induce Ca2+ influx in mouse antigen-specific T cells engaged by antigen-pulsed antigen presenting cells (APC). We propose that the scarcity of CD45 phosphatase activity at the tips of MV enables or facilitates TCR triggering from brief T cell-APC contacts before formation of a stable IS, and that these MV-mediated contacts represent the earliest step in the initiation of a T cell adaptive immune response.
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Affiliation(s)
- Yunmin Jung
- Center for Autoimmunity and Inflammation, La Jolla Institute for Immunology, La Jolla, CA, USA.
| | - Lai Wen
- Center for Autoimmunity and Inflammation, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Amnon Altman
- Center for Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Klaus Ley
- Center for Autoimmunity and Inflammation, La Jolla Institute for Immunology, La Jolla, CA, USA
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
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8
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Sevillano J, Sánchez-Alonso MG, Pizarro-Delgado J, Ramos-Álvarez MDP. Role of Receptor Protein Tyrosine Phosphatases (RPTPs) in Insulin Signaling and Secretion. Int J Mol Sci 2021; 22:ijms22115812. [PMID: 34071721 PMCID: PMC8198922 DOI: 10.3390/ijms22115812] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 01/12/2023] Open
Abstract
Changes in lifestyle in developed countries have triggered the prevalence of obesity and type 2 diabetes mellitus (T2DM) in the latest years. Consequently, these metabolic diseases associated to insulin resistance, and the morbidity associated with them, accounts for enormous costs for the health systems. The best way to face this problem is to identify potential therapeutic targets and/or early biomarkers to help in the treatment and in the early detection. In the insulin receptor signaling cascade, the activities of protein tyrosine kinases and phosphatases are coordinated, thus, protein tyrosine kinases amplify the insulin signaling response, whereas phosphatases are required for the regulation of the rate and duration of that response. The focus of this review is to summarize the impact of transmembrane receptor protein tyrosine phosphatase (RPTPs) in the insulin signaling cascade and secretion, and their implication in metabolic diseases such as obesity and T2DM.
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Senis YA, Nagy Z, Mori J, Lane S, Lane P. Platelet Src family kinases: A tale of reversible phosphorylation. Res Pract Thromb Haemost 2021; 5:376-389. [PMID: 33870023 PMCID: PMC8035799 DOI: 10.1002/rth2.12495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 11/07/2022] Open
Abstract
Sarcoma (Src) family kinases (SFKs) have occupied a central place in platelet research for over 40 years. Discovered by virologists and oncologists as the proto proto-oncogene, Src tyrosine kinase spurred a phenomenal burst of research on reversible tyrosine phosphorylation and signal transduction. For a time, platelets were adopted as the model of choice for studying the biological functions of Src, owing to their ease of isolation, high Src expression, and lack of a nucleus, only to be abandoned due to challenges of culturing and manipulating using common molecular biology-based techniques. For platelet biologists, SFKs have remained an important area of investigation, initiating and amplifying signals from all major adhesion, activation, and inhibitory receptors, including the integrin αIIbβ3, the collagen receptor complex glycoprotein VI-Fc receptor γ-chain, the G protein-coupled ADP receptor P2Y12 and the inhibitory receptors platelet endothelial cell adhesion molecule-1 and G6b-B. The vital roles of SFKs in platelets is highlighted by the severe phenotypes of null and gain-of-function mutations in SFKs in mice and humans, and effects of pharmacologic inhibitors on platelet activation, thrombosis, and hemostasis. The recent description of critical regulators of SFKs in platelets, namely, C-terminal Src kinase (Csk), Csk homologous kinase (Chk), the receptor-type protein-tyrosine phosphatase receptor type J (PTPRJ) helps explain some of the bleeding side effects of tyrosine kinase inhibitors and are novel therapeutic targets for regulating the thrombotic and hemostatic capacity of platelets. Recent findings from Chk, Csk, and PTPRJ knockout mouse models highlighted that SFKs are able to autoinhibit by phosphorylating their C-terminal tyrosine residues, providing fundamental insights into SFK autoregulation.
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Affiliation(s)
- Yotis A Senis
- Unité Mixte de Recherche-S 1255 Fédération de Médecine Translationnelle de Strasbourg Université de Strasbourg Institut National de la Santé et de la Recherche Médicale Etablissement Français du Sang Grand Est Strasbourg France
| | - Zoltan Nagy
- Institute of Experimental Biomedicine University Hospital and Rudolf Virchow Center University of Würzburg Würzburg Germany
| | - Jun Mori
- Research and Development Align Technology Inc. Yokohama Japan
| | - Sophia Lane
- Illustration and Design, ScEYEnce Studios Elkins Park PA USA
| | - Patrick Lane
- Illustration and Design, ScEYEnce Studios Elkins Park PA USA
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10
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Ash NF, Massengill MT, Harmer L, Jafri A, Lewin AS. Automated segmentation and analysis of retinal microglia within ImageJ. Exp Eye Res 2020; 203:108416. [PMID: 33359513 DOI: 10.1016/j.exer.2020.108416] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 11/18/2020] [Accepted: 12/16/2020] [Indexed: 01/12/2023]
Abstract
Microglia are immune cells of the central nervous system capable of distinct phenotypic changes and migration in response to injury. These changes most notably include the retraction of fine dendritic structures and adoption of a globular, phagocytic morphology. Due to their characteristic responses, microglia frequently act as histological indicators of injury progression. While algorithms seeking to automate microglia counts and morphological analysis are becoming increasingly popular, few exist that are adequate for use within the retina and manual analysis remains prevalent. To address this, we propose a novel segmentation routine, implemented within FIJI-ImageJ, to perform automated segmentation and cell counting of retinal microglia. We show that our routine could perform cell counts with accuracy similar to manual observers using the I307N Rho model. Tracking cell position relative to retinal vasculature, we observed population migration towards the photoreceptor layer beginning 12 h post light damage. Using feature selection with Chi2 and principal component analysis, we resolved cells along a morphological gradient, demonstrating that extracted features were sufficiently descriptive to capture subtle morphological changes within cell populations in I307N Rho and Balb/c TLR2-/- retinal degeneration models. Taken together, we introduce a novel automated routine capable of efficient image processing and segmentation. Using data retrieved following segmentation, we perform morphological analysis simultaneously on whole populations of cells, rather than individually. Our algorithm was built entirely with open-source software, for use on retinal microglia.
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Affiliation(s)
- Neil F Ash
- University of Florida Department of Molecular Genetics and Microbiology, Box 100266 Gainesville, FL, 32610, USA
| | - Michael T Massengill
- University of Florida Department of Molecular Genetics and Microbiology, Box 100266 Gainesville, FL, 32610, USA
| | - Lindsey Harmer
- University of Florida Department of Molecular Genetics and Microbiology, Box 100266 Gainesville, FL, 32610, USA
| | - Ahmed Jafri
- University of Florida Department of Molecular Genetics and Microbiology, Box 100266 Gainesville, FL, 32610, USA
| | - Alfred S Lewin
- University of Florida Department of Molecular Genetics and Microbiology, Box 100266 Gainesville, FL, 32610, USA.
