1
|
Hernandez-Lara MA, Richard J, Deshpande DA. Diacylglycerol kinase is a keystone regulator of signaling relevant to the pathophysiology of asthma. Am J Physiol Lung Cell Mol Physiol 2024; 327:L3-L18. [PMID: 38742284 DOI: 10.1152/ajplung.00091.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/05/2024] [Accepted: 04/23/2024] [Indexed: 05/16/2024] Open
Abstract
Signal transduction by G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and immunoreceptors converge at the activation of phospholipase C (PLC) for the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). This is a point for second-messenger bifurcation where DAG via protein kinase C (PKC) and IP3 via calcium activate distinct protein targets and regulate cellular functions. IP3 signaling is regulated by multiple calcium influx and efflux proteins involved in calcium homeostasis. A family of lipid kinases belonging to DAG kinases (DGKs) converts DAG to phosphatidic acid (PA), negatively regulating DAG signaling and pathophysiological functions. PA, through a series of biochemical reactions, is recycled to produce new molecules of PIP2. Therefore, DGKs act as a central switch in terminating DAG signaling and resynthesis of membrane phospholipids precursor. Interestingly, calcium and PKC regulate the activation of α and ζ isoforms of DGK that are predominantly expressed in airway and immune cells. Thus, DGK forms a feedback and feedforward control point and plays a crucial role in fine-tuning phospholipid stoichiometry, signaling, and functions. In this review, we discuss the previously underappreciated complex and intriguing DAG/DGK-driven mechanisms in regulating cellular functions associated with asthma, such as contraction and proliferation of airway smooth muscle (ASM) cells and inflammatory activation of immune cells. We highlight the benefits of manipulating DGK activity in mitigating salient features of asthma pathophysiology and shed light on DGK as a molecule of interest for heterogeneous diseases such as asthma.
Collapse
Affiliation(s)
- Miguel A Hernandez-Lara
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - Joshua Richard
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - Deepak A Deshpande
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| |
Collapse
|
2
|
Chen Z, Zhang W, Selmi C, Ridgway WM, Leung PS, Zhang F, Gershwin ME. The myristoylated alanine-rich C-kinase substrates (MARCKS): A membrane-anchored mediator of the cell function. Autoimmun Rev 2021; 20:102942. [PMID: 34509657 PMCID: PMC9746065 DOI: 10.1016/j.autrev.2021.102942] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 06/26/2021] [Indexed: 12/15/2022]
Abstract
The myristoylated alanine-rich C-kinase substrate (MARCKS) and the MARCKS-related protein (MARCKSL1) are ubiquitous, highly conserved membrane-associated proteins involved in the structural modulation of the actin cytoskeleton, chemotaxis, motility, cell adhesion, phagocytosis, and exocytosis. MARCKS includes an N-terminal myristoylated domain for membrane binding, a highly conserved MARCKS Homology 2 (MH2) domain, and an effector domain (which is the phosphorylation site). MARCKS can sequester phosphatidylinositol-4, 5-diphosphate (PIP2) at lipid rafts in the plasma membrane of quiescent cells, an action reversed by protein kinase C (PKC), ultimately modulating the immune function. Being expressed mostly in innate immune cells, MARCKS promotes the inflammation-driven migration and adhesion of cells and the secretion of cytokines such as tumor necrosis factor (TNF). From a clinical point of view, MARCKS is overexpressed in patients with schizophrenia and bipolar disorders, while the brain level of MARCKS phosphorylation is associated with Alzheimer's disease. Furthermore, MARCKS is associated with the development and progression of numerous types of cancers. Data in autoimmune diseases are limited to rheumatoid arthritis models in which a connection between MARCKS and the JAK-STAT pathway is mediated by miRNAs. We provide a comprehensive overview of the structure of MARCKS, its molecular characteristics and functions from a biological and pathogenetic standpoint, and will discuss the clinical implications of this pathway.
