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Yamaguchi Y, Shirai Y, Matsubara T, Sanse K, Kuriyama M, Oshiro N, Yoshino KI, Yonezawa K, Ono Y, Saito N. Phosphorylation and Up-regulation of Diacylglycerol Kinase γ via Its Interaction with Protein Kinase Cγ. J Biol Chem 2006. [DOI: 10.1016/s0021-9258(19)84076-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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52
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Yamaguchi Y, Shirai Y, Matsubara T, Sanse K, Kuriyama M, Oshiro N, Yoshino KI, Yonezawa K, Ono Y, Saito N. Phosphorylation and Up-regulation of Diacylglycerol Kinase γ via Its Interaction with Protein Kinase Cγ. J Biol Chem 2006; 281:31627-37. [PMID: 16905533 DOI: 10.1074/jbc.m606992200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Diacylglycerol (DAG) acts as an allosteric activator of protein kinase C (PKC) and is converted to phosphatidic acid by DAG kinase (DGK). Therefore, DGK is thought to be a negative regulator of PKC activation. Here we show molecular mechanisms of functional coupling of the two kinases. gammaPKC directly associated with DGKgamma through its accessory domain (AD), depending on Ca2+ as well as phosphatidylserine/diolein in vitro. Mass spectrometric analysis and mutation studies revealed that gammaPKC phosphorylated Ser-776 and Ser-779 in the AD of DGKgamma. The phosphorylation by gammaPKC resulted in activation of DGKgamma because a DGKgamma mutant in which Ser-776 and Ser-779 were substituted with glutamic acid to mimic phosphorylation exhibited significantly higher activity compared with wild type DGKgamma and an unphosphorylatable DGKgamma mutant. Importantly, the interaction of the two kinases and the phosphorylation of DGKgamma by gammaPKC could be confirmed in vivo, and overexpression of the AD of DGKgamma inhibited re-translocation of gammaPKC. These results demonstrate that localization and activation of the functionally correlated kinases, gammaPKC and DGKgamma, are spatio-temporally orchestrated by their direct association and phosphorylation, contributing to subtype-specific regulation of DGKgamma and DAG signaling.
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Affiliation(s)
- Yasuto Yamaguchi
- Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
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53
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Abstract
Diacylglycerol kinases (DGKs) attenuate diacylglycerol signaling by converting this lipid to phosphatidic acid (PA). The nine mammalian DGKs that have been identified are widely expressed, but each isoform has a unique tissue and subcellular distribution. Their kinase activity is regulated by mechanisms that modify their access to diacylglycerol, directly affect their kinase activity, or alter their ability to bind to other proteins. In many cases, these enzymes regulate the activity of proteins that are modulated by either diacylglycerol or PA. Experiments using cultured cells and model organisms have demonstrated that DGKs have prominent roles in neuronal transmission, lymphocyte signaling, and carcinogenesis.
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Affiliation(s)
- Matthew K Topham
- Department of Internal Medicine, The Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112-5550, USA.
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54
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Takahashi H, Shibuya M. The vascular endothelial growth factor (VEGF)/VEGF receptor system and its role under physiological and pathological conditions. Clin Sci (Lond) 2005; 109:227-41. [PMID: 16104843 DOI: 10.1042/cs20040370] [Citation(s) in RCA: 631] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The VEGF (vascular endothelial growth factor) family and its receptors are essential regulators of angiogenesis and vascular permeability. Currently, the VEGF family consists of VEGF-A, PlGF (placenta growth factor), VEGF-B, VEGF-C, VEGF-D, VEGF-E and snake venom VEGF. VEGF-A has at least nine subtypes due to the alternative splicing of a single gene. Although the VEGF165 isoform plays a central role in vascular development, recent studies have demonstrated that each VEGF isoform plays distinct roles in vascular patterning and arterial development. VEGF-A binds to and activates two tyrosine kinase receptors, VEGFR (VEGF receptor)-1 and VEGFR-2. VEGFR-2 mediates most of the endothelial growth and survival signals, but VEGFR-1-mediated signalling plays important roles in pathological conditions such as cancer, ischaemia and inflammation. In solid tumours, VEGF-A and its receptor are involved in carcinogenesis, invasion and distant metastasis as well as tumour angiogenesis. VEGF-A also has a neuroprotective effect on hypoxic motor neurons, and is a modifier of ALS (amyotrophic lateral sclerosis). Recent progress in the molecular and biological understanding of the VEGF/VEGFR system provides us with novel and promising therapeutic strategies and target proteins for overcoming a variety of diseases.
