Abstract
Erythropoietin (Epo)-induced glycosylphosphatidylinositol (GPI) hydrolysis was previously described to be correlated with phospholipase C-gamma 2 (PLC-gamma2) activation. Here, we analyzed the involvement of phosphatidylinositol (PtdIns) 3-kinase in GPI hydrolysis through PLC-gamma2 tyrosine phosphorylation in response to Epo in FDC-P1 cells transfected with a wild type (WT) erythropoietin-receptor (Epo-R). We showed that phosphatidylinositol 3-kinase (PtdIns 3-kinase) inhibitor LY294002 inhibits Epo-induced hydrolysis of endogenous GPI and Epo-induced PLC-gamma2 tyrosine phosphorylation in a dose-dependent manner. Wortmannin, another PtdIns 3-kinase inhibitor, also suppressed Epo-induced PLC-gamma2 tyrosine phosphorylation. We also present evidence that PLC-gamma2 translocation to the membrane fraction on Epo stimulation is completely inhibited by LY294002. Upon Epo stimulation, the tyrosine-phosphorylated PLC-gamma2 was found to be associated with the tyrosine-phosphorylated Grb2-associated binder (GAB)2, SHC and SHP2 proteins. LY294002 cell preincubation did not affect GAB2, SHC and SHP2 tyrosine phosphorylation but inhibited the binding of PLC-gamma2 to GAB2 and SHP2. Taken together, these results show that PtdIns 3-kinase controls Epo-induced GPI hydrolysis through PLC-gamma2.
Copyright 2002 Elsevier Science Inc.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Adaptor Proteins, Vesicular Transport*
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Animals
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Cell Differentiation / drug effects
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Cell Differentiation / physiology
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Cell Division / drug effects
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Cell Division / physiology
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Cell Membrane / drug effects
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Cell Membrane / enzymology*
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Cells, Cultured
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Dose-Response Relationship, Drug
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Enzyme Inhibitors / pharmacology
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Erythrocytes / enzymology*
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Erythroid Precursor Cells / enzymology*
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Erythropoietin / genetics
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Erythropoietin / metabolism*
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Glycosylphosphatidylinositols / metabolism*
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Helminth Proteins / metabolism
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Humans
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Hydrolysis / drug effects
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Isoenzymes / metabolism*
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Phosphatidylinositol 3-Kinases / metabolism*
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Phospholipase C gamma
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Phosphoproteins / metabolism
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Phosphorylation
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Protein Binding / physiology
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Protein Transport / drug effects
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Protein Transport / physiology
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Proteins / metabolism
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Shc Signaling Adaptor Proteins
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Src Homology 2 Domain-Containing, Transforming Protein 1
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Subcellular Fractions
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Transfection
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Type C Phospholipases / metabolism*
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Tyrosine / metabolism
Substances
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Adaptor Proteins, Signal Transducing
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Adaptor Proteins, Vesicular Transport
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Enzyme Inhibitors
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GAB2 protein, human
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Glycosylphosphatidylinositols
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Helminth Proteins
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Isoenzymes
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Phosphoproteins
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Proteins
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SHC1 protein, human
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Shc Signaling Adaptor Proteins
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Src Homology 2 Domain-Containing, Transforming Protein 1
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Erythropoietin
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microfilarial sheath protein, Helminth
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Tyrosine
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Phosphatidylinositol 3-Kinases
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Type C Phospholipases
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Phospholipase C gamma