Abstract
Insulin stimulates a rapid phosphorylation and sequestration of the beta(2)-adrenergic receptor. Analysis of the signaling downstream of the insulin receptor with enzyme inhibitors revealed roles for both phosphatidylinositol 3-kinase and pp60Src. Inhibition of Src with PP2, like the inhibition of phosphatidylinositol 3-kinase with LY294002 [2-(4-morpholynyl)-8-phenyl-4H-1-benzopyran-4-one], blocked the activation of Src as well as insulin-stimulated sequestration of the beta(2)-adrenergic receptor. Depletion of Src with antisense morpholinos also suppressed insulin-stimulated receptor sequestration. Src is shown to be phosphorylated/activated in response to insulin in human epidermoid carcinoma A431 cells as well as in mouse 3T3-L1 adipocytes and their derivative 3T3-F422A cells, well-known models of insulin signaling. Inhibition of Src with PP2 blocks the ability of insulin to sequester beta(2)-adrenergic receptors and the translocation of the GLUT4 glucose transporters. Insulin stimulates Src to associate with the beta(2)-adrenergic receptor/AKAP250/protein kinase A/protein kinase C signaling complex. We report a novel positioning of Src, mediating signals from insulin to phosphatidylinositol 3-kinase and to beta(2)-adrenergic receptor trafficking.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3T3 Cells
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Adrenergic beta-Agonists / metabolism
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Animals
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Enzyme Activation
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Enzyme Inhibitors / metabolism
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Glucose Transporter Type 4
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Humans
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Insulin / metabolism*
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Isoproterenol / metabolism
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Mice
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Models, Biological
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Monosaccharide Transport Proteins / genetics
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Monosaccharide Transport Proteins / metabolism
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Muscle Proteins*
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Oligonucleotides, Antisense / metabolism
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphorylation
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-fyn
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Proto-Oncogene Proteins pp60(c-src) / metabolism*
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Receptors, Adrenergic, beta-2 / genetics
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Receptors, Adrenergic, beta-2 / metabolism*
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Signal Transduction / physiology*
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Tumor Cells, Cultured
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src-Family Kinases / metabolism
Substances
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Adrenergic beta-Agonists
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Enzyme Inhibitors
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Glucose Transporter Type 4
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Insulin
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Monosaccharide Transport Proteins
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Muscle Proteins
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Oligonucleotides, Antisense
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Proto-Oncogene Proteins
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Receptors, Adrenergic, beta-2
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Recombinant Fusion Proteins
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SLC2A4 protein, human
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Slc2a4 protein, mouse
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Phosphatidylinositol 3-Kinases
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FYN protein, human
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Fyn protein, mouse
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Proto-Oncogene Proteins c-fyn
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Proto-Oncogene Proteins pp60(c-src)
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lyn protein-tyrosine kinase
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src-Family Kinases
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Isoproterenol