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Eriksson AM, Leikfoss IS, Abrahamsen G, Sundvold V, Isom MM, Keshari PK, Rognes T, Landsverk OJB, Bos SD, Harbo HF, Spurkland A, Berge T. Exploring the role of the multiple sclerosis susceptibility gene CLEC16A in T cells. Scand J Immunol 2021; 94:e13050. [PMID: 34643957 DOI: 10.1111/sji.13050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 04/20/2021] [Accepted: 04/28/2021] [Indexed: 12/29/2022]
Abstract
C-type lectin-like domain family 16 member A (CLEC16A) is associated with autoimmune disorders, including multiple sclerosis (MS), but its functional relevance is not completely understood. CLEC16A is expressed in several immune cells, where it affects autophagic processes and receptor expression. Recently, we reported that the risk genotype of an MS-associated single nucleotide polymorphism in CLEC16A intron 19 is associated with higher expression of CLEC16A in CD4+ T cells. Here, we show that CLEC16A expression is induced in CD4+ T cells upon T cell activation. By the use of imaging flow cytometry and confocal microscopy, we demonstrate that CLEC16A is located in Rab4a-positive recycling endosomes in Jurkat TAg T cells. CLEC16A knock-down in Jurkat cells resulted in lower cell surface expression of the T cell receptor, however, this did not have a major impact on T cell activation response in vitro in Jurkat nor in human, primary CD4+ T cells.
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Affiliation(s)
- Anna M Eriksson
- Department of Neurology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ingvild Sørum Leikfoss
- Department of Neurology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Neuroscience Research Unit, Department of Research, Innovation and Education, Oslo University Hospital, Oslo, Norway
| | - Greger Abrahamsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Vibeke Sundvold
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | | | - Pankaj K Keshari
- Department of Neurology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Torbjørn Rognes
- Department of Informatics, University of Oslo, Oslo, Norway.,Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | | | - Steffan D Bos
- Department of Neurology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Hanne F Harbo
- Department of Neurology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Anne Spurkland
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Tone Berge
- Neuroscience Research Unit, Department of Research, Innovation and Education, Oslo University Hospital, Oslo, Norway.,Department of Mechanical, Electronic and Chemical Engineering, Oslo Metropolitan University, Oslo, Norway
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2
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Shenker BJ, Boesze-Battaglia K, Zekavat A, Walker L, Besack D, Ali H. Inhibition of mast cell degranulation by a chimeric toxin containing a novel phosphatidylinositol-3,4,5-triphosphate phosphatase. Mol Immunol 2010; 48:203-10. [PMID: 20863570 DOI: 10.1016/j.molimm.2010.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 07/21/2010] [Accepted: 08/11/2010] [Indexed: 10/19/2022]
Abstract
It is well established that many cell functions are controlled by the PI-3K signaling pathway and the signaling lipid, phosphatidylinositol-3,4,5-triphosphate (PIP3). This is particularly true for mast cells which play a key regulatory role in allergy and inflammation through activation via high-affinity IgE receptors (FcɛRI) leading to activation of signaling cascades and subsequent release of histamine and other pro-inflammatory mediators. A pivotal component of this cascade is the activation of PI-3K and a rise in intracellular levels of PIP3. In this study, we developed a novel chimeric toxin that selectively binds to mast cells and which functions as a PIP3 phosphatase. Specifically, the chimeric toxin was composed of the FcɛRI binding region of IgE and the active subunit of the cytolethal distending toxin, CdtB, which we have recently demonstrated to function as a PIP3 phosphatase. We demonstrate that the chimeric toxin retains PIP3 phosphatase activity and selectively binds to mast cells. Moreover, the toxin is capable of altering intracellular levels of PIP3, block antigen-induced Akt phosphorylation and degranulation. These studies provide further evidence for the pivotal role of PIP3 in regulating mast cell activation and for this signaling lipid serving as a novel target for therapeutic intervention of mast cell-mediated disease. Moreover, these studies provide evidence for the utilization of CdtB as a novel therapeutic agent for targeting the PI-3K signaling pathway.