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11
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Sectoral activation of glia in an inducible mouse model of autosomal dominant retinitis pigmentosa. Sci Rep 2020; 10:16967. [PMID: 33046772 PMCID: PMC7552392 DOI: 10.1038/s41598-020-73749-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 09/18/2020] [Indexed: 12/20/2022] Open
Abstract
Retinitis pigmentosa (RP) is a group of blinding disorders caused by diverse mutations, including in rhodopsin (RHO). Effective therapies have yet to be discovered. The I307N Rho mouse is a light-inducible model of autosomal dominant RP. Our purpose was to describe the glial response in this mouse model to educate future experimentation. I307N Rho mice were exposed to 20,000 lx of light for thirty minutes to induce retinal degeneration. Immunofluorescence staining of cross-sections and flat-mounts was performed to visualize the response of microglia and Müller glia. Histology was correlated with spectral-domain optical coherence tomography imaging (SD-OCT). Microglia dendrites extended between photoreceptors within two hours of induction, withdrew their dendrites between twelve hours and one day, appeared ameboid by three days, and assumed a ramified morphology by one month. Glial activation was more robust in the inferior retina and modulated across the boundary of light damage. SD-OCT hyper-reflectivity overlapped with activated microglia. Finally, microglia transiently adhered to the RPE before which RPE cells appeared dysmorphic. Our data demonstrate the spatial and temporal pattern of glial activation in the I307N Rho mouse, and correlate these patterns with SD-OCT images, assisting in interpretation of SD-OCT images in preclinical models and in human RP.
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12
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Chiarugi V, Dello Sbarba P, Magnelli L, Chiarugi P, Pacini S, Ruggiero M. Cytokine Receptor Signal Transduction Mechanisms in Immuno-Hematopoietic Cells. TUMORI JOURNAL 2018; 79:92-9. [PMID: 8394037 DOI: 10.1177/030089169307900202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Novel aspects of cytokine receptor signal transduction are discussed and cytokine receptors classified based on ligand-dependent signalling. An introductory section presents an overview of the role of cytokines in hematopoiesis. A brief explanation of basic concepts, such as redundancy, pleiotropy, synergism, etc., important for the understanding of cell response to cytokines, is also included. Three of five classes of receptors show the involvement of tyrosine kinase activity as the key step in signal transduction. The importance of tyrosine phosphorylation in cellular response to cytokines is pointed out.
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Affiliation(s)
- V Chiarugi
- Laboratory of Molecular Biology, University of Florence
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13
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Mining the Complex Family of Protein Tyrosine Phosphatases for Checkpoint Regulators in Immunity. Curr Top Microbiol Immunol 2017; 410:191-214. [PMID: 28929190 DOI: 10.1007/82_2017_68] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The family of protein tyrosine phosphatases (PTPs) includes 107 genes in humans that are diverse in their structures and expression profiles. The majority are present in immune cells and play various roles in either inhibiting or promoting the duration and amplitude of signaling cascades. Several PTPs, including TC-PTP (PTPN2) and SHP-1 (PTPN6), have been recognized as being crucial for maintaining proper immune response and self-tolerance, and have gained recognition as true immune system checkpoint modulators. This chapter details the most recent literature on PTPs and immunity by examining their known functions in regulating signaling from either established checkpoint inhibitors or by their intrinsic properties, as modulators of the immune response. Notably, we review PTP regulatory properties in macrophages, antigen-presenting dendritic cells, and T cells. Overall, we present the PTP gene family as a remarkable source of novel checkpoint inhibitors wherein lies a great number of new targets for immunotherapies.
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14
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Abstract
Receptor protein tyrosine phosphatases (RPTPs) form a group of over 20 enzymes in vertebrates, each with unique ectodomains subject to potential extracellular interactions with ligands. It has recently become clear that a remarkably diverse range of ligands exist, including homophilic binders, adhesion molecules, neurotrophin receptors, and proteoglycans. Individual RPTPs can bind several ligands, and vice versa, suggesting that complex cell signaling networks exist. The identification of RPTP ligands and where they are located in tissues remains a challenge for a large number of these enzymes. Here we describe some powerful methods that have proved successful for several research groups, leading to our improved understanding of RPTP-ligand interactions and functional regulation.
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Affiliation(s)
- Andrew William Stoker
- UCL Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK.
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15
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Alonso A, Pulido R. The extended human PTPome: a growing tyrosine phosphatase family. FEBS J 2015; 283:1404-29. [PMID: 26573778 DOI: 10.1111/febs.13600] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 10/02/2015] [Accepted: 11/13/2015] [Indexed: 12/13/2022]
Abstract
Tyr phosphatases are, by definition, enzymes that dephosphorylate phospho-Tyr (pTyr) from proteins. This activity is found in several structurally diverse protein families, including the protein Tyr phosphatase (PTP), arsenate reductase, rhodanese, haloacid dehalogenase (HAD) and His phosphatase (HP) families. Most of these families include members with substrate specificity for non-pTyr substrates, such as phospho-Ser/phospho-Thr, phosphoinositides, phosphorylated carbohydrates, mRNAs, or inorganic moieties. A Cys is essential for catalysis in PTPs, rhodanese and arsenate reductase enzymes, whereas this work is performed by an Asp in HAD phosphatases and by a His in HPs, via a catalytic mechanism shared by all of the different families. The category that contains most Tyr phosphatases is the PTP family, which, although it received its name from this activity, includes Ser, Thr, inositide, carbohydrate and RNA phosphatases, as well as some inactive pseudophosphatase proteins. Here, we propose an extended collection of human Tyr phosphatases, which we call the extended human PTPome. The addition of new members (SACs, paladin, INPP4s, TMEM55s, SSU72, and acid phosphatases) to the currently categorized PTP group of enzymes means that the extended human PTPome contains up to 125 proteins, of which ~ 40 are selective for pTyr. We set criteria to ascribe proteins to the extended PTPome, and summarize the more important features of the new PTPome members in the context of their phosphatase activity and their relationship with human disease.
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Affiliation(s)
- Andrés Alonso
- Instituto de Biología y Genética Molecular (IBGM), CSIC-Universidad de Valladolid, Valladolid, Spain
| | - Rafael Pulido
- Biocruces Health Research Institute, Barakaldo, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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16
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Schafer JR, Lee DA. Trace Evidence: Identifying Natural Cancer Killers After the Crime. EBioMedicine 2015; 2:1276-7. [PMID: 26629505 PMCID: PMC4634752 DOI: 10.1016/j.ebiom.2015.09.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 09/15/2015] [Accepted: 09/15/2015] [Indexed: 11/29/2022] Open
Affiliation(s)
- Jolie R Schafer
- Division of Pediatrics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dean A Lee
- Division of Pediatrics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
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17
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Whitehead KA, Dorkin JR, Vegas AJ, Chang PH, Veiseh O, Matthews J, Fenton OS, Zhang Y, Olejnik KT, Yesilyurt V, Chen D, Barros S, Klebanov B, Novobrantseva T, Langer R, Anderson DG. Degradable lipid nanoparticles with predictable in vivo siRNA delivery activity. Nat Commun 2014; 5:4277. [PMID: 24969323 PMCID: PMC4111939 DOI: 10.1038/ncomms5277] [Citation(s) in RCA: 397] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 06/02/2014] [Indexed: 12/16/2022] Open
Abstract
One of the most significant challenges in the development of clinically viable delivery systems for RNA interference therapeutics is to understand how molecular structures influence delivery efficacy. Here, we have synthesized 1,400 degradable lipidoids and evaluate their transfection ability and structure-function activity. We show that lipidoid nanoparticles mediate potent gene knockdown in hepatocytes and immune cell populations on IV administration to mice (siRNA EC50 values as low as 0.01 mg kg(-1)). We identify four necessary and sufficient structural and pKa criteria that robustly predict the ability of nanoparticles to mediate greater than 95% protein silencing in vivo. Because these efficacy criteria can be dictated through chemical design, this discovery could eliminate our dependence on time-consuming and expensive cell culture assays and animal testing. Herein, we identify promising degradable lipidoids and describe new design criteria that reliably predict in vivo siRNA delivery efficacy without any prior biological testing.