Collapse
Affiliation(s)
- Zhilei Chen
- Division of Rheumatology, Allergy, and Clinical Immunology, University of California Davis, Davis, CA 95616, United States,Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
| | - Weici Zhang
- Division of Rheumatology, Allergy, and Clinical Immunology, University of California Davis, Davis, CA 95616, United States,Corresponding authors. (W. Zhang), (F. Zhang)
| | - Carlo Selmi
- Humanitas Research Hospital - IRCCS, Rozzano, Milan, Italy
| | - William M. Ridgway
- Division of Rheumatology, Allergy, and Clinical Immunology, University of California Davis, Davis, CA 95616, United States
| | - Patrick S.C. Leung
- Division of Rheumatology, Allergy, and Clinical Immunology, University of California Davis, Davis, CA 95616, United States
| | - Fengchun Zhang
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China,Corresponding authors. (W. Zhang), (F. Zhang)
| | - M. Eric Gershwin
- Division of Rheumatology, Allergy, and Clinical Immunology, University of California Davis, Davis, CA 95616, United States
| |
Collapse
|
3
|
Diacylglycerol kinase ζ is a negative regulator of GPVI-mediated platelet activation. Blood Adv 2020; 3:1154-1166. [PMID: 30967391 DOI: 10.1182/bloodadvances.2018026328] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 03/08/2019] [Indexed: 02/07/2023] Open
Abstract
Diacylglycerol kinases (DGKs) are a family of enzymes that convert diacylglycerol (DAG) into phosphatidic acid (PA). The ζ isoform of DGK (DGKζ) has been reported to inhibit T-cell responsiveness by downregulating intracellular levels of DAG. However, its role in platelet function remains undefined. In this study, we show that DGKζ was expressed at significant levels in both platelets and megakaryocytes and that DGKζ-knockout (DGKζ-KO) mouse platelets were hyperreactive to glycoprotein VI (GPVI) agonists, as assessed by aggregation, spreading, granule secretion, and activation of relevant signal transduction molecules. In contrast, they were less responsive to thrombin. Platelets from DGKζ-KO mice accumulated faster on collagen-coated microfluidic surfaces under conditions of arterial shear and stopped blood flow faster after ferric chloride-induced carotid artery injury. Other measures of hemostasis, as measured by tail bleeding time and rotational thromboelastometry analysis, were normal. Interestingly, DGKζ deficiency led to increased GPVI expression on the platelet and megakaryocyte surfaces without affecting the expression of other platelet surface receptors. These results implicate DGKζ as a novel negative regulator of GPVI-mediated platelet activation that plays an important role in regulating thrombus formation in vivo.
Collapse
|
4
|
Honda S, Murakami C, Yamada H, Murakami Y, Ishizaki A, Sakane F. Analytical Method for Diacylglycerol Kinase ζ Activity in Cells Using Protein Myristoylation and Liquid Chromatography-Tandem Mass Spectrometry. Lipids 2019; 54:763-771. [PMID: 31736090 DOI: 10.1002/lipd.12201] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/06/2019] [Accepted: 10/24/2019] [Indexed: 01/05/2023]
Abstract
Specific inhibitors of diacylglycerol kinase (DGK) ζ can be promising anticancer medications via the activation of cancer immunity. Although the detection of cellular activities of target enzymes is essential for drug screening in addition to in vitro assays, it is difficult to detect the activity of DGKζ in cells. In the present study, we generated AcGFP-DGKζ cDNA with a consensus N-myristoylation sequence at the 5' end (Myr-AcGFP-DGKζ) to target DGKζ to membranes. Using liquid chromatography (LC)-tandem mass spectrometry (MS/MS) (LC-MS/MS), we showed that Myr-AcGFP-DGKζ, but not AcGFP-DGKζ without the myristoylation sequence, substantially augmented the levels of several phosphatidic acid (PtdOH) species. In contrast to Myr-AcGFP-DGKζ, its inactive mutant did not exhibit an increase in PtdOH production, indicating that the increase in PtdOH production was DGK activity-dependent. This method will be useful in chemical compound selection for the development of drugs targeting DGKζ and can be applicable to various soluble (nonmembrane bound) lipid-metabolizing enzymes, including other DGK isozymes.
Collapse
Affiliation(s)
- Shotaro Honda
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Haruka Yamada
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Yuki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Ayuka Ishizaki
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| |
Collapse
|
5
|
Singh BK, Lu W, Schmidt Paustian AM, Ge MQ, Koziol-White CJ, Flayer CH, Killingbeck SS, Wang N, Dong X, Riese MJ, Deshpande DA, Panettieri RA, Haczku A, Kambayashi T. Diacylglycerol kinase ζ promotes allergic airway inflammation and airway hyperresponsiveness through distinct mechanisms. Sci Signal 2019; 12:12/597/eaax3332. [PMID: 31481522 DOI: 10.1126/scisignal.aax3332] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Asthma is a chronic allergic inflammatory airway disease caused by aberrant immune responses to inhaled allergens, which leads to airway hyperresponsiveness (AHR) to contractile stimuli and airway obstruction. Blocking T helper 2 (TH2) differentiation represents a viable therapeutic strategy for allergic asthma, and strong TCR-mediated ERK activation blocks TH2 differentiation. Here, we report that targeting diacylglycerol (DAG) kinase zeta (DGKζ), a negative regulator of DAG-mediated cell signaling, protected against allergic asthma by simultaneously reducing airway inflammation and AHR though independent mechanisms. Targeted deletion of DGKζ in T cells decreased type 2 inflammation without reducing AHR. In contrast, loss of DGKζ in airway smooth muscle cells decreased AHR but not airway inflammation. T cell-specific enhancement of ERK signaling was only sufficient to limit type 2 airway inflammation, not AHR. Pharmacological inhibition of DGK diminished both airway inflammation and AHR in mice and also reduced bronchoconstriction of human airway samples in vitro. These data suggest that DGK is a previously unrecognized therapeutic target for asthma and reveal that the inflammatory and AHR components of asthma are not as interdependent as generally believed.
