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Martin-Salgado M, Ochoa-Echeverría A, Mérida I. Diacylglycerol kinases: A look into the future of immunotherapy. Adv Biol Regul 2024; 91:100999. [PMID: 37949728 DOI: 10.1016/j.jbior.2023.100999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023]
Abstract
Cancer still represents the second leading cause of death right after cardiovascular diseases. According to the World Health Organization (WHO), cancer provoked around 10 million deaths in 2020, with lung and colon tumors accounting for the deadliest forms of cancer. As tumor cells become resistant to traditional therapeutic approaches, immunotherapy has emerged as a novel strategy for tumor control. T lymphocytes are key players in immune responses against tumors. Immunosurveillance allows identification, targeting and later killing of cancerous cells. Nevertheless, tumors evolve through different strategies to evade the immune response and spread in a process called metastasis. The ineffectiveness of traditional strategies to control tumor growth and expansion has led to novel approaches considering modulation of T cell activation and effector functions. Program death receptor 1 (PD-1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) showed promising results in the early 90s and nowadays are still being exploited together with other drugs for several cancer types. Other negative regulators of T cell activation are diacylglycerol kinases (DGKs) a family of enzymes that catalyze the conversion of diacylglycerol (DAG) into phosphatidic acid (PA). In T cells, DGKα and DGKζ limit the PLCγ/Ras/ERK axis thus attenuating DAG mediated signaling and T cell effector functions. Upregulation of either of both isoforms results in impaired Ras activation and anergy induction, whereas germline knockdown mice showed enhanced antitumor properties and more effective immune responses against pathogens. Here we review the mechanisms used by DGKs to ameliorate T cell activation and how inhibition could be used to reinvigorate T cell functions in cancer context. A better knowledge of the molecular mechanisms involved upon T cell activation will help to improve current therapies with DAG promoting agents.
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Affiliation(s)
- Miguel Martin-Salgado
- Department of Immunology and Oncology. National Centre for Biotechnology. Spanish Research Council (CNB-CSIC), Spain
| | - Ane Ochoa-Echeverría
- Department of Immunology and Oncology. National Centre for Biotechnology. Spanish Research Council (CNB-CSIC), Spain
| | - Isabel Mérida
- Department of Immunology and Oncology. National Centre for Biotechnology. Spanish Research Council (CNB-CSIC), Spain.
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2
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Traczyk G, Świątkowska A, Hromada-Judycka A, Janikiewicz J, Kwiatkowska K. An intact zinc finger motif of the C1B domain is critical for stability and activity of diacylglycerol kinase-ε. Int J Biochem Cell Biol 2022; 152:106295. [PMID: 36113832 DOI: 10.1016/j.biocel.2022.106295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/08/2022] [Accepted: 09/08/2022] [Indexed: 10/31/2022]
Abstract
Diacylglycerol kinase-ε (DGKε) phosphorylates DAG to phosphatidic acid with unique specificity toward 18:0/20:4 DAG (SAG). SAG is a typical backbone of phosphatidylinositol and its derivatives, therefore DGKε activity is crucial for the turnover of these signaling lipids. Malfunction of DGKε contributes to several pathophysiological conditions, including atypical hemolytic uremic syndrome (aHUS) linked with DGKE mutations. In the present study we analyzed the role of a zinc finger motif of the C1B domain of DGKε, as some aHUS-linked mutations affect this ill-defined part of the kinase. For this, we introduce a novel fluorescent assay for determination of DGKε activity which relies on the use of NBD-SAG in mixed micelles as a substrate, followed by TLC separation of NBD-phosphatidic acid formed. The assay reliably determines the activity of purified human GST-DGKε, also endogenous DGKε or overexpressed mouse DGKε-Myc in cell lysates, homogenates, and kinase immunoprecipitates. Using the above assay we found that four amino acids, Cys135, Cys138, His161 and Cys164, forming the zinc finger motif in the C1B domain are required for the DGKε-Myc activity and stability. Substitution of any of these amino acids with Ala or Trp in DGKε-Myc abolished its activity and led to its proteasomal degradation, possibly assisted by Hsp70/90/40 chaperones. Inhibition of the 26S proteasome prevented the degradation but the mutated proteins were inactive. The present data on the deleterious effect of the zinc finger motif disruption contribute to the understanding of the DGKε-linked aHUS, as the Cys164Trp substitution in mouse DGKε corresponds to the Cys167Trp one in human DGKε found in some aHUS patients.
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Affiliation(s)
- Gabriela Traczyk
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
| | - Anna Świątkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
| | - Aneta Hromada-Judycka
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
| | - Justyna Janikiewicz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093 Warsaw, Poland.
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3
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González-Mancha N, Rodríguez-Rodríguez C, Alcover A, Merida I. Sorting Nexin 27 Enables MTOC and Secretory Machinery Translocation to the Immune Synapse. Front Immunol 2022; 12:814570. [PMID: 35095913 PMCID: PMC8790036 DOI: 10.3389/fimmu.2021.814570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 12/20/2021] [Indexed: 11/24/2022] Open
Abstract
Sorting nexin 27 (SNX27) association to the retromer complex mediates intracellular trafficking of cargoes containing PSD95/Dlg1/ZO-1 (PDZ)-binding C-terminal sequences from endosomes to the cell surface, preventing their lysosomal degradation. Antigen recognition by T lymphocyte leads to the formation of a highly organized structure named the immune synapse (IS), which ensures cell-cell communication and sustained T cell activation. At the neuronal synapse, SNX27 recycles PDZ-binding receptors and its defective expression is associated with synaptic dysfunction and cognitive impairment. In T lymphocytes, SNX27 was found localized at recycling endosomal compartments that polarized to the IS, suggesting a function in polarized traffic to this structure. Proteomic analysis of PDZ-SNX27 interactors during IS formation identify proteins with known functions in cytoskeletal reorganization and lipid regulation, such as diacylglycerol (DAG) kinase (DGK) ζ, as well as components of the retromer and WASH complex. In this study, we investigated the consequences of SNX27 deficiency in cytoskeletal reorganization during IS formation. Our analyses demonstrate that SNX27 controls the polarization towards the cell-cell interface of the PDZ-interacting cargoes DGKζ and the retromer subunit vacuolar protein sorting protein 26, among others. SNX27 silencing abolishes the formation of a DAG gradient at the IS and prevents re-localization of the dynactin complex component dynactin-1/p150Glued, two events that correlate with impaired microtubule organizing center translocation (MTOC). SNX27 silenced cells show marked alteration in cytoskeleton organization including a failure in the organization of the microtubule network and defects in actin clearance at the IS. Reduced SNX27 expression was also found to hinder the arrangement of signaling microclusters at the IS, as well as the polarization of the secretory machinery towards the antigen presenting cells. Our results broaden the knowledge of SNX27 function in T lymphocytes by showing a function in modulating IS organization through regulated trafficking of cargoes.
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Affiliation(s)
- Natalia González-Mancha
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Cristina Rodríguez-Rodríguez
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
| | - Andrés Alcover
- Institut Pasteur, Université de Paris, Unité Biologie Cellulaire des Lymphocytes, INSERM U1224, Ligue Nationale Contre le Cancer, Équipe Labellisée Ligue-2018, Paris, France
| | - Isabel Merida
- Department of Immunology and Oncology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid, Spain
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4
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Ard R, Maillet JC, Daher E, Phan M, Zinoviev R, Parks RJ, Gee SH. PKCα-mediated phosphorylation of the diacylglycerol kinase ζ MARCKS domain switches cell migration modes by regulating interactions with Rac1 and RhoA. J Biol Chem 2021; 296:100516. [PMID: 33676892 PMCID: PMC8042443 DOI: 10.1016/j.jbc.2021.100516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 01/04/2023] Open
Abstract
Cells can switch between Rac1 (lamellipodia-based) and RhoA (blebbing-based) migration modes, but the molecular mechanisms regulating this shift are not fully understood. Diacylglycerol kinase ζ (DGKζ), which phosphorylates diacylglycerol to yield phosphatidic acid, forms independent complexes with Rac1 and RhoA, selectively dissociating each from their common inhibitor RhoGDI. DGKζ catalytic activity is required for Rac1 dissociation but is dispensable for RhoA dissociation; instead, DGKζ stimulates RhoA release via a kinase-independent scaffolding mechanism. The molecular determinants that mediate the selective targeting of DGKζ to Rac1 or RhoA signaling complexes are unknown. Here, we show that protein kinase Cα (PKCα)-mediated phosphorylation of the DGKζ MARCKS domain increased DGKζ association with RhoA and decreased its interaction with Rac1. The same modification also enhanced DGKζ interaction with the scaffold protein syntrophin. Expression of a phosphomimetic DGKζ mutant stimulated membrane blebbing in mouse embryonic fibroblasts and C2C12 myoblasts, which was augmented by inhibition of endogenous Rac1. DGKζ expression in differentiated C2 myotubes, which have low endogenous Rac1 levels, also induced substantial membrane blebbing via the RhoA-ROCK pathway. These events were independent of DGKζ catalytic activity, but dependent upon a functional C-terminal PDZ-binding motif. Rescue of RhoA activity in DGKζ-null cells also required the PDZ-binding motif, suggesting that syntrophin interaction is necessary for optimal RhoA activation. Collectively, our results define a switch-like mechanism whereby DGKζ phosphorylation by PKCα plays a role in the interconversion between Rac1 and RhoA signaling pathways that underlie different cellular migration modes.