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Affiliation(s)
- Bruce J Shenker
- Department of Pathology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104-6030, USA.
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Abstract
Signal transduction via PI 3-kinases plays an important role in regulating the cellular processes of cell growth, survival, proliferation, and motility. The stimulated generation of reactive oxygen species is a necessary component of the signal transduction mechanisms by which many growth factors and cytokines activate this signaling pathway and elicit their cellular responses. Evidence now supports the oxidative inactivation of both tyrosine phosphatases acting upstream of PI 3-kinase, and of the lipid phosphatase PTEN as components of the normal stimulated regulation of PI 3-kinase signaling. However, the effects of chronic oxidative stress appear rather different, particularly a proposed role for nitrosylation of Akt and other targets leading to inhibition of PI 3-kinase signaling during diabetic insulin resistance in muscle. Recently, evidence has also begun to emerge, indicating that physiological redox signaling may display the same tight spatial and temporal specificity as seen with many other signal transduction systems in terms of targeting individual proteins for modification, and of enzymatic reversal mechanisms. This review will focus upon the details of these and other roles for reactive oxygen and nitrogen species in the regulation of PI 3-kinase signaling, both during acute stimulation and chronic oxidative stress, and the evidence for their significance.
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Affiliation(s)
- Nick R Leslie
- Division of Molecular Physiology, School of Life Sciences, University of Dundee, Wellcome Trust Biocentre, Dundee, United Kingdom.
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Pinal N, Goberdhan DCI, Collinson L, Fujita Y, Cox IM, Wilson C, Pichaud F. Regulated and polarized PtdIns(3,4,5)P3 accumulation is essential for apical membrane morphogenesis in photoreceptor epithelial cells. Curr Biol 2006; 16:140-9. [PMID: 16431366 DOI: 10.1016/j.cub.2005.11.068] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 11/09/2005] [Accepted: 11/23/2005] [Indexed: 12/31/2022]
Abstract
BACKGROUND In a specialized epithelial cell such as the Drosophila photoreceptor, a conserved set of proteins is essential for the establishment of polarity, its maintenance, or both--in Drosophila, these proteins include the apical factors Bazooka, D-atypical protein kinase C, and D-Par6 together with D-Ecadherin. However, little is known about the mechanisms by which such apical factors might regulate the differentiation of the apical membrane into functional domains such as an apical-most stack of microvilli or more lateral sub-apical membrane. RESULTS We show that in photoreceptors Bazooka (D-Par3) recruits the tumor suppressor lipid phosphatase PTEN to developing cell-cell junctions (Zonula Adherens, za). za-localized PTEN controls the spatially restricted accumulation of optimum levels of the lipid PtdIns(3,4,5)P3 within the apical membrane domain. This in turn finely tunes activation of Akt1, a process essential for proper morphogenesis of the light-gathering organelle, consisting of a stack of F-actin rich microvilli within the apical membrane. CONCLUSIONS Spatially localized PtdIns(3,4,5)P3 mediates directional sensing during neutrophil and Dictyostelium chemotaxis. We conclude that a conserved mechanism also operates during photoreceptor epithelial cell morphogenesis in order to achieve normal differentiation of the apical membrane.
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Affiliation(s)
- Noelia Pinal
- Medical Research Council Laboratory for Molecular Cell Biology and Cell Biology Unit, Department of Anatomy and Developmental Biology, University College London, Gower Street, WC1E 6BT London, United Kingdom
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5
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Barata JT, Cardoso AA, Boussiotis VA. Interleukin-7 in T-cell acute lymphoblastic leukemia: an extrinsic factor supporting leukemogenesis? Leuk Lymphoma 2005; 46:483-95. [PMID: 16019476 DOI: 10.1080/10428190400027852] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The malignant transformation and expansion of tumor cells involve both cell-autonomous mechanisms and microenvironment signals that regulate viability, nutrient utilization, metabolic activity and cell growth. In T-cell acute lymphoblastic leukemia (T-ALL), the co-culture of leukemic cells with stroma or the addition of particular cytokines prevents ex vivo spontaneous apoptosis. Interleukin-7 (IL-7), a cytokine produced by thymic and bone marrow stroma, increases the viability and proliferation of T-ALL cells. IL-7 induces the activation of Jak/STAT, MEK/Erk and PI3K/Akt signaling pathways in T-ALL cells. PI3K/Akt is the dominant pathway that mediates the effects of IL-7 on T-ALL. PI3K signaling is required for the induction of Bcl-2, the down-regulation of p27(kip1) and cell cycle progression. PI3K signaling is also required for the expression of the glucose transporter Glut1, uptake of glucose, activation of the metabolic machinery, increase in cell size, and maintenance of mitochondrial integrity. These observations suggest that substrates of molecular pathways activated by microenvironmental factors represent attractive molecular targets for the regulation of the viability and proliferation of T-ALL cells and provide the means for the development of novel treatment strategies.