Collapse
Affiliation(s)
- Brenal K Singh
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wen Lu
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amanda M Schmidt Paustian
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Moyar Q Ge
- Pulmonary, Critical Care and Sleep Division, University of California, Davis, Davis, CA 95616, USA
| | - Cynthia J Koziol-White
- Rutgers Institute for Translational Medicine and Science, Rutgers University, New Brunswick, NJ 08901, USA
| | - Cameron H Flayer
- Pulmonary, Critical Care and Sleep Division, University of California, Davis, Davis, CA 95616, USA
| | - Sara S Killingbeck
- Pulmonary, Critical Care and Sleep Division, University of California, Davis, Davis, CA 95616, USA
| | - Nadan Wang
- Department of Medicine, Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Matthew J Riese
- Blood Research Institute, Blood Center of Wisconsin, Milwaukee, WI 53226, USA
| | - Deepak A Deshpande
- Department of Medicine, Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Rutgers University, New Brunswick, NJ 08901, USA
| | - Angela Haczku
- Pulmonary, Critical Care and Sleep Division, University of California, Davis, Davis, CA 95616, USA
| | - Taku Kambayashi
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
6
|
Benziane B, Borg ML, Tom RZ, Riedl I, Massart J, Björnholm M, Gilbert M, Chibalin AV, Zierath JR. DGKζ deficiency protects against peripheral insulin resistance and improves energy metabolism. J Lipid Res 2017; 58:2324-2333. [PMID: 29066466 DOI: 10.1194/jlr.m079723] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/16/2017] [Indexed: 12/25/2022] Open
Abstract
Diacylglycerol kinases (DGKs) regulate the balance between diacylglycerol (DAG) and phosphatidic acid. DGKζ is highly abundant in skeletal muscle and induces fiber hypertrophy. We hypothesized that DGKζ influences functional and metabolic adaptations in skeletal muscle and whole-body fuel utilization. DAG content was increased in skeletal muscle and adipose tissue, but unaltered in liver of DGKζ KO mice. Linear growth, body weight, fat mass, and lean mass were reduced in DGKζ KO versus wild-type mice. Conversely, male DGKζ KO and wild-type mice displayed a similar robust increase in plantaris weight after functional overload, suggesting that DGKζ is dispensable for muscle hypertrophy. Although glucose tolerance was similar, insulin levels were reduced in high-fat diet (HFD)-fed DGKζ KO versus wild-type mice. Submaximal insulin-stimulated glucose transport and p-Akt Ser473 were increased, suggesting enhanced skeletal muscle insulin sensitivity. Energy homeostasis was altered in DGKζ KO mice, as evidenced by an elevated respiratory exchange ratio, independent of altered physical activity or food intake. In conclusion, DGKζ deficiency increases tissue DAG content and leads to modest growth retardation, reduced adiposity, and protection against insulin resistance. DGKζ plays a role in the control of growth and metabolic processes, further highlighting specialized functions of DGK isoforms in type 2 diabetes pathophysiology.
