Abstract
Methyl-beta-cyclodextrin (MbetaCD) was used to explore a role for cholesterol-enriched plasma membrane microdomains in coupling lysophosphatidic acid (LPA) stimulation to phosphoinositide 3-kinase (PI3K) activation. Cholesterol depletion strongly inhibited the production of phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 3,4,5-trisphosphate in Vero cells stimulated with LPA. In agreement, the phosphorylation of Akt/protein kinase B, but not of Erk kinases, was suppressed by MbetaCD. MbetaCD did not interfere with the overall phospholipid metabolism, and its effects were reversed in cholesterol add-back experiments. Finally, PI3K was detected in lipid rafts prepared from control but not MbetaCD-treated cells, suggesting that these microdomains contribute to LPA signalling by compartmentalising component(s) of the PI3K pathway.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Chlorocebus aethiops
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Cholesterol / metabolism*
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Cholesterol / pharmacology
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Cyclodextrins / pharmacology
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Enzyme Activation / drug effects
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ErbB Receptors / drug effects
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ErbB Receptors / metabolism
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Lipid Metabolism*
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Lysophospholipids / metabolism*
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Lysophospholipids / pharmacology
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Mitogen-Activated Protein Kinases / metabolism
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Phosphatidylinositol 3-Kinases / drug effects
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Phosphatidylinositol 3-Kinases / metabolism*
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Phosphatidylinositol Phosphates / metabolism
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Phospholipids / metabolism
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Phosphorylation
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Protein Serine-Threonine Kinases*
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Proto-Oncogene Proteins / drug effects
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-akt
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Signal Transduction
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Vero Cells / drug effects
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beta-Cyclodextrins*
Substances
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Cyclodextrins
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Lysophospholipids
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Phosphatidylinositol Phosphates
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Phospholipids
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Proto-Oncogene Proteins
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beta-Cyclodextrins
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methyl-beta-cyclodextrin
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phosphatidylinositol 3,4,5-triphosphate
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phosphatidylinositol 3,4-diphosphate
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Cholesterol
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ErbB Receptors
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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Mitogen-Activated Protein Kinases