Abstract
Little is known about the physiological role and mechanism of activation of class II phosphoinositide 3-kinases (PI3Ks), although it has been shown that the PI3K-C2alpha isoform is activated by insulin. Using chimaeric receptor constructs which can be activated independently of endogenous receptors in transfected cells, we found that PI3K-C2alpha activity was stimulated to a greater extent by insulin receptors than IGF receptors in 3T3-L1 adipocytes. Activation of PI3K-C2alpha required an intact NPEY motif in the receptor juxtamembrane domain. We conclude that PI3K-C2alpha is a candidate for participation in insulin-specific intracellular signalling.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3 Cells / enzymology
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Adipocytes / enzymology
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Amino Acid Motifs / genetics
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Amino Acid Substitution / genetics
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Animals
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Cell Line
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Humans
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Isoenzymes / physiology*
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Mice
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Mutagenesis, Site-Directed / genetics
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Phenylalanine / genetics
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Phosphatidylinositol 3-Kinases / physiology*
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Receptor, IGF Type 1 / biosynthesis
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Receptor, IGF Type 1 / genetics
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Receptor, IGF Type 1 / physiology*
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Receptor, Insulin / genetics
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Receptor, Insulin / physiology*
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Recombinant Fusion Proteins / biosynthesis
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Recombinant Fusion Proteins / genetics
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Tyrosine / genetics
Substances
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Isoenzymes
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Recombinant Fusion Proteins
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Tyrosine
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Phenylalanine
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Phosphatidylinositol 3-Kinases
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Receptor, IGF Type 1
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Receptor, Insulin