Collapse
Affiliation(s)
- Boubacar Benziane
- Department of Physiology and Pharmacology Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Melissa L Borg
- Department of Physiology and Pharmacology Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Robby Z Tom
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Isabelle Riedl
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Julie Massart
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Marie Björnholm
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Marc Gilbert
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Juleen R Zierath
- Department of Physiology and Pharmacology Karolinska Institutet, 171 77 Stockholm, Sweden .,Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 77 Stockholm, Sweden
| |
Collapse
|
7
|
Attia M, Rachez C, Avner P, Rogner UC. Nucleosome assembly proteins and their interacting proteins in neuronal differentiation. Arch Biochem Biophys 2013; 534:20-6. [DOI: 10.1016/j.abb.2012.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 09/21/2012] [Accepted: 09/22/2012] [Indexed: 12/21/2022]
|
8
|
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]
|
9
|
Yang J, Seo J, Nair R, Han S, Jang S, Kim K, Han K, Paik SK, Choi J, Lee S, Bae YC, Topham MK, Prescott SM, Rhee JS, Choi SY, Kim E. DGKι regulates presynaptic release during mGluR-dependent LTD. EMBO J 2010; 30:165-80. [PMID: 21119615 DOI: 10.1038/emboj.2010.286] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 10/21/2010] [Indexed: 12/18/2022] Open
Abstract
Diacylglycerol (DAG) is an important lipid second messenger. DAG signalling is terminated by conversion of DAG to phosphatidic acid (PA) by diacylglycerol kinases (DGKs). The neuronal synapse is a major site of DAG production and action; however, how DGKs are targeted to subcellular sites of DAG generation is largely unknown. We report here that postsynaptic density (PSD)-95 family proteins interact with and promote synaptic localization of DGKι. In addition, we establish that DGKι acts presynaptically, a function that contrasts with the known postsynaptic function of DGKζ, a close relative of DGKι. Deficiency of DGKι in mice does not affect dendritic spines, but leads to a small increase in presynaptic release probability. In addition, DGKι-/- synapses show a reduction in metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD) at neonatal (∼2 weeks) stages that involve suppression of a decrease in presynaptic release probability. Inhibition of protein kinase C normalizes presynaptic release probability and mGluR-LTD at DGKι-/- synapses. These results suggest that DGKι requires PSD-95 family proteins for synaptic localization and regulates presynaptic DAG signalling and neurotransmitter release during mGluR-LTD.
Collapse
Affiliation(s)
- Jinhee Yang
- Department of Biological Sciences, National Creative Research Initiative Center for Synaptogenesis, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
|
11
|
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.
Collapse
|
12
|
Abramovici H, Gee SH. Morphological changes and spatial regulation of diacylglycerol kinase-zeta, syntrophins, and Rac1 during myoblast fusion. ACTA ACUST UNITED AC 2007; 64:549-67. [PMID: 17410543 DOI: 10.1002/cm.20204] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The fusion of mononuclear myoblasts into multinucleated myofibers is essential for the formation and growth of skeletal muscle. Myoblast fusion follows a well-defined sequence of cellular events, from initial recognition and adhesion, to alignment, and finally plasma membrane fusion. These processes depend upon coordinated remodeling of the actin cytoskeleton. Our recent studies suggest diacylglycerol kinase-zeta (DGK-zeta), an enzyme that metabolizes diacylglycerol to yield phosphatidic acid, plays an important role in actin reorganization. Here, we investigated whether DGK-zeta has a role in the fusion of cultured C2C12 myoblasts. We show that DGK-zeta and syntrophins, scaffold proteins of the dystrophin glycoprotein complex that bind directly to DGK-zeta, are spatially regulated during fusion. Both proteins accumulated with the GTPase Rac1 at sites where fine filopodia mediate the initial contact between myoblasts. In addition, DGK-zeta codistributed with the Ca(2+)-dependent cell adhesion molecule N-cadherin at nascent, but not previously established cell contacts. We provide evidence that C2 cells are pulled together at cell-cell junctions by N-cadherin-containing filopodia reminiscent of epithelial adhesion zippers, which guide the advance of lamellipodia from apposing cells. At later times, vesicles with properties of macropinosomes formed close to cell-cell junctions. Reconstruction of confocal optical sections showed these form dome-like protrusions from the dorsal surface of contacting cells. Collectively, these results suggest DGK-zeta and syntrophins play a role at multiple stages of the fusion process. Moreover, our findings provide a potential link between changes in the lipid content of the membrane bilayer and reorganization of the actin cytoskeleton during myoblast fusion.
Collapse
Affiliation(s)
- Hanan Abramovici
- Department of Cellular and Molecular Medicine, Center for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario, Canada
| | | |
Collapse
|
13
|
Crotty T, Cai J, Sakane F, Taketomi A, Prescott SM, Topham MK. Diacylglycerol kinase delta regulates protein kinase C and epidermal growth factor receptor signaling. Proc Natl Acad Sci U S A 2006; 103:15485-90. [PMID: 17021016 PMCID: PMC1622849 DOI: 10.1073/pnas.0604104103] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Diacylglycerol kinases (DGKs) phosphorylate diacylglycerol (DAG) to terminate its signaling. To study DGKdelta, we disrupted its gene in mice and found that DGKdelta deficiency reduced EGF receptor (EGFR) protein expression and activity. Similar to EGFR knockout mice, DGKdelta-deficient pups were born with open eyelids and died shortly after birth. PKCs are activated by DAG and phosphorylate EGFR to reduce its expression and activity. We found DAG accumulation, increased threonine phosphorylation of EGFR, enhanced phosphorylation of other PKC substrates, and increased PKC autophosphorylation in DGKdelta knockout cells, indicating that DGKdelta regulates EGFR by modulating PKC signaling.