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Affiliation(s)
- Hiroyuki Takahashi
- Division of Genetics, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639, Japan
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55
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Riboldi E, Musso T, Moroni E, Urbinati C, Bernasconi S, Rusnati M, Adorini L, Presta M, Sozzani S. Cutting edge: proangiogenic properties of alternatively activated dendritic cells. THE JOURNAL OF IMMUNOLOGY 2005; 175:2788-92. [PMID: 16116163 DOI: 10.4049/jimmunol.175.5.2788] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Angiogenesis plays an important role in tissue remodeling and repair during the late phase of inflammation. In the present study, we show that human dendritic cells (DC) that matured in the presence of anti-inflammatory molecules such as calcitriol, PGE2, or IL-10 (alternatively activated DC) selectively secrete the potent angiogenic cytokine vascular endothelial growth factor (VEGF) isoforms VEGF165 and VEGF121. No VEGF production was observed in immature or classically activated DC. Also, the capacity to produce VEGF was restricted to the myeloid DC subset. When implanted in the chick embryo chorioallantoic membrane, alternatively activated DC elicit a marked angiogenic response, which is inhibited by neutralizing anti-VEGF Abs and by the VEGFR-2 inhibitor SU5416. Therefore, alternatively activated DC may contribute to the resolution of the inflammatory reaction by promoting VEGF-induced angiogenesis.
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Affiliation(s)
- Elena Riboldi
- Unit of General Pathology and Immunology, Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy
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56
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Imai SI, Kai M, Yasuda S, Kanoh H, Sakane F. Identification and characterization of a novel human type II diacylglycerol kinase, DGK kappa. J Biol Chem 2005; 280:39870-81. [PMID: 16210324 DOI: 10.1074/jbc.m500669200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Diacylglycerol kinase (DGK) plays an important role in signal transduction through modulating the balance between two signaling lipids, diacylglycerol and phosphatidic acid. Here we identified a tenth member of the DGK family designated DGK kappa. The kappa-isozyme (1271 amino acids, calculated molecular mass, 142 kDa) contains a pleckstrin homology domain, two cysteine-rich zinc finger-like structures, and a separated catalytic region as have been found commonly for the type II isozymes previously cloned (DGKdelta and DGKeta). The new DGK isozyme has additionally 33 tandem repeats of Glu-Pro-Ala-Pro at the N terminus. Reverse transcriptase-PCR showed that the DGK kappa mRNA is most abundant in the testis, and to a lesser extent in the placenta. DGK kappa, when expressed in HEK293 cells, was persistently localized at the plasma membrane even in the absence of cell stimuli. Deletion analysis revealed that the short C-terminal sequence (amino acid residues 1199-1268) is necessary and sufficient for the plasma membrane localization. Interestingly, DGK kappa, but not other type II DGKs, was specifically tyrosine-phosphorylated at Tyr78 through the Src family kinase pathway in H2O2-treated cells. Moreover, H2O2 selectively inhibited DGK kappa activity in a Src family kinase-independent manner, suggesting that the isozyme changes the balance of signaling lipids in the plasma membrane in response to oxidative stress. The expression patterns, subcellular distribution, and regulatory mechanisms of DGK kappa are distinct from those of DGKdelta and DGKeta despite high structural similarity, suggesting unique functions of the individual type II isozymes.
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Affiliation(s)
- Shin-ichi Imai
- Department of Biochemistry, Sapporo Medical University School of Medicine, Chuo-ku, Sapporo 060-8556, Japan
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57
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Abstract
Cancer and many other serious diseases are characterized by the uncontrolled growth of new blood vessels. Recently, RNA interference (RNAi) has reinvigorated the therapeutic prospects for inhibiting gene expression and promises many advantages over binding inhibitors, including high specificity, which is essential for targeted therapeutics. This article describes the latest developments using small-interfering RNA (siRNA) inhibitors to downregulate various angiogenic and tumor-associated factors, both in cell-culture assays and in animal disease models. The majority of research efforts are currently focused on understanding gene function, as well as proof-of-concept for siRNA-mediated anti-angiogenesis. The prospects for siRNA therapeutics, both advantages and looming hurdles, are evaluated.
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Affiliation(s)
- Patrick Y Lu
- Intradigm Corporation, 12115 K Parklawn Drive, Rockville, MD 20852, USA.
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58
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Abstract
The key determinants of tumour progression and discriminators of benign and malignant lesions include neoangiogenesis (the induction of a new blood supply) and the capacity of malignant cells to invade and metastasise. It is now recognized that these processes can be co-ordinately regulated by the activity of specific genes -- often distinct from those involved in early oncogenesis -- and involve common signalling pathways. Cell motility and chemotaxis (the ability to respond to gradients of chemoattractants) are implicated in both tumour-cell invasion and response of activated endothelial cells to angiogenic cytokines, and provide interesting and novel points for therapeutic intervention.
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Affiliation(s)
- Suzanne A Eccles
- Tumour Biology and Metastasis, Cancer Research UK Centre for Cancer Therapeutics, Institute of Cancer Research, McElwain Laboratories, Cotswold Road, Belmont, Sutton, Surrey, SM2 5NG, UK.