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Affiliation(s)
- Ryan Ard
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Jean-Christian Maillet
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Elias Daher
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Michael Phan
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Radoslav Zinoviev
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | - Robin J Parks
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada; Molecular Medicine Program, Ottawa Health Research Institute, Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Stephen H Gee
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada; Centre for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada.
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5
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Subcellular Localization Relevance and Cancer-Associated Mechanisms of Diacylglycerol Kinases. Int J Mol Sci 2020; 21:ijms21155297. [PMID: 32722576 PMCID: PMC7432101 DOI: 10.3390/ijms21155297] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/21/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
An increasing number of reports suggests a significant involvement of the phosphoinositide (PI) cycle in cancer development and progression. Diacylglycerol kinases (DGKs) are very active in the PI cycle. They are a family of ten members that convert diacylglycerol (DAG) into phosphatidic acid (PA), two-second messengers with versatile cellular functions. Notably, some DGK isoforms, such as DGKα, have been reported to possess promising therapeutic potential in cancer therapy. However, further studies are needed in order to better comprehend their involvement in cancer. In this review, we highlight that DGKs are an essential component of the PI cycle that localize within several subcellular compartments, including the nucleus and plasma membrane, together with their PI substrates and that they are involved in mediating major cancer cell mechanisms such as growth and metastasis. DGKs control cancer cell survival, proliferation, and angiogenesis by regulating Akt/mTOR and MAPK/ERK pathways. In addition, some DGKs control cancer cell migration by regulating the activities of the Rho GTPases Rac1 and RhoA.
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Xie D, Zhang S, Chen P, Deng W, Pan Y, Xie J, Wang J, Liao B, Sleasman JW, Zhong XP. Negative control of diacylglycerol kinase ζ-mediated inhibition of T cell receptor signaling by nuclear sequestration in mice. Eur J Immunol 2020; 50:1729-1745. [PMID: 32525220 DOI: 10.1002/eji.201948442] [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: 10/17/2019] [Revised: 04/17/2020] [Accepted: 06/09/2020] [Indexed: 12/16/2022]
Abstract
Diacylglycerol kinases (DGKs) play important roles in restraining diacylglycerol (DAG)-mediated signaling. Within the DGK family, the ζ isoform appears to be the most important isoform in T cells for controlling their development and function. DGKζ has been demonstrated to regulate T cell maturation, activation, anergy, effector/memory differentiation, defense against microbial infection, and antitumor immunity. Given its critical functions, DGKζ function should be tightly regulated to ensure proper signal transduction; however, mechanisms that control DGKζ function are still poorly understood. We report here that DGKζ dynamically translocates from the cytosol into the nuclei in T cells after TCR stimulation. In mice, DGKζ mutant defective in nuclear localization displayed enhanced ability to inhibit TCR-induced DAG-mediated signaling in primary T cells, maturation of conventional αβT and iNKT cells, and activation of peripheral T cells compared with WT DGKζ. Our study reveals for the first time nuclear sequestration of DGKζ as a negative control mechanism to spatially restrain it from terminating DAG mediated signaling in T cells. Our data suggest that manipulation of DGKζ nucleus-cytosol shuttling as a novel strategy to modulate DGKζ activity and immune responses for treatment of autoimmune diseases and cancer.
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Affiliation(s)
- Danli Xie
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Shimeng Zhang
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Pengcheng Chen
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Wenhai Deng
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Yun Pan
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Jinhai Xie
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Jinli Wang
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Bryce Liao
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - John W Sleasman
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Xiao-Ping Zhong
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina.,Department of Immunology, Duke University Medical Center, Durham, North Carolina.,Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina
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7
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Beyond the Cell Surface: Targeting Intracellular Negative Regulators to Enhance T cell Anti-Tumor Activity. Int J Mol Sci 2019; 20:ijms20235821. [PMID: 31756921 PMCID: PMC6929154 DOI: 10.3390/ijms20235821] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 02/07/2023] Open
Abstract
It is well established that extracellular proteins that negatively regulate T cell function, such as Cytotoxic T-Lymphocyte-Associated protein 4 (CTLA-4) and Programmed Cell Death protein 1 (PD-1), can be effectively targeted to enhance cancer immunotherapies and Chimeric Antigen Receptor T cells (CAR-T cells). Intracellular proteins that inhibit T cell receptor (TCR) signal transduction, though less well studied, are also potentially useful therapeutic targets to enhance T cell activity against tumor. Four major classes of enzymes that attenuate TCR signaling include E3 ubiquitin kinases such as the Casitas B-lineage lymphoma proteins (Cbl-b and c-Cbl), and Itchy (Itch), inhibitory tyrosine phosphatases, such as Src homology region 2 domain-containing phosphatases (SHP-1 and SHP-2), inhibitory protein kinases, such as C-terminal Src kinase (Csk), and inhibitory lipid kinases such as Src homology 2 (SH2) domain-containing inositol polyphosphate 5-phosphatase (SHIP) and Diacylglycerol kinases (DGKs). This review describes the mechanism of action of eighteen intracellular inhibitory regulatory proteins in T cells within these four classes, and assesses their potential value as clinical targets to enhance the anti-tumor activity of endogenous T cells and CAR-T cells.
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8
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Diacylglycerol kinase control of protein kinase C. Biochem J 2019; 476:1205-1219. [DOI: 10.1042/bcj20180620] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 12/27/2022]
Abstract
Abstract
The diacylglycerol kinases (DGK) are lipid kinases that transform diacylglycerol (DAG) into phosphatidic acid (PA) in a reaction that terminates DAG-based signals. DGK provide negative regulation to conventional and novel protein kinase C (PKC) enzymes, limiting local DAG availability in a tissue- and subcellular-restricted manner. Defects in the expression/activity of certain DGK isoforms contribute substantially to cognitive impairment and mental disorders. Abnormal DGK overexpression in tumors facilitates invasion and resistance to chemotherapy preventing tumor immune destruction by tumor-infiltrating lymphocytes. Effective translation of these findings into therapeutic approaches demands a better knowledge of the physical and functional interactions between the DGK and PKC families. DGKζ is abundantly expressed in the nervous and immune system, where physically and functionally interacts with PKCα. The latest discoveries suggest that PDZ-mediated interaction facilitates spatial restriction of PKCα by DGKζ at the cell–cell contact sites in a mechanism where the two enzymes regulate each other. In T lymphocytes, DGKζ interaction with Sorting Nexin 27 (SNX27) guarantees the basal control of PKCα activation. SNX27 is a trafficking component required for normal brain function whose deficit has been linked to Alzheimer's disease (AD) pathogenesis. The enhanced PKCα activation as the result of SNX27 silencing in T lymphocytes aligns with the recent correlation found between gain-of-function PKCα mutations and AD and suggests that disruption of the mechanisms that provides a correct spatial organization of DGKζ and PKCα may lie at the basis of immune and neuronal synapse impairment.
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9
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Xu C, Xie H, Guo X, Gong H, Liu L, Qi H, Xu C, Liu W. A PIP 2-derived amplification loop fuels the sustained initiation of B cell activation. Sci Immunol 2018; 2:2/17/eaan0787. [PMID: 29150438 DOI: 10.1126/sciimmunol.aan0787] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 10/04/2017] [Indexed: 12/28/2022]
Abstract
Lymphocytes have evolved sophisticated signaling amplification mechanisms to efficiently activate downstream signaling after detection of rare ligands in their microenvironment. B cell receptor microscopic clusters (BCR microclusters) are assembled on the plasma membrane and recruit signaling molecules for the initiation of lymphocyte signaling after antigen binding. We identified a signaling amplification loop derived from phosphatidylinositol 4,5-biphosphate (PIP2) for the sustained B cell activation. Upon antigen recognition, PIP2 was depleted by phospholipase C-γ2 (PLC-γ2) within the BCR microclusters and was regenerated by phosphatidic acid-dependent type I phosphatidylinositol 4-phosphate 5-kinase outside the BCR microclusters. The hydrolysis of PIP2 inside the BCR microclusters induced a positive feedback mechanism for its synthesis outside the BCR microclusters. The falling gradient of PIP2 across the boundary of BCR microclusters was important for the efficient formation of BCR microclusters. Our results identified a PIP2-derived amplification loop that fuels the sustained initiation of B cell activation.
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Affiliation(s)
- Chenguang Xu
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing 100084, China
| | - Hengyi Xie
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing 100084, China
| | - Xingdong Guo
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Haipeng Gong
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lei Liu
- Tsinghua-Peking Center for Life Sciences, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (MOE), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Hai Qi
- Tsinghua-Peking Center for Life Sciences, Laboratory of Dynamic Immunobiology, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Chenqi Xu
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.,School of Life Science, ShanghaiTech University, Shanghai 201210, China
| | - Wanli Liu
- Ministry of Education (MOE) Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing 100084, China.