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Affiliation(s)
- Joao T Barata
- Tumor Biology Unit, Institute of Molecular Medicine, University of Lisbon Medical School, Lisbon, Portugal.
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Lacalle RA, Gómez-Moutón C, Barber DF, Jiménez-Baranda S, Mira E, Martínez-A C, Carrera AC, Mañes S. PTEN regulates motility but not directionality during leukocyte chemotaxis. J Cell Sci 2005; 117:6207-15. [PMID: 15564381 DOI: 10.1242/jcs.01545] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The localization at opposite cell poles of phosphatidylinositol-3 kinases and PTEN (phosphatase and tensin homolog on chromosome 10) governs Dictyostelium chemotaxis. To study this model in mammalian cells, we analyzed the dynamic redistribution of green fluorescent protein (GFP)-tagged PTEN chimeras during chemotaxis. N- or C-terminus GFP-tagged PTEN was distributed homogeneously in the cytoplasm of chemotaxing PTEN-negative Jurkat cells and PTEN-positive HL60 cells. Moreover, we did not detect uropod accumulation of endogenous PTEN in chemoattractant-stimulated HL60 cells. Cell fractionation indicated that both endogenous and ectopically expressed PTEN were confined largely to the cytosol, and that chemoattractant stimulation did not alter this location. PTEN re-expression in Jurkat cells or PTEN depletion by specific siRNA in HL60 cells did not affect cell gradient sensing; PTEN nonetheless modulated chemoattractant-induced actin polymerization and the speed of cell movement. The results suggest a role for PTEN in regulating actin polymerization, but not directionality during mammalian cell chemotaxis.
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Affiliation(s)
- Rosa Ana Lacalle
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, UAM Campus de Cantoblanco, 28049 Madrid, Spain
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Fabre S, Lang V, Harriague J, Jobart A, Unterman TG, Trautmann A, Bismuth G. Stable activation of phosphatidylinositol 3-kinase in the T cell immunological synapse stimulates Akt signaling to FoxO1 nuclear exclusion and cell growth control. THE JOURNAL OF IMMUNOLOGY 2005; 174:4161-71. [PMID: 15778376 DOI: 10.4049/jimmunol.174.7.4161] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We have previously reported at the single cell level that PI3K is activated after conjugate formation between T lymphocytes and APCs. However, in contrast to cells exposed to an asymmetrical signal that usually increase 3'-phosphoinositides (3'-PI) transiently in the region of the activated receptors, T cells contacting APC accumulate 3'-PI across their whole plasma membrane far beyond the region of the immunological synapse (IS). Importantly, this effect is maintained over time, for hours, and although PI3K-dependent pathways translate in various cell types extracellular stimuli into a wide range of biological events, in primary T cells this stability is mostly required for cell division induced by Ag. Using imaging methodologies, the present article elucidates the molecular mechanisms responsible for this particular functioning of the PI3K pathway in primary human T lymphocytes interacting with APCs, especially with dendritic cells. The results reveal that the IS unremittingly recruits PI3K to maintain high 3'-PI levels in T cells through phosphotyrosine-dependent mechanisms, suggesting a major participation of class Ia PI3K. This persistent activation of PI3K results in the Akt-dependent sequestration of the FoxO transcription factor, FoxO1, outside the nucleus of T cells interacting with APCs. Using an active form of FoxO1, we demonstrate that this compartmentalization process can affect T cell growth after Ag recognition. We conclude that the need for sustained PI3K signaling within the consolidated IS is probably an undemanding tactic used by primary T cells critical for initiating cell cycle progression through the prolonged inactivation of FoxO1, one important factor that can control cell quiescence.
