1
|
Zhang X, Duan X, Liu X. The role of kinases in peripheral nerve regeneration: mechanisms and implications. Front Neurol 2024; 15:1340845. [PMID: 38689881 PMCID: PMC11058862 DOI: 10.3389/fneur.2024.1340845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 04/02/2024] [Indexed: 05/02/2024] Open
Abstract
Peripheral nerve injury disease is a prevalent traumatic condition in current medical practice. Despite the present treatment approaches, encompassing surgical sutures, autologous nerve or allograft nerve transplantation, tissue engineering techniques, and others, an effective clinical treatment method still needs to be discovered. Exploring novel treatment methods to improve peripheral nerve regeneration requires more effort in investigating the cellular and molecular mechanisms involved. Many factors are associated with the regeneration of injured peripheral nerves, including the cross-sectional area of the injured nerve, the length of the nerve gap defect, and various cellular and molecular factors such as Schwann cells, inflammation factors, kinases, and growth factors. As crucial mediators of cellular communication, kinases exert regulatory control over numerous signaling cascades, thereby participating in various vital biological processes, including peripheral nerve regeneration after nerve injury. In this review, we examined diverse kinase classifications, distinct nerve injury types, and the intricate mechanisms involved in peripheral nerve regeneration. Then we stressed the significance of kinases in regulating autophagy, inflammatory response, apoptosis, cell cycle, oxidative processes, and other aspects in establishing conductive microenvironments for nerve tissue regeneration. Finally, we briefly discussed the functional roles of kinases in different types of cells involved in peripheral nerve regeneration.
Collapse
Affiliation(s)
- Xu Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, School of Life Science, Nantong Laboratory of Development and Diseases, Medical College, Clinical Medical Research Center, Affiliated Wuxi Clinical College of Nantong University, Nantong University, Nantong, China
- Clinical Medical Research Center, Wuxi No. 2 People's Hospital, Jiangnan University Medical Center, Wuxi, China
| | - Xuchu Duan
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, School of Life Science, Nantong Laboratory of Development and Diseases, Medical College, Clinical Medical Research Center, Affiliated Wuxi Clinical College of Nantong University, Nantong University, Nantong, China
| | - Xiaoyu Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, School of Life Science, Nantong Laboratory of Development and Diseases, Medical College, Clinical Medical Research Center, Affiliated Wuxi Clinical College of Nantong University, Nantong University, Nantong, China
| |
Collapse
|
2
|
Myers AK, Morel M, Gee SH, Hoffmann KA, Long W. ERK3 and DGKζ interact to modulate cell motility in lung cancer cells. Front Cell Dev Biol 2023; 11:1192221. [PMID: 37287450 PMCID: PMC10242005 DOI: 10.3389/fcell.2023.1192221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/09/2023] [Indexed: 06/09/2023] Open
Abstract
Extracellular signal-regulated kinase 3 (ERK3) promotes cell migration and tumor metastasis in multiple cancer types, including lung cancer. The extracellular-regulated kinase 3 protein has a unique structure. In addition to the N-terminal kinase domain, ERK3 includes a central conserved in extracellular-regulated kinase 3 and ERK4 (C34) domain and an extended C-terminus. However, relatively little is known regarding the role(s) of the C34 domain. A yeast two-hybrid assay using extracellular-regulated kinase 3 as bait identified diacylglycerol kinase ζ (DGKζ) as a binding partner. DGKζ was shown to promote migration and invasion in some cancer cell types, but its role in lung cancer cells is yet to be described. The interaction of extracellular-regulated kinase 3 and DGKζ was confirmed by co-immunoprecipitation and in vitro binding assays, consistent with their co-localization at the periphery of lung cancer cells. The C34 domain of ERK3 was sufficient for binding to DGKζ, while extracellular-regulated kinase 3 bound to the N-terminal and C1 domains of DGKζ. Surprisingly, in contrast to extracellular-regulated kinase 3, DGKζ suppresses lung cancer cell migration, suggesting DGKζ might inhibit ERK3-mediated cell motility. Indeed, co-overexpression of exogenous DGKζ and extracellular-regulated kinase 3 completely blocked the ability of ERK3 to promote cell migration, but DGKζ did not affect the migration of cells with stable ERK3 knockdown. Furthermore, DGKζ had little effect on cell migration induced by overexpression of an ERK3 mutant missing the C34 domain, suggesting DGKζ requires this domain to prevent ERK3-mediated increase in cell migration. In summary, this study has identified DGKζ as a new binding partner and negative regulator of extracellular-regulated kinase 3 in controlling lung cancer cell migration.