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10
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Franks CE, Campbell ST, Purow BW, Harris TE, Hsu KL. The Ligand Binding Landscape of Diacylglycerol Kinases. Cell Chem Biol 2017; 24:870-880.e5. [PMID: 28712745 DOI: 10.1016/j.chembiol.2017.06.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/15/2017] [Accepted: 06/16/2017] [Indexed: 11/17/2022]
Abstract
Diacylglycerol kinases (DGKs) are integral components of signal transduction cascades that regulate cell biology through ATP-dependent phosphorylation of the lipid messenger diacylglycerol. Methods for direct evaluation of DGK activity in native biological systems are lacking and needed to study isoform-specific functions of these multidomain lipid kinases. Here, we utilize ATP acyl phosphate activity-based probes and quantitative mass spectrometry to define, for the first time, ATP and small-molecule binding motifs of representative members from all five DGK subtypes. We use chemical proteomics to discover an unusual binding mode for the DGKα inhibitor, ritanserin, including interactions at the atypical C1 domain distinct from the ATP binding region. Unexpectedly, deconstruction of ritanserin yielded a fragment compound that blocks DGKα activity through a conserved binding mode and enhanced selectivity against the kinome. Collectively, our studies illustrate the power of chemical proteomics to profile protein-small molecule interactions of lipid kinases for fragment-based lead discovery.
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Affiliation(s)
- Caroline E Franks
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA
| | - Sean T Campbell
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA; Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Benjamin W Purow
- Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Ku-Lung Hsu
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA; Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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11
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Predominant contribution of DGKζ over DGKα in the control of PKC/PDK‐1‐regulated functions in T cells. Immunol Cell Biol 2017; 95:549-563. [DOI: 10.1038/icb.2017.7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/16/2017] [Accepted: 01/31/2017] [Indexed: 12/14/2022]
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12
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Riese MJ, Moon EK, Johnson BD, Albelda SM. Diacylglycerol Kinases (DGKs): Novel Targets for Improving T Cell Activity in Cancer. Front Cell Dev Biol 2016; 4:108. [PMID: 27800476 PMCID: PMC5065962 DOI: 10.3389/fcell.2016.00108] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/14/2016] [Indexed: 01/23/2023] Open
Abstract
Diacylglycerol kinases (DGKs) are a family of enzymes that catalyze the metabolism of diacylglycerol (DAG). Two isoforms of DGK, DGKα, and DGKζ, specifically regulate the pool of DAG that is generated as a second messenger after stimulation of the T cell receptor (TCR). Deletion of either isoform in mouse models results in T cells bearing a hyperresponsive phenotype and enhanced T cell activity against malignancy. Whereas, DGKζ appears to be the dominant isoform in T cells, rationale exists for targeting both isoforms individually or coordinately. Additional work is needed to rigorously identify the molecular changes that result from deletion of DGKs in order to understand how DAG contributes to T cell activation, the effect of DGK inhibition in human T cells, and to rationally develop combined immunotherapeutic strategies that target DGKs.
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Affiliation(s)
- Matthew J. Riese
- Division of Hematology/Oncology, Department of Medicine, Medical College of WisconsinMilwaukee, WI, USA
- Blood Center of Wisconsin, Blood Research InstituteMilwaukee, WI, USA
| | - Edmund K. Moon
- Division of Pulmonary, Allergy, and Critical Care, Department of Medicine, University of PennsylvaniaPhiladelphia, PA, USA
| | - Bryon D. Johnson
- Division of Hematology/Oncology/Transplant, Department of Pediatrics, Medical College of WisconsinMilwaukee, WI, USA
| | - Steven M. Albelda
- Division of Pulmonary, Allergy, and Critical Care, Department of Medicine, University of PennsylvaniaPhiladelphia, PA, USA
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13
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A molecular code for endosomal recycling of phosphorylated cargos by the SNX27-retromer complex. Nat Struct Mol Biol 2016; 23:921-932. [PMID: 27595347 DOI: 10.1038/nsmb.3290] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 08/11/2016] [Indexed: 12/11/2022]
Abstract
Recycling of internalized receptors from endosomal compartments is essential for the receptors' cell-surface homeostasis. Sorting nexin 27 (SNX27) cooperates with the retromer complex in the recycling of proteins containing type I PSD95-Dlg-ZO1 (PDZ)-binding motifs. Here we define specific acidic amino acid sequences upstream of the PDZ-binding motif required for high-affinity engagement of the human SNX27 PDZ domain. However, a subset of SNX27 ligands, such as the β2 adrenergic receptor and N-methyl-D-aspartate (NMDA) receptor, lack these sequence determinants. Instead, we identified conserved sites of phosphorylation that substitute for acidic residues and dramatically enhance SNX27 interactions. This newly identified mechanism suggests a likely regulatory switch for PDZ interaction and protein transport by the SNX27-retromer complex. Defining this SNX27 binding code allowed us to classify more than 400 potential SNX27 ligands with broad functional implications in signal transduction, neuronal plasticity and metabolite transport.
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Purow B. Molecular Pathways: Targeting Diacylglycerol Kinase Alpha in Cancer. Clin Cancer Res 2015; 21:5008-12. [PMID: 26420856 DOI: 10.1158/1078-0432.ccr-15-0413] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 09/10/2015] [Indexed: 02/02/2023]
Abstract
Lipid kinases have largely been neglected as targets in cancer, and an increasing number of reports suggest diacylglycerol kinase alpha (DGKα) may be one with promising therapeutic potential. DGKα is one of 10 DGK family members that convert diacylglycerol (DAG) to phosphatidic acid (PA), and both DAG and PA are critical lipid second messengers in the plasma membrane. A host of important oncogenic proteins and pathways affect cancer cells in part through DGKα, including the c-Met and VEGF receptors. Others partially mediate the effects of DGKα inhibition in cancer, such as mTOR and HIF-1α. DGKα inhibition can directly impair cancer cell viability, inhibits angiogenesis, and notably may also boost T-cell activation and enhance cancer immunotherapies. Although two structurally similar inhibitors of DGKα were established decades ago, they have seen minimal in vivo usage, and it is unlikely that either of these older DGKα inhibitors will have utility for cancer. An abandoned compound that also inhibits serotonin receptors may have more translational potential as a DGKα inhibitor, but more potent and specific DGKα inhibitors are sorely needed. Other DGK family members may also provide therapeutic targets in cancer, but require further investigation.
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Affiliation(s)
- Benjamin Purow
- Department of Neurology, University of Virginia, Charlottesville, Virginia.
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Merida I, Andrada E, Gharbi SI, Avila-Flores A. Redundant and specialized roles for diacylglycerol kinases and in the control of T cell functions. Sci Signal 2015; 8:re6. [DOI: 10.1126/scisignal.aaa0974] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Chauveau A, Le Floc'h A, Bantilan NS, Koretzky GA, Huse M. Diacylglycerol kinase α establishes T cell polarity by shaping diacylglycerol accumulation at the immunological synapse. Sci Signal 2014; 7:ra82. [PMID: 25161317 DOI: 10.1126/scisignal.2005287] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Polarization of the T cell microtubule-organizing center (MTOC) to the immunological synapse between the T cell and an antigen-presenting cell (APC) maintains the specificity of T cell effector responses by enabling directional secretion toward the APC. The reorientation of the MTOC is guided by a sharp gradient of the second messenger diacylglycerol (DAG), which is centered at the immunological synapse. We used a single-cell photoactivation approach to demonstrate that diacylglycerol kinase α (DGK-α), which catalyzes the conversion of DAG to phosphatidic acid, determined T cell polarity by limiting the diffusion of DAG. DGK-α-deficient T cells exhibited enlarged accumulations of DAG at the immunological synapse, as well as impaired reorientation of the MTOC. In contrast, T cells lacking the related isoform DGK-ζ did not display polarization defects. We also found that DGK-α localized preferentially to the periphery of the immunological synapse, suggesting that it constrained the area over which DAG accumulated. Phosphoinositide 3-kinase activity was required for the peripheral localization pattern of DGK-α, which suggests a link between DAG and phosphatidylinositol signaling during T cell activation. These results reveal a previously unappreciated function of DGK-α and provide insight into the mechanisms that determine lymphocyte polarity.
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Affiliation(s)
- Anne Chauveau
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Audrey Le Floc'h
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Niels S Bantilan
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Gary A Koretzky
- Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Morgan Huse
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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Ishisaka M, Hara H. The Roles of Diacylglycerol Kinases in the Central Nervous System: Review of Genetic Studies in Mice. J Pharmacol Sci 2014; 124:336-43. [DOI: 10.1254/jphs.13r07cr] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Joshi RP, Schmidt AM, Das J, Pytel D, Riese MJ, Lester M, Diehl JA, Behrens EM, Kambayashi T, Koretzky GA. The ζ isoform of diacylglycerol kinase plays a predominant role in regulatory T cell development and TCR-mediated ras signaling. Sci Signal 2013; 6:ra102. [PMID: 24280043 DOI: 10.1126/scisignal.2004373] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diacylglycerol (DAG) is a critical second messenger that mediates T cell receptor (TCR)-stimulated signaling. The abundance of DAG is reduced by the diacylglycerol kinases (DGKs), which catalyze the conversion of DAG to phosphatidic acid (PA) and thus inhibit DAG-mediated signaling. In T cells, the predominant DGK isoforms are DGKα and DGKζ, and deletion of the genes encoding either isoform enhances DAG-mediated signaling. We found that DGKζ, but not DGKα, suppressed the development of natural regulatory T (T(reg)) cells and predominantly mediated Ras and Akt signaling downstream of the TCR. The differential functions of DGKα and DGKζ were not attributable to differences in protein abundance in T cells or in their localization to the contact sites between T cells and antigen-presenting cells. RasGRP1, a key DAG-mediated activator of Ras signaling, associated to a greater extent with DGKζ than with DGKα; however, in silico modeling of TCR-stimulated Ras activation suggested that a difference in RasGRP1 binding affinity was not sufficient to cause differences in the functions of each DGK isoform. Rather, the model suggested that a greater catalytic rate for DGKζ than for DGKα might lead to DGKζ exhibiting increased suppression of Ras-mediated signals compared to DGKα. Consistent with this notion, experimental studies demonstrated that DGKζ was more effective than DGKα at catalyzing the metabolism of DAG to PA after TCR stimulation. The enhanced effective enzymatic production of PA by DGKζ is therefore one possible mechanism underlying the dominant functions of DGKζ in modulating T(reg) cell development.
