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Ragupathy S, Brunner J, Borchard G. Short peptide sequence enhances epithelial permeability through interaction with protein kinase C. Eur J Pharm Sci 2021; 160:105747. [PMID: 33582284 DOI: 10.1016/j.ejps.2021.105747] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 11/25/2020] [Accepted: 02/04/2021] [Indexed: 01/13/2023]
Abstract
We have identified a short peptide sequence (L-R5) acting as partial inhibitor of intracellular protein kinase C, capable of tight junction modulation in terms of reversible and non-toxic drug permeation enhancement. L-R5 is a pentapeptide with a cell-penetrating group at the N-terminus and of the sequence myristoyl-ARRWR. Apically applied in vitro, L-R5 transiently increased epithelial permeability within minutes, enhancing apical-to-basolateral (AB) transport of 4-kDa dextran and BCS class III drug naloxone. L-R5 was shown to be stable and effective at 37°C over a period of 24 hours. L-R5 was shown to be non-cytotoxic in consecutive exposure studies on primary human nasal epithelial cells by LDH release assay and ciliary beating frequency test. Finally, L-R5 by itself showed very low diffusion across epithelial monolayers, which is of advantage with regard to its expected negligible systemic bioavailability and side effects. Taken together, these data demonstrate the potential of short peptide partial inhibitor L-R5 to enhance the epithelial paracellular permeability via a reversible mechanism, and in a non-toxic manner.
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Affiliation(s)
- Sakthikumar Ragupathy
- Section of Pharmaceutical Sciences, Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO) University of Geneva, CH-1211Geneva, Switzerland
| | - Joël Brunner
- Section of Pharmaceutical Sciences, Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO) University of Geneva, CH-1211Geneva, Switzerland
| | - Gerrit Borchard
- Section of Pharmaceutical Sciences, Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO) University of Geneva, CH-1211Geneva, Switzerland.
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2
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Lee-Rivera I, López E, Alvarez-Arce A, López-Colomé AM. The PKC-ζ pseudosubstrate peptide induces glutamate release from retinal pigment epithelium cells through kinase- independent activation of Best1. Life Sci 2020; 265:118860. [PMID: 33301813 DOI: 10.1016/j.lfs.2020.118860] [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: 08/25/2020] [Revised: 11/19/2020] [Accepted: 12/01/2020] [Indexed: 10/22/2022]
Abstract
AIMS The retinal pigment epithelium (RPE) is a highly specialized cell monolayer, that plays a key role in the maintenance of photoreceptor function and the blood-retina barrier (BRB). In this study, we found that a myristoylated pseudosubstrate of PKC-ζ (PKCζ PS), considered as a PKC-ζ inhibitor, plays a distinct role in RPE. MAIN METHODS We demonstrated that PKCζ PS stimulates the release of Glutamate (Glu) using in vitro3H-Glutamate release experiments. By western blot, kinase assays, and Fluoresence Ca+2 Concentration Measurements, we determined the cellular mechanisms involved in such release. KEY FINDINGS Surprisingly, PKCζ PS has no effect on either phosphorylation of T560, essential for catalytic activity, nor it has an effect on kinase activity. It induces the dose-dependent release of Glu by increasing intracellular Ca+2 levels. Interestingly, this release was not observed upon stimulation by other non-competitive PKC-ζ inhibitors. We here demonstrated that the PKCζ PS stimulates the release of Glutamate from RPE by activating the Ca2+-dependent Cl channel Bestrophin 1 (Best1). SIGNIFICANCE These results question PKCζ PS specificity as an inhibitor of this enzyme. Furthermore, the present results underline the relevance of clarifying the molecular mechanisms involved in glutamate release from the retina under conditions derived from excitotoxic stimuli.
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Affiliation(s)
- Irene Lee-Rivera
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, UNAM, Apartado Postal 70-253, Ciudad Universitaria, México City, CdMx, Mexico
| | - Edith López
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, UNAM, Apartado Postal 70-253, Ciudad Universitaria, México City, CdMx, Mexico
| | - Alejandro Alvarez-Arce
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, UNAM, Apartado Postal 70-253, Ciudad Universitaria, México City, CdMx, Mexico
| | - Ana María López-Colomé
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, UNAM, Apartado Postal 70-253, Ciudad Universitaria, México City, CdMx, Mexico.