Collapse
Affiliation(s)
- Amanda K. Myers
- Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH, United States
| | - Marion Morel
- Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH, United States
| | - Stephen H. Gee
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Katherine A. Hoffmann
- Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH, United States
| | - Weiwen Long
- Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH, United States
| |
Collapse
|
3
|
Wu G, Cheng H, Guo H, Li Z, Li D, Xie Z. Tea polyphenol EGCG ameliorates obesity-related complications by regulating lipidomic pathway in leptin receptor knockout rats. J Nutr Biochem 2023; 118:109349. [PMID: 37085056 DOI: 10.1016/j.jnutbio.2023.109349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 03/20/2023] [Accepted: 04/04/2023] [Indexed: 04/23/2023]
Abstract
Tea polyphenol EGCG has been widely recognized for antiobesity effects. However, the molecular mechanism of lipidomic pathway related to lipid-lowering effect of EGCG is still not well understood. The aim of this study was to investigate the effects and mechanism of EGCG activated hepatic lipidomic pathways on ameliorating obesity-related complications by using newly developed leptin receptor knockout (Lepr KO) rats. Results showed that EGCG supplementation (100 mg/kg body weight) significantly decreased total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels both in the serum and liver, and significantly improved glucose intolerance. In addition, EGCG alleviated fatty liver development and restored the normal liver function in Lepr KO rats. Liver lipidomic analysis revealed that EGCG dramatically changes overall composition of lipid classes. Notably, EGCG significantly decreased an array of triglycerides (TGs) and diglycerides (DGs) levels. While EGCG increased 31 glycerophospholipid species and 1 sphingolipid species levels, such as phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), phosphatidylserines (PSs) and phosphatidylinositols (PIs) levels in the liver of Lepr KO rats. Moreover, 14 diversely regulated lipid species were identified as potential lipid biomarkers. Mechanistic analysis revealed that EGCG significantly activated the SIRT6/AMPK/SREBP1/FAS pathway to decrease DGs and TGs levels and upregulated glycerophospholipids synthesis pathways to increase glycerophospholipid level in the liver of Lepr KO rats. These findings suggested that the regulation of glycerolipids and glycerophospholipid homeostasis might be the key pathways for EGCG in ameliorating obesity-related complications in Lepr KO rats.
Collapse
Affiliation(s)
- Guohuo Wu
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Sciences & Technology, Anhui Agricultural University, Hefei, Anhui 230036, PR China
| | - Huijun Cheng
- College of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, PR China
| | - Huimin Guo
- Center for Biotechnology, Anhui Agricultural University, Anhui 230036, PR China
| | - Zhuang Li
- Center for Biotechnology, Anhui Agricultural University, Anhui 230036, PR China
| | - Daxiang Li
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Sciences & Technology, Anhui Agricultural University, Hefei, Anhui 230036, PR China.
| | - Zhongwen Xie
- State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Sciences & Technology, Anhui Agricultural University, Hefei, Anhui 230036, PR China; College of Life Sciences, Anhui Agricultural University, Hefei, Anhui 230036, PR China.
| |
Collapse
|
4
|
DGKZ promotes TGFβ signaling pathway and metastasis in triple-negative breast cancer by suppressing lipid raft-dependent endocytosis of TGFβR2. Cell Death Dis 2022; 13:105. [PMID: 35115500 PMCID: PMC8814002 DOI: 10.1038/s41419-022-04537-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/14/2021] [Accepted: 01/13/2022] [Indexed: 02/07/2023]
Abstract
Diacylglycerol kinase ζ (DGKZ) is a diacylglycerol kinase that metabolizes diacylglycerol to yield phosphatidic acid, and its function in breast cancer progression remains unclear. In this study, via screening of a CRISPR-Cas9 knockout library containing lipid metabolic genes, DGKZ was identified as a potential prometastatic gene. We first confirmed that high DGKZ expression correlated with tumor progression and poor prognosis in patients. Next, knockout of DGKZ in triple-negative breast cancer cell lines were found to significantly inhibit metastatic behaviors in vitro and in vivo, whereas its overexpression increased the metastatic potential of cell lines. Mechanistic studies based on RNA sequencing and bioinformatic analysis indicated that DGKZ might regulate cell metastasis by promoting epithelial–mesenchymal transition via the transforming growth factor β (TGFβ) signaling pathway. Furthermore, we found that overexpression of DGKZ activated the TGFβ/TGFβR2/Smad3 signaling pathway by inhibiting the degradation of TGFβR2 through suppression of caveolin/lipid raft-dependent endocytosis. Moreover, the caveolin/lipid raft-dependent endocytosis of TGFβR2 was regulated by the metabolite phosphatidic acid, which might alter TGFβR2 partitioning in lipid rafts and nonlipid rafts by affecting the fluidity of the plasma membrane. These findings suggested that DGKZ is a novel promoter of metastasis and that it could be a potential prognostic indicator in patients with triple-negative breast cancer.