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Affiliation(s)
- Rohan P Joshi
- 1Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Abstract
Diacylglycerol (DAG), a second messenger generated by phospholipase Cγ1 activity upon engagement of a T-cell receptor, triggers several signaling cascades that play important roles in T cell development and function. A family of enzymes called DAG kinases (DGKs) catalyzes the phosphorylation of DAG to phosphatidic acid, acting as a braking mechanism that terminates DAG-mediated signals. Two DGK isoforms, α and ζ, are expressed predominantly in T cells and synergistically regulate the development of both conventional αβ T cells and invariant natural killer T cells in the thymus. In mature T cells, the activity of these DGK isoforms aids in the maintenance of self-tolerance by preventing T-cell hyperactivation upon T cell receptor stimulation and by promoting T-cell anergy. In CD8 cells, reduced DGK activity is associated with enhanced primary responses against viruses and tumors. Recent work also has established an important role for DGK activity at the immune synapse and identified partners that modulate DGK function. In addition, emerging evidence points to previously unappreciated roles for DGK function in directional secretion and T-cell adhesion. This review describes the multitude of roles played by DGKs in T cell development and function and emphasizes recent advances in the field.
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Affiliation(s)
- Sruti Krishna
- Department of Pediatrics, Division of Allergy and Immunology and Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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Krishna S, Zhong XP. Regulation of Lipid Signaling by Diacylglycerol Kinases during T Cell Development and Function. Front Immunol 2013; 4:178. [PMID: 23847619 PMCID: PMC3701226 DOI: 10.3389/fimmu.2013.00178] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 06/19/2013] [Indexed: 01/14/2023] Open
Abstract
Diacylglycerol (DAG) and phosphatidic acid (PA) are bioactive lipids synthesized when the T cell receptor binds to a cognate peptide-MHC complex. DAG triggers signaling by recruiting Ras guanyl-releasing protein 1, PKCθ, and other effectors, whereas PA binds to effector molecules that include mechanistic target of rapamycin, Src homology region 2 domain-containing phosphatase 1, and Raf1. While DAG-mediated pathways have been shown to play vital roles in T cell development and function, the importance of PA-mediated signals remains less clear. The diacylglycerol kinase (DGK) family of enzymes phosphorylates DAG to produce PA, serving as a molecular switch that regulates the relative levels of these critical second messengers. Two DGK isoforms, α and ζ, are predominantly expressed in T lineage cells and play an important role in conventional αβ T cell development. In mature T cells, the activity of these DGK isoforms aids in the maintenance of self-tolerance by preventing T cell hyper-activation and promoting T cell anergy. In this review, we discuss the roles of DAG-mediated pathways, PA-effectors, and DGKs in T cell development and function. We also highlight recent work that has uncovered previously unappreciated roles for DGK activity, for instance in invariant NKT cell development, anti-tumor and anti-viral CD8 responses, and the directional secretion of soluble effectors.
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Affiliation(s)
- Sruti Krishna
- Department of Pediatrics, Division of Allergy and Immunology, Duke University Medical Center , Durham, NC , USA ; Department of Immunology, Duke University Medical Center , Durham, NC , USA
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Joshi RP, Koretzky GA. Diacylglycerol kinases: regulated controllers of T cell activation, function, and development. Int J Mol Sci 2013; 14:6649-73. [PMID: 23531532 PMCID: PMC3645659 DOI: 10.3390/ijms14046649] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/07/2013] [Accepted: 03/14/2013] [Indexed: 01/22/2023] Open
Abstract
Diacylglycerol kinases (DGKs) are a diverse family of enzymes that catalyze the conversion of diacylglycerol (DAG), a crucial second messenger of receptor-mediated signaling, to phosphatidic acid (PA). Both DAG and PA are bioactive molecules that regulate a wide set of intracellular signaling proteins involved in innate and adaptive immunity. Clear evidence points to a critical role for DGKs in modulating T cell activation, function, and development. More recently, studies have elucidated factors that control DGK function, suggesting an added complexity to how DGKs act during signaling. This review summarizes the available knowledge of the function and regulation of DGK isoforms in signal transduction with a particular focus on T lymphocytes.
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Affiliation(s)
- Rohan P. Joshi
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA; E-Mail:
| | - Gary A. Koretzky
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA; E-Mail:
- Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-215-746-5522; Fax: +1-215-746-5525
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Gharbi SI, Avila-Flores A, Soutar D, Orive A, Koretzky GA, Albar JP, Mérida I. Transient PKCα shuttling to the immunological synapse is governed by (DGK)ζ and regulates L-selectin shedding. J Cell Sci 2013; 126:2176-86. [DOI: 10.1242/jcs.118513] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Considerable evidence indicates that diacylglycerol (DAG) generation at the immunological synapse (IS) determines T cell functions by regulating the duration and amplitude of Ras/ERK signals. The exact mechanism by which DAG regulates Ras/ERK activation downstream of the T cell receptor (TCR) nonetheless remains poorly understood. Here we characterize PKCα as a previously unrecognized component of the machinery that translates cell receptor occupancy into Ras/ERK-propagated signals. We show transient translocation of PKCα to the IS, mediated by DAG generation at the contact area. Diacylglycerol kinase (DGK)ζ negatively regulated PKCα translocation kinetics, whereas PKCα activity limited its own persistence at the IS. Coordinated activation of DGKζ and PKCα in response to antigen recognition regulated the amplitude and duration of Ras/ERK activation; this in turn mediated early processes of T cell surface proteolysis such as L-selectin shedding. Analysis of DGKζ-deficient mice further showed that increased DAG signaling is translated to downstream elements of this pathway, as reflected by enhanced PKCα-dependent L-selectin shedding. We propose that early activation of a DAG/PKCα axis contributes to the mechanisms by which antigen affinity translates into TCR biological responses.
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Rincón E, Gharbi SI, Santos-Mendoza T, Mérida I. Diacylglycerol kinase ζ: At the crossroads of lipid signaling and protein complex organization. Prog Lipid Res 2012; 51:1-10. [DOI: 10.1016/j.plipres.2011.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Gharbi SI, Rincón E, Avila-Flores A, Torres-Ayuso P, Almena M, Cobos MA, Albar JP, Mérida I. Diacylglycerol kinase ζ controls diacylglycerol metabolism at the immunological synapse. Mol Biol Cell 2011; 22:4406-14. [PMID: 21937721 PMCID: PMC3216665 DOI: 10.1091/mbc.e11-03-0247] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
DGKα and DGKζ negatively regulate the DAG/RasGRP1/Ras pathway in T cells. Study of the specific contribution of each isoform to DAG metabolism during immune synapse formation by use of a combination of RNAi and videomicroscopy techniques identifies DGKζ as mainly responsible for DAG consumption at the immunological synapse. Diacylglycerol (DAG) generation at the T cell immunological synapse (IS) determines the correct activation of antigen-specific immune responses. DAG kinases (DGKs) α and ζ act as negative regulators of DAG-mediated signals by catalyzing DAG conversion to phosphatidic acid (PA). Nonetheless, the specific input of each enzyme and their spatial regulation during IS formation remain uncharacterized. Here we report recruitment of endogenous DGKα and DGKζ to the T cell receptor (TCR) complex following TCR/CD28 engagement. Specific DGK gene silencing shows that PA production at the activated complex depends mainly on DGKζ, indicating functional differences between these proteins. DGKζ kinase activity at the TCR is enhanced by phorbol-12-myristate-13-acetate cotreatment, suggesting DAG-mediated regulation of DGKζ responsiveness. We used GFP-DGKζ and -DGKα chimeras to assess translocation dynamics during IS formation. Only GFP-DGKζ translocated rapidly to the plasma membrane at early stages of IS formation, independent of enzyme activity. Finally, use of a fluorescent DAG sensor confirmed rapid, sustained DAG accumulation at the IS and allowed us to directly correlate membrane translocation of active DGKζ with DAG consumption at the IS. This study highlights a DGKζ-specific function for local DAG metabolism at the IS and offers new clues to its mode of regulation.