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3
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Chau DDL, Yung KWY, Chan WWL, An Y, Hao Y, Chan HYE, Ngo JCK, Lau KF. Attenuation of amyloid-β generation by atypical protein kinase C-mediated phosphorylation of engulfment adaptor PTB domain containing 1 threonine 35. FASEB J 2019; 33:12019-12035. [PMID: 31373844 DOI: 10.1096/fj.201802825rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Amyloid-β (Aβ) is derived from the proteolytic processing of amyloid precursor protein (APP), and the deposition of extracellular Aβ to form amyloid plaques is a pathologic hallmark of Alzheimer's disease (AD). Although reducing Aβ generation and accumulation has been proposed as a means of treating the disease, adverse side effects and unsatisfactory efficacy have been reported in several clinical trials that sought to lower Aβ levels. Engulfment adaptor phosphotyrosine-binding (PTB) domain containing 1 (GULP1) is a molecular adaptor that has been shown to interact with APP to alter Aβ production. Therefore, the modulation of the GULP1-APP interaction may be an alternative approach to reducing Aβ. However, the mechanisms that regulate GULP1-APP binding remain elusive. As GULP1 is a phosphoprotein, and because phosphorylation is a common mechanism that regulates protein interaction, we anticipated that GULP1 phosphorylation would influence GULP1-APP interaction and thereby Aβ production. We show here that the phosphorylation of GULP1 threonine 35 (T35) reduces GULP1-APP interaction and suppresses the stimulatory effect of GULP1 on APP processing. The residue is phosphorylated by an isoform of atypical PKC (PKCζ). Overexpression of PKCζ reduces both GULP1-APP interaction and GULP1-mediated Aβ generation. Moreover, the activation of PKCζ via insulin suppresses APP processing. In contrast, GULP1-mediated APP processing is enhanced in PKCζ knockout cells. Similarly, PKC ι, another member of atypical PKC, also decreases GULP1-mediated APP processing. Intriguingly, our X-ray crystal structure of GULP1 PTB-APP intracellular domain (AICD) peptide reveals that GULP1 T35 is not located at the GULP1-AICD binding interface; rather, it immediately precedes the β1-α2 loop that forms a portion of the binding groove for the APP helix αC. Phosphorylating the residue may induce an allosteric effect on the conformation of the binding groove. Our results indicate that GULP1 T35 phosphorylation is a mechanism for the regulation of GULP1-APP interaction and thereby APP processing. Moreover, the activation of atypical PKC, such as by insulin, may confer a beneficial effect on AD by lowering GULP1-mediated Aβ production.-Chau, D. D.-L., Yung, K. W.-Y., Chan, W. W.-L., An, Y., Hao, Y., Chan, H.-Y. E., Ngo, J. C.-K., Lau, K.-F. Attenuation of amyloid-β generation by atypical protein kinase C-mediated phosphorylation of engulfment adaptor PTB domain containing 1 threonine 35.
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Affiliation(s)
- Dennis Dik-Long Chau
- Faculty of Science, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Kristen Wing-Yu Yung
- Faculty of Science, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - William Wai-Lun Chan
- Faculty of Science, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ying An
- Faculty of Science, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yan Hao
- Faculty of Science, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ho-Yin Edwin Chan
- Faculty of Science, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Jacky Chi-Ki Ngo
- Faculty of Science, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Kwok-Fai Lau
- Faculty of Science, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
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4
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Hurtado B, Trakala M, Ximénez-Embún P, El Bakkali A, Partida D, Sanz-Castillo B, Álvarez-Fernández M, Maroto M, Sánchez-Martínez R, Martínez L, Muñoz J, García de Frutos P, Malumbres M. Thrombocytopenia-associated mutations in Ser/Thr kinase MASTL deregulate actin cytoskeletal dynamics in platelets. J Clin Invest 2018; 128:5351-5367. [PMID: 30252678 DOI: 10.1172/jci121876] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 09/18/2018] [Indexed: 12/18/2022] Open
Abstract
MASTL, a Ser/Thr kinase that inhibits PP2A-B55 complexes during mitosis, is mutated in autosomal dominant thrombocytopenia. However, the connections between the cell-cycle machinery and this human disease remain unexplored. We report here that, whereas Mastl ablation in megakaryocytes prevented proper maturation of these cells, mice carrying the thrombocytopenia-associated mutation developed thrombocytopenia as a consequence of aberrant activation and survival of platelets. Activation of mutant platelets was characterized by hyperstabilized pseudopods mimicking the effect of PP2A inhibition and actin polymerization defects. These aberrations were accompanied by abnormal hyperphosphorylation of multiple components of the actin cytoskeleton and were rescued both in vitro and in vivo by inhibiting upstream kinases such as PKA, PKC, or AMPK. These data reveal an unexpected role of Mastl in actin cytoskeletal dynamics in postmitotic cells and suggest that the thrombocytopenia-associated mutation in MASTL is a pathogenic dominant mutation that mimics decreased PP2A activity resulting in altered phosphorylation of cytoskeletal regulatory pathways.
