Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The phagocytosis of beta-glucan particles by human neutrophils and the associated activation of NADPH O2- forming oxidase were accompanied by an increased hydrolysis of phosphoinositides by phospholipase C, hydrolysis of phosphatidylcholine by phospholipase D, accumulation of diglyceride (DG) mass, and [Ca2+]i rise. The reaction of phospholipid hydrolysis played a minor role in the formation of DG, which was mainly formed by de novo synthesis from glucose. The activation of this pathway was shown by the stimulation of the incorporation of [U-14C]glucose into DG, which occurred very rapidly after the challenge of neutrophils with beta-glucan particles. This DG derived from glucose was found almost completely as 1-acyl-2-acyl-glycerol (DAG). On the basis of the finding that phosphatidic acid was the precursor of DAG, an increase in the incorporation of [U-14C]acetate into DAG did not occur, and the [14C]radioactivity was in the glycerol backbone, the synthesis of DAG from [U-14C]glucose occurred very likely via dihydroxyacetone phosphate and glycerol 3-phosphate, stepwise acylation to phosphatidic acid, and dephosphorylation by phosphatidate phosphatase.
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PMID:De novo synthesis of diacylglycerol from glucose. A new pathway of signal transduction in human neutrophils stimulated during phagocytosis of beta-glucan particles. 185 Jul 33

Hepatocellular membranes (1000 X g) containing membrane-associated, labeled phosphatidic acid were incubated (1-30 min) with 2 mM oleate or 5 mM bromobenzene in the presence or absence of various metals and NaF. Under the appropriate incubation conditions, membranes displayed rapid and significant oleate- and bromobenzene-dependent increases in the dephosphorylation of labeled phosphatidic acid. However, oleate and bromobenzene activated the dephosphorylation of phosphatidate by phosphatidate phosphatase and phospholipase C, respectively. This conclusion is supported by the observation that the phosphatase stimulated by oleate is: (1) Mg2+ -dependent; (2) inhibited by other metals, such as Ca2+; (3) inhibited by NaF; (4) specific for phosphatidic acid; and (5) associated with a rise in liver cell triacylglycerol production. Bromobenzene, however, activated a phospholipase C that is: (1) stimulated by various metals, such as Mg2+, Ca2+ and Ba2+; (2) insensitive to NaF; (3) associated with the degradation of various membrane phospholipids; (4), associated with liver cell injury; and (5) not associated with a rise in liver cell triacylglycerol formation. These results suggest that under appropriate conditions in vitro the dephosphorylation of phosphatidic acid can be used to assess changes in phosphatidate phosphatase and/or phospholipase C activity. The distinction between these enzymes is important, since phosphatidate phosphatase and phospholipase C regulate key steps in phospholipid biosynthesis and degradation, respectively.
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PMID:A distinction in vitro between rat liver phosphatidate phosphatase and phospholipase C. 304 Jan 7

Lung surfactant, a lipid-protein complex purified from dog lungs, contains a highly active phosphomonoesterase associated with it. This phosphatase is quite specific for the hydrolysis of phosphatidic acid and 1-acyl-2-lysophosphatidic acid. The enzyme possesses many of the characteristics of the microsomal enzyme, phosphatidate phosphohydrolase (EC 3.1.3.4). In addition, we have shown that this enzyme will also convert phosphatidylglycerol phosphate [1-(3-sn-phosphatidyl)-sn-glycerol-1-P] to phosphatidylglycerol [1-(3-sn-phosphatidyl)-sn-glycerol] and Pi. The phosphatidylglycerol phosphate was made available to the surfactant enzyme in a coupled assay by hydrolysis of cardiolipin [1-(3-sn-phosphatidyl)-3-(3-sn-phosphatidyl)-sn-glycerol] by stereospecific cleavage with phospholipase C (phosphatidylcholine cholinephosphohydrolase, EC 3.1.4.3) from Bacillus cereus. This enzyme has been previously shown to generate the naturally occurring isomer of phosphatidylglycerol phosphate because it has specificity for the 3-(3-sn-phosphatidyl) group of cardiolipin. Other properties of the surfactant enzyme are discussed in relation to its presence in lung surface active material.
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PMID:Properties of an acid phosphatase in pulmonary surfactant. 692 79

We have characterized a membrane-bound phosphatidylcholine (PC) specific phospholipase C (PC-PLC) in plasma membranes from rat cardiac muscle, and have investigated the role of PC-PLC and PC-specific phospholipase D (PC-PLD) activities in the mechanism of action of atrial natriuretic factor (ANF). In purified sarcolemma, ANF stimulated over a wide range of concentrations with a maximum at 10(-11) M the hydrolysis of phosphatidylcholine through PC-PLD giving phosphatidate and choline, whereas higher concentrations of ANF (10(-10) M) preferentially stimulated PC breakdown through PC-PLC to form diacylglycerol and phosphocholine. To confirm the involvement of the PC-PLD in the mechanism of ANF action, we measured the transphosphatidylation reaction, a specific assay for this phospholipase which in the presence of ethanol catalyses the phosphatidylethanol formation from PC. ANF stimulated phosphatidylethanol formation with the same dose-response behavior as phosphatidate formation. The significant diacylglycerol increase at 10(-10) M ANF, in the presence of propranolol, a potent inhibitor of phosphatidate phosphatase which can hydrolyse phosphatidate to give diacylglycerol, suggested a direct involvement of PC-PLC. The use of GTP-gamma-S, a non hydrolysable analog of GTP, and of pertussis toxin showed the involvement of a pertussis toxin insensitive G protein in PC-PLC mediated ANF signal transduction. We suggest a differential effect of ANF on PC breakdown by phospholipases C and D depending on the concentration of the peptide.
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PMID:Selective activation by atrial natriuretic factor of phosphatidylcholine-specific phospholipase activities in purified heart muscle plasma membranes. 773 Oct 62

Phosphate is an essential nutrient for plant viability. It is well-established that phosphate starvation triggers membrane lipid remodeling, a process that converts significant portion of phospholipids to non-phosphorus-containing galactolipids. This remodeling is mediated by either phospholipase C (PLC) or phospholipase D (PLD) in combination with phosphatidate phosphatase (PAP). Two PLC genes, NPC4 and NPC5, and PLD genes, PLDzeta1 and PLDzeta2, are shown to be involved in the remodeling. However, gene knockout studies show that none of them plays decisive roles in the remodeling. Thus, although this phenomenon is widely observed among plants, the key enzyme(s) responsible for the lipid remodeling in a whole plant body is unknown; therefore, the physiological significance of this conversion process has remained to be elucidated. We herein focused on PAP as a key enzyme for this adaptation, and identified Arabidopsis lipin homologs, AtPAH1 and AtPAH2, that encode the PAPs involved in galactolipid biosynthesis. Double mutant pah1pah2 plants had decreased phosphatidic acid hydrolysis, thus affecting the eukaryotic pathway of galactolipid synthesis. Upon phosphate starvation, pah1pah2 plants were severely impaired in growth and membrane lipid remodeling. These results indicate that PAH1 and PAH2 are the PAP responsible for the eukaryotic pathway of galactolipid synthesis, and the membrane lipid remodeling mediated by these two enzymes is an essential adaptation mechanism to cope with phosphate starvation.
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PMID:Arabidopsis lipins mediate eukaryotic pathway of lipid metabolism and cope critically with phosphate starvation. 1992 26