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Affiliation(s)
- Kathryn A. Whitehead
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - J. Robert Dorkin
- Department of Biology, Massachusetts Institute of Technology, 77
Massachusetts Ave., Cambridge, MA 02139 USA
| | - Arturo J. Vegas
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Philip H. Chang
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Omid Veiseh
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Jonathan Matthews
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Owen S. Fenton
- Department of Chemistry, Massachusetts Institute of Technology, 77
Massachusetts Ave., Cambridge, MA 02139 USA
| | - Yunlong Zhang
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Karsten T. Olejnik
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Volkan Yesilyurt
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Delai Chen
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Scott Barros
- Alnylam Pharmaceuticals, 300 Third St., Cambridge, MA 02142
| | - Boris Klebanov
- Alnylam Pharmaceuticals, 300 Third St., Cambridge, MA 02142
| | | | - Robert Langer
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
- Department of Chemical Engineering, Massachusetts Institute of Technology,
77 Massachusetts Ave., Cambridge, MA 02139 USA
- The Institute for Medical Engineering and Science, Massachusetts Institute
of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
| | - Daniel G. Anderson
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of
Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
- Department of Chemical Engineering, Massachusetts Institute of Technology,
77 Massachusetts Ave., Cambridge, MA 02139 USA
- The Institute for Medical Engineering and Science, Massachusetts Institute
of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 USA
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18
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Tonks NK. Protein tyrosine phosphatases--from housekeeping enzymes to master regulators of signal transduction. FEBS J 2013; 280:346-78. [PMID: 23176256 DOI: 10.1111/febs.12077] [Citation(s) in RCA: 339] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/13/2012] [Accepted: 11/15/2012] [Indexed: 12/12/2022]
Abstract
There are many misconceptions surrounding the roles of protein phosphatases in the regulation of signal transduction, perhaps the most damaging of which is the erroneous view that these enzymes exert their effects merely as constitutively active housekeeping enzymes. On the contrary, the phosphatases are critical, specific regulators of signalling in their own right and serve an essential function, in a coordinated manner with the kinases, to determine the response to a physiological stimulus. This review is a personal perspective on the development of our understanding of the protein tyrosine phosphatase family of enzymes. I have discussed various aspects of the structure, regulation and function of the protein tyrosine phosphatase family, which I hope will illustrate the fundamental importance of these enzymes in the control of signal transduction.
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Affiliation(s)
- Nicholas K Tonks
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724-2208, USA.
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19
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Singh RS, Walia AK. Microbial lectins and their prospective mitogenic potential. Crit Rev Microbiol 2012; 40:329-47. [DOI: 10.3109/1040841x.2012.733680] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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20
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Zhang X, Wang B, O’Callaghan P, Hjertström E, Jia J, Gong F, Zcharia E, Nilsson LNG, Lannfelt L, Vlodavsky I, Lindahl U, Li JP. Heparanase overexpression impairs inflammatory response and macrophage-mediated clearance of amyloid-β in murine brain. Acta Neuropathol 2012; 124:465-78. [PMID: 22692572 PMCID: PMC3444710 DOI: 10.1007/s00401-012-0997-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 05/11/2012] [Accepted: 05/11/2012] [Indexed: 12/24/2022]
Abstract
Neuroinflammation is typically observed in neurodegenerative diseases such as Alzheimer’s disease, as well as after traumatic injury and pathogen infection. Resident immune cells, microglia and astrocytes, are activated and joined by blood-borne monocytes that traverse the blood–brain barrier and convert into activated macrophages. The activated cells express various cytokines, chemokines and proteolytic enzymes. To study the role of heparan sulfate proteoglycans in neuroinflammation, we employed a transgenic mouse overexpressing heparanase, an endoglucuronidase that specifically degrades heparan sulfate side chains. Neuroinflammation was induced by systemic challenge with lipopolysaccharide, or by localized cerebral microinjection of aggregated amyloid-β peptide, implicated in Alzheimer’s disease. Lipopolysaccharide-treated control mice showed massive activation of resident microglia as well as recruitment of monocyte-derived macrophages into the brain parenchyma. Microinjection of aggregated amyloid-β elicited a similar inflammatory response, albeit restricted to the injection site, which led to dispersion and clearance of the amyloid. In the heparanase-overexpressing mice, all aspects of immune cell recruitment and activation were significantly attenuated in both inflammation models, as was amyloid dispersion. Accordingly, an in vitro blood–brain barrier model constructed from heparanase-overexpressing cerebral vascular cells showed impaired transmigration of monocytes compared to a corresponding assembly of control cells. Our data indicate that intact heparan sulfate chains are required at multiple sites to mediate neuroinflammatory responses, and further point to heparanase as a modulator of this process, with potential implications for Alzheimer’s disease.
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Receptor type protein tyrosine phosphatases (RPTPs) - roles in signal transduction and human disease. J Cell Commun Signal 2012; 6:125-38. [PMID: 22851429 DOI: 10.1007/s12079-012-0171-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 07/12/2012] [Indexed: 01/06/2023] Open
Abstract
Protein tyrosine phosphorylation is a fundamental regulatory mechanism controlling cell proliferation, differentiation, communication, and adhesion. Disruption of this key regulatory mechanism contributes to a variety of human diseases including cancer, diabetes, and auto-immune diseases. Net protein tyrosine phosphorylation is determined by the dynamic balance of the activity of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Mammals express many distinct PTKs and PTPs. Both of these families can be sub-divided into non-receptor and receptor subtypes. Receptor protein tyrosine kinases (RPTKs) comprise a large family of cell surface proteins that initiate intracellular tyrosine phosphorylation-dependent signal transduction in response to binding of extracellular ligands, such as growth factors and cytokines. Receptor-type protein tyrosine phosphatases (RPTPs) are enzymatic and functional counterparts of RPTKs. RPTPs are a family of integral cell surface proteins that possess intracellular PTP activity, and extracellular domains that have sequence homology to cell adhesion molecules. In comparison to extensively studied RPTKs, much less is known about RPTPs, especially regarding their substrate specificities, regulatory mechanisms, biological functions, and their roles in human diseases. Based on the structure of their extracellular domains, the RPTP family can be grouped into eight sub-families. This article will review one representative member from each RPTP sub-family.
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22
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Mohebiany AN, Nikolaienko RM, Bouyain S, Harroch S. Receptor-type tyrosine phosphatase ligands: looking for the needle in the haystack. FEBS J 2012; 280:388-400. [PMID: 22682003 DOI: 10.1111/j.1742-4658.2012.08653.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reversible protein phosphorylation plays a pivotal role in intercellular communication. Together with protein tyrosine kinases, protein tyrosine phosphatases (PTPs) are involved in the regulation of key cellular processes by controlling the phosphorylation levels of diverse effectors. Among PTPs, receptor-like protein tyrosine phosphatases (RPTPs) are involved in important developmental processes, particularly in the formation of the nervous system. Until recently, few ligands had been identified for RPTPs, making it difficult to grasp the effects these receptors have on cellular processes, as well as the mechanisms through which their functions are mediated. However, several potential RPTP ligands have now been identified to provide us with unparalleled insights into RPTP function. In this review, we focus on the nature and biological outcomes of these extracellular interactions between RPTPs and their associated ligands.
