Abstract
The lipidic metabolite, diacylglycerol pyrophosphate (DGPP), in its dioctanoyl form (DGPP 8:0), has been described as an antagonist for mammalian lysophosphatidic acid (LPA) receptors LPA1 and LPA3. In this study we show that DGPP 8:0 does not antagonize LPA dependent activation of ERK(1/2) MAP kinases but strongly stimulated them in various mammalian cell lines. LPA and DGPP 8:0 stimulation of ERK(1/2) occurred through different pathways. The DGPP 8:0 effect appeared to be dependent on PKC, Raf and MEK but was insensitive to pertussis toxin and did not involve G protein activation. Finally we showed that DGPP 8:0 effect on ERK(1/2) was dependent on its dephosphorylation by a phosphatase activity sharing lipid phosphate phosphatase properties. The inhibition of this phosphatase activity by VPC32183, a previously characterized LPA receptor antagonist, blocked the DGPP 8:0 effect on ERK(1/2) activation. Moreover, down-regulation of lipid phosphate phosphatase 1 (LPP1) expression by RNA interference technique also reduced DGPP 8:0-induced ERK(1/2) activation. Consistently, over expression of LPP1 in HEK293 cells increases DGPP 8:0 hydrolysis and this increased activity was inhibited by VPC32183. In conclusion, DGPP 8:0 does not exert its effect by acting on a G protein coupled receptor, but through its dephosphorylation by LPP1, generating dioctanoyl phosphatidic acid which in turn activates PKC. These results suggest that LPP1 could have a positive regulatory function on cellular signaling processes such as ERK(1/2) activation.
Copyright © 2012 Elsevier B.V. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Blotting, Western
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Cell Membrane / metabolism
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Cells, Cultured
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Diphosphates / pharmacology*
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Glycerol / analogs & derivatives*
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Glycerol / pharmacology
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Humans
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Hydrolysis
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Kidney / cytology
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Kidney / drug effects
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Kidney / metabolism
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Lysophospholipids / pharmacology
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MAP Kinase Kinase 1 / genetics
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MAP Kinase Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 1 / genetics
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Mitogen-Activated Protein Kinase 1 / metabolism*
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Mitogen-Activated Protein Kinase 3 / genetics
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Mitogen-Activated Protein Kinase 3 / metabolism*
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Organophosphates / pharmacology*
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Phosphatidate Phosphatase / antagonists & inhibitors*
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Phosphatidate Phosphatase / genetics
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Phosphatidate Phosphatase / metabolism
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Phosphatidic Acids / pharmacology
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Phosphorylation / drug effects
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Protein Kinase C / genetics
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Protein Kinase C / metabolism
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Pyridines / pharmacology*
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RNA, Messenger / genetics
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Real-Time Polymerase Chain Reaction
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Receptors, Lysophosphatidic Acid / antagonists & inhibitors
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Receptors, Lysophosphatidic Acid / genetics
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Receptors, Lysophosphatidic Acid / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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raf Kinases / genetics
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raf Kinases / metabolism
Substances
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Diphosphates
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Lysophospholipids
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Organophosphates
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Phosphatidic Acids
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Pyridines
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RNA, Messenger
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Receptors, Lysophosphatidic Acid
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VPC32183
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diacylglycerol pyrophosphate
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dioctanoylphosphatidic acid
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raf Kinases
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Protein Kinase C
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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MAP Kinase Kinase 1
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MAP2K1 protein, human
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lipid phosphate phosphatase
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Phosphatidate Phosphatase
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Glycerol
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lysophosphatidic acid