Insulin Activates Glycerol-3-phosphate Acyltransferase (de Novo Phosphatidic Acid Synthesis) through a Phospholipid-Derived Mediator. Apparent Involvement of Giα and Activation of a Phospholipase C
We studied the mechanism whereby insulin activates de novo phosphatidic acid synthesis in BC3H-1 myocytes. Insulin rapidly activated glycerol-3-phosphate acyltransferase (G3PAT) in intact and cell-free preparations of myocytes in a dose-related manner. The apparent Km of the enzyme was decreased by...
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1990
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00062960_v29_n37_p8735_delVila http://hdl.handle.net/20.500.12110/paper_00062960_v29_n37_p8735_delVila |
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paper:paper_00062960_v29_n37_p8735_delVila2023-06-08T14:30:38Z Insulin Activates Glycerol-3-phosphate Acyltransferase (de Novo Phosphatidic Acid Synthesis) through a Phospholipid-Derived Mediator. Apparent Involvement of Giα and Activation of a Phospholipase C 1-phosphatidylinositol phosphodiesterase Bordetella virulence factor fluoride sodium glycerol 3 phosphate acyltransferase Glycerol 3 Phosphate O Acyltransferase GTP Binding Proteins guanine nucleotide binding protein inositol phosphate inositol phosphate glycan insulin phosphatidic acid phosphatidylinositol phosphodiesterase phosphodiesterase polysaccharide diacylglycerol glycerol 3 phosphate acyltransferase insulin phospholipase c animal article biosynthesis cell culture chemistry cytosol drug effect enzyme activation kinetics metabolism mouse muscle signal transduction muscle cell nonhuman priority journal signal transduction Animal Cells, Cultured Cytosol Enzyme Activation Glycerol-3-Phosphate O-Acyltransferase GTP-Binding Proteins Inositol Phosphates Insulin Kinetics Mice Muscles Phosphatidic Acids Phosphoric Diester Hydrolases Polysaccharides Signal Transduction Sodium Fluoride Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Virulence Factors, Bordetella We studied the mechanism whereby insulin activates de novo phosphatidic acid synthesis in BC3H-1 myocytes. Insulin rapidly activated glycerol-3-phosphate acyltransferase (G3PAT) in intact and cell-free preparations of myocytes in a dose-related manner. The apparent Km of the enzyme was decreased by treatment with insulin, whereas the Vmax was unaffected. No activation was found by ACTH, insulin-like growth factor-I, angiotensin II, or phenylephrine, but epidermal growth factor, which, like insulin, is known to activate de novo phosphatidic acid synthesis in intact myocytes, also stimulated G3PAT activity. In homogenates or membrane fractions, the effect of insulin on G3PAT was fully mimicked by nonspecific or phosphatidylinositol (PI)-specific phospholipase C (PLC). An antiserum raised against PI-glycan-PLC completely blocked the effect of insulin on G3PAT. Although the above findings suggested involvement of a PLC in insulin-induced activation of G3PAT, neither diacylglycerol nor protein kinase C activation appeared to be involved. On the other hand, insulin stimulated the release of a cytosolic factor, which activated membrane-associated G3PAT. This cytosolic factor had a molecular weight of less than 5K as determined by Sephadex G-25 chromatography. NaF, a phosphatase inhibitor, blocked the activation of G3PAT by insulin, suggesting involvement of a phosphatase. Insulin-induced activation of G3PAT was also blocked by pretreatment of intact myocytes with pertussis toxin and by prior addition, to homogenates, of an antiserum that recognizes the C-terminal decapeptide of Giα. Our results suggest that insulin activates a pertussis toxin sensitive, Giα-protein-requiring PI-glycan-PLC in BC3H-1 myocytes, resulting in the release of a cytosolic, low molecular weight factor, which decreases the Km of G3PAT, probably by a phosphatasemediated mechanism. This activation of G3PAT may account for insulin-induced increases in de novo synthesis of phosphatidic acid, which, in turn, may amplify diacylglycerol-protein kinase C signaling and provide a mechanism to replenish phospholipids that are hydrolyzed during insulin action. © 1990, American Chemical Society. All rights reserved. 1990 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00062960_v29_n37_p8735_delVila http://hdl.handle.net/20.500.12110/paper_00062960_v29_n37_p8735_delVila |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
1-phosphatidylinositol phosphodiesterase Bordetella virulence factor fluoride sodium glycerol 3 phosphate acyltransferase Glycerol 3 Phosphate O Acyltransferase GTP Binding Proteins guanine nucleotide binding protein inositol phosphate inositol phosphate glycan insulin phosphatidic acid phosphatidylinositol phosphodiesterase phosphodiesterase polysaccharide diacylglycerol glycerol 3 phosphate acyltransferase insulin phospholipase c animal article biosynthesis cell culture chemistry cytosol drug effect enzyme activation kinetics metabolism mouse muscle signal transduction muscle cell nonhuman priority journal signal transduction Animal Cells, Cultured Cytosol Enzyme Activation Glycerol-3-Phosphate O-Acyltransferase GTP-Binding Proteins Inositol Phosphates Insulin Kinetics Mice Muscles Phosphatidic Acids Phosphoric Diester Hydrolases Polysaccharides Signal Transduction Sodium Fluoride Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Virulence Factors, Bordetella |
| spellingShingle |