Collapse
|
5
|
Podgorniak T, Dhanasiri A, Chen X, Ren X, Kuan PF, Fernandes J. Early fish domestication affects methylation of key genes involved in the rapid onset of the farmed phenotype. Epigenetics 2022; 17:1281-1298. [PMID: 35006036 PMCID: PMC9542679 DOI: 10.1080/15592294.2021.2017554] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Animal domestication is a process of environmental modulation and artificial selection leading to permanent phenotypic modifications. Recent studies showed that phenotypic changes occur very early in domestication, i.e., within the first generation in captivity, which raises the hypothesis that epigenetic mechanisms may play a critical role on the early onset of the domestic phenotype. In this context, we applied reduced representation bisulphite sequencing to compare methylation profiles between wild Nile tilapia females and their offspring reared under farmed conditions. Approximately 700 differentially methylated CpG sites were found, many of them associated not only with genes involved in muscle growth, immunity, autophagy and diet response but also related to epigenetic mechanisms, such as RNA methylation and histone modifications. This bottom-up approach showed that the phenotypic traits often related to domestic animals (e.g., higher growth rate and different immune status) may be regulated epigenetically and prior to artificial selection on gene sequences. Moreover, it revealed the importance of diet in this process, as reflected by differential methylation patterns in genes critical to fat metabolism. Finally, our study highlighted that the TGF-β1 signalling pathway may regulate and be regulated by several differentially methylated CpG-associated genes. This could be an important and multifunctional component in promoting adaptation of fish to a domestic environment while modulating growth and immunity-related traits.
Collapse
Affiliation(s)
- Tomasz Podgorniak
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Anusha Dhanasiri
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Xianquan Chen
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway.,School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Xu Ren
- Department of Applied Mathematics and Statistics, Stony Brook University, New York, NY, USA
| | - Pei-Fen Kuan
- Department of Applied Mathematics and Statistics, Stony Brook University, New York, NY, USA
| | - Jorge Fernandes
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| |
Collapse
|
6
|
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
|
7
|
Asami M, Suzuki Y, Sakane F. Dopamine and the phosphorylated dopamine transporter are increased in the diacylglycerol kinase η-knockout mouse brain. FEBS Lett 2021; 595:1313-1321. [PMID: 33599293 DOI: 10.1002/1873-3468.14059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/26/2021] [Accepted: 02/09/2021] [Indexed: 12/19/2022]
Abstract
The molecular mechanisms generating the mania-like abnormal behaviors caused by diacylglycerol (DG) kinase (DGK) η deficiency remain unclear. Here, we found that DGKη knockout markedly increased dopamine (DA) levels in the midbrain (DA-producing region, 2.8-fold) and cerebral cortex (DA projection region, 1.2-fold). Moreover, DGKη deficiency significantly augmented phosphorylated DA transporter (DAT) levels (1.4-fold increase), which induce DA efflux to the synaptic cleft, in the cerebral cortex. Moreover, phosphorylation levels of protein kinase C-β, which is activated by DG and involved in DAT phosphorylation, were also increased. DAT expressed in Neuro-2a cells recruited DGKη to the plasma membrane and colocalized with it. These results strongly suggest that dopaminergic hyperfunction caused by DGKη deficiency in the brain leads to mania-like behaviors.
Collapse
Affiliation(s)
- Maho Asami
- Department of Chemistry, Graduate School of Science, Chiba University, Japan
| | - Yuji Suzuki
- Department of Chemistry, Graduate School of Science, Chiba University, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Japan
| |
Collapse
|
8
|
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
|
9
|
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.