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Affiliation(s)
- Begoña Hurtado
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.,Department of Cell Death and Proliferation, Institut d'Investigacions Biomèdiques de Barcelona-Consejo Superior de Investigaciones Científicas- Institut d'Investigacions Biomèdiques August Pi i Sunyer- (IIBB-CSIC-IDIBAPS), Barcelona, Spain
| | - Marianna Trakala
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Pilar Ximénez-Embún
- ProteoRed - Instituto de Salud Carlos III (ISCIII) and Proteomics Unit, CNIO, Madrid, Spain
| | - Aicha El Bakkali
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - David Partida
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Belén Sanz-Castillo
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | | | - María Maroto
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Ruth Sánchez-Martínez
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | | | - Javier Muñoz
- ProteoRed - Instituto de Salud Carlos III (ISCIII) and Proteomics Unit, CNIO, Madrid, Spain
| | - Pablo García de Frutos
- Department of Cell Death and Proliferation, Institut d'Investigacions Biomèdiques de Barcelona-Consejo Superior de Investigaciones Científicas- Institut d'Investigacions Biomèdiques August Pi i Sunyer- (IIBB-CSIC-IDIBAPS), Barcelona, Spain
| | - Marcos Malumbres
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
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5
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Beck S, Leitges M, Stegner D. Protein kinase Cι/λ is dispensable for platelet function in thrombosis and hemostasis in mice. Cell Signal 2017; 38:223-229. [PMID: 28739484 DOI: 10.1016/j.cellsig.2017.07.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/05/2017] [Accepted: 07/20/2017] [Indexed: 11/17/2022]
Abstract
Platelet activation at sites of vascular injury is crucial for hemostasis, but it may also cause myocardial infarction or ischemic stroke. Upon platelet activation, cytoskeletal reorganization is essential for platelet secretion and thrombus formation. Members of the protein kinase C family, which includes 12 isoforms, are involved in most platelet responses required for thrombus formation. The atypical protein kinase Cι/λ (PKCι/λ) has been implicated as an important mediator of cell polarity, carcinogenesis and immune cell responses. PKCι/λ is known to be associated with the small GTPase Cdc42, an important mediator of multiple platelet functions; however, its exact function in platelets is not known. To study the role of PKCι/λ, we generated platelet- and megakaryocyte-specific PKCι/λ knockout mice (Prkcifl/fl, Pf4-Cre) and used them to investigate the function of PKCι/λ in platelet activation and aggregation in vitro and in vivo. Surprisingly, lack of PKCι/λ had no detectable effect on platelet spreading and function in vitro and in vivo under all tested conditions. These results indicate that PKCι/λ is dispensable for Cdc42-triggered processes and for thrombosis and hemostasis in mice.
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Affiliation(s)
- Sarah Beck
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | | | - David Stegner
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany.
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Unsworth AJ, Bye AP, Gibbins JM. Platelet-Derived Inhibitors of Platelet Activation. PLATELETS IN THROMBOTIC AND NON-THROMBOTIC DISORDERS 2017. [PMCID: PMC7123044 DOI: 10.1007/978-3-319-47462-5_37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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7
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Bye AP, Unsworth AJ, Gibbins JM. Platelet signaling: a complex interplay between inhibitory and activatory networks. J Thromb Haemost 2016; 14:918-30. [PMID: 26929147 PMCID: PMC4879507 DOI: 10.1111/jth.13302] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/11/2016] [Indexed: 01/22/2023]
Abstract
The role of platelets in hemostasis and thrombosis is dependent on a complex balance of activatory and inhibitory signaling pathways. Inhibitory signals released from the healthy vasculature suppress platelet activation in the absence of platelet receptor agonists. Activatory signals present at a site of injury initiate platelet activation and thrombus formation; subsequently, endogenous negative signaling regulators dampen activatory signals to control thrombus growth. Understanding the complex interplay between activatory and inhibitory signaling networks is an emerging challenge in the study of platelet biology, and necessitates a systematic approach to utilize experimental data effectively. In this review, we will explore the key points of platelet regulation and signaling that maintain platelets in a resting state, mediate activation to elicit thrombus formation, or provide negative feedback. Platelet signaling will be described in terms of key signaling molecules that are common to the pathways activated by platelet agonists and can be described as regulatory nodes for both positive and negative regulators.
