Abstract
Stimulation of phosphatidylinositol-4,5-bisphosphate (PIP2) hydrolysis is a widespread mechanism for receptor-mediated signaling in eukaryotes. Cytosolic phosphatidylinositol transfer protein (PITP) is necessary for guanosine triphosphate (GTP)-dependent hydrolysis of PIP2 by phospholipase C-beta (PLC-beta), but the role of PITP is unclear. Stimulation of phospholipase C-gamma (PLC-gamma) in A431 human epidermoid carcinoma cells treated with epidermal growth factor (EGF) required PITP. Stimulation of PI-4 kinase in cells treated with EGF also required PITP. Coprecipitation studies revealed an EGF-dependent association of PITP with the EGF receptor, with PI-4 kinase, and with PLC-gamma.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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1-Phosphatidylinositol 4-Kinase
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Animals
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Carrier Proteins / metabolism
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Carrier Proteins / physiology*
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Cytosol / metabolism
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Epidermal Growth Factor / metabolism
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Epidermal Growth Factor / physiology*
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ErbB Receptors / metabolism
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Humans
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Isoenzymes / metabolism
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Isoenzymes / physiology
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Membrane Proteins*
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Phosphatidylinositols / metabolism
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Phospholipase C gamma
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Phospholipid Transfer Proteins
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Phosphotransferases (Alcohol Group Acceptor) / metabolism
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Protein Binding
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Rats
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Signal Transduction / physiology*
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Tumor Cells, Cultured
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Type C Phospholipases / metabolism
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Type C Phospholipases / physiology
Substances
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Carrier Proteins
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Isoenzymes
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Membrane Proteins
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Phosphatidylinositols
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Phospholipid Transfer Proteins
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Epidermal Growth Factor
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Phosphotransferases (Alcohol Group Acceptor)
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1-Phosphatidylinositol 4-Kinase
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ErbB Receptors
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Type C Phospholipases
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Phospholipase C gamma