Collapse
|
10
|
Yu W, Tang L, Lin F, Yao Y, Shen Z. DGKZ Acts as a Potential Oncogene in Osteosarcoma Proliferation Through Its Possible Interaction With ERK1/2 and MYC Pathway. Front Oncol 2019; 8:655. [PMID: 30662872 PMCID: PMC6328465 DOI: 10.3389/fonc.2018.00655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 12/11/2018] [Indexed: 11/18/2022] Open
Abstract
Osteosarcoma (OS) is one of the most common primary bone tumors in children and young adults. The majority of osteosarcoma patients have limited alternative therapeutic options and metastatic patients generally have a poor prognosis. Thus, it is important to explore novel effective therapeutic targets in the treatment of osteosarcoma. Diacylglycerol kinase zeta (DGKZ) is a recently identified gene potentially associated with certain human carcinogenesis. However, the role of DGKZ in proliferation of osteosarcoma is still unclear. In this study, DGKZ's expression was firstly investigated in OS tumor samples and correlated with poor outcome in OS patients. Silence of DGKZ by shRNA hampered osteosarcoma cell growth and promoted cell apoptosis in vitro. In vivo, DGKZ's knockout also suppressed xenograft tumor proliferation as determined by bioluminescence imaging and weight/volume measurements. Meanwhile, Affymetrix GeneChip and Ingenuity Pathway Analysis (IPA) revealed that DGKZ knockdown resulted in a decreased activity of MYC pathway, and several target genes expression in MYC pathway were altered, including CCND1, CDKN2B, CDK6, PCNA, and EGR1. Furthermore, immunoprecipitation coupled with mass spectrometry (IP-MS) analysis was used to identify proteins that interacted with DGKZ in OS cells and revealed ERK1/2, a key MYC-interactor, to associate with DGKZ. Together, our study demonstrated that DGKZ might act as an oncogene in osteosarcoma via its possible interaction with ERK1/2 and MYC pathway.
Collapse
Affiliation(s)
- Wenxi Yu
- Department of Oncology, Affiliated Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Lina Tang
- Department of Oncology, Affiliated Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Feng Lin
- Department of Oncology, Affiliated Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Yang Yao
- Department of Oncology, Affiliated Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Zan Shen
- Department of Oncology, Affiliated Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, China
| |
Collapse
|
11
|
Matthews AM, Blydt-Hansen I, Al-Jabri B, Andersen J, Tarailo-Graovac M, Price M, Selby K, Demos M, Connolly M, Drögemoller B, Shyr C, Mwenifumbo J, Elliott AM, Lee J, Ghani A, Stöckler S, Salvarinova R, Vallance H, Sinclair G, Ross CJ, Wasserman WW, McKinnon ML, Horvath GA, Goez H, van Karnebeek CD. Atypical cerebral palsy: genomics analysis enables precision medicine. Genet Med 2018; 21:1621-1628. [DOI: 10.1038/s41436-018-0376-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/08/2018] [Indexed: 11/09/2022] Open
|
12
|
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
|
13
|
Qiu Y, Hassaninasab A, Han GS, Carman GM. Phosphorylation of Dgk1 Diacylglycerol Kinase by Casein Kinase II Regulates Phosphatidic Acid Production in Saccharomyces cerevisiae. J Biol Chem 2016; 291:26455-26467. [PMID: 27834677 DOI: 10.1074/jbc.m116.763839] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/08/2016] [Indexed: 11/06/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, Dgk1 diacylglycerol (DAG) kinase catalyzes the CTP-dependent phosphorylation of DAG to form phosphatidic acid (PA). The enzyme in conjunction with Pah1 PA phosphatase controls the levels of PA and DAG for the synthesis of triacylglycerol and membrane phospholipids, the growth of the nuclear/endoplasmic reticulum membrane, and the formation of lipid droplets. Little is known about how DAG kinase activity is regulated by posttranslational modification. In this work, we examined the phosphorylation of Dgk1 DAG kinase by casein kinase II (CKII). When phosphate groups were globally reduced using nonspecific alkaline phosphatase, Triton X-100-solubilized membranes from DGK1-overexpressing cells showed a 7.7-fold reduction in DAG kinase activity; the reduced enzyme activity could be increased 5.5-fold by treatment with CKII. Dgk1(1-77) expressed heterologously in Escherichia coli was phosphorylated by CKII on a serine residue, and its phosphorylation was dependent on time as well as on the concentrations of CKII, ATP, and Dgk1(1-77). We used site-specific mutagenesis, coupled with phosphorylation analysis and phosphopeptide mapping, to identify Ser-45 and Ser-46 of Dgk1 as the CKII target sites, with Ser-46 being the major phosphorylation site. In vivo, the S46A and S45A/S46A mutations of Dgk1 abolished the stationary phase-dependent stimulation of DAG kinase activity. In addition, the phosphorylation-deficient mutations decreased Dgk1 function in PA production and in eliciting pah1Δ phenotypes, such as the expansion of the nuclear/endoplasmic reticulum membrane, reduced lipid droplet formation, and temperature sensitivity. This work demonstrates that the CKII-mediated phosphorylation of Dgk1 regulates its function in the production of PA.
