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Kaori Fukushima, Shiho Otagaki, Kaede Takahashi, Kanako Minami, Kaichi Ishimoto, Nobuyuki Fukushima, Kanya Honoki, Toshifumi Tsujiuchi
Lysophosphatidic acid (LPA) is a simple biological lipid and mediates several biological functions with LPA receptors (LPA1 to LPA6 ). In the present study, to assess whether LPA receptors promote cell-invasive activity of pancreatic cancer cells, highly invasion PANC-R9 cells were established from PANC-1 cells, using Matrigel-coated Cell Culture Insert. The cell-invasive activity of PANC-R9 cells was shown to be approximately 15 times higher than that of PANC-1 cells. LPAR1 expression level was markedly elevated in PANC-R9 cells in comparison with PANC-1 cells, while LPAR3 expression level was reduced...
August 2018: Journal of Receptor and Signal Transduction Research
Kaede Takahashi, Kaori Fukushima, Kosuke Tanaka, Kanako Minami, Kaichi Ishimoto, Shiho Otagaki, Nobuyuki Fukushima, Kanya Honoki, Toshifumi Tsujiuchi
Lysophosphatidic acid (LPA) signaling via G protein-coupled LPA receptors mediates various biological effects in cancer cells. This study aimed to investigate the roles of LPA receptors in the regulation of cellular functions during tumor progression in osteosarcoma cells. Long-term cisplatin (CDDP)-treated MG63-C and MG63-R7-C cells were generated from osteosarcoma MG-63 and highly-migratory MG63-R7 cells, respectively. LPAR2 and LPAR3 expression levels were significantly higher in MG63-C cells than in MG-63 cells, while LPAR1 expression was reduced...
August 15, 2018: Experimental Cell Research
Michael Kroiher, Michael Walther, Stefan Berking
In the marine colonial hydroidHydractinia echinata metamorphosis from the larval to the adult (polyp) stage is induced by various agents, including CsCI and dioctanoylglycerol (diC8). Induction is prevented when the inhibitors of protein synthesis cycloheximide or ementine were applied simultaneously with the metamorphosis-inducing agents. With diC8 treatment, the inhibitors caused most animals to transform into mosaics consisting of larval and polyp body parts instead of normal shaped polyps. In contrast, treatment with cycloheximide or ementine just before or after incubation with the metamorphosis-inducing agents did not prevent larvae from metamorphosis...
November 1991: Roux's Archives of Developmental Biology: the Official Organ of the EDBO
Thomas Leitz, Gabriele Klingmann
Metamorphosis of planula larvae involves an activation of morphogenetically quiescent cells. The present work extends a previous study [Leitz T and Müller WA (1987) Dev Biol 121:82-89] on the participation of the phosphatidylinositol/diacylglycerol/protein kinase C system. Metamorphosis is stereospecifically induced by diacylglycerols, 1,2,-sn-dioctanoylglycerol (diC8) being by far the most effective substance. K-252a and sphingosine, inhibitors of mammalian protein kinases C, profoundly inhibited metamorphosis...
October 1990: Roux's Archives of Developmental Biology: the Official Organ of the EDBO
Werner A Müller, Thomas Leitz, Michael Stephan, Wolf D Lehmann
Repeated stimulation ofHydra magnipapillata with the diacylglycerol (DG) 1,2-sn-dioctanoylglycerol (diC8) induces an increase in positional value and eventually the development of ectopic heads. Upon stimulation, the polyps release [(14)C]-arachidonic acid from previously labelled endogenous sources. Arachidonic acid (AA) is not released into the external medium but remains within the animal, AA, linoleic acid and their lipoxygenase products were identified by gas chromatography-mass spectrometry. Several metabolites were found, most abundantly 12-HETE (hydroxy-eicosa-tetraenoic acid), 8-HETE, 9-HODE (hydroxy-octadecadienoic acid), and 13-HODE; this is the first evidence of their presence in coelenterates...
March 1993: Roux's Archives of Developmental Biology: the Official Organ of the EDBO
Longfei Li, Yoshiaki Ohtsu, Yuko Nakagawa, Katsuyoshi Masuda, Itaru Kojima
Sucralose is an artificial sweetener and activates the glucose-sensing receptor expressed in pancreatic β-cells. Although sucralose does not enter β-cells nor acts as a substrate for glucokinase, it induces a marked elevation of intracellular ATP ([ATP]c). The present study was conducted to identify the signaling pathway responsible for the elevation of [ATP]c induced by sucralose. Previous studies have shown that sucralose elevates cyclic AMP (cAMP), activates phospholipase C (PLC) and stimulates Ca(2+) entry by a Na(+)-dependent mechanism in MIN6 cells...