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Affiliation(s)
- Severine I Gharbi
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Científicas, E-28049 Madrid, Spain
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Shulga YV, Topham MK, Epand RM. Regulation and functions of diacylglycerol kinases. Chem Rev 2011; 111:6186-208. [PMID: 21800853 DOI: 10.1021/cr1004106] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yulia V Shulga
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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Tu-Sekine B, Raben DM. Regulation and roles of neuronal diacylglycerol kinases: a lipid perspective. Crit Rev Biochem Mol Biol 2011; 46:353-64. [PMID: 21539478 DOI: 10.3109/10409238.2011.577761] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diacylglycerol kinases (DGKs) are a class of enzymes that catalyze the ATP-dependent conversion of diacylglycerol (DAG) to phosphatidic acid (PtdOH), resulting in the coordinate regulation of these two lipid second messengers. This regulation is particularly important in the nervous system where it is now well-established that DAG and PtdOH serve very important roles in modulating a variety of neurological functions. There are currently 10 identified mammalian DGKs, organized into five classes or "Types" based upon similarities in their primary sequences. A number of studies have identified eight of these isoforms in various regions of the mammalian central nervous system (CNS): DGK-α, DGK-β, DGK-γ, DGK-η, DGK-ζ, DGK-ι, DGK-ϵ, and DGK-θ. Further studies have provided compelling evidence supporting roles for these enzymes in neuronal spine density, myelination, synaptic activity, neuronal plasticity, epileptogenesis and neurotransmitter release. The physiological regulation of these enzymes is less clear. Like all interfacial enzymes, DGKs metabolize their hydrophobic substrate (DAG) at a membrane-aqueous interface. Therefore, these enzymes can be regulated by alterations in their subcellular localization, enzymatic activity, and/or membrane association. In this review, we summarize what is currently understood about the localization and regulation of the neuronal DGKs in the mammalian CNS.
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Affiliation(s)
- Becky Tu-Sekine
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, 21205 MD, USA
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Rincón E, de Guinoa JS, Gharbi SI, Sorzano COS, Carrasco YR, Mérida I. Translocation dynamics of sorting nexin 27 in activated T cells. J Cell Sci 2011; 124:776-88. [DOI: 10.1242/jcs.072447] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Sorting nexin 27 (SNX27) belongs to the sorting nexin family of proteins, which participate in vesicular and protein trafficking. Similarly to all sorting nexin proteins, SNX27 has a functional PX domain that is important for endosome binding, but it is the only sorting nexin with a PDZ domain. We identified SNX27 as a partner of diacylglycerol kinase ζ (DGKζ), a negative regulator of T cell function that metabolises diacylglycerol to yield phosphatidic acid. SNX27 interacts with the DGKζ PDZ-binding motif in early/recycling endosomes in resting T cells; however, the dynamics and mechanisms underlying SNX27 subcellular localisation during T cell activation are unknown. We demonstrate that in T cells that encounter pulsed antigen-presenting cells, SNX27 in transit on early/recycling endosomes polarise to the immunological synapse. A fraction of SNX27 accumulates at the mature immunological synapse in a process that is dependent on vesicular trafficking, binding of the PX domain to phosphatidylinositol 3-phosphate and the presence of the PDZ region. Downmodulation of expression of either SNX27 or DGKζ results in enhanced basal and antigen-triggered ERK phosphorylation. These results identify SNX27 as a PDZ-containing component of the T cell immunological synapse, and demonstrate a role for this protein in the regulation of the Ras–ERK pathway, suggesting a functional relationship between SNX27 and DGKζ.
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Affiliation(s)
- Esther Rincón
- Lipid signalling Laboratory, Centro Nacional de Biotecnología (CNB)/CSIC, E-28049 Madrid, Spain
| | - Julia Sáez de Guinoa
- B cell Dynamics Laboratory, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, E-28049 Madrid, Spain
| | - Severine I. Gharbi
- Lipid signalling Laboratory, Centro Nacional de Biotecnología (CNB)/CSIC, E-28049 Madrid, Spain
| | - Carlos O. S. Sorzano
- Biocomputing Unit, Centro Nacional de Biotecnología (CNB)/CSIC, E-28049 Madrid, Spain
| | - Yolanda R. Carrasco
- B cell Dynamics Laboratory, Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB)/CSIC, E-28049 Madrid, Spain
| | - Isabel Mérida
- Lipid signalling Laboratory, Centro Nacional de Biotecnología (CNB)/CSIC, E-28049 Madrid, Spain
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Diacylglycerol kinase α regulates the formation and polarisation of mature multivesicular bodies involved in the secretion of Fas ligand-containing exosomes in T lymphocytes. Cell Death Differ 2011; 18:1161-73. [PMID: 21252909 DOI: 10.1038/cdd.2010.184] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Multivesicular bodies (MVBs) are endocytic compartments that contain intraluminal vesicles formed by inward budding from the limiting membrane of endosomes. In T lymphocytes, these vesicles contain pro-apoptotic Fas ligand (FasL), which may be secreted as 'lethal exosomes' upon fusion of MVBs with the plasma membrane. Diacylglycerol kinase α (DGKα) regulate the secretion of exosomes, but it is unclear how this control is mediated. T-lymphocyte activation increases the number of MVBs that contain FasL. DGKα is recruited to MVBs and to exosomes in which it has a double function. DGKα kinase activity exerts a negative role in the formation of mature MVBs, as we demonstrate by the use of an inhibitor. Downmodulation of DGKα protein resulted in inhibition of both the polarisation of MVBs towards immune synapse and exosome secretion. The subcellular location of DGKα together with its complex role in the formation and polarised traffic of MVBs support the notion that DGKα is a key regulator of the polarised secretion of exosomes.
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Mérida I, Avila-Flores A, García J, Merino E, Almena M, Torres-Ayuso P. Diacylglycerol kinase alpha, from negative modulation of T cell activation to control of cancer progression. ACTA ACUST UNITED AC 2009; 49:174-88. [PMID: 19534031 DOI: 10.1016/j.advenzreg.2009.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Isabel Mérida
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus de Cantoblanco, E-28049 Madrid, Spain.
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Diacylglycerol kinases as sources of phosphatidic acid. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:942-8. [PMID: 19264149 DOI: 10.1016/j.bbalip.2009.02.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 02/18/2009] [Accepted: 02/18/2009] [Indexed: 11/22/2022]
Abstract
There are ten mammalian diacylglycerol kinases (DGKs) whose primary role is to terminate diacylglycerol (DAG) signaling. However, it is becoming increasingly apparent that DGKs also influence signaling events through their product, phosphatidic acid (PA). They do so in some cases by associating with proteins and then modifying their activity by generating PA. In other cases, DGKs broadly regulate signaling events by virtue of their ability to provide PA for the synthesis of phosphatidylinositols (PtdIns).
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33
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Topham MK, Epand RM. Mammalian diacylglycerol kinases: molecular interactions and biological functions of selected isoforms. Biochim Biophys Acta Gen Subj 2009; 1790:416-24. [PMID: 19364481 DOI: 10.1016/j.bbagen.2009.01.010] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 01/27/2009] [Accepted: 01/30/2009] [Indexed: 12/28/2022]
Abstract
The mammalian diacylglycerol kinases (DGK) are a group of enzymes having important roles in regulating many biological processes. Both the product and the substrate of these enzymes, i.e. diacylglycerol and phosphatidic acid, are important lipid signalling molecules. Each DGK isoform appears to have a distinct biological function as a consequence of its location in the cell and/or the proteins with which it associates. This review discusses three of the more extensively studied forms of this enzyme, DGKalpha, DGKvarepsilon, and DGKzeta. DGKalpha has an important role in immune function and its activity is modulated by several mechanisms. DGKvarepsilon has several unique features among which is its specificity for arachionoyl-containing substrates, suggesting its importance in phosphatidylinositol cycling. DGKzeta is expressed in many tissues and also has several mechanisms to regulate its functions. It is localized in several subcellular organelles, including the nucleus. The current state of our understanding of the properties and functions of these proteins is reviewed.
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Affiliation(s)
- Matthew K Topham
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112, USA
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Zhong XP, Guo R, Zhou H, Liu C, Wan CK. Diacylglycerol kinases in immune cell function and self-tolerance. Immunol Rev 2008; 224:249-64. [PMID: 18759932 DOI: 10.1111/j.1600-065x.2008.00647.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Both diacylglycerol (DAG) and phosphatidic acid (PA) are important second messengers involved in signal transduction from many immune cell receptors and can be generated and metabolized through multiple mechanisms. Recent studies indicate that diacylglycerol kinases (DGKs), the enzymes that catalyze phosphorylation of DAG to produce PA, play critical roles in regulating the functions of multiple immune cell lineages. In T cells, two DGK isoforms, alpha and zeta, inhibit DAG-mediated signaling following T-cell receptor engagement and prevent T-cell hyperactivation. DGK alpha and zeta synergistically promote T-cell anergy and are critical for T-cell tolerance. In mast cells, DGKzeta plays differential roles in their activation by promoting degranulation but attenuating cytokine production following engagement of the high affinity receptor for immunoglobulin E. In dendritic cells and macrophages, DGKzeta positively regulates Toll-like receptor-induced proinflammatory cytokine production through its product PA and is critical for host defense against Toxoplasma gondii infection. These studies demonstrate pivotal roles of DGKs in regulating immune cell function by acting both as signal terminator and initiator.