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Affiliation(s)
- Alma N Mohebiany
- Department of Neuroscience, Institut Pasteur de Paris, Paris, France
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23
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Marozzi C, Bertoni F, Randelli E, Buonocore F, Timperio AM, Scapigliati G. A monoclonal antibody for the CD45 receptor in the teleost fish Dicentrarchus labrax. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2012; 37:342-353. [PMID: 22504161 DOI: 10.1016/j.dci.2012.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 03/27/2012] [Accepted: 03/28/2012] [Indexed: 05/31/2023]
Abstract
The CD45 tyrosine phosphatase plays an important role in regulating T lymphocyte activation in vertebrate species. In this study we describe some molecular and functional features of the CD45 receptor molecule from the European sea bass Dicentrarchus labrax. Following immunization with fixed sea bass thymocytes, we obtained a murine monoclonal antibody (mAb) able to stain fish leucocytes both alive, by immunofluorescence of thymus and mucosal tissues, and fixed, by in situ immunohistochemistry of tissue sections. The selected IgG(2) mAb (DLT22) was able to recognise by western blots polypeptides mainly at 180 kDa and 130 kDa in thymus, spleen, intestine and gill leucocyte. Accordingly, a 130 kDa polypeptide immunoprecipitated with DLT22 from thymocytes and analysed by nano-RP-HPLC-ESI-MS/MS, gave peptide sequences homologous to Fugu CD45, that were employed for the homology cloning of a partial sea bass CD45 cDNA sequence. This cDNA sequence was employed to measure by quantitative PCR the transcription of the CD45 gene both in unstimulated and in in vitro stimulated leucocytes, showing that the gene transcription was specifically modulated by LPS, ConA, PHA, IL-1, and poly I:C. When splenocytes were stimulated in vitro with ConA and PHA, a cell proliferation paralleled by an increase of DLT22-positive leucocytes was also observed. These data indicate that the DLT22 mAb recognizes a putative CD45 molecule in sea bass, documenting the presence of CD45-like developing lymphocytes in thymus and CD45-associated functional stages of lymphocytes in this species, thus dating back to teleost fish the functional activities of these cell populations in vertebrates.
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Affiliation(s)
- Catia Marozzi
- Department for Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, 01100 Viterbo, Italy
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Placental expression of CD100, CD72 and CD45 is dysregulated in human miscarriage. PLoS One 2012; 7:e35232. [PMID: 22606231 PMCID: PMC3350501 DOI: 10.1371/journal.pone.0035232] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 03/13/2012] [Indexed: 11/29/2022] Open
Abstract
Context and Objective The etiology of miscarriage is often multifactorial. One major cause, immunological rejection of the fetus, has not been clearly elucidated. Our aim was to establish whether the semaphorin CD100, its natural receptor CD72, and the glycoprotein CD45, implicated in immune mechanisms, are involved in pregnancy loss by examining their placental expression with real-time PCR, immunohistochemistry and western blotting techniques. Patients Placenta tissue from 72 Caucasian women undergoing surgical uterine evacuation due to early spontaneous pregnancy loss between the 8th and 12th week of gestation was divided into four groups based on miscarriage number. Gestational age-matched placentas from 18 healthy women without a history of miscarriage undergoing voluntary pregnancy termination were the control group. Placenta from 6 Caesarean deliveries performed at 38–40 weeks of gestation was also studied. Results CD100, CD72 and CD45 were expressed in placenta and exhibited different mRNA and protein levels in normal pregnancy and miscarriage. In particular, protein levels were highly dysregulated around 10 weeks of gestation in first and second miscarriage placentas. The CD100 soluble form was produced and immediately shed from placental tissue in all samples. Conclusions Fetal CD100, CD72 and CD45 seem to play a role in miscarriage. The present data support the involvement of the fetal immune system in pregnancy maintenance as well as failure.
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25
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Cell surface markers in HTLV-1 pathogenesis. Viruses 2011; 3:1439-59. [PMID: 21994790 PMCID: PMC3185802 DOI: 10.3390/v3081439] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 07/25/2011] [Accepted: 08/08/2011] [Indexed: 12/19/2022] Open
Abstract
The phenotype of HTLV-1-transformed CD4+ T lymphocytes largely depends on defined viral effector molecules such as the viral oncoprotein Tax. In this review, we exemplify the expression pattern of characteristic lineage markers, costimulatory receptors and ligands of the tumor necrosis factor superfamily, cytokine receptors, and adhesion molecules on HTLV-1-transformed cells. These molecules may provide survival signals for the transformed cells. Expression of characteristic surface markers might therefore contribute to persistence of HTLV-1-transformed lymphocytes and to the development of HTLV-1-associated disease.
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Arimura Y, Yagi J. Comprehensive expression profiles of genes for protein tyrosine phosphatases in immune cells. Sci Signal 2010; 3:rs1. [PMID: 20807954 DOI: 10.1126/scisignal.2000966] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The phosphorylation and dephosphorylation of signaling molecules play a crucial role in various cellular processes, including immune responses. To date, the global expression profile of protein tyrosine phosphatases (PTPs) in various immune cells has not been described. With the RefDIC (Reference Genomics Database of Immune Cells) database compiled by RIKEN (Rikagaku Kenkyusho), we examined the expression patterns of PTP-encoding genes in mice and identified between 57 and 64 PTP-encoding genes (depending on cutoff values) that were commonly expressed in immune cells. Cells of different lineages contained additional, unique PTP-encoding genes, which resulted in a total of 58 to 76 genes. Compared with cells from nonimmune tissues, immune cells exhibited enhanced expression of the genes encoding 8 PTP-encoding genes, including Ptprc, Ptpn6, and Ptpn22, but had barely detectable expression of 11 PTP-encoding genes, including Ptprd and Tns1. Each immune cell lineage had between 2 and 18 PTP-encoding genes expressed at relatively high or low extents relative to the average expression among immune cells; for example, Ptprj in B cells, Dusp3 in macrophages, Ptpro in dendritic cells, and Ptprg in mast cells. These PTPs potentially play important roles in each cell lineage, and our analysis provides insight for future functional studies.
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Affiliation(s)
- Yutaka Arimura
- Microbiology and Immunology, Tokyo Women's Medical University School of Medicine, 8-1 Kawada, Shinjuku, Tokyo 162-8666, Japan.
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Saunders AE, Johnson P. Modulation of immune cell signalling by the leukocyte common tyrosine phosphatase, CD45. Cell Signal 2010; 22:339-48. [PMID: 19861160 DOI: 10.1016/j.cellsig.2009.10.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 10/18/2009] [Indexed: 01/01/2023]
Abstract
CD45 is a leukocyte specific transmembrane glycoprotein and a receptor-like protein tyrosine phosphatase (PTP). CD45 can be expressed as several alternatively spliced isoforms that differ in the extracellular domain. The isoforms are regulated in a cell type and activation state-dependent manner, yet their function has remained elusive. The Src family kinase members Lck and Lyn are key substrates for CD45 in T and B lymphocytes, respectively. CD45 lowers the threshold of antigen receptor signalling, which impacts T and B cell activation and development. CD45 also regulates antigen triggered Fc receptor signalling in mast cells and Toll-like receptor (TLR) signalling in dendritic cells, thus broadening the role of CD45 to other recognition receptors involved in adaptive and innate immunity. In addition, CD45 can affect immune cell adhesion and migration and can modulate cytokine production and signalling. Here we review what is known about the substrate specificity and regulation of CD45 and summarise its effect on immune cell signalling pathways, from its established role in T and B antigen receptor signalling to its emerging role regulating innate immune cell recognition and cytokine production.