August 31, 2016: Endocrine Journal
Constanza B Kamerbeek, Melina V Mateos, Ana S Vallés, María F Pediconi, Francisco J Barrantes, Virginia Borroni
Diacylglycerol (DAG), a second messenger involved in different cell signaling cascades, activates protein kinase C (PKC) and D (PKD), among other kinases. The present work analyzes the effects resulting from the alteration of DAG levels on neuronal and muscle nicotinic acetylcholine receptor (AChR) distribution. We employ CHO-K1/A5 cells, expressing adult muscle-type AChR in a stable manner, and hippocampal neurons, which endogenously express various subtypes of neuronal AChR. CHO-K1/A5 cells treated with dioctanoylglycerol (DOG) for different periods showed augmented AChR cell surface levels at short incubation times (30min-4h) whereas at longer times (18h) the AChR was shifted to intracellular compartments...
May 2016: International Journal of Biochemistry & Cell Biology
Chunguang Zhang, Martha A Bosch, Oline K Rønnekleiv, Martin J Kelly
Kisspeptin signaling via its Gαq-coupled receptor GPR54 plays a crucial role in modulating GnRH neuronal excitability, which controls pituitary gonadotropins secretion and ultimately reproduction. Kisspeptin potently depolarizes GnRH neurons primarily through the activation of canonical transient receptor potential (TRPC) channels, but the intracellular signaling cascade has not been elucidated. Presently, we have established that kisspeptin activation of TRPC channels requires multiple membrane and intracellular signaling molecules...
August 2013: Endocrinology
Ghazi M Rahman, Sreejesh Shanker, Nancy E Lewin, Noemi Kedei, Colin S Hill, B V Venkataram Prasad, Peter M Blumberg, Joydip Das
PKC (protein kinase C) θ is predominantly expressed in T-cells and is critically involved in immunity. Design of PKCθ-selective molecules to manage autoimmune disorders by targeting its activator-binding C1 domain requires the knowledge of its structure and the activator-binding residues. The C1 domain consists of twin C1 domains, C1A and C1B, of which C1B plays a critical role in the membrane translocation and activation of PKCθ. In the present study we determined the crystal structure of PKCθC1B to 1...
April 1, 2013: Biochemical Journal
Sawsan Amara, Vincent Delorme, Michel Record, Frédéric Carrière
Methyl arachidonyl fluorophosphonate (MAFP) is a known inhibitor of cytosolic phospholipase A2 and some other serine enzymes. MAFP was found here to be an irreversible inhibitor of human pancreatic lipase-related protein 2 (HPLRP2), an enzyme displaying lipase, phospholipase A1 and galactolipase activities. In the presence of MAFP, mass spectrometry analysis of HPLRP2 revealed a mass increase of 351Da, suggesting a covalent binding of MAFP to the active site serine residue. When HPLRP2 was pre-incubated with MAFP before measuring residual activity, a direct inhibition of HPLRP2 occurred, confirming that HPLRP2 has an active site freely accessible to solvent and differs from most lipases in solution...
November 2012: Biochimica et Biophysica Acta
Chiara Ghezzi, Ernest M Wright
The human Na(+)-glucose cotransporter SGLT2 is expressed mainly in the kidney proximal convoluted tubule where it is considered to be responsible for the bulk of glucose reabsorption. Phosphorylation profiling has revealed that SGLT2 exists in a phosphorylated state in the rat renal proximal tubule cortex, so we decided to investigate the regulation of human SGLT2 (hSGLT2) by protein kinases. hSGLT2 was expressed in human embryonic kidney (HEK) 293T cells, and the activity of the protein was measured using radiotracer and whole cell patch-clamp electrophysiology assays before and after activation of protein kinases...
August 1, 2012: American Journal of Physiology. Cell Physiology
M A Orchard, M C Scrutton
Studies were performed to determine whether formation of platelet aggregates itself, could cause an increase in cytosolic [Ca(2+)]([Ca(2+)](i)) which is independent of that resulting from the addition of agonists which induce aggregation. An increase in [Ca(2+)](i) did not coincide with aggregate formation when this response was dissociated from the addition of ADP or thrombin by delay either in initiating stirring or, for ADP, in adding fibrinogen. No increase in [Ca(2+)](i) occurred when aggregation was induced by addition of 1,2-dioctanoylglycerol or of ristocetin, or for chymotrypsin-treated platelets by addition of fibrinogen...
1993: Platelets
P P Godfrey, Z Taghavi
The effects of various modulators of excitatory amino acid stimulated inositol phosphate (IP) formation were investigated in slices of rat cerebral cortex. Both quisqualic acid (Quis) and ibotenic acid (Ibo) stimulated IP formation in a dose-dependent manner. Quis (0.3mM) stimulated the rapid formation of inositol bis, tris and tetrakis-phosphates, with a slower linear rise in the monophosphate which plateaued after 20 min. The responses to both Ibo (0.3 mM) and Quis (0.3 mM) were dose-dependently inhibited by phorbol dibutyrate (PDBu); the Ibo response was particularly sensitive to PDBu, with a 90% inhibition of the response at 1 ?M and an IC(50) of 200 nM; Quis stimulated IP formation was less sensitive with a 50% inhibition observed at 10 ?M PDBu...