Collapse
Affiliation(s)
| | | | | | | | - Stephen M. Prescott
- *Huntsman Cancer Institute and
- Department of Internal Medicine, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112
| | - Matthew K. Topham
- *Huntsman Cancer Institute and
- Department of Internal Medicine, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112
- To whom correspondence should be addressed. E-mail:
| |
Collapse
|
14
|
Adachi N, Oyasu M, Taniguchi T, Yamaguchi Y, Takenaka R, Shirai Y, Saito N. Immunocytochemical localization of a neuron-specific diacylglycerol kinase beta and gamma in the developing rat brain. ACTA ACUST UNITED AC 2006; 139:288-99. [PMID: 16019106 DOI: 10.1016/j.molbrainres.2005.06.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 05/31/2005] [Accepted: 06/01/2005] [Indexed: 11/17/2022]
Abstract
Diacylglycerol kinase (DGK) phosphorylates diacylglycerol (DG) to produce phosphatidic acid (PA) and is, therefore, a potential terminator of DG signaling. DG and PA are important intracellular second messengers. DG directly binds protein kinase C (PKC) then activates this multifunctional enzyme. Ca2+-dependent and brain-specific DGKs, alpha, beta, and gamma, are suggested to play pivotal roles in the central nervous system. To elucidate the DGK function in neuronal development, we studied the developmental changes of DGKalpha, beta, and gamma in the postnatal rat brain. By immunoblot analysis, DGKalpha and gamma subtypes were present at birth and then gradually increased, while DGKbeta was not present at birth or postnatal day 3, then increased rapidly from day 14 to reach maximum at day 28. Immunohistochemically, DGKbeta and gamma were distributed in different brain regions. In most brain regions, DGKgamma showed sustained expression throughout the postnatal developmental periods. Interestingly, a temporal expression of DGKgamma was observed in the medial geniculate nucleus during day 3 to 14, and a delay of DGKgamma expression was seen in Purkinje cells, which was coincident with dendritic growth of Purkinje cells. In the hippocampal pyramidal cell, both DGKbeta and gamma were abundant but subcellular localization was different. DGKgamma localized in the cytosol while DGKbeta localized along the membrane structure. These findings suggest that each DGK subtype has a spatio-temporally different function in the developmental neurons.
Collapse
Affiliation(s)
- Naoko Adachi
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | | | | | | | | | | | | |
Collapse
|
15
|
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.
Collapse
Affiliation(s)
- Yury Yakubchyk
- Department of Cellular and Molecular Medicine, University of Ottawa, Ontario, Canada
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Ali H, Nakano T, Saino-Saito S, Hozumi Y, Katagiri Y, Kamii H, Sato S, Kayama T, Kondo H, Goto K. Selective translocation of diacylglycerol kinase ζ in hippocampal neurons under transient forebrain ischemia. Neurosci Lett 2004; 372:190-5. [PMID: 15542238 DOI: 10.1016/j.neulet.2004.09.052] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Revised: 09/10/2004] [Accepted: 09/11/2004] [Indexed: 10/26/2022]
Abstract
The molecular mechanisms responsible for differential neuronal vulnerability to ischemic injury are incompletely understood. Previous studies have reported that the expression and activity of protein kinase C (PKC), some subtypes of which are activated by Ca(2+) and diacylglycerol (DG), are altered after ischemic insults. Therefore, DG kinase (DGK), which is responsible for controlling PKC activity through DG metabolism, may also be involved in this process. DGKzeta, which is abundantly expressed in the brain, contains a nuclear localization signal (NLS), suggesting its involvement in some nuclear processes in neuronal cells. To elucidate the functional implications of DGKzeta in ischemia, we examined detailed localization of DGKzeta in rat brain after ischemic insults. We used an ischemic model of global cerebral ischemia for 20 min by bilateral common carotid artery occlusion combined with hypotension and followed time-points of reperfusion. DGKzeta expression was evaluated by immunohistochemistry using affinity-purified anti-DGKzeta antibody. In sham-operated rats, a strong DGKzeta-immunoreactivity was observed in the nucleus of neurons in various parts of the brain. In the global ischemic model DGKzeta-immunoreactivity was reduced in intensity in the hippocampal formation and detected in the cytoplasm of CA1 pyramidal neurons throughout reperfusion time courses. Change in the subcellular localization was restricted to the pyramidal cells in CA1 and later in CA3, but not observed in other areas of hippocampus. No change was observed in the cerebral and cerebellar cortices. The present study suggests that DGKzeta might be involved in the process of selective vulnerability of hippocampal pyramidal neurons in postischemic brain.