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Affiliation(s)
- A E Saunders
- Department of Microbiology and Immunology, Life Sciences Institute, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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Extracellular ligation-dependent CD45RB enzymatic activity negatively regulates lipid raft signal transduction. Blood 2008; 113:594-603. [PMID: 18840711 DOI: 10.1182/blood-2008-04-150987] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CD45 is the most prominent membrane protein on lymphocytes. The function and regulation of this protein tyrosine phosphatase remain largely obscure, mainly because of the lack of a known ligand, and it still remains unknown whether such tyrosine phosphatases are subject to extracellular control at all. We report that an anti-CD45RB antibody (Ab) that prevents rejection and induces tolerance activates CD45RB tyrosine phosphatase enzymatic activity in T lymphocytes, allowing us to directly monitor the effects of increased CD45RB activity on signal transduction. Using both kinase substrate peptide arrays as well as conventional biochemistry, we also provide evidence of the various kinases involved in bringing about the inhibitory effect of this Ab on CD3-induced T-cell receptor signaling. Furthermore, we report that activated CD45RB translocates to lipid rafts and interferes with lipid raft localization and activation state of CD45 substrate Lck. Thus, these findings indeed prove that CD45 is subject to extracellular control and also define a novel mechanism by which receptor tyrosine phosphatases control lymphocyte biology and provide further insight into the intracellular signaling pathways effected by anti-CD45RB monoclonal Ab treatment.
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29
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The cytoplasmic tail of CD45 is released from activated phagocytes and can act as an inhibitory messenger for T cells. Blood 2008; 112:1240-8. [DOI: 10.1182/blood-2008-02-138131] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AbstractCD45 is the prototypic transmembrane protein tyrosine phosphatase (PTP), which is expressed on all nucleated hematopoietic cells and plays a central role in the integration of environmental signals into immune cell responses. Here we report an alternative function for the intracellular domain of CD45. We dis-covered that CD45 is sequentially cleaved by serine/metalloproteinases and γ-secretases during activation of human monocytes and granulocytes by fungal stimuli or phorbol 12-myristate 13-acetate but not by other microbial stimuli. Proteolytic processing of CD45 occurred upon activation of monocytes or granulocytes but not of T cells, B cells, or dendritic cells and resulted in a 95-kDa fragment of the cytoplasmic tail of CD45 (ct-CD45). ct-CD45 was released from monocytes and granulocytes upon activation-induced cell death. Binding studies with ct-CD45 revealed a counter-receptor on preactivated T cells. Moreover, T-cell proliferation induced by dendritic cells or CD3 antibodies was inhibited in the presence of ct-CD45. Taken together, the results of our study demonstrate that fragments of the intracellular domain of CD45 from human phagocytes can function as intercellular regulators of T-cell activation.
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Abstract
Phosphorylation, the most intensively studied and common PTM on proteins, is a complex biological phenomenon. Its complexity manifests itself in the large numbers of proteins that attach it, remove it and recognise it as a protein code. Since the first report of protein phosphorylation on vitellin 100 years ago, a wide variety of biochemical and analytical chemical approaches have been developed to enrich and detect protein phosphorylation. The last 5 years have witnessed a renaissance in methodologies capable of characterising protein phosphorylation on a proteome-scale. These technological advances have allowed identification of hundreds to thousands of phosphorylation sites in a proteome and have resulted in a profound paradigm shift. For the first time, using quantitative MS, the topology and significance of global phosphorylation networks may be investigated, marking a new era of cell signalling research. This review addresses recent technological advances in the purification of phosphorylated proteins and peptides and current MS-based strategies used to qualitatively and quantitatively probe these enriched phosphoproteomes. In addition, we review the application of complementary array-based technologies to derive signalling networks from kinase-substrate interactions and discuss future challenges in the field.
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Affiliation(s)
- Mark O Collins
- Proteomic Mass Spectrometry, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.
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31
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Docking Studies on Formylchromone Derivatives as Protein Tyrosine Phosphatase 1B (PTP1B) Inhibitors. B KOREAN CHEM SOC 2007. [DOI: 10.5012/bkcs.2007.28.7.1141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
The discovery that a single amino acid substitution in the PTPN22 protein tyrosine phosphatase can predispose to so many autoimmune diseases (see chapters 2 and 3), even when present in a single copy, raises many questions regarding the broader significance of this observation. Is there something unique about PTPN22 or are genetic variants of other protein tyrosine phosphatases likely also associated with autoimmune disease? If so, will polymorphisms in other phosphatases be found in the same spectrum of diseases? Are protein tyrosine phosphatases like PTPN22 good drug targets for the treatment of human autoimmunity? In this review, I offer some basis for thinking about these questions.
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Affiliation(s)
- Tomas Mustelin
- Program on Inflammatory Disease Research Infectious and Inflammatory Disease Center, The Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Murphy AM, Sheils OM, McDonald GSA, Kelleher DP. Detection of a tyrosine phosphatase LAR on intestinal epithelial cells and intraepithelial lymphocytes in the human duodenum. Mediators Inflamm 2005; 2005:23-30. [PMID: 15770063 PMCID: PMC1513056 DOI: 10.1155/mi.2005.23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Studies of tyrosine phosphorylation in the human duodenum have
indicated that proliferating cells in the middle portion of the
duodenal crypt were devoid of this feature, suggesting that
tyrosine kinase activation is not a dominant factor in crypt cell
proliferation, and that consequently tyrosine phosphatase
activity may be a more critical factor in crypt cell development.
We investigated the expression of the leukocyte common
antigen-related receptor (LAR) family of tyrosine phosphatases. A
flow cytometry system was used to examine cells from the surface,
mid-portion, and lower part of the crypt. Individual cell
populations were immunostained with anti-LAR antibodies using
phycoerythrin-conjugated anti-CD3 to discriminate between
epithelial cells (CD3−) and intraepithelial
lymphocytes (CD3+). Epithelial cells expressed LAR
throughout the crypt. Expression of LAR was maximal in the
mid-portion of the crypt with lower expression at the top of the
villi. Intraepithelial lymphocytes expressed low levels of LAR at
the tips of the villi with stronger expression extending towards
the base of the crypt. These findings were confirmed by
immunohistochemistry on paraffin-fixed sections. Of note,
peripheral blood lymphocytes expressed less LAR than IEL. These
observations suggest the possibility that tyrosine phosphatase
LAR may be of importance in the regulation of crypt cell
proliferation. Moreover, as the extracellular domain of LAR has
homology with adhesion molecules, the finding of this molecule on
IEL could suggest a possible functional role in homing of this
unique lymphocyte.
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Affiliation(s)
- Anne M. Murphy
- Department of Clinical
Medicine, Institute of Molecular Medicine, Trinity Centre for
Health Sciences, Saint James Hospital, Dublin 8,
Ireland
| | - Orla M. Sheils
- Department of
Histopathology, Institute of Molecular Medicine, Trinity Centre
for Health Sciences, Saint James Hospital, Dublin 8,
Ireland
| | - George S. A. McDonald
- Department of
Histopathology, Institute of Molecular Medicine, Trinity Centre
for Health Sciences, Saint James Hospital, Dublin 8,
Ireland
| | - Dermot P. Kelleher
- Department of Clinical
Medicine, Institute of Molecular Medicine, Trinity Centre for
Health Sciences, Saint James Hospital, Dublin 8,
Ireland
- * Dermot P. Kelleher;
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Müller S, Lamszus K, Nikolich K, Westphal M. Receptor protein tyrosine phosphatase ζ as a therapeutic target for glioblastoma therapy. Expert Opin Ther Targets 2005; 8:211-20. [PMID: 15161428 DOI: 10.1517/14728222.8.3.211] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Astrocytomas are the most frequent brain tumour type in adults. The most common astrocytoma is the glioblastoma (GBM), which is also the most malignant and refractory to treatment--ultimately leading to the patient's death within a year of diagnosis. Neither the classical nor more experimental therapeutic approaches have significantly improved the clinical outcome of this disease. Expression profile analysis of primary tumours has provided recent insight into the identification of new GBM therapeutic targets. These proteins serve as excellent candidates to either inhibit the target molecule's functions (e.g., angiogenesis, migration or proliferation) or, coupled with a toxin or radionucleotide, to bind and exterminate the tumour cells. The receptor protein tyrosine phosphatase zeta (RPTPzeta) and one of its main ligands, pleiotropin (Ptn), are overexpressed in GBMs, thus making them potentially very good targets for the development of new immunotherapeutics. This review will summarise recent advances in GBM therapies focusing on RPTPzeta as a target for immunotherapeutics.