1-phosphatidylinositol phosphodiesterase Bordetella virulence factor fluoride sodium glycerol 3 phosphate acyltransferase Glycerol 3 Phosphate O Acyltransferase GTP Binding Proteins guanine nucleotide binding protein inositol phosphate inositol phosphate glycan insulin phosphatidic acid phosphatidylinositol phosphodiesterase phosphodiesterase polysaccharide diacylglycerol glycerol 3 phosphate acyltransferase insulin phospholipase c animal article biosynthesis cell culture chemistry cytosol drug effect enzyme activation kinetics metabolism mouse muscle signal transduction muscle cell nonhuman priority journal signal transduction Animal Cells, Cultured Cytosol Enzyme Activation Glycerol-3-Phosphate O-Acyltransferase GTP-Binding Proteins Inositol Phosphates Insulin Kinetics Mice Muscles Phosphatidic Acids Phosphoric Diester Hydrolases Polysaccharides Signal Transduction Sodium Fluoride Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Virulence Factors, Bordetella Insulin Activates Glycerol-3-phosphate Acyltransferase (de Novo Phosphatidic Acid Synthesis) through a Phospholipid-Derived Mediator. Apparent Involvement of Giα and Activation of a Phospholipase C |
| topic_facet |
1-phosphatidylinositol phosphodiesterase Bordetella virulence factor fluoride sodium glycerol 3 phosphate acyltransferase Glycerol 3 Phosphate O Acyltransferase GTP Binding Proteins guanine nucleotide binding protein inositol phosphate inositol phosphate glycan insulin phosphatidic acid phosphatidylinositol phosphodiesterase phosphodiesterase polysaccharide diacylglycerol glycerol 3 phosphate acyltransferase insulin phospholipase c animal article biosynthesis cell culture chemistry cytosol drug effect enzyme activation kinetics metabolism mouse muscle signal transduction muscle cell nonhuman priority journal signal transduction Animal Cells, Cultured Cytosol Enzyme Activation Glycerol-3-Phosphate O-Acyltransferase GTP-Binding Proteins Inositol Phosphates Insulin Kinetics Mice Muscles Phosphatidic Acids Phosphoric Diester Hydrolases Polysaccharides Signal Transduction Sodium Fluoride Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Virulence Factors, Bordetella |
| description |
We studied the mechanism whereby insulin activates de novo phosphatidic acid synthesis in BC3H-1 myocytes. Insulin rapidly activated glycerol-3-phosphate acyltransferase (G3PAT) in intact and cell-free preparations of myocytes in a dose-related manner. The apparent Km of the enzyme was decreased by treatment with insulin, whereas the Vmax was unaffected. No activation was found by ACTH, insulin-like growth factor-I, angiotensin II, or phenylephrine, but epidermal growth factor, which, like insulin, is known to activate de novo phosphatidic acid synthesis in intact myocytes, also stimulated G3PAT activity. In homogenates or membrane fractions, the effect of insulin on G3PAT was fully mimicked by nonspecific or phosphatidylinositol (PI)-specific phospholipase C (PLC). An antiserum raised against PI-glycan-PLC completely blocked the effect of insulin on G3PAT. Although the above findings suggested involvement of a PLC in insulin-induced activation of G3PAT, neither diacylglycerol nor protein kinase C activation appeared to be involved. On the other hand, insulin stimulated the release of a cytosolic factor, which activated membrane-associated G3PAT. This cytosolic factor had a molecular weight of less than 5K as determined by Sephadex G-25 chromatography. NaF, a phosphatase inhibitor, blocked the activation of G3PAT by insulin, suggesting involvement of a phosphatase. Insulin-induced activation of G3PAT was also blocked by pretreatment of intact myocytes with pertussis toxin and by prior addition, to homogenates, of an antiserum that recognizes the C-terminal decapeptide of Giα. Our results suggest that insulin activates a pertussis toxin sensitive, Giα-protein-requiring PI-glycan-PLC in BC3H-1 myocytes, resulting in the release of a cytosolic, low molecular weight factor, which decreases the Km of G3PAT, probably by a phosphatasemediated mechanism. This activation of G3PAT may account for insulin-induced increases in de novo synthesis of phosphatidic acid, which, in turn, may amplify diacylglycerol-protein kinase C signaling and provide a mechanism to replenish phospholipids that are hydrolyzed during insulin action. © 1990, American Chemical Society. All rights reserved. |
| title |
Insulin Activates Glycerol-3-phosphate Acyltransferase (de Novo Phosphatidic Acid Synthesis) through a Phospholipid-Derived Mediator. Apparent Involvement of Giα and Activation of a Phospholipase C |
| title_short |
Insulin Activates Glycerol-3-phosphate Acyltransferase (de Novo Phosphatidic Acid Synthesis) through a Phospholipid-Derived Mediator. Apparent Involvement of Giα and Activation of a Phospholipase C |
| title_full |
Insulin Activates Glycerol-3-phosphate Acyltransferase (de Novo Phosphatidic Acid Synthesis) through a Phospholipid-Derived Mediator. Apparent Involvement of Giα and Activation of a Phospholipase C |
| title_fullStr |
Insulin Activates Glycerol-3-phosphate Acyltransferase (de Novo Phosphatidic Acid Synthesis) through a Phospholipid-Derived Mediator. Apparent Involvement of Giα and Activation of a Phospholipase C |
| title_full_unstemmed |
Insulin Activates Glycerol-3-phosphate Acyltransferase (de Novo Phosphatidic Acid Synthesis) through a Phospholipid-Derived Mediator. Apparent Involvement of Giα and Activation of a Phospholipase C |
| title_sort |
insulin activates glycerol-3-phosphate acyltransferase (de novo phosphatidic acid synthesis) through a phospholipid-derived mediator. apparent involvement of giα and activation of a phospholipase c |
| publishDate |
1990 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00062960_v29_n37_p8735_delVila http://hdl.handle.net/20.500.12110/paper_00062960_v29_n37_p8735_delVila |
| _version_ |
1768544437300887552 |