1990: Neurochemistry International
Peter J Wickley, Ryo Yuge, Brad A Martin, Jacob S Meyer, Derek S Damron
BACKGROUND: Myocardial protection by anesthetics is known to involve activation of protein kinase C epsilon (PKC epsilon). A key step in the activation process is autophosphorylation of the enzyme at serine 729. This study's objectives were to identify the extent to which propofol interacts with PKC epsilon and to identify the molecular mechanism(s) of interaction. METHODS: Immunoblot analysis of recombinant PKC epsilon was used to assess autophosphorylation of PKC epsilon at serine 729 before and after exposure to propofol...
July 2009: Anesthesiology
Shirlynn Chen, Mayur S Dudhedia, Zeren Wang, Richard T Darrington, Toby Tamblyn, John A Smoliga, Paul-James Jones, Steven L Krill
This report describes the solubility properties of a poorly soluble drug-excipient complex in a lipid based formulation. Tipranavir (TPV) was used as the model drug and 1,3-dioctanoylglycerol (DOG) as the excipient. The TPV-DOG complex was prepared by dissolving TPV and DOG in ethanol at 60 degrees C followed by evaporation of ethanol. The formation of the complex with a 4:1 TPV-to-DOG molar ratio was confirmed by XRPD, DSC, and NMR. At 25 degrees C, total solubility of TPV decreased with increasing DOG concentration...
May 2009: Journal of Pharmaceutical Sciences
Gianni F Guidetti, Paolo Lova, Bruno Bernardi, Francesca Campus, Gianluca Baldanzi, Andrea Graziani, Cesare Balduini, Mauro Torti
Stimulation of G(q)-coupled receptors activates phospholipase C and is supposed to promote both intracellular Ca(2+) mobilization and protein kinase C (PKC) activation. We found that ADP-induced phosphorylation of pleckstrin, the main platelet substrate for PKC, was completely inhibited not only by an antagonist of the G(q)-coupled P2Y1 receptor but also upon blockade of the G(i)-coupled P2Y12 receptor. The role of G(i) on PKC regulation required stimulation of phosphatidylinositol 3-kinase rather than inhibition of adenylyl cyclase...
October 24, 2008: Journal of Biological Chemistry
Swaminathan Murugappan, Ramya Chari, Vasu M Palli, Jianguo Jin, Satya P Kunapuli
Phosphorylation of activation loop threonine (Thr(505)) and regulatory domain tyrosine (Tyr(311)) residues are key regulators of PKC (protein kinase C) delta function in platelets. In the present study, we show that G(q) and G(12/13) pathways regulate the Thr(505) and Tyr(311) phosphorylation on PKCdelta in an interdependent manner. DiC8 (1,2-dioctanoylglycerol), a synthetic analogue of DAG (diacylglycerol), caused Thr(505), but not Tyr(311), phosphorylation on PKCdelta, whereas selective activation of G(12/13) pathways by the YFLLRNP peptide failed to cause phosphorylation of either residue...
January 1, 2009: Biochemical Journal
Karin Lichte, Roberto Rossi, Kerstin Danneberg, Michael ter Braak, Ulrich Kürschner, Karl H Jakobs, Burkhard Kleuser, Dagmar Meyer zu Heringdorf
The lysophospholipids, sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA), stimulate chemotaxis and induce differentiation of human keratinocytes. As Ca(2+) plays an important role in keratinocyte differentiation, we studied Ca(2+) signaling by S1P and LPA in these cells, known to express mRNA transcripts of the S1P(1-5) and LPA(1-3) receptors, and the receptor subtypes involved in this process. S1P and LPA caused transient increases in intracellular free Ca(2+) concentration ([Ca(2+)](i)), with pEC(50) values of 8...
June 2008: Journal of Investigative Dermatology
Nicola Tommasino, Maristella Villani, Asfia Qureshi, Jennifer Henry, Chiara Luberto, Maurizio Del Poeta
The fungus Cryptococcus neoformans is an environmental human pathogen which enters the lung via the respiratory tract and produces a unique protein, called antiphagocytic protein 1 (App1), that protects it from phagocytosis by macrophages. In previous studies, we proposed genetic evidences that transcription of APP1 is controlled by the enzymatic reaction catalyzed by inositol phosphorylceramide synthase 1 (Ipc1) via the production of diacylglycerol through the activating transcription factor 2 (Atf2). We investigated here the mechanism by which Atf2 binds to the APP1 promoter in vitro and in vivo...
February 2008: Eukaryotic Cell
Johnny Näsman, Genevieve Bart, Kim Larsson, Lauri Louhivuori, Hanna Peltonen, Karl E O Akerman
We studied the cellular response to orexin type 1 receptor (OX1R) stimulation in differentiated IMR-32 neuroblastoma cells. In vitro differentiation of IMR-32 cells with 5-bromo-2'-deoxyuridine leads to a neuronal phenotype with long neurite extensions and an upregulation of mainly N-type voltage-gated calcium channels. Transduction of differentiated IMR-32 cells with baculovirus harboring an OX1R-green fluorescent protein cDNA fusion construct resulted in appearance of fluorescence that was confined mainly to the plasma membrane in the cell body and to neurites...
October 18, 2006: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
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