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Affiliation(s)
- Sabine Müller
- AGY Therapeutics, 270 East Grant Avenue, South San Francisco, CA 94080, USA.
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Mustelin T, Vang T, Bottini N. Protein tyrosine phosphatases and the immune response. Nat Rev Immunol 2005; 5:43-57. [PMID: 15630428 DOI: 10.1038/nri1530] [Citation(s) in RCA: 263] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Reversible tyrosine phosphorylation of proteins is a key regulatory mechanism for numerous important aspects of eukaryotic physiology and is catalysed by kinases and phosphatases. Together, cells of the immune system express at least half of the 107 protein tyrosine phosphatase (PTP) genes in the human genome, most of which encode multidomain proteins that contain protein- and phospholipid-interaction domains. Here, we discuss the diverse but specific, and important, roles that PTPs have in immune cells, focusing mainly on T and B cells, and we highlight recent evidence that even subtle alterations in PTPs can cause immune dysfunction and human disease.
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Affiliation(s)
- Tomas Mustelin
- Program of Inflammation, Inflammatory and Infectious Disease Center, and Program of Signal Transduction, Cancer Center, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, USA.
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Nam HJ, Poy F, Saito H, Frederick CA. Structural basis for the function and regulation of the receptor protein tyrosine phosphatase CD45. ACTA ACUST UNITED AC 2005; 201:441-52. [PMID: 15684325 PMCID: PMC2213029 DOI: 10.1084/jem.20041890] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
CD45 is the prototypic member of transmembrane receptor-like protein tyrosine phosphatases (RPTPs) and has essential roles in immune functions. The cytoplasmic region of CD45, like many other RPTPs, contains two homologous protein tyrosine phosphatase domains, active domain 1 (D1) and catalytically impaired domain 2 (D2). Here, we report crystal structure of the cytoplasmic D1D2 segment of human CD45 in native and phosphotyrosyl peptide-bound forms. The tertiary structures of D1 and D2 are very similar, but doubly phosphorylated CD3ζ immunoreceptor tyrosine-based activation motif peptide binds only the D1 active site. The D2 “active site” deviates from the other active sites significantly to the extent that excludes any possibility of catalytic activity. The relative orientation of D1 and D2 is very similar to that observed in leukocyte common antigen–related protein with both active sites in an open conformation and is restrained through an extensive network of hydrophobic interactions, hydrogen bonds, and salt bridges. This crystal structure is incompatible with the wedge model previously suggested for CD45 regulation.
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Affiliation(s)
- Hyun-Joo Nam
- Dana-Farber Cancer Institute, Boston, MA 02115, USA
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Chang YY, Chen SJ, Liang HC, Sung HW, Lin CC, Huang RN. The effect of galectin 1 on 3T3 cell proliferation on chitosan membranes. Biomaterials 2004; 25:3603-11. [PMID: 15020134 DOI: 10.1016/j.biomaterials.2003.10.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2003] [Accepted: 10/13/2003] [Indexed: 11/22/2022]
Abstract
Galectin-1 (GAL1), a beta-galactoside-binding protein, functions in cell adhesion, development, and growth regulation. A number of studies suggest that GAL1 play an important role in enhancing cell adhesion to extracellular matrix and inducing cell proliferation. Chitosan is a derivative of chitin extracted from lobsters, crabs and shrimps' exoskeletons. In clinical medicine, chitosan membrane had been used as a semi-permeable biological dressing. Although chitosan membranes show no cytotoxicity, some cell types (e.g. 3T3 cells) fail to attach and proliferate on their surface. In these studies, we show that over-expression of GAL1 does not enhance 3T3 cell proliferation on chitosan membranes. However, coating the chitosan membrane with recombinant GAL1 proteins significantly expedites 3T3 cells proliferation. The enhanced cell growth was inhibited by thiodigalactoside (TDG, a potent inhibitor of beta-galactoside binding) and GAL1 monoclonal antibodies, suggesting GAL1's specific effect on the proliferation of 3T3 cells upon chitosan membranes. Moreover, immunoblotting detected a markedly suppressed tyrosine phosphorylation in several proteins on 3T3 cell growths upon GAL1-coated chitosan membrane. Pretreating the cells with sodium fluoride (NaF, a phosphatase inhibitor) inhibits the attachment and proliferation of 3T3 cells. These findings support a proposed role for altered levels of protein phosphorylation in GAL1-mediated cell attachment and proliferation on chitosan membranes.
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Affiliation(s)
- Yu-Ying Chang
- Department of Life Science, National Central University, Chung-Li, 32054 Taoyuan, Taiwan, Republic of China
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Mustelin T, Alonso A, Bottini N, Huynh H, Rahmouni S, Nika K, Louis-dit-Sully C, Tautz L, Togo SH, Bruckner S, Mena-Duran AV, al-Khouri AM. Protein tyrosine phosphatases in T cell physiology. Mol Immunol 2004; 41:687-700. [PMID: 15220004 DOI: 10.1016/j.molimm.2004.04.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The molecular mechanisms of signal transduction have been the focus of intense research during the last decade. In T cells, much of the work has centered on protein tyrosine kinase-mediated signaling from the TCR and cytokine receptors, while the study of protein tyrosine phosphatases has lagged behind. Nevertheless, it has now become clear that many protein tyrosine phosphatases play equally important roles in T cell physiology and that no kinase-regulated system would work without the counterbalancing participation of phosphatases. In fact, we have learned that many processes are regulated primarily on the phosphatase side. This minireview summarizes the current state-of-the art in our understanding of the regulation and biology of protein tyrosine phosphatases in T lymphocyte physiology.
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Affiliation(s)
- Tomas Mustelin
- Program of Signal Transduction, Cancer Research Center, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Ouellet M, Barbeau B, Tremblay MJ. Protein tyrosyl phosphatases in T cell activation: implication for human immunodeficiency virus transcriptional activity. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2004; 73:69-105. [PMID: 12882515 DOI: 10.1016/s0079-6603(03)01003-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The protein tyrosine phosphatases (PTPs) superfamily is a large group of enzymes showing a wide diversity of structure and biological functions. Their implication in the regulation of signal transduction processes is critical for homeostasis and efficient cellular activation. Disturbance of the delicate balance between protein tyrosine kinase and protein tyrosine phosphatase activities is at the heart of a large number of diseases. Control of cellular activation is especially important for human immunodeficiency virus type 1 (HIV-1) since this retrovirus requires activated T cells in order to replicate efficiently. Identification of PTPs implicated in signaling pathways leading to upregulation of HIV-1 gene transcription therefore contributes to the general understanding of cellular factors needed for strong HIV-1 replication and progression to AIDS. The use of bisperoxovanadium compounds as potent, specific, and highly purified PTP inhibitors releases HIV-1 from PTP control and strongly increases HIV-1 gene expression. These inhibitors can thus be used to study signal transduction mechanisms regulated by PTP activity that are important for HIV-1 replication and provide new and interesting therapeutic avenues for the efficient control of this debilitating retroviral infection.