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Affiliation(s)
- Stéphanie Fabre
- Département de Biologie Cellulaire, Institut Cochin, Institut National de la Santé et de la Recherche Médicale, Unité 567, Centre National de la Recherche Scientifique, Université René Descartes, Paris, France
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Abraham RT, Weiss A. Jurkat T cells and development of the T-cell receptor signalling paradigm. Nat Rev Immunol 2004; 4:301-8. [PMID: 15057788 DOI: 10.1038/nri1330] [Citation(s) in RCA: 405] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Robert T Abraham
- Program in Signal Transduction Research at The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, California 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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10
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Goberdhan DCI, Wilson C. PTEN: tumour suppressor, multifunctional growth regulator and more. Hum Mol Genet 2003; 12 Spec No 2:R239-48. [PMID: 12928488 DOI: 10.1093/hmg/ddg288] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The tumour suppressor gene PTEN is mutated in a wide range of human cancers at a frequency roughly comparable with p53. In addition, germline PTEN mutations are associated with several dominant growth disorders. The molecular and cellular basis of these disorders has been elucidated by detailed in vivo genetic analysis in model organisms, in particular the fruit fly and mouse. Studies in the fly have shown that PTEN's growth regulatory functions are primarily mediated via its lipid phosphatase activity, which specifically reduces the cellular levels of phosphatidylinositol 3,4,5-trisphosphate. This activity antagonizes the effects of activated PI3-kinase in the nutritionally controlled insulin receptor pathway, thereby reducing protein synthesis and restraining cell and organismal growth, while also regulating other biological processes, such as fertility and ageing. Remarkably, this range of functions appears to be conserved in all higher organisms. PTEN also plays a role as a specialized cytoskeletal regulator, which, for example, is involved in directional movement of some migratory cells and may be important in metastasis. Furthermore, conditional knockouts in the mouse have recently revealed functions for PTEN in other processes, such as cell type specification and cardiac muscle contractility. Genetic approaches have therefore revealed a surprising diversity of global and cell type-specific PTEN-regulated functions that appear to be primarily controlled by modulation of a single phosphoinositide. Together with evidence from studies in cell culture that suggests links between PTEN and other growth regulatory genes such as p53, these studies provide new insights into PTEN-linked disorders and are beginning to suggest potential clinical strategies to combat these and other diseases.
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11
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Abstract
The phosphoinositides PtdIns(4,5)P2 and PtdIns(3,4,5)P3 are concentrated in plasma membranes of eukaryotic cells, and excluded from endosomes, whereas PtdIns(3)P is formed in these latter intracellular membranes and is apparently excluded from the plasma membrane. The logic of this asymmetric disposition is now revealed by the nature of the effector proteins that selectively bind these lipids through specific modules and by the processes that they catalyze. PtdIns(3,4,5)P3 has a role in directing exocytosis, in addition to many other signaling events, whereas PtdIns(4,5)P2 directs endocytosis through its ability to anchor several coat proteins to the plasma membrane. Remarkably, the elimination of PtdIns(4,5)P2 from forming endosomes may be required for membrane fission to occur. Thus membrane insertion and retrieval can be regulated by plasma membrane concentrations of PtdIns(3,4,5)P3 and PtdIns(4,5)P2, whereas PtdIns(3)P directs the downstream trafficking and recycling of intracellular membranes through its attraction of proteins that catalyze these processes. The phosphoinositides thereby control many cell features that depend upon protein sorting, including the composition of the plasma membrane itself, which in turn determines the cell's responses to its environment.