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Affiliation(s)
- A P Bye
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK
| | - A J Unsworth
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK
| | - J M Gibbins
- Institute of Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK
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8
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Li CH, Shyu MK, Jhan C, Cheng YW, Tsai CH, Liu CW, Lee CC, Chen RM, Kang JJ. Gold Nanoparticles Increase Endothelial Paracellular Permeability by Altering Components of Endothelial Tight Junctions, and Increase Blood-Brain Barrier Permeability in Mice. Toxicol Sci 2015; 148:192-203. [PMID: 26272951 DOI: 10.1093/toxsci/kfv176] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Gold nanoparticles (Au-NPs) are being increasingly used as constituents in cosmetics, biosensors, bioimaging, photothermal therapy, and targeted drug delivery. This elevated exposure to Au-NPs poses systemic risks in humans, particularly risks associated with the biodistribution of Au-NPs and their potent interaction with biological barriers. We treated human umbilical vein endothelial cells with Au-NPs and comprehensively examined the expression levels of tight junction (TJ) proteins such as occludin, claudin-5, junctional adhesion molecules, and zonula occludens-1 (ZO-1), as well as endothelial paracellular permeability and the intracellular signaling required for TJ organization. Moreover, we validated the effects of Au-NPs on the integrity of TJs in mouse brain microvascular endothelial cells in vitro and obtained direct evidence of their influence on blood-brain barrier (BBB) permeability in vivo. Treatment with Au-NPs caused a pronounced reduction of PKCζ-dependent threonine phosphorylation of occludin and ZO-1, which resulted in the instability of endothelial TJs and led to proteasome-mediated degradation of TJ components. This impairment in the assembly of TJs between endothelial cells increased the permeability of the transendothelial paracellular passage and the BBB. Au-NPs increased endothelial paracellular permeability in vitro and elevated BBB permeability in vivo. Future studies must investigate the direct and indirect toxicity caused by Au-NP-induced endothelial TJ opening and thereby address the double-edged-sword effect of Au-NPs.
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Affiliation(s)
- Ching-Hao Li
- *Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan;
| | - Ming-Kwang Shyu
- Department of Obstetrics and Gynecology, National Taiwan University Hospital, Taipei, Taiwan
| | - Cheng Jhan
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Wen Cheng
- School of Pharmacy, Taipei Medicine University, Taipei, Taiwan
| | - Chi-Hao Tsai
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chen-Wei Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chen-Chen Lee
- Department of Microbiology and Immunology, School of Medicine, China Medicine University, Taichung, Taiwan
| | - Ruei-Ming Chen
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Cell Physiology and Molecular Image Research Center, Taipei Medical University's Wan-Fang Hospital, Taipei, Taiwan; and Anesthetics Toxicology Research Center, Taipei Medical University Hospital, Taipei, Taiwan
| | - Jaw-Jou Kang
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan;
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9
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Korrodi-Gregório L, Esteves SLC, Fardilha M. Protein phosphatase 1 catalytic isoforms: specificity toward interacting proteins. Transl Res 2014; 164:366-91. [PMID: 25090308 DOI: 10.1016/j.trsl.2014.07.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 01/21/2023]
Abstract
The coordinated and reciprocal action of serine-threonine protein kinases and protein phosphatases produces transitory phosphorylation, a fundamental regulatory mechanism for many biological processes. Phosphoprotein phosphatase 1 (PPP1), a major serine-threonine phosphatase, in particular, is ubiquitously distributed and regulates a broad range of cellular functions, including glycogen metabolism, cell cycle progression, and muscle relaxation. PPP1 has evolved effective catalytic machinery but in vitro lacks substrate specificity. In vivo, its specificity is achieved not only by the existence of different PPP1 catalytic isoforms, but also by binding of the catalytic moiety to a large number of regulatory or targeting subunits. Here, we will address exhaustively the existence of diverse PPP1 catalytic isoforms and the relevance of their specific partners and consequent functions.