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Affiliation(s)
- Michel Ouellet
- Centre de Recherche en Infectiologie, Hôpital CHUL, Centre Hospitalier Universitaire de Québec, Canada, G1V 4G2
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Abstract
Although initially viewed as housekeeping enzymes, research over the last 15 years has revealed that the protein tyrosine phosphatases (PTPs) are critical regulators of tyrosine phosphorylation-dependent signaling events and may represent novel targets for therapeutic intervention in a variety of human diseases. In this review I will describe some of the key advances in the characterization of the structure, regulation and function of the prototypic PTP, PTP1B, and illustrate how our understanding of the properties of this enzyme has revealed principles that apply to the PTP family as a whole.
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Affiliation(s)
- Nicholas K Tonks
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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Abstract
The last decade has seen an exponentially increasing interest in the molecular mechanisms of signal transduction. In T cells, much of the focus has been on protein tyrosine kinase (PTK)-mediated signaling from the T cell receptor (TCR) and cytokine receptors, while the study of protein tyrosine phosphatases (PTPases) has lagged behind. However, recent discoveries have revealed that several PTPases play important roles in many different aspects of T cell physiology. We predict that the phosphatases will become a 'hot topic' in the field within the next few years. This review summarizes the current understanding of the regulation and biology of PTPases in T lymphocyte activation.
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Affiliation(s)
- Tomas Mustelin
- Program of Signal Transduction, Cancer Research Center, The Burnham Institute, La Jolla, CA 92037, USA.
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42
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Abstract
Phosphorylation and dephosphorylation of a protein often serve as an "on-and-off" switch in the regulation of cellular activities. Recent studies demonstrate the involvement of protein phosphorylation in almost all signaling pathways in plants. A significant portion of the sequenced Arabidopsis genome encodes protein kinases and protein phosphatases that catalyze reversible phosphorylation. For optimal regulation, kinases and phosphatases must strike a balance in any given cell. Only a very small fraction of the thousands of protein kinases and phosphatases in plants has been studied experimentally. Nevertheless, the available results have demonstrated critical functions for these enzymes in plant growth and development. While serine/threonine phosphorylation is widely accepted as a predominant modification of plant proteins, the function of tyrosine phosphorylation, desptie its overwhelming importance in animal systems, had been largely neglected until recently when tyrosine phosphatases (PTPs) were characterized from plants. This review focuses on the structure, regulation, and function of protein phosphatases in higher plants.
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Affiliation(s)
- Sheng Luan
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, California 94720, USA.
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Abstract
Receptor protein tyrosine phosphatases (RPTPs) are key regulators of neuronal morphogenesis in a variety of different vertebrate and invertebrate systems, yet the mechanisms by which these proteins regulate central nervous system development are poorly understood. In the past few years, studies have begun to outline possible models for RPTP function by demonstrating in vivo roles for RPTPs in axon outgrowth, guidance, and synaptogenesis. In addition, the crystal structures of several RPTPs have been solved, numerous downstream effectors of RPTP signaling have been identified, and a small number of RPTP ligands have been described. In this review, we focus on how RPTPs transduce signals from the extracellular environment to the cytoplasm, using a detailed comparative analysis of the different RPTP subfamilies. Focusing on the roles RPTPs play in the development of the central nervous system, we discuss how the elucidation of RPTP crystal structures, the biochemical analysis of phosphatase enzyme catalysis, and the characterization of complex signal transduction cascades downstream of RPTPs have generated testable models of RPTP structure and function.
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Affiliation(s)
- Karl G Johnson
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02446, USA
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Hooft van Huijsduijnen R, Bombrun A, Swinnen D. Selecting protein tyrosine phosphatases as drug targets. Drug Discov Today 2002; 7:1013-9. [PMID: 12546919 DOI: 10.1016/s1359-6446(02)02438-8] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein tyrosine phosphatases (PTPs) have emerged as a new and promising class of signaling targets, since the discovery of PTP1B as a major drug target for diabetes and obesity. Blocking individual PTPs results in the activation of specific tyrosine phosphorylation events, but matching PTPs with such pathways and therapeutic indications is a complex undertaking. The history of PTP1B shows that its unusual knockout phenotype and observations with generic and antisense inhibitors in vivo, but not its classical molecular biology, triggered the rapid development of inhibitors that are today being developed for the clinic.
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Affiliation(s)
- Rob Hooft van Huijsduijnen
- Serono Pharmaceutical Research Institute, 14 Chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland.
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45
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Fajka-Boja R, Szemes M, Ion G, Légrádi A, Caron M, Monostori E. Receptor tyrosine phosphatase, CD45 binds galectin-1 but does not mediate its apoptotic signal in T cell lines. Immunol Lett 2002; 82:149-54. [PMID: 12008046 DOI: 10.1016/s0165-2478(02)00030-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Galectin-1 (Gal-1) is an endogenous mammalian S-type lectin with highly pleiotropic effect on different tissues. The viability of the lymphoid cells is reduced by gal-1 by triggering apoptosis, however, the mechanism of the gal-1 induced apoptosis is still under investigation. The receptor tyrosine phosphatase, CD45, a heavily glycosylated cell surface molecule binds to gal-1 with high affinity, however, its contribution to the gal-1 induced apoptosis is still controversial. In this study we show that galectin-1 binds to cells deficient for CD45, although CD45 is one of the galectin-1-binding cell surface proteins on T cells. Moreover, the CD45 deficient Jurkat variant, J45.01 responds readily with tyrosine phosphorylation and subsequent apoptosis to galectin-1 treatment in a similar degree as its wild type counterpart, Jurkat does. These results strongly indicate that CD45 is not the receptor via gal-1 mediates the apoptotic signal into the cells as it was suggested in previous studies.
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Affiliation(s)
- Roberta Fajka-Boja
- Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Center of Hungarian Academy of Sciences, Szeged, Hungary
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46
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Fukuhara K, Okumura M, Shiono H, Inoue M, Kadota Y, Miyoshi S, Matsuda H. A study on CD45 isoform expression during T-cell development and selection events in the human thymus. Hum Immunol 2002; 63:394-404. [PMID: 11975983 DOI: 10.1016/s0198-8859(02)00379-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CD45 molecules are known to appear as various isoforms generated by alternative splicing of variable exons 4, 5, and 6, but the detailed profile of CD45 isoform expression during thymocyte development has not been revealed. We examined the CD45 isoforms expressed in the various human thymocytes' subsets defined by CD3, CD4, and CD8 expressions using RT-PCR and 4-color flow cytometry. RT-PCR study revealed that RABC, RAB, RBC, RB, and R0 isoforms were expressed in thymocytes while any of RAC, RA, or RC isoforms were not detected. RABC, RAB and RBC isoforms were expressed at CD3(-)CD4(-)CD8(-) and CD3(+)CD4(+)CD8(-) stages, but were barely detectable at CD3(-)CD4(+)CD8(+) stage. RB isoform was consistently expressed at a relatively high level at all stages. R0 isoform was expressed at a low level at CD3(-)CD4(-)CD8(-) and CD3(-)CD4(+)CD8(-) stages but upregulated at CD3(+)CD4(+)CD8(+) and CD3(+)CD4(+)CD8(-) stages. In combination with the results obtained by 4-color flow cytometric study, CD45 isoform expression on human thymocytes were determined to be RABC(+)RAB(+/-)RBC(+)RB(+)R0(+/-) at CD3(-)CD4(-)CD8(-) stage, RABC(-)RAB(-)RBC(-)RB(+)R0(+) at CD3(-)CD4(+)CD8(-) and CD3(-)CD4(+)CD8(+) stages, RABC(+/-)RAB(+)RBC(+)RB(++)R0(++) at CD3(+)CD4(+)CD8(+) stage, and RABC(+)RAB(+)RBC(+)RB(++)R0(+) at CD3(+)CD4(+)CD8(-) stage. Bcl-2 expression was upregulated between CD3(-)CD4(+)CD8(+)CD45R0(+) and CD3(+)CD4(+)CD8(+)CD45R0(+) stages. Expression of CD45R0 epitope was upregulated between CD3(-)CD4(+)CD8(+)CD69(-) and CD3(+)CD4(+)CD8(+)CD69(+) stages while CD45RA epitope expression was unchanged. Thus, when thymocytes are positively selected, CD45R0 isoform expression seems to be upregulated while CD45RABC isoform expression stays at a very low level. In summary, various isoforms of CD45 were shown to be tightly regulated during thymocyte development and through the selection process.