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Affiliation(s)
- Xiao-Ping Zhong
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
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Terabayashi T, Funato Y, Miki H. Dishevelled-induced phosphorylation regulates membrane localization of Par1b. Biochem Biophys Res Commun 2008; 375:660-5. [PMID: 18760999 DOI: 10.1016/j.bbrc.2008.08.098] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 08/16/2008] [Indexed: 11/16/2022]
Abstract
Par1b is an evolutionarily conserved kinase that plays crucial roles in cell polarity. Controlling intracellular localization of Par1b is important for its biological activity. We previously reported that Wnt stimulation or expression of Dvl promotes accumulation of Par1b in the membrane (T. Terabayashi, T.J. Itoh, H. Yamaguchi, Y. Yoshimura, Y. Funato, S. Ohno, H. Miki, Polarity-Regulating Kinase Partitioning-Defective 1/Microtubule Affinity-Regulating Kinase 2 Negatively Regulates Development of Dendrites on Hippocampal Neurons, J. Neurosci. 27 (2007) 13098-13107). However, its molecular mechanism remains unclear. Here we show the importance of Par1b phosphorylation in the regulation of membrane localization. We find that Thr-324 is phosphorylated in a Dvl-dependent manner. Interestingly, the conversion of Thr-324 to Glu results in a significant accumulation of Par1b in the membrane, without any effects on the kinase activity. Moreover, the phospho-mimicking Par1b mutant does not antagonistically function against Dvl in microtubule stabilization and neurite extension, although wildtype Par1b does. These results suggest that membrane accumulation of Par1b induced by Dvl is regulated by its phosphorylation status, which is important for Par1b to regulate the microtubule dynamics.
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Affiliation(s)
- Takeshi Terabayashi
- Laboratory of Intracellular Signaling, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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36
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Abstract
DGKs (diacylglycerol kinases) are members of a unique and conserved family of intracellular lipid kinases that phosphorylate DAG (diacylglycerol), catalysing its conversion into PA (phosphatidic acid). This reaction leads to attenuation of DAG levels in the cell membrane, regulating a host of intracellular signalling proteins that have evolved the ability to bind this lipid. The product of the DGK reaction, PA, is also linked to the regulation of diverse functions, including cell growth, membrane trafficking, differentiation and migration. In multicellular eukaryotes, DGKs provide a link between lipid metabolism and signalling. Genetic experiments in Caenorhabditis elegans, Drosophila melanogaster and mice have started to unveil the role of members of this protein family as modulators of receptor-dependent responses in processes such as synaptic transmission and photoreceptor transduction, as well as acquired and innate immune responses. Recent discoveries provide new insights into the complex mechanisms controlling DGK activation and their participation in receptor-regulated processes. After more than 50 years of intense research, the DGK pathway emerges as a key player in the regulation of cell responses, offering new possibilities of therapeutic intervention in human pathologies, including cancer, heart disease, diabetes, brain afflictions and immune dysfunctions.
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37
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Merino E, Sanjuán MA, Moraga I, Ciprés A, Mérida I. Role of the diacylglycerol kinase alpha-conserved domains in membrane targeting in intact T cells. J Biol Chem 2007; 282:35396-404. [PMID: 17911109 DOI: 10.1074/jbc.m702085200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Diacylglycerol kinase (DGK) phosphorylates diacylglycerol to phosphatidic acid, modifying the cellular levels of these two lipid mediators. Ten DGK isoforms, grouped into five subtypes, are found in higher organisms. All contain a conserved C-terminal domain and at least two cysteine-rich motifs of unknown function. DGKalpha is a type I enzyme that acts as a negative modulator of diacylglycerol-based signals during T cell activation. Here we studied the functional role of the DGKalpha domains using mutational analysis to investigate membrane binding in intact cells. We show that the two atypical C1 domains are essential for plasma membrane targeting of the protein in intact cells but unnecessary for catalytic activity. We also identify the C-terminal sequence of the protein as essential for membrane binding in a phosphatidic acid-dependent manner. Finally we demonstrate that, in the absence of the calcium binding domain, receptor-dependent translocation of the truncated protein is regulated by phosphorylation of Tyr(335). This functional study provides new insight into the role of the so-called conserved domains of this lipid kinase family and demonstrates the existence of additional domains that confer specific plasma membrane localization to this particular isoform.
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Affiliation(s)
- Ernesto Merino
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Científicas, Cantoblanco, E-28049 Madrid, Spain
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38
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Rincón E, Santos T, Avila-Flores A, Albar JP, Lalioti V, Lei C, Hong W, Mérida I. Proteomics Identification of Sorting Nexin 27 as a Diacylglycerol Kinase ζ-associated Protein. Mol Cell Proteomics 2007; 6:1073-87. [PMID: 17351151 DOI: 10.1074/mcp.m700047-mcp200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Diacylglycerol kinase zeta is a member of the diacylglycerol kinase family of enzymes, which generate phosphatidic acid through diacylglycerol phosphorylation. In addition to the catalytic and cysteine-rich domains found in all diacylglycerol kinases, diacylglycerol kinase zeta has a MARCKS domain as well as a C-terminal region containing four ankyrin repeats and a PDZ-binding motif. Previous reports demonstrated that diacylglycerol kinase zeta interaction with several proteins is an important mechanism for modulating the localization and activity of this enzyme. Here we used a proteomics approach to search for novel diacylglycerol kinase zeta-interacting proteins and identified sorting nexin 27 (SNX27), a recently described member of a protein family involved in intracellular trafficking, which has a PDZ domain in addition to the phox homology domain characteristic of SNX proteins. Co-immunoprecipitation studies and two-hybrid analysis confirmed physical, PDZ-dependent association between SNX27 and diacylglycerol kinase zeta. Because diacylglycerol kinase zeta is expressed abundantly in T lymphocytes, we characterized SNX27 expression and subcellular localization in these cells. SNX27 co-localized with transferrin receptor-positive vesicles, pointing to its participation in T cell endocytic recycling. Expression of deletion mutants revealed that in addition to the phox homology domain the SNX27 PDZ domain contributed to vesicle localization of this protein, suggesting that interaction with diacylglycerol kinase zeta regulates SNX27 localization. Analysis of cells with RNA interference-mediated knockdown of diacylglycerol kinase zeta showed accelerated transferrin receptor exit from the lymphocyte endocytic recycling compartment back to the plasma membrane, further confirming diacylglycerol kinase zeta-dependent control of vesicle trafficking. These data support a previously unreported role for diacylglycerol kinase zeta in the modulation of membrane trafficking, which may also help to define SNX27 function.
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Affiliation(s)
- Esther Rincón
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, E-28049 Madrid, Spain
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39
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Nelson CD, Perry SJ, Regier DS, Prescott SM, Topham MK, Lefkowitz RJ. Targeting of diacylglycerol degradation to M1 muscarinic receptors by beta-arrestins. Science 2007; 315:663-6. [PMID: 17272726 DOI: 10.1126/science.1134562] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Seven-transmembrane receptor (7TMR) signaling is transduced by second messengers such as diacylglycerol (DAG) generated in response to the heterotrimeric guanine nucleotide-binding protein Gq and is terminated by receptor desensitization and degradation of the second messengers. We show that beta-arrestins coordinate both processes for the Gq-coupled M1 muscarinic receptor. beta-Arrestins physically interact with diacylglycerol kinases (DGKs), enzymes that degrade DAG. Moreover, beta-arrestins are essential for conversion of DAG to phosphatidic acid after agonist stimulation, and this activity requires recruitment of the beta-arrestin-DGK complex to activated 7TMRs. The dual function of beta-arrestins, limiting production of diacylglycerol (by receptor desensitization) while enhancing its rate of degradation, is analogous to their ability to recruit adenosine 3',5'-monophosphate phosphodiesterases to Gs-coupled beta2-adrenergic receptors. Thus, beta-arrestins can serve similar regulatory functions for disparate classes of 7TMRs through structurally dissimilar enzymes that degrade chemically distinct second messengers.
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Affiliation(s)
- Christopher D Nelson
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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40
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Los AP, de Widt J, Topham MK, van Blitterswijk WJ, Divecha N. Protein kinase C inhibits binding of diacylglycerol kinase-zeta to the retinoblastoma protein. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1773:352-7. [PMID: 17239975 DOI: 10.1016/j.bbamcr.2006.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 11/07/2006] [Accepted: 12/11/2006] [Indexed: 11/20/2022]
Abstract
We previously showed that the retinoblastoma protein (pRB), a key regulator of G1 to S-phase transition of the cell cycle, binds to and stimulates diacylglycerol kinase-zeta (DGKzeta) to phosphorylate the lipid second messenger diacylglycerol into phosphatidic acid. pRB binds to the MARCKS phosphorylation-site domain of DGKzeta that can be phosphorylated by protein kinase C (PKC). Here, we report that activation of PKC by phorbol ester inhibits DGKzeta binding to pRB. Ro 31-8220, a specific inhibitor of PKC, alleviated this inhibition of binding. Mimicking of PKC phosphorylation of serine residues (by S/D but not S/N mutations) within the DGKzeta-MARCKS phosphorylation-site domain also prevented DGKzeta binding to pRB, suggesting that PKC phosphorylation of these residues negatively regulates the interaction between DGKzeta and pRB. In PKC overexpression studies, it appeared that activation of particularly the (wild-type) PKCalpha isoform inhibits DGKzeta binding to pRB, whereas dominant-negative PKCalpha neutralized this inhibition. PKCalpha activation thus prevents DGKzeta regulation by pRB, which may have implications for nuclear diacylglycerol and phosphatidic acid levels during the cell cycle.