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Affiliation(s)
- Michael P Czech
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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Seminario MC, Wange RL. Lipid phosphatases in the regulation of T cell activation: living up to their PTEN-tial. Immunol Rev 2003; 192:80-97. [PMID: 12670397 DOI: 10.1034/j.1600-065x.2003.00013.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The initiating events associated with T activation in response to stimulation of the T cell antigen receptor (TCR) and costimulatory receptors, such as CD28, are intimately associated with the enzymatically catalyzed addition of phosphate not only to key tyrosine, threonine and serine residues in proteins but also to the D3 position of the myo-inositol ring of phosphatidylinositol (PtdIns). This latter event is catalyzed by the lipid kinase phosphoinositide 3-kinase (PI3K). The consequent production of PtdIns(3,4)P2 and PtdIns(3,4,5)P3 serves both to recruit signaling proteins to the plasma membrane and to induce activating conformational changes in proteins that contain specialized domains for the binding of these phospholipids. The TCR signaling proteins that are subject to regulation by PI3K include Akt, phospholipase Cgamma1 (PLCgamma1), protein kinase C zeta (PKC-zeta), Itk, Tec and Vav, all of which play critical roles in T cell activation. As is the case for phosphorylation of protein substrates, the phosphorylation of PtdIns is under dynamic regulation, with the D3 phosphate being subject to hydrolysis by the 3-phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome 10), thereby placing PTEN in direct opposition to PI3K. In this review we consider recent data concerning how PTEN may act in regulating the process of T cell activation.
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Affiliation(s)
- Maria-Cristina Seminario
- Laboratory of Cellular and Molecular Biology, National Institutes on Aging/IRP/NIH/DHHS, Baltimore, MD 21224, USA.
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Zhong XP, Hainey EA, Olenchock BA, Zhao H, Topham MK, Koretzky GA. Regulation of T cell receptor-induced activation of the Ras-ERK pathway by diacylglycerol kinase zeta. J Biol Chem 2002; 277:31089-98. [PMID: 12070163 DOI: 10.1074/jbc.m203818200] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
T cell development in the thymus and activation of mature T cells in the periphery depend on signals stimulated by engagement of the T cell antigen receptor (TCR). Among the second messenger cascades initiated by TCR ligation include the phosphatidylinositol pathway where the membrane phospholipid, phosphatidylinositol 4,5-bisphosphate, is hydrolyzed to inositol 1,4,5-trisphosphate and diacylglycerol (DAG). Inositol 1,4,5-trisphosphate signals a rise in intracellular free calcium, leading to translocation of nuclear factor of activated T cells into the nucleus. DAG activates RasGRP and protein kinase C theta. Because both RasGRP and protein kinase C theta are essential for thymocyte and T cell function, it is critical to understand how DAG is regulated. In this report, we demonstrate expression of DAG kinase zeta (DGKzeta, the enzyme that catalyzes the conversion of DAG to phosphatidic acid) in multiple lymphoid organs, with highest expression observed within the T cell compartment. Overexpression studies in Jurkat T cells indicate that DGKzeta interferes with TCR-induced Ras and ERK activation, AP-1 induction, and expression of the activation marker CD69. In contrast, TCR-stimulated calcium influx is not altered. Mutational analysis indicates that the kinase and DAG binding domains, but not the ankyrin repeats of DGKzeta, are required for its inhibitory effects. Collectively these studies demonstrate a potential role of DGKzeta to function as a selective negative regulator of DAG signaling on T cell activation and provide the first structure/function analysis of this enzyme in T cells.
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Affiliation(s)
- Xiao-Ping Zhong
- Signal Transduction Program, The Abramson Family Cancer Research Institute, Immunology Graduate Program, University of Pennsylvania School of Medicine, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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14
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Abstract
Phosphatidylinositol lipids, such as PI(4,5)P2 and PI(3,4,5)P3, are key mediators in diverse intracellular signaling pathways. Two recent reports examine how the metabolism of these lipids by phosphatidylinositol 3-kinases and the PTEN 3-phosphoinositide phosphatase may coordinate G protein coupled signaling pathways during eukaryotic chemotaxis.
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Affiliation(s)
- Frank I Comer
- PRAT Research Fellowship Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20892, USA
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