Collapse
Affiliation(s)
- Hasmat Ali
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iida-nishi 2-2-2, Yamagata 990-9585, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Marszalek JR, Kitidis C, Dararutana A, Lodish HF. Acyl-CoA synthetase 2 overexpression enhances fatty acid internalization and neurite outgrowth. J Biol Chem 2004; 279:23882-91. [PMID: 15051725 DOI: 10.1074/jbc.m313460200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During neurodevelopment neurons increase phospholipid synthesis to generate additional plasma membrane that makes up the growing neurites. Compared with most cell types, neurons contain a high percentage of the polyunsaturated fatty acids (PUFAs) arachidonic acid (AA) and docosahexaenoic acid (DHA). By utilizing PC12 cell lines as a model neuronal cell line, we examined the internalization rate of AA, DHA, and non-essential oleic acid (OA), as well as their effects on neurite outgrowth. When wild type cells were differentiated, the rate of AA and DHA internalization increased 50% more than the rate of OA internalization. When media were supplemented with AA or DHA, the average neurite length was increased by approximately 40%, but supplementation with the same amount of OA had no effect. We also increased the levels of acyl-CoA synthetase-1 (ACS1) and ACS2 proteins to determine whether they contribute to PUFA internalization or neurite outgrowth. Overexpression of ACS1 increased the rate of OA internalization by 55%, and AA and DHA uptake was increased by 25%, but there was no significant change in neurite outgrowth. In ACS2-overexpressing cells, in contrast, the rate of OA internalization increased by 90%, AA by 115%, and DHA by 70%. The average aggregate neurite length in ACS2-overexpressing cells was increased by approximately 40% when the media were supplemented with PUFAs, but there was no change with OA supplementation. Taken together, these results support the hypotheses that ACSs are rate-limiting for fatty acid internalization and that ACS2 enhances neurite outgrowth by promoting PUFA internalization.
Collapse
Affiliation(s)
- Joseph R Marszalek
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
| | | | | | | |
Collapse
|
18
|
Zhong XP, Hainey EA, Olenchock BA, Zhao H, Topham MK, Koretzky GA. Regulation of T cell receptor-induced activation of the Ras-ERK pathway by diacylglycerol kinase zeta. J Biol Chem 2002; 277:31089-98. [PMID: 12070163 DOI: 10.1074/jbc.m203818200] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
T cell development in the thymus and activation of mature T cells in the periphery depend on signals stimulated by engagement of the T cell antigen receptor (TCR). Among the second messenger cascades initiated by TCR ligation include the phosphatidylinositol pathway where the membrane phospholipid, phosphatidylinositol 4,5-bisphosphate, is hydrolyzed to inositol 1,4,5-trisphosphate and diacylglycerol (DAG). Inositol 1,4,5-trisphosphate signals a rise in intracellular free calcium, leading to translocation of nuclear factor of activated T cells into the nucleus. DAG activates RasGRP and protein kinase C theta. Because both RasGRP and protein kinase C theta are essential for thymocyte and T cell function, it is critical to understand how DAG is regulated. In this report, we demonstrate expression of DAG kinase zeta (DGKzeta, the enzyme that catalyzes the conversion of DAG to phosphatidic acid) in multiple lymphoid organs, with highest expression observed within the T cell compartment. Overexpression studies in Jurkat T cells indicate that DGKzeta interferes with TCR-induced Ras and ERK activation, AP-1 induction, and expression of the activation marker CD69. In contrast, TCR-stimulated calcium influx is not altered. Mutational analysis indicates that the kinase and DAG binding domains, but not the ankyrin repeats of DGKzeta, are required for its inhibitory effects. Collectively these studies demonstrate a potential role of DGKzeta to function as a selective negative regulator of DAG signaling on T cell activation and provide the first structure/function analysis of this enzyme in T cells.