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Affiliation(s)
- Alrik P Los
- Division of Cellular Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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41
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Imai SI, Kai M, Yasuda S, Kanoh H, Sakane F. Identification and characterization of a novel human type II diacylglycerol kinase, DGK kappa. J Biol Chem 2005; 280:39870-81. [PMID: 16210324 DOI: 10.1074/jbc.m500669200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Diacylglycerol kinase (DGK) plays an important role in signal transduction through modulating the balance between two signaling lipids, diacylglycerol and phosphatidic acid. Here we identified a tenth member of the DGK family designated DGK kappa. The kappa-isozyme (1271 amino acids, calculated molecular mass, 142 kDa) contains a pleckstrin homology domain, two cysteine-rich zinc finger-like structures, and a separated catalytic region as have been found commonly for the type II isozymes previously cloned (DGKdelta and DGKeta). The new DGK isozyme has additionally 33 tandem repeats of Glu-Pro-Ala-Pro at the N terminus. Reverse transcriptase-PCR showed that the DGK kappa mRNA is most abundant in the testis, and to a lesser extent in the placenta. DGK kappa, when expressed in HEK293 cells, was persistently localized at the plasma membrane even in the absence of cell stimuli. Deletion analysis revealed that the short C-terminal sequence (amino acid residues 1199-1268) is necessary and sufficient for the plasma membrane localization. Interestingly, DGK kappa, but not other type II DGKs, was specifically tyrosine-phosphorylated at Tyr78 through the Src family kinase pathway in H2O2-treated cells. Moreover, H2O2 selectively inhibited DGK kappa activity in a Src family kinase-independent manner, suggesting that the isozyme changes the balance of signaling lipids in the plasma membrane in response to oxidative stress. The expression patterns, subcellular distribution, and regulatory mechanisms of DGK kappa are distinct from those of DGKdelta and DGKeta despite high structural similarity, suggesting unique functions of the individual type II isozymes.
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Affiliation(s)
- Shin-ichi Imai
- Department of Biochemistry, Sapporo Medical University School of Medicine, Chuo-ku, Sapporo 060-8556, Japan
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42
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Yakubchyk Y, Abramovici H, Maillet JC, Daher E, Obagi C, Parks RJ, Topham MK, Gee SH. Regulation of neurite outgrowth in N1E-115 cells through PDZ-mediated recruitment of diacylglycerol kinase zeta. Mol Cell Biol 2005; 25:7289-302. [PMID: 16055737 PMCID: PMC1190239 DOI: 10.1128/mcb.25.16.7289-7302.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Syntrophins are scaffold proteins that regulate the subcellular localization of diacylglycerol kinase zeta (DGK-zeta), an enzyme that phosphorylates the lipid second-messenger diacylglycerol to yield phosphatidic acid. DGK-zeta and syntrophins are abundantly expressed in neurons of the developing and adult brain, but their function is unclear. Here, we show that they are present in cell bodies, neurites, and growth cones of cultured cortical neurons and differentiated N1E-115 neuroblastoma cells. Overexpression of DGK-zeta in N1E-115 cells induced neurite formation in the presence of serum, which normally prevents neurite outgrowth. This effect was independent of DGK-zeta kinase activity but dependent on a functional C-terminal PDZ-binding motif, which specifically interacts with syntrophin PDZ domains. DGK-zeta mutants with a blocked C terminus acted as dominant-negative inhibitors of outgrowth from serum-deprived N1E-115 cells and cortical neurons. Several lines of evidence suggest DGK-zeta promotes neurite outgrowth through association with the GTPase Rac1. DGK-zeta colocalized with Rac1 in neuronal processes and DGK-zeta-induced outgrowth was inhibited by dominant-negative Rac1. Moreover, DGK-zeta directly interacts with Rac1 through a binding site located within its C1 domains. Together with syntrophin, these proteins form a tertiary complex in N1E-115 cells. A DGK-zeta mutant that mimics phosphorylation of the MARCKS domain was unable to bind an activated Rac1 mutant (Rac1(V12)) and phorbol myristate acetate-induced protein kinase C activation inhibited the interaction of DGK-zeta with Rac1(V12), suggesting protein kinase C-mediated phosphorylation of the MARCKS domain negatively regulates DGK-zeta binding to active Rac1. Collectively, these findings suggest DGK-zeta, syntrophin, and Rac1 form a regulated signaling complex that controls polarized outgrowth in neuronal cells.
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Affiliation(s)
- Yury Yakubchyk
- Department of Cellular and Molecular Medicine, University of Ottawa, Ontario, Canada
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43
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Yahagi H, Takeda M, Asaumi Y, Okumura K, Takahashi R, Takahashi J, Ohta J, Tada H, Minatoya Y, Sakuma M, Watanabe J, Goto K, Shirato K, Kagaya Y. Differential regulation of diacylglycerol kinase isozymes in cardiac hypertrophy. Biochem Biophys Res Commun 2005; 332:101-8. [PMID: 15896305 DOI: 10.1016/j.bbrc.2005.04.094] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Accepted: 04/21/2005] [Indexed: 11/20/2022]
Abstract
To examine the involvement of diacylglycerol kinase (DGK) and phosphatidic acid phosphatase (PAP) in pressure overloaded cardiac hypertrophy, rats were subjected to either ascending aortic banding for 3, 7, and 28 days or sham operation. In comparison with sham-operated rats, the left ventricular (LV) weight of the aortic-banded rats increased progressively. At 28 days after surgery, the expression of DGKepsilon mRNA but not DGKzeta or PAP2b mRNA in the LV myocardium significantly decreased in the aortic-banded rats compared with the sham-operated rats. DGKzeta protein in the LV myocardium translocated from the particulate to the cytosolic compartment in the aortic-banded rats. Furthermore, the myocardial content of 1,2-diacylglycerol and PKCdelta protein expression in the particulate fraction of the LV myocardium significantly increased in aortic-banded rats compared with sham-operated rats. These results suggest that DGKepsilon and DGKzeta play distinct roles in the development of pressure overloaded cardiac hypertrophy and that the two isozymes are differentially regulated.
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Affiliation(s)
- Hirokazu Yahagi
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
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44
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van Baal J, de Widt J, Divecha N, van Blitterswijk WJ. Translocation of diacylglycerol kinase theta from cytosol to plasma membrane in response to activation of G protein-coupled receptors and protein kinase C. J Biol Chem 2005; 280:9870-8. [PMID: 15632189 DOI: 10.1074/jbc.m409301200] [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: 01/01/2023] Open
Abstract
Diacylglycerol kinase (DGK) phosphorylates the second messenger diacylglycerol (DAG) to phosphatidic acid. We previously identified DGK as one of nine mammalian DGK isoforms and reported on its regulation by interaction with RhoA and by translocation to the plasma membrane in response to noradrenaline. Here, we have investigated how the localization of DGK, fused to green fluorescent protein, is controlled upon activation of G protein-coupled receptors in A431 cells. Extracellular ATP, bradykinin, or thrombin induced DGK translocation from the cytoplasm to the plasma membrane within 2-6 min. This translocation, independent of DGK activity, was preceded by protein kinase C (PKC) translocation and was blocked by PKC inhibitors. Conversely, activation of PKC by 12-O-tetradecanoylphorbol-13-acetate induced DGK translocation. Membrane-permeable DAG (dioctanoylglycerol) also induced DGK translocation but in a PKC (staurosporin)-independent fashion. Mutations in the cysteine-rich domains of DGK abrogated its hormone- and DAG-induced translocation, suggesting that these domains are essential for DAG binding and DGK recruitment to the membrane. We show that DGK interacts selectively with and is phosphorylated by PKCepsilon and -eta and that peptide agonist-induced selective activation of PKCepsilon directly leads to DGK translocation. Our data are consistent with the concept that hormone-induced PKC activation regulates the intracellular localization of DGK, which may be important in the negative regulation of PKCepsilon and/or PKCeta activity.
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Affiliation(s)
- Jürgen van Baal
- Division of Cellular Biochemistry, The Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
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45
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Avila-Flores A, Santos T, Rincón E, Mérida I. Modulation of the mammalian target of rapamycin pathway by diacylglycerol kinase-produced phosphatidic acid. J Biol Chem 2005; 280:10091-9. [PMID: 15632115 DOI: 10.1074/jbc.m412296200] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protein known as mammalian target of rapamycin (mTOR) regulates cell growth by integrating different stimuli, such as available nutrients and mitogenic factors. The lipid messenger phosphatidic acid (PA) binds and positively regulates the mitogenic response of mTOR. PA generator enzymes are consequently potential regulators of mTOR. Here we explored the contribution to this pathway of the enzyme diacylglycerol kinase (DGK), which produces PA through phosphorylation of diacylglycerol. We found that overexpression of the DGKzeta, but not of the alpha isoform, in serum-deprived HEK293 cells induced mTOR-dependent phosphorylation of p70S6 kinase (p70S6K). After serum addition, p70S6K phosphorylation was higher and more resistant to rapamycin treatment in cells overexpressing DGKzeta. The effect of this DGK isoform on p70S6K hyperphosphorylation required the mTOR PA binding region. Down-regulation of endogenous DGKzeta by small interfering RNA in HEK293 cells diminished serum-induced p70S6K phosphorylation, highlighting the role of this isoform in the mTOR pathway. Our results confirm a role for PA in mTOR regulation and describe a novel pathway in which DGKzeta-derived PA acts as a mediator of mTOR signaling.