Collapse
Affiliation(s)
- Yixuan Qiu
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Azam Hassaninasab
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Gil-Soo Han
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - George M Carman
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| |
Collapse
|
14
|
Functional and Physical Interaction of Diacylglycerol Kinase ζ with Protein Kinase Cα Is Required for Cerebellar Long-Term Depression. J Neurosci 2016; 35:15453-65. [PMID: 26586831 DOI: 10.1523/jneurosci.1991-15.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The balance between positive and negative regulators required for synaptic plasticity must be well organized at synapses. Protein kinase Cα (PKCα) is a major mediator that triggers long-term depression (LTD) at synapses between parallel fibers and Purkinje cells in the cerebellum. However, the precise mechanisms involved in PKCα regulation are not clearly understood. Here, we analyzed the role of diacylglycerol kinase ζ (DGKζ), a kinase that physically interacts with PKCα as well as postsynaptic density protein 95 (PSD-95) family proteins and functionally suppresses PKCα by metabolizing diacylglycerol (DAG), in the regulation of cerebellar LTD. In Purkinje cells of DGKζ-deficient mice, LTD was impaired and PKCα was less localized in dendrites and synapses. This impaired LTD was rescued by virus-driven expression of wild-type DGKζ, but not by a kinase-dead mutant DGKζ or a mutant lacking the ability to localize at synapses, indicating that both the kinase activity and synaptic anchoring functions of DGKζ are necessary for LTD. In addition, experiments using another DGKζ mutant and immunoprecipitation analysis revealed an inverse regulatory mechanism, in which PKCα phosphorylates, inactivates, and then is released from DGKζ, is required for LTD. These results indicate that DGKζ is localized to synapses, through its interaction with PSD-95 family proteins, to promote synaptic localization of PKCα, but maintains PKCα in a minimally activated state by suppressing local DAG until its activation and release from DGKζ during LTD. Such local and reciprocal regulation of positive and negative regulators may contribute to the fine-tuning of synaptic signaling. SIGNIFICANCE STATEMENT Many studies have identified signaling molecules that mediate long-term synaptic plasticity. In the basal state, the activities and concentrations of these signaling molecules must be maintained at low levels, yet be ready to be boosted, so that synapses can undergo synaptic plasticity only when they are stimulated. However, the mechanisms involved in creating such conditions are not well understood. Here, we show that diacylglycerol kinase ζ (DGKζ) creates optimal conditions for the induction of cerebellar long-term depression (LTD). DGKζ works by regulating localization and activity of protein kinase Cα (PKCα), an important mediator of LTD, so that PKCα effectively responds to the stimulation that triggers LTD.
Collapse
|
15
|
Loss of Diacylglycerol Kinase-Ζ Inhibits Cell Proliferation and Survival in Human Gliomas. Mol Neurobiol 2015; 53:5425-35. [DOI: 10.1007/s12035-015-9419-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 09/02/2015] [Indexed: 12/25/2022]
|
16
|
Skorve J, Hilvo M, Vihervaara T, Burri L, Bohov P, Tillander V, Bjørndal B, Suoniemi M, Laaksonen R, Ekroos K, Berge RK, Alexson SEH. Fish oil and krill oil differentially modify the liver and brain lipidome when fed to mice. Lipids Health Dis 2015; 14:88. [PMID: 26260413 PMCID: PMC4531896 DOI: 10.1186/s12944-015-0086-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/24/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Marine food is an important source of omega-3 fatty acids with beneficial health effects. Oils from marine organisms have different fatty acid composition and differ in their molecular composition. Fish oil (FO) has a high content of eicosapentaenoic and docosahexaenoic acids mainly esterified to triacylglycerols, while in krill oil (KO) these fatty acids are mainly esterified to phospholipids. The aim was to study the effects of these oils on the lipid content and fatty acid distribution in the various lipid classes in liver and brain of mice. METHODS Mice were fed either a high-fat diet (HF), a HF diet supplemented with FO or with KO (n = 6). After six weeks of feeding, liver and brain lipid extracts were analysed using a shotgun and TAG lipidomics approach. Student t-test was performed after log-transformation to compare differences between study groups. RESULTS Six weeks of feeding resulted in significant changes in the relative abundance of many lipid classes compared to control mice. In both FO and KO fed mice, the triacylglycerol content in the liver was more than doubled. The fatty acid distribution was affected by the oils in both liver and brain with a decrease in the abundance of 18:2 and 20:4, and an increase in 20:5 and 22:6 in both study groups. 18:2 decreased in all lipid classes in the FO group but with only minor changes in the KO group. Differences between the feeding groups were particularly evident in some of the minor lipid classes that are associated with inflammation and insulin resistance. Ceramides and diacylglycerols were decreased and cholesteryl esters increased in the liver of the KO group, while plasmalogens were decreased in the FO group. In the brain, diacylglycerols were decreased, more by KO than FO, while ceramides and lactosylceramides were increased, more by FO than KO. CONCLUSION The changes in the hepatic sphingolipids and 20:4 fatty acid levels were greater in the KO compared to the FO fed mice, and are consistent with a hypothesis that krill oil will have a stronger anti-inflammatory action and enhances insulin sensitivity more potently than fish oil.