Collapse
Affiliation(s)
- Xiao-Ping Zhong
- Signal Transduction Program, The Abramson Family Cancer Research Institute, Immunology Graduate Program, University of Pennsylvania School of Medicine, 421 Curie Boulevard, Philadelphia, PA 19104, USA
| | | | | | | | | | | |
Collapse
|
19
|
Caricasole A, Bettini E, Sala C, Roncarati R, Kobayashi N, Caldara F, Goto K, Terstappen GC. Molecular cloning and characterization of the human diacylglycerol kinase beta (DGKbeta) gene: alternative splicing generates DGKbeta isotypes with different properties. J Biol Chem 2002; 277:4790-6. [PMID: 11719522 DOI: 10.1074/jbc.m110249200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Diacylglycerol kinases are key modulators of levels of diacylglycerol, a second messenger involved in a variety of cellular responses to extracellular stimuli. A number of diacylglycerol kinases encoded by separate genes are present in mammalian genomes. We have cloned cDNAs encoding several isoforms of the human homologue of the rat diacylglycerol kinase beta gene and characterized two such isoforms that differ at their carboxyl terminus through alternative splicing and the usage of different polyadenylation signals. Quantitative analysis of gene expression in a panel of human tissue cDNAs revealed that transcripts corresponding to both isoforms are co-expressed in central nervous system tissues and in the uterus, with one variant being expressed at relatively higher levels. As green fluorescent protein fusions, the two isoforms displayed localization to different subcellular compartments, with one variant being associated with the plasma membrane, while the other isoform was predominantly localized within the cytoplasm. Differences were also observed in their subcellular localization in response to phorbol ester stimulation. Enzymatic assays demonstrated that the two isoforms display comparable diacylglycerol kinase activities. Therefore, the human diacylglycerol kinase beta gene can generate several enzyme isoforms, which can display different expression levels and subcellular localization but similar enzymatic activities in vitro.
Collapse
Affiliation(s)
- Andrea Caricasole
- GlaxoSmithKline Systems Research and Department of Biology, Via Fleming 4, 37135 Verona, Italy
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Hogan A, Shepherd L, Chabot J, Quenneville S, Prescott SM, Topham MK, Gee SH. Interaction of γ1-Syntrophin with Diacylglycerol Kinase-ζ. J Biol Chem 2001; 276:26526-33. [PMID: 11352924 DOI: 10.1074/jbc.m104156200] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Syntrophins are modular adapter proteins that link ion channels and signaling proteins to dystrophin and its homologues. A yeast two-hybrid screen of a human brain cDNA library using the PDZ domain of gamma 1- syntrophin, a recently identified brain-specific isoform, yielded overlapping clones encoding the C terminus of diacylglycerol kinase-zeta (DGK-zeta), an enzyme that converts diacylglycerol into phosphatidic acid. In biochemical assays, the C terminus of DGK-zeta, which contains a consensus PDZ-binding motif, was found to be necessary and sufficient for association with gamma 1-syntrophin. When coexpressed in HeLa cells, DGK-zeta and gamma 1-syntrophin formed a stable complex that partitioned between the cytoplasm and nucleus. DGK-zeta translocates from the cytosol to the nucleus, a process negatively regulated by protein kinase C phosphorylation. We found that DGK-zeta recruits gamma 1-syntrophin into the nucleus and that the PDZ-binding motif is required. Disrupting the interaction altered the intracellular localization of both proteins; DGK-zeta accumulated in the nucleus, whereas gamma 1-syntrophin remained in the cytoplasm. The level of endogenous syntrophins in the nucleus of HeLa cells also reflected the amount of nuclear DGK-zeta. In the brain, DGK-zeta and gamma 1-syntrophin were colocalized in cell bodies and dendrites of cerebellar Purkinjie neurons and other neuronal cell types, suggesting that their interaction is physiologically relevant. Moreover, coimmunoprecipitation and pull-down experiments from brain extracts and cells suggest that DGK-zeta, gamma 1-syntrophin, and dystrophin form a ternary complex. Collectively, our results suggest that gamma 1-syntrophin participates in regulating the subcellular localization of DGK-zeta to ensure correct termination of diacylglycerol signaling.