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Affiliation(s)
- Luís Korrodi-Gregório
- Laboratório de Transdução de Sinais, Departamento de Biologia, Secção Autónoma de Ciências de Saúde, Centro de Biologia Celular, Universidade de Aveiro, Aveiro, Portugal
| | - Sara L C Esteves
- Laboratório de Transdução de Sinais, Departamento de Biologia, Secção Autónoma de Ciências de Saúde, Centro de Biologia Celular, Universidade de Aveiro, Aveiro, Portugal
| | - Margarida Fardilha
- Laboratório de Transdução de Sinais, Departamento de Biologia, Secção Autónoma de Ciências de Saúde, Centro de Biologia Celular, Universidade de Aveiro, Aveiro, Portugal.
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10
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Senis YA. Protein-tyrosine phosphatases: a new frontier in platelet signal transduction. J Thromb Haemost 2013; 11:1800-13. [PMID: 24015866 DOI: 10.1111/jth.12359] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Indexed: 08/31/2023]
Abstract
Platelet activation must be tightly controlled in order to allow platelets to respond rapidly to vascular injury and prevent thrombosis from occurring. Protein-tyrosine phosphorylation is one of the main ways in which activation signals are transmitted in platelets. Although much is known about the protein-tyrosine kinases (PTKs) that initiate and propagate activation signals, relatively little is known about the protein-tyrosine phosphatases (PTPs) that modulate these signals in platelets. PTPs are a family of enzymes that dephosphorylate tyrosine residues in proteins and regulate signals transmitted within cells. PTPs have been implicated in a variety of pathological conditions, including cancer, diabetes and autoimmunity, but their functions in hemostasis and thrombosis remain largely undefined. Exciting new findings from a number of groups have revealed that PTPs are in fact critical regulators of platelet activation and thrombosis. The primary aim of this review is to highlight the unique and important functions of PTPs in regulating platelet activity. Establishing the functions of PTPs in platelets is essential to better understand the molecular basis of thrombosis and may lead to the development of improved antithrombotic therapies.
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Affiliation(s)
- Y A Senis
- Centre for Cardiovascular and Respiratory Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
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Carriba P, Pardo L, Parra-Damas A, Lichtenstein MP, Saura CA, Pujol A, Masgrau R, Galea E. ATP and noradrenaline activate CREB in astrocytes via noncanonical Ca(2+) and cyclic AMP independent pathways. Glia 2012; 60:1330-44. [PMID: 22593004 DOI: 10.1002/glia.22352] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 04/20/2012] [Indexed: 12/20/2022]
Abstract
In neurons, it is well established that CREB contributes to learning and memory by orchestrating the translation of experience into the activity-dependent (i.e., driven by neurotransmitters) transcription of plasticity-related genes. The activity-dependent CREB-triggered transcription requires the concerted action of cyclic AMP/protein kinase A and Ca(2+) /calcineurin via the CREB-regulated transcription co-activator (CRTC). It is not known, however, whether a comparable molecular sequence occurs in astrocytes, despite the unquestionable contribution of these cells to brain plasticity. Here we sought to determine whether and how ATP and noradrenaline cause CREB-dependent transcription in rat cortical astrocyte cultures. Both transmitters induced CREB phosphorylation (Western Blots), CREB-dependent transcription (CRE-luciferase reporter assays), and the transcription of Bdnf, a canonical regulator of synaptic plasticity (quantitative RT-PCR). We indentified a Ca(2+) and diacylglycerol-independent protein kinase C at the uppermost position of the cascade leading to CREB-dependent transcription. Notably, CREB-dependent transcription was partially dependent on ERK1/2 and CRTC, but independent of cyclic AMP/protein kinase A or Ca(2+) /calcineurin. We conclude that ATP and noradrenaline activate CREB-dependent transcription in cortical astrocytes via an atypical protein kinase C. It is of relevance that the signaling involved be starkly different to the one described in neurons since there is no convergence of Ca(2+) and cyclic AMP-dependent pathways on CRTC, which, moreover, exerts a modulatory rather than a central role. Our data thus point to the existence of an alternative, non-neuronal, glia-based role of CREB in plasticity.
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Affiliation(s)
- Paulina Carriba
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
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12
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Protein kinase C-theta in platelet activation. FEBS Lett 2011; 585:3208-15. [DOI: 10.1016/j.febslet.2011.09.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 08/20/2011] [Accepted: 09/12/2011] [Indexed: 02/05/2023]
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