Collapse
Affiliation(s)
- Jon Skorve
- Department of Clinical Science, University of Bergen, N-5021, Bergen, Norway.
| | - Mika Hilvo
- Zora Biosciences Oy, Biologinkuja 1, 02150, Espoo, Finland.
| | | | - Lena Burri
- Department of Clinical Science, University of Bergen, N-5021, Bergen, Norway. .,Present address: Aker BioMarine ASA, Fjordalléen 16, NO-0115, Oslo, Norway.
| | - Pavol Bohov
- Department of Clinical Science, University of Bergen, N-5021, Bergen, Norway.
| | - Veronika Tillander
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, S-14186, Stockholm, Sweden.
| | - Bodil Bjørndal
- Department of Clinical Science, University of Bergen, N-5021, Bergen, Norway.
| | - Matti Suoniemi
- Zora Biosciences Oy, Biologinkuja 1, 02150, Espoo, Finland.
| | | | - Kim Ekroos
- Zora Biosciences Oy, Biologinkuja 1, 02150, Espoo, Finland.
| | - Rolf K Berge
- Department of Clinical Science, University of Bergen, N-5021, Bergen, Norway. .,Department of Heart Disease, Haukeland University Hospital, N-5021, Bergen, Norway.
| | - Stefan E H Alexson
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, S-14186, Stockholm, Sweden.
| |
Collapse
|
17
|
Cellular expression and localization of DGKζ-interacting NAP1-like proteins in the brain and functional implications under hypoxic stress. Histochem Cell Biol 2014; 142:461-71. [DOI: 10.1007/s00418-014-1226-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2014] [Indexed: 11/27/2022]
|
18
|
Goto K, Tanaka T, Nakano T, Okada M, Hozumi Y, Topham MK, Martelli AM. DGKζ under stress conditions: “to be nuclear or cytoplasmic, that is the question”. Adv Biol Regul 2014; 54:242-253. [PMID: 24119575 DOI: 10.1016/j.jbior.2013.08.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 08/31/2013] [Indexed: 06/02/2023]
Abstract
Eukaryotic cells have evolved to possess a distinct subcellular compartment, the nucleus, separated from the cytoplasm in a manner that allows the precise operation of the chromatin, thereby permitting controlled access to the regulatory elements in the DNA for transcription and replication. In the cytoplasm, genetic information contained in the DNA sequence is translated into proteins, including enzymes that catalyze various reactions, such as metabolic processes, energy control, and responses to changing environments. One mechanism that regulates these events involves phosphoinositide turnover signaling, which generates a lipid second messenger, diacylglycerol (DG). Since DG acts as a potent activator of several signaling molecules, it should be tightly regulated to keep cellular responsiveness within a physiological range. DG kinase (DGK) metabolizes DG by phosphorylating it to generate phosphatidic acid, thus serving as a critical regulator of DG signaling. Phosphoinositide turnover is employed differentially in the nucleus and the cytoplasm. A member of the DGK family, DGKζ, localizes to the nucleus in various cell types and is considered to regulate nuclear DG signaling. Recent studies have provided evidence that DGKζ shuttles between the nucleus and the cytoplasm in neurons under pathophysiological conditions. Transport of a signal regulator between the nucleus and the cytoplasm should be a critical function for maintaining basic processes in the nucleus, such as cell cycle regulation and gene expression, and to ensure communication between nuclear processes and cytoplasmic functions. In this review, a series of studies on nucleocytoplasmic translocation of DGKζ have been summarized, and the functional implications of this phenomenon in postmitotic neurons and cancer cells under stress conditions are discussed.