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Affiliation(s)
- Antonia Avila-Flores
- Department of Immunology and Oncology, National Centre for Biotechnology, Consejo Superior de Investigaciones Científicas, Campus Cantoblanco, E-28049 Madrid, Spain
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46
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Jose AM, Koelle MR. Domains, amino acid residues, and new isoforms of Caenorhabditis elegans diacylglycerol kinase 1 (DGK-1) important for terminating diacylglycerol signaling in vivo. J Biol Chem 2004; 280:2730-6. [PMID: 15563467 PMCID: PMC2048986 DOI: 10.1074/jbc.m409460200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Diacylglycerol kinases (DGKs) inhibit diacylglycerol (DAG) signaling by phosphorylating DAG. DGK-1, the Caenorhabditis elegans ortholog of human neuronal DGK, inhibits neurotransmission to control behavior. DGK-1, like DGK, has three cysteine-rich domains (CRDs), a pleckstrin homology domain, and a kinase domain. To identify DGK domains and amino acid residues critical for terminating DAG signaling in vivo, we analyzed 20 dgk-1 mutants defective in DGK-1-controlled behaviors. We found by sequencing that the mutations included nine amino acid substitutions and seven premature stop codons that impair the physiological functions of DGK-1. All nine amino acid substitutions are in the second CRD, the third CRD, or the kinase domain. Thus, these domains are important for the termination of DAG signaling by DGK-1 in vivo. Seven of the substituted amino acid residues are present in all human DGKs and likely define key residues required for the function of all DGKs. An ATP-binding site mutation expected to inactivate the kinase domain retained very little physiological function, but we found two stop codon mutants predicted to truncate DGK-1 before its kinase domain that retained significantly more function. We detected novel splice forms of dgk-1 that can reconcile this apparent conflict, as they skip exons containing the stop codons to produce DGK-1 isoforms that contain the kinase domain. Two of these isoforms lack an intact pleckstrin homology domain and yet appear to have significant function. Additional novel isoform(s) account for all of the DGK-1 function necessary for one behavior, dopamine response.
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Affiliation(s)
- Antony M. Jose
- Departments of Molecular, Cellular, and Developmental Biology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Michael R. Koelle
- Departments of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520
- ¶ To whom correspondence should be addressed: Dept. of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 333 Cedar St., SHM CE-30, New Haven, CT 06520. Tel.: 203-737-5808; Fax: 203-785-6404; E-mail:
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47
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Los AP, van Baal J, de Widt J, Divecha N, van Blitterswijk WJ. Structure-activity relationship of diacylglycerol kinase theta. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1636:169-74. [PMID: 15164764 DOI: 10.1016/j.bbalip.2003.11.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2003] [Accepted: 11/27/2003] [Indexed: 10/26/2022]
Abstract
Diacylglycerol kinase (DGK) phosphorylates the second messenger diacylglycerol (DAG) to phosphatidic acid (PA). Among the nine mammalian isotypes identified, DGKtheta is the only one with three cysteine-rich domains (CRDs) (instead of two) in its N-terminal regulatory region. We previously reported that DGKtheta binds to and is negatively regulated by active RhoA. We now report that RhoA strongly binds to the C-terminal catalytic domain, which would explain its inhibition of DGK activity. To help finding a physiological function of DGKtheta, we further determined its activity in vitro as a function of 15 different truncations and point mutations in the primary structure. Most of these alterations, located throughout the protein, inactivated the enzyme, suggesting that catalytic activity depends on all of its conserved domains. The most C-terminal CRD is elongated with a stretch of 15 amino acids that is highly conserved among DGK isotypes. Mutation analysis revealed a number of residues in this region that were essential for enzyme activity. We suggest that this CRD extension plays an essential role in the correct folding of the protein and/or in substrate presentation to the catalytic region of the protein.
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Affiliation(s)
- Alrik P Los
- Division of Cellular Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CXAmsterdam, The Netherlands
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48
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Davidson L, Pawson AJ, López de Maturana R, Freestone SH, Barran P, Millar RP, Maudsley S. Gonadotropin-releasing hormone-induced activation of diacylglycerol kinase-zeta and its association with active c-src. J Biol Chem 2004; 279:11906-16. [PMID: 14707140 DOI: 10.1074/jbc.m310784200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Gonadotropin-releasing hormone (GnRH)-induced receptor activation has been demonstrated to entrain a wide variety of signaling modalities. Most signaling pathways are concerned with the control of serine, threonine, or tyrosine-protein kinases, however, in the current article we demonstrate that in both a model cell line and in gonadotropes, GnRH additionally mediates the activation of lipid-directed kinases. We have shown that there is a functional connection between protein-tyrosine kinase modulation and lipid kinase activation. In HEK293 cells stably expressing the Type I mammalian GnRH receptor, we employed a proteomic approach to identify novel protein binding partners for GnRH-activated c-Src. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry we identified a GnRH-induced association between c-Src and the lipid kinase, diacylglycerol kinase-zeta (DGK-zeta). Using reciprocal co-immunoprecipitation we show that there is a significant elevation of the association between catalytically active c-Src with DGK-zeta in both HEK293 cells and murine gonadotrope LbetaT2 cells. Employing lipid kinase assays we have shown that the catalytic activity of DGK-zeta is significantly heightened in both HEK293 and LbetaT2 cells by GnRH. In addition, we demonstrate that the activation of DGK-zeta exerts a functional role in the murine gonadotrope LbetaT2 cell line. Elevated expression of DGK-zeta resulted in a shortening of the time scale of ERK activation in these cells suggesting a potential role of endogenous DGK-zeta in controlling the induction of LHbeta transcription by ERK1/2.
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Affiliation(s)
- Lindsay Davidson
- MRC Human Reproductive Sciences Unit, Edinburgh Royal Infirmary, The University of Edinburgh Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, Scotland, United Kingdom
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49
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Luo B, Prescott SM, Topham MK. Protein kinase C alpha phosphorylates and negatively regulates diacylglycerol kinase zeta. J Biol Chem 2003; 278:39542-7. [PMID: 12890670 DOI: 10.1074/jbc.m307153200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Diacylglycerol kinase (DGK) terminates diacylglycerol (DAG) signaling by phosphorylating DAG to produce phosphatidic acid, which also has signaling properties. Thus, precise control of DGK activity is essential for proper signal transduction. We demonstrated previously that a peptide corresponding to the myristoylated alanine-rich C kinase substrate (MARCKS) phosphorylation site domain (PSD) in DGK zeta was phosphorylated in vitro by an active fragment of protein kinase C (PKC). In the present study, we tested full-length DGK zeta and found that PKC alpha phosphorylated DGK zeta on serines within the MARCKS PSD in vitro and in vivo. DGK zeta also coimmunoprecipitated with PKC alpha, suggesting that they reside in a regulated signaling complex. We then tested whether phosphorylation affected DAG kinase activity. We found that a mutant (DGK zeta S/D) in which serines within the MARCKS PSD were altered to aspartates (to mimic phosphorylation) had lower activity compared with wild-type DGK zeta or a control mutant (DGK zeta S/N) in which the same serines were changed to asparagines. Furthermore, activation of PKC alpha by phorbol 12-myristate 13-acetate inhibited the activity of wild-type DGK zeta, but not DGK zeta S/D, in human embryonic kidney 293 cells. These results suggest that by phosphorylating the MARCKS PSD, PKC alpha attenuates DGK zeta activity. Supporting this, we found that cells expressing DGK zeta S/D had higher DAG levels and grew more rapidly compared with cells expressing DGK zeta S/N that could not be phosphorylated. Taken together, these results indicate that PKC alpha phosphorylates DGK zeta in cells, and this phosphorylation inhibits its kinase activity to remove cellular DAG, thereby affecting cell growth.
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Affiliation(s)
- Bai Luo
- Huntsman Cancer Institute, and Department of Oncological Sciences, University of Utah, Salt Lake City, Utah 84112, USA
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50
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Ciprés A, Carrasco S, Merino E, Díaz E, Krishna UM, Falck JR, Martínez-A C, Mérida I. Regulation of diacylglycerol kinase alpha by phosphoinositide 3-kinase lipid products. J Biol Chem 2003; 278:35629-35. [PMID: 12832407 DOI: 10.1074/jbc.m305635200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Diacylglycerol kinase alpha (DAGK alpha), like all type I DAGKs, has calcium regulatory motifs that act as negative regulators of enzyme activity and localization. Accordingly, DAGK alpha is activated by phospholipase C-coupled receptors in a calcium-dependent manner. One of the first functions attributed to DAGK alpha in lymphocytes was that of regulating interleukin 2-induced cell cycle entry. Interleukin-2 nonetheless exerts its action in the absence of cytosolic calcium increase. We have studied alternative receptor-derived signals to explain calcium-independent DAGK alpha activation, and show that DAGK alpha is stimulated by Src-like kinase-dependent phosphoinositide 3 kinase (PI3K) activation in lymphocytes. Our results demonstrate that, in vivo, the increase in cellular levels of PI3K products is sufficient to induce DAGK alpha activation, allowing DAGK alpha relocation to the intact lymphocyte plasma membrane. This activation is isoform-specific, because other type I DAGKs are not subject to this type of regulation. These studies are the first to describe a pathway in which, in the absence of receptor-regulated calcium increase, DAGK alpha activation and membrane localization is a direct consequence of PI3K activation.
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Affiliation(s)
- Angel Ciprés
- Department of Immunology and Oncology, National Center for Biotechnology, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, E-28049 Madrid, Spain
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