Collapse
Affiliation(s)
- A Hogan
- Department of Cellular and Molecular Medicine, Center for Neuromuscular Disease, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | | | | | | | | | | | | |
Collapse
|
21
|
Liu Z, Chang GQ, Leibowitz SF. Diacylglycerol kinase zeta in hypothalamus interacts with long form leptin receptor. Relation to dietary fat and body weight regulation. J Biol Chem 2001; 276:5900-7. [PMID: 11078732 DOI: 10.1074/jbc.m007311200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leptin and its long form receptor, Ob-Rb, in hypothalamic nuclei play a key role in regulating energy balance. The mutation of Ob-Rb into one of its natural variants, Ob-Ra, results in severe obesity in rodents. We demonstrate here that diacylglycerol kinase zeta (DGKzeta) interacts, via its ankyrin repeats, with the cytoplasmic portion of Ob-Rb in yeast two-hybrid systems, in protein precipitation experiments in vitro and in vivo. It does not interact, however, with the short form, Ob-Ra, which mediates the entry of leptin into the brain. Furthermore, we show by in situ hybridization that DGKzeta is expressed in neurons of hypothalamic nuclei known to synthesize Ob-Rb and to participate in energy homeostasis. The mutant ob-/ob- and db-/db- mice exhibit increased hypothalamic DGKzeta mRNA level compared with their wild-type controls, suggesting a role for the leptin/OB-Rb system in regulating DGKzeta expression. Further experiments show that hypothalamic DGKzeta mRNA level is stimulated by the consumption of a high-fat diet. In addition, DGKzeta mRNA is statistically significantly lower in rats and inbred mice that become obese on a high-fat diet compared with their lean counterparts. In fact, it is strongly, negatively correlated with both body fat and circulating levels of leptin. Taken together, our evidence suggests that DGKzeta constitutes a downstream component of the leptin signaling pathway and that reduced hypothalamic DGKzeta mRNA, and possibly activity, is associated with obesity.
Collapse
Affiliation(s)
- Z Liu
- Rockefeller University, New York, New York 10021, USA
| | | | | |
Collapse
|
22
|
Abstract
Diacylglycerol kinases (DGKs) phosphorylate the second-messenger diacylglycerol (DAG) to phosphatidic acid (PA). The family of DGKs is well conserved among most species. Nine mammalian isotypes have been identified, and are classified into five subgroups based on their primary structure. DGKs contain a conserved catalytic domain and an array of other conserved motifs that are likely to play a role in lipid-protein and protein-protein interactions in various signalling pathways dependent on DAG and/or PA production. DGK is therefore believed to be activated at the (plasma) membrane where DAG is generated. Some isotypes are found associated with and/or regulated by small GTPases of the Rho family, presumably acting in cytoskeletal rearrangements. Others are (also) found in the nucleus, in association with other regulatory enzymes of the phosphoinositide cycle, and have an effect on cell cycle progression. Most DGK isotypes show high expression in the brain, often in distinct brain regions, suggesting that each individual isotype has a unique function.
Collapse
Affiliation(s)
- W J van Blitterswijk
- Division of Cellular Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
| | | |
Collapse
|
23
|
Pettitt TR, Wakelam MJ. Diacylglycerol kinase epsilon, but not zeta, selectively removes polyunsaturated diacylglycerol, inducing altered protein kinase C distribution in vivo. J Biol Chem 1999; 274:36181-6. [PMID: 10593903 DOI: 10.1074/jbc.274.51.36181] [Citation(s) in RCA: 53] [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
Porcine aortic endothelial cells have previously been shown to contain particularly high basal levels of polyunsaturated diacylglycerol (DAG) together with a very high degree of membrane-associated protein kinase C (PKC), which is largely insensitive to further activation (Pettitt, T. R., Martin, A., Horton, T., Liossis, C., Lord, J. M., and Wakelam, M. J. O. (1997) J. Biol. Chem. 272, 17354-17359). To investigate the possibility that the high polyunsaturated DAG levels were constitutively activating PKC, we transfected porcine aortic endothelial cells with two different forms of human diacylglycerol kinase, epsilon and zeta. In vitro, the former is specific for polyunsaturated structures, whereas the latter shows no apparent selectivity. Overexpression of DAGKepsilon specifically reduced the level of polyunsaturated DAG in the transfected cells while having little effect on the more saturated structures. It also caused the redistribution of PKCalpha and epsilon from the membrane to the cytosol. Overexpression of DAGKzeta caused a general reduction in DAG levels but had little effect on PKC distribution. These results for the first time show that DAGKepsilon specifically phosphorylates polyunsaturated DAG in vivo and that in so doing it regulates PKC localization and activity. This provides support for the proposal that it is the polyunsaturated DAGs that function as messengers and convincing evidence for DAGKepsilon being a physiological terminator of DAG second messenger signaling.
Collapse
Affiliation(s)
- T R Pettitt
- Institute for Cancer Studies, The University of Birmingham, Birmingham B15 2TA, United Kingdom
| | | |
Collapse
|
24
|
Topham MK, Prescott SM. Mammalian diacylglycerol kinases, a family of lipid kinases with signaling functions. J Biol Chem 1999; 274:11447-50. [PMID: 10206945 DOI: 10.1074/jbc.274.17.11447] [Citation(s) in RCA: 238] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- M K Topham
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112, USA
| | | |
Collapse
|