Abstract
The hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) by phospholipase C yields the second messengers inositol 1,4,5-trisphosphate (InsP3) and 1,2-diacylglycerol. This activity is regulated by a variety of hormones through G protein pathways. However, the specific G protein or proteins involved has not been identified. The alpha subunit of a newly discovered pertussis toxin-insensitive G protein (Gq) has recently been isolated and is now shown to stimulate the activity of polyphosphoinositide-specific phospholipase C (PI-PLC) from bovine brain. Both the maximal activity and the affinity of PI-PLC for calcium ion were affected. These results identify Gq as a G protein that regulates PI-PLC.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Aluminum / pharmacology
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Aluminum Compounds*
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Animals
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Calcium / physiology
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Cattle
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Enzyme Activation / drug effects
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Fluorides / pharmacology
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GTP-Binding Proteins / drug effects
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GTP-Binding Proteins / physiology*
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Guanosine Diphosphate
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In Vitro Techniques
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Phosphatidylinositol Diacylglycerol-Lyase
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Phosphoinositide Phospholipase C
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Phosphoric Diester Hydrolases / metabolism*
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Substrate Specificity
Substances
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Aluminum Compounds
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Guanosine Diphosphate
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Aluminum
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Phosphoric Diester Hydrolases
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Phosphoinositide Phospholipase C
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GTP-Binding Proteins
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Phosphatidylinositol Diacylglycerol-Lyase
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Fluorides
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Calcium
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aluminum fluoride