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Affiliation(s)
- Kenjiro Fukuhara
- Department of Surgery, Division of General Thoracic Surgery and Immunology Laboratory, Osaka University Graduate School of Medicine, Japan
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Abstract
The reversible phosphorylation of proteins is central to the regulation of most aspects of cell function but, even after the first protein kinase was identified, the general significance of this discovery was slow to be appreciated. Here I review the discovery of protein phosphorylation and give a personal view of the key findings that have helped to shape the field as we know it today.
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Affiliation(s)
- Philip Cohen
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Scotland, UK.
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Barbeau B, Robichaud GA, Fortin JF, Tremblay MJ. Negative regulation of the NFAT1 factor by CD45: implication in HIV-1 long terminal repeat activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:2700-13. [PMID: 11509614 DOI: 10.4049/jimmunol.167.5.2700] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
HIV-1 gene regulation is greatly dependent on the presence of the -104/-81 enhancer region which is regulated by both NF-kappaB and NFAT transcription factors. We have found that a greater induction in HIV-1 long terminal repeat-driven gene expression was observed upon PMA/ionomycin (Iono) stimulation of a CD45-deficient cell line (J45.01) in comparison to the parental Jurkat cells. Unlike NF-kappaB which was not affected by the absence of CD45, NFAT showed a much greater augmentation in nuclear translocation and transcriptional activity in J45.01 cells upon PMA/Iono stimulation. PMA/Iono-induced NFAT activation, NFAT translocation and calcium influx peaked at similar time points for both Jurkat and J45.01 cell lines. The NFAT-dependent promoters from the IL-2 and TNF-alpha genes were also more potently activated by PMA/Iono in J45.01 cells. Interestingly, higher levels of intracellular calcium were consistently demonstrated in PMA/Iono-induced CD45-deficient cell lines (J45.01 and HPB45.0). Furthermore, PMA/Iono induction of calcium mobilization in both Jurkat and J45.01 cell lines was observed to be EGTA-sensitive. Mechanistic studies revealed that CD3zeta and ZAP-70 were more heavily tyrosine phosphorylated in J45.01 cells than Jurkat cells. Analysis of the HIV-1 enhancer by EMSAs demonstrated that the bound NFAT complex was present at higher levels in J45.01 nuclear extracts and that the NFAT1 member was predominant. In conclusion, our results indicate that NFAT activation by stimuli acting in a more distal fashion from the TCR-mediated signaling pathway can be down-regulated by CD45 and that this CD45-dependent regulation in turn affects HIV-1 long terminal repeat activation.
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Affiliation(s)
- B Barbeau
- Centre de Recherche en Infectiologie, Hôpital Centre Hospitalier de l'Université Laval, Canada
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49
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Lara-Marquez ML, Moan MJ, Cartwright S, Listman J, Israel E, Perkins DL, Christiani DC, Finn PW. Atopic asthma: differential activation phenotypes among memory T helper cells. Clin Exp Allergy 2001; 31:1232-41. [PMID: 11529893 DOI: 10.1046/j.1365-2222.2001.01146.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND T cells have been implicated in the pathogenesis of atopic asthma. We have previously shown that memory T helper cells (CD4+CD45RO+) are preferentially activated relative to naïve T helper cells (CD4+CD45RA+) after bronchial allergen challenge. However, specific T helper subpopulations that are activated in atopy and/or asthma remain undefined. OBJECTIVE To determine the T helper subpopulations and activation phenotypes relevant to acute and stable asthma that may be common with or distinct from atopy. METHODS Two groups of atopic asthmatics (ten acute and nine stable asthmatics) and two non-asthmatic groups (14 non-asthmatic atopics and eight normal non-atopic controls) were analysed. Ten acute asthmatics were assessed in the emergency room during an acute episode (FEV1 43.6% +/- 18.4). Nine stable asthmatics were assessed during a symptom-free period (FEV1 85% +/- 6). Using multiple colour flow cytometry we analysed T cell subpopulations and the expression of IL-2-receptor (IL-2R) and MHC-class II antigens (MHC II) on naïve and memory T helper cells in the peripheral blood of asthmatic and non-asthmatic groups. RESULTS Atopic asthmatics (acute and stable) had an increased percentage of memory T helper cells expressing IL-2R compared with normal non-atopics (mean SD 16.1 +/- 6%, 12.4 +/- 2% and 7.7 +/- 1.8%, P < 0.05) but not compared with non-asthmatic atopics (10 +/- 3.5%). Naïve T helper cells had low expression of IL-2R and MHC II in all four groups. MHC II antigen expression was increased in memory T helper cells of asthmatics (acute and stable) compared with normal non-atopics (13.9 +/- 7.5, 10.6 +/- 5 and 4.9 +/- 2.5, P < 0.05) but not compared with non-asthmatic atopics (7.92 4). A novel finding was that IL-2R and the MHC II molecules were mainly expressed in non-overlapping populations and coexpression was found predominantly on memory T helper cells. Asthmatics (acute and stable) had higher proportion of double positive memory T helper cells (IL-2R+MHC II+) compared with both non-asthmatic groups (P < 0.05). CONCLUSIONS We demonstrate a differential expression of IL-2R+ and MCH II+ on CD45RO+ T helper cells that would suggest that there are three subsets of activated memory T helper cells in asthmatics. Two non-overlapping IL-2R+ or MHC II+ CD45RO+ T helper cells and a third subpopulation of activated cells that coexpress IL-2R and MHC II (double positives). This latter subpopulation is significantly higher in asthmatics (acute or stable) compared with both non-asthmatic groups, suggesting a specific T helper activation phenotype distinct to atopic asthmatics as compared with atopic non-asthmatics.
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Affiliation(s)
- M L Lara-Marquez
- Respiratory Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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50
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Penninger JM, Irie-Sasaki J, Sasaki T, Oliveira-dos-Santos AJ. CD45: new jobs for an old acquaintance. Nat Immunol 2001; 2:389-96. [PMID: 11323691 DOI: 10.1038/87687] [Citation(s) in RCA: 224] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Identified as the first and prototypic transmembrane protein tyrosine phosphatase (PTPase), CD45 has been extensively studied for over two decades and is thought to be important for positively regulating antigen-receptor signaling via the dephosphorylation of Src kinases. However, new evidence indicates that CD45 can function as a Janus kinase PTPase that negatively controls cytokine-receptor signaling. A point mutation in CD45, which appears to affect CD45 dimerization, and a genetic polymorphism that affects alternative CD45 splicing are implicated in autoimmunity in mice and multiple sclerosis in humans. CD45 is expressed in multiple isoforms and the modulation of specific CD45 splice variants with antibodies can prevent transplant rejections. In addition, loss of CD45 can affect microglia activation in a mouse model for Alzheimer's disease. Thus, CD45 is moving rapidly back into the spotlight as a drug target and central regulator involved in differentiation of multiple hematopoietic cell lineages, autoimmunity and antiviral immunity.
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Affiliation(s)
- J M Penninger
- Amgen Research Institute and Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, Department of Medical Biophysics, University of Toronto, 620 University Avenue, Toronto, ON M5G 2C1, Canada.
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