Collapse
|
19
|
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.
Collapse
Affiliation(s)
- Sruti Krishna
- Department of Pediatrics, Division of Allergy and Immunology and Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
| | | |
Collapse
|
20
|
Symoens S, Malfait F, D'hondt S, Callewaert B, Dheedene A, Steyaert W, Bächinger HP, De Paepe A, Kayserili H, Coucke PJ. Deficiency for the ER-stress transducer OASIS causes severe recessive osteogenesis imperfecta in humans. Orphanet J Rare Dis 2013; 8:154. [PMID: 24079343 PMCID: PMC3850743 DOI: 10.1186/1750-1172-8-154] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 09/15/2013] [Indexed: 12/21/2022] Open
Abstract
Osteogenesis imperfecta (OI) is a clinically and genetically heterogeneous brittle bone disorder. Whereas dominant OI is mostly due to heterozygous mutations in either COL1A1 or COL1A2, encoding type I procollagen, recessive OI is caused by biallelic mutations in genes encoding proteins involved in type I procollagen processing or chaperoning. Hitherto, some OI cases remain molecularly unexplained. We detected a homozygous genomic deletion of CREB3L1 in a family with severe OI. CREB3L1 encodes OASIS, an endoplasmic reticulum-stress transducer that regulates type I procollagen expression during murine bone formation. This is the first report linking CREB3L1 to human recessive OI, thereby expanding the OI gene spectrum.
Collapse
Affiliation(s)
- Sofie Symoens
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Qiu Y, Fakas S, Han GS, Barbosa AD, Siniossoglou S, Carman GM. Transcription factor Reb1p regulates DGK1-encoded diacylglycerol kinase and lipid metabolism in Saccharomyces cerevisiae. J Biol Chem 2013; 288:29124-33. [PMID: 23970552 PMCID: PMC3790011 DOI: 10.1074/jbc.m113.507392] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, the DGK1-encoded diacylglycerol kinase catalyzes the CTP-dependent phosphorylation of diacylglycerol to form phosphatidate. This enzyme, in conjunction with PAH1-encoded phosphatidate phosphatase, controls the levels of phosphatidate and diacylglycerol for phospholipid synthesis, membrane growth, and lipid droplet formation. In this work, we showed that a functional level of diacylglycerol kinase is regulated by the Reb1p transcription factor. In the electrophoretic mobility shift assay, purified recombinant Reb1p was shown to specifically bind its consensus recognition sequence (CGGGTAA, -166 to -160) in the DGK1 promoter. Analysis of cells expressing the PDGK1-lacZ reporter gene showed that mutations (GT→TG) in the Reb1p-binding sequence caused an 8.6-fold reduction in β-galactosidase activity. The expression of DGK1(reb1), a DGK1 allele containing the Reb1p-binding site mutation, was greatly lower than that of the wild type allele, as indicated by analyses of DGK1 mRNA, Dgk1p, and diacylglycerol kinase activity. In the presence of cerulenin, an inhibitor of de novo fatty acid synthesis, the dgk1Δ mutant expressing DGK1(reb1) exhibited a significant defect in growth as well as in the synthesis of phospholipids from triacylglycerol mobilization. Unlike DGK1, the DGK1(reb1) expressed in the dgk1Δ pah1Δ mutant did not result in the nuclear/endoplasmic reticulum membrane expansion, which occurs in cells lacking phosphatidate phosphatase activity. Taken together, these results indicate that the Reb1p-mediated regulation of diacylglycerol kinase plays a major role in its in vivo functions in lipid metabolism.
Collapse
Affiliation(s)
- Yixuan Qiu
- From the Department of Food Science, Rutgers Center for Lipid Research, and New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901 and
| | | | | | | | | | | |
Collapse
|
22
|
Foster DA. Phosphatidic acid and lipid-sensing by mTOR. Trends Endocrinol Metab 2013; 24:272-8. [PMID: 23507202 PMCID: PMC3669661 DOI: 10.1016/j.tem.2013.02.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 02/15/2013] [Accepted: 02/17/2013] [Indexed: 02/06/2023]
Abstract
Mammalian target of rapamycin (mTOR) has been implicated as a sensor of nutrient sufficiency for dividing cells and is activated by essential amino acids and glucose. However, cells also require lipids for membrane biosynthesis. A central metabolite in the synthesis of membrane phospholipids is phosphatidic acid (PA), which is required for the stability and activity of mTOR complexes. Although PA is commonly generated by the phospholipase D-catalyzed hydrolysis of phosphatidylcholine, PA is also generated by diacylglycerol kinases and lysophosphatidic acid acyltransferases, which are at the center of phospholipid biosynthesis. It is proposed that the responsiveness of mTOR/TOR to PA evolved as a means for sensing lipid precursors for membrane biosynthesis prior to doubling the mass of a cell and dividing.