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59
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Fukunaga-Takenaka R, Shirai Y, Yagi K, Adachi N, Sakai N, Merino E, Merida I, Saito N. Importance of chroman ring and tyrosine phosphorylation in the subtype-specific translocation and activation of diacylglycerol kinase α by d-α-tocopherol. Genes Cells 2005; 10:311-9. [PMID: 15773894 DOI: 10.1111/j.1365-2443.2005.00842.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Diacylglycerol kinase (DGK) has been suggested to be a pharmacological target of D-alpha-tocopherol for diabetic renal dysfunctions. However, the DGK subtypes involved in the D-alpha-tocopherol-induced improvement of diabetic renal dysfunctions and the activation mechanisms of DGK by D-alpha-tocopherol are still unknown. Therefore, using GFP-tagged DGKalpha, beta, gamma, epsilon and zeta, we analyzed their response to D-alpha-tocopherol and its derivatives. Only DGKalpha was translocated from the cytoplasm to the plasma membrane with elevation of kinase activity. In addition, troglitazone and trolox possessing 'chroman ring' similarly to D-alpha-tocopherol, induced the subtype-specific translocation of DGKalpha. Furthermore, the translocation of DGKalpha was abolished by pretreatment with tyrosine kinase inhibitors or by mutation on Tyr-334 of the kinase (YF mutant). D-alpha-tocopheryl succinate enhanced the Src-mediated tyrosine phosphorylation of wild-type DGKalpha but the same reagent did not enhance that of the YF mutant. These results demonstrate that tyrosine phosphorylation on Tyr-334 and chroman ring are important for the D-alpha-tocopherol-induced translocation of DGKalpha.
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Affiliation(s)
- Rika Fukunaga-Takenaka
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Nadaku, Kobe 657-8501, Japan
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60
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van Baal J, de Widt J, Divecha N, van Blitterswijk WJ. Translocation of diacylglycerol kinase theta from cytosol to plasma membrane in response to activation of G protein-coupled receptors and protein kinase C. J Biol Chem 2005; 280:9870-8. [PMID: 15632189 DOI: 10.1074/jbc.m409301200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Diacylglycerol kinase (DGK) phosphorylates the second messenger diacylglycerol (DAG) to phosphatidic acid. We previously identified DGK as one of nine mammalian DGK isoforms and reported on its regulation by interaction with RhoA and by translocation to the plasma membrane in response to noradrenaline. Here, we have investigated how the localization of DGK, fused to green fluorescent protein, is controlled upon activation of G protein-coupled receptors in A431 cells. Extracellular ATP, bradykinin, or thrombin induced DGK translocation from the cytoplasm to the plasma membrane within 2-6 min. This translocation, independent of DGK activity, was preceded by protein kinase C (PKC) translocation and was blocked by PKC inhibitors. Conversely, activation of PKC by 12-O-tetradecanoylphorbol-13-acetate induced DGK translocation. Membrane-permeable DAG (dioctanoylglycerol) also induced DGK translocation but in a PKC (staurosporin)-independent fashion. Mutations in the cysteine-rich domains of DGK abrogated its hormone- and DAG-induced translocation, suggesting that these domains are essential for DAG binding and DGK recruitment to the membrane. We show that DGK interacts selectively with and is phosphorylated by PKCepsilon and -eta and that peptide agonist-induced selective activation of PKCepsilon directly leads to DGK translocation. Our data are consistent with the concept that hormone-induced PKC activation regulates the intracellular localization of DGK, which may be important in the negative regulation of PKCepsilon and/or PKCeta activity.
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Affiliation(s)
- Jürgen van Baal
- Division of Cellular Biochemistry, The Netherlands Cancer Institute, Amsterdam 1066 CX, The Netherlands
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61
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Kieć-Wilk B, Polus A, Grzybowska J, Mikołajczyk M, Hartwich J, Pryjma J, Skrzeczyńska J, Dembińska-Kieć A. β-Carotene stimulates chemotaxis of human endothelial progenitor cells. Clin Chem Lab Med 2005; 43:488-98. [PMID: 15899670 DOI: 10.1515/cclm.2005.087] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractAngiogenesis is a crucial process in tissue remodeling during growth, both in the embryo and the adult. In our study we concentrated on the direct effect of β-carotene on human umbilical cord originating from endothelial progenitor cells (EPCs). β-Carotene uptake by EPCs was measured using a HPLC method. The determination of cell surface antigens was performed by flow cytometry. The effect on cell proliferation was estimated by measuring bromo-deoxyuridine incorporation. The influence on the formation of a tubular-like structure was investigated in a 3D assay in matrigel. Quantitative gene expression was estimated using real-time PCR. We demonstrated that β-carotene in the physiological range of concentrations found in human blood is a potent activator of EPC chemotaxis, which is accompanied by a change in the expression of genes mediating cell adhesion and homing, but does not activate the final markers of endothelial differentiation. This study points to the prochemotactic and homing activity of β-carotene in undifferentiated endothelial cell progenitors for the first time, which may suggest a potential role of this carotenoid in progenitor cell therapy aimed at angiogenesis and tissue repair.
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Affiliation(s)
- Beata Kieć-Wilk
- Department of Clinical Biochemistry, Medical College, Jagiellonian University, Kraków, Poland
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