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)

Both phosphatidylethanolamine(PE)-N-methylation and phosphatidyl-inositol bisphosphate (PI-bisphosphate) breakdown potentially modify the microdomains in the sarcolemmal lipid bilayer. In this study the possibility of a mutual interaction between the enzymes responsible for these phospholipid reactions is examined. In sarcolemma purified from rat heart, prior hydrolysis of PI lipids by exogenous specific phospholipase C inhibited (to 75, 59 and 78% of control for sites I, II and II, respectively) the PE-N-methyltransferase system. In cultured rat cardiomyocytes the addition of L-methionine, a precursor for the methyl donor S-adenosylmethionine, stimulated PE-N-methylation in a concentration (0.2-300 microM)-dependent manner. Methionine (50 microM) decreased the basal rate of PI-bisphosphate hydrolysis (to 72% of control), but had no effect on the phenylephrine-stimulated PI-bisphosphate hydrolysis. Maximal activation of the PI-bisphosphate breakdown by 30 microM phenylephrine did not affect the rate of PE-N-methylation in the presence of exogenous methionine (50 microM). These findings support the existence of interactions, although discrete, between the enzymes involved in the PE-N-methylation and PI turnover.
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PMID:Discrete interactions between phosphatidylethanolamine-N-methylation and phosphatidylinositolbisphosphate hydrolysis in rat myocardium. 257 24

Phosphatidylethanolamine of rat liver microsomes is rapidly methylated by S-adenosyl[methyl-14C]methionine to produce phosphatidyl-N-monomethylethanolamine, phosphatidyl-N,N-dimethylethanolamine and phosphatidylcholine. Using phospholipase C as a probe, on both opened (0.4% taurocholate or French pressure cell treatment) and unopened microsomes, it is demonstrated that phosphatidylcholine is labelled in the inner leaflet of the bilayer and, to a greater extent, in the outer leaflet. Phosphatidyl-N,N-dimethylethanolamine is labelled in the outer leaflet and in a pool sequestered from phospholipase C in open and closed vesicles. Phosphatidyl-N-monomethylethanolamine is labelled in a similarly sequestered pool. When microsomes containing labelled phosphatidyl-N-monomethylethanolamine and phosphatidyl-N,N-dimethylethanolamine were incubated with unlabeled S-adenosylmethionine, these phospholipids were methylated to produce phosphatidylcholine in the outer leaflet. This metabolism was inhibited by S-adenosylhomocysteine. Trypsin treatment of unopened microsomes inhibited 95% of the incorporation of 14CH3 into the outer leaflet of the bilayer with no effect on incorporation into sequestered phosphatidyl-N-monomethylethanolamine, phosphatidyl-N,N-dimethylethanolamine and phosphatidylcholine. Therefore, sequestered phosphatidyl-N-monomethylethanolamine and phosphatidyl-N,N-dimethylethanolamine are apparently synthesized by enzymes located at the inner surface of the microsomal membranes. These observations suggest that initial methylation of phosphatidylethanolamine takes place at the inner surface of the microsomes and that phosphatidyl-N-monomethylethanolamine is transferred to the outer leaflet to produce phosphatidylcholine. However, phosphatidyl-N-monomethylethanolamine is also methylated at the inner leaflet to produce phosphatidylcholine which does not equilibrate with that of the outer leaflet. Phosphatidylcholine of both the inner and outer bilayer leaflets is uniformly labelled by injection of [14C]methionine, in vivo.
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PMID:Biogenesis of endoplasmic reticulum phosphatidylcholine. Translocation of intermediates across the membrane bilayer during methylation of phosphatidylethanolamine. 721 79

Carboxylmethylation of ras-related proteins is stimulated immediately on exposure of myeloid cells to inflammatory agonists. When the methylation reaction is inhibited with prenylcysteine analogs, G-protein-mediated signal transduction responses are disrupted, but responses to phorbol ester, calcium ionophore, and phospholipase C (PLC) remain intact. Furthermore, prenylcysteine analogs block GTP gamma S-induced aggregation of permeabilized platelets. Together, these results suggest that protein prenylcysteine methylation can play a role in signal transduction. A number of studies with AdoMet antagonists have suggested a role for methylation in cell-cycle regulation and stimulus-response coupling. Because the compounds generally inhibit all cellular methylation events, however, their effects have been difficult to interpret. On the other hand, prenylcysteine analogs have proved to be specific inhibitors of protein prenylcysteine methylation, as opposed to other types of methylation reactions. This enables the segregation of the role of methylation at C-terminal prenylcysteine residues from methylation at other sites, such as the carboxyl terminus of the catalytic subunit of PP2A. It should be emphasized, however, that prenylcysteine tails of proteins may interact with other target sites in addition to the methyltransferase enzyme(s), and prenylcysteine analogs may compete for these sites as well. One cannot assume that the inhibition of a response by the drugs necessarily implicates the involvement of a prenylcysteine methylation reaction. Studies with the analogs must be interpreted in conjunction with other results to ascertain the locus of their effects.
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PMID:Prenylcysteine analogs to study function of carboxylmethylation in signal transduction. 765 Nov 53