Collapse
Affiliation(s)
- David A Foster
- Department of Biological Sciences, Hunter College of the City University of New York, New York, NY 10065, USA.
| |
Collapse
|
23
|
Scott SA, Xiang Y, Mathews TP, Cho HP, Myers DS, Armstrong MD, Tallman KA, O'Reilly MC, Lindsley CW, Brown HA. Regulation of phospholipase D activity and phosphatidic acid production after purinergic (P2Y6) receptor stimulation. J Biol Chem 2013; 288:20477-87. [PMID: 23723068 DOI: 10.1074/jbc.m113.451708] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Phosphatidic acid (PA) is a lipid second messenger located at the intersection of several lipid metabolism and cell signaling events including membrane trafficking, survival, and proliferation. Generation of signaling PA has long been primarily attributed to the activation of phospholipase D (PLD). PLD catalyzes the hydrolysis of phosphatidylcholine into PA. A variety of both receptor-tyrosine kinase and G-protein-coupled receptor stimulations have been shown to lead to PLD activation and PA generation. This study focuses on profiling the PA pool upon P2Y6 receptor signaling manipulation to determine the major PA producing enzymes. Here we show that PLD, although highly active, is not responsible for the majority of stable PA being produced upon UDP stimulation of the P2Y6 receptor and that PA levels are tightly regulated. By following PA flux in the cell we show that PLD is involved in an initial increase in PA upon receptor stimulation; however, when PLD is blocked, the cell compensates by increasing PA production from other sources. We further delineate the P2Y6 signaling pathway showing that phospholipase Cβ3 (PLCβ3), PLCδ1, DGKζ and PLD are all downstream of receptor activation. We also show that DGKζ is a novel negative regulator of PLD activity in this system that occurs through an inhibitory mechanism with PKCα. These results further define the downstream events resulting in PA production in the P2Y6 receptor signaling pathway.
Collapse
Affiliation(s)
- Sarah A Scott
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Shulga YV, Anderson RA, Topham MK, Epand RM. Phosphatidylinositol-4-phosphate 5-kinase isoforms exhibit acyl chain selectivity for both substrate and lipid activator. J Biol Chem 2012; 287:35953-63. [PMID: 22942276 DOI: 10.1074/jbc.m112.370155] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate is mostly produced in the cell by phosphatidylinositol-4-phosphate 5-kinases (PIP5K) and has a crucial role in numerous signaling events. Here we demonstrate that in vitro all three isoforms of PIP5K, α, β, and γ, discriminate among substrates with different acyl chains for both the substrates phosphatidylinositol 4-phosphate (PtdIns4P) and phosphatidylinositol (PtdIns) although to different extents, with isoform γ being the most selective. Fully saturated dipalmitoyl-PtdIns4P was a poor substrate for all three isoforms, but both the 1-stearoyl-2-arachidonoyl and the 1-stearoyl-2-oleoyl forms of PtdIns4P were good substrates. V(max) was greater for the 1-stearoyl-2-arachidonoyl form compared with the 1-stearoyl-2-oleoyl form, although for PIP5Kβ the difference was small. For the α and γ isoforms, K(m) was much lower for 1-stearoyl-2-oleoyl PtdIns4P, making this lipid the better substrate of the two under most conditions. Activation of PIP5K by phosphatidic acid is also acyl chain-dependent. Species of phosphatidic acid with two unsaturated acyl chains are much better activators of PIP5K than those containing one saturated and one unsaturated acyl chain. PtdIns is a poor substrate for PIP5K, but it also shows acyl chain selectivity. Curiously, there is no acyl chain discrimination among species of phosphatidic acid in the activation of the phosphorylation of PtdIns. Together, our findings indicate that PIP5K isoforms α, β, and γ act selectively on substrates and activators with different acyl chains. This could be a tightly regulated mechanism of producing physiologically active unsaturated phosphatidylinositol 4,5-bisphosphate species in the cell.
Collapse
Affiliation(s)
- Yulia V Shulga
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | | | | | | |
Collapse
|