An approach was developed for the isolation and characterization of soybean plasma membrane-associated proteins by immunoscreening of a cDNA expression library. An antiserum was raised against purified plasma membrane vesicles. In a differential screening of approximately 500,000 plaque-forming units with the anti-(plasma membrane) serum and DNA probes derived from highly abundant clones isolated in a preliminary screening, 261 clones were selected from approximately 1,200 antiserum-positive plaques. These clones were classified into 40 groups by hybridization analysis and 5'- and 3'-terminal sequencing. By searching nucleic acid and protein sequence data bases, 11 groups of cDNAs were identified, among which valosin-containing protein (VCP), clathrin heavy chain, phospholipase C, and S-adenosylmethionine:delta 24-sterol-C-methyltransferase have not to date been cloned from plants. The remaining 29 groups did not match any current data base entries and may, therefore, represent additional or yet uncharacterized genes. A full-length cDNA encoding the soybean VCP was sequenced. The high level of amino acid identity with vertebrate VCP and yeast CDC48 protein indicates that the soybean protein is a plant homolog of vertebrate VCP and yeast CDC48 protein.
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PMID:Identification of cDNA clones encoding valosin-containing protein and other plant plasma membrane-associated proteins by a general immunoscreening strategy. 775 26

Phospholipids of isolated rat hepatocytes were labelled by preincubation with either 2 microM -methyl-14C-S-adenosylmethionine (AdoMet) or 2 microM [methyl-14C]methionine. Subsequent addition of phospholipase C to the suspension removed 95% of the radioactivity from phospholipids methylated by [methyl-14C]AdoMet within a few minutes, but was without effect on phospholipids methylated by [methyl-14C]methionine radioactivity from the latter could, nevertheless, be removed by phospholipase C after permeabilization of the cells with digitonin. The results clearly show that the methyl group of exogenous AdoMet, contrary to that of methionine, is transferred on to phospholipids located on the external face of the plasma membrane. Accordingly, pretreatment of isolated hepatocytes with trypsin prevented the methylation of phospholipids from exogenous AdoMet by 60-80%, whereas it was almost without effect when exogenous methionine was the methyl donor. Our data corroborate previous work [Bontemps and Van den Berghe (1997) Biochem. J. 327, 383-389], which indicated that AdoMet methylates hepatocyte phospholipids without penetrating the cells.
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PMID:Novel evidence for an ecto-phospholipid methyltransferase in isolated rat hepatocytes. 946 82

Changes in gene expression within roots of Glycine max (soybean), cv. Kent, susceptible to infection by Heterodera glycines (the soybean cyst nematode [SCN]), at 6, 12, and 24 h, and 2, 4, 6, and 8 days post-inoculation were monitored using microarrays containing more than 6,000 cDNA inserts. Replicate, independent biological samples were examined at each time point. Gene expression was analyzed statistically using T-tests, ANOVA, clustering algorithms, and online analytical processing (OLAP). These analyses allow the user to query the data in several ways without importing the data into third-party software. RT-PCR confirmed that WRKY6 transcription factor, trehalose phosphate synthase, EIF4a, Skp1, and CLB1 were differentially induced across most time-points. Other genes induced across most timepoints included lipoxygenase, calmodulin, phospholipase C, metallothionein-like protein, and chalcone reductase. RT-PCR demonstrated enhanced expression during the first 12 h of infection for Kunitz trypsin inhibitor and sucrose synthase. The stress-related gene, SAM-22, phospholipase D and 12-oxophytodienoate reductase were also induced at the early time-points. At 6 and 8 dpi there was an abundance of transcripts expressed that encoded genes involved in transcription and protein synthesis. Some of those genes included ribosomal proteins, and initiation and elongation factors. Several genes involved in carbon metabolism and transport were also more abundant. Those genes included glyceraldehyde 3-phosphate dehydrogenase, fructose-bisphosphate aldolase and sucrose synthase. These results identified specific changes in gene transcript levels triggered by infection of susceptible soybean roots by SCN.
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PMID:Timecourse microarray analyses reveal global changes in gene expression of susceptible Glycine max (soybean) roots during infection by Heterodera glycines (soybean cyst nematode). 1657 92