Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Daily subcutaneous administration of 20 or 100 mg/kg gentamicin for 4 days significantly decreased pyridoxal-5'-phosphate and lysosomal specific phosphatidylinositol-phospholipase C (PI-PLC) in newborn rat kidney. The fall in PI-PLC was associated with an elevation in renal phosphatidylinositol, phosphatidylserine, and phosphatidylcholine. The 100 mg/kg gentamicin dose also produced a rise in renal sphingomyelin, phosphatidylethanolamine, phosphatidylglycerol, and total phospholipid (TPL) accompanied by inhibition in the activities of Na+,K+-ATPase and alkaline phosphatase. In contrast, daily intraperitoneal injection of 100 mg/kg vancomycin for 4 days failed to markedly alter renal metabolic parameters. However, the 500 mg/kg vancomycin dose increased kidney weight, TPL, and all individual phospholipid class concentrations accompanied by inhibition of lysosomal specific PI-PLC activity and reduced pyridoxal-5'-phosphate levels. Simultaneous administration of 20 mg/kg gentamicin with either vancomycin dose resulted in renal alterations similar to those produced by gentamicin alone. Concurrent treatment with 100 mg/kg aminoglycoside and either vancomycin dose produced changes in kidney which were similar to those produced by gentamicin alone, except for a synergistic rise in PI as well as a greater fall in alkaline phosphatase and pyridoxal-5'-phosphate. Surprisingly, the concentration of gentamicin and vancomycin was less in newborn kidneys of rats receiving a simultaneous high dose of vancomycin and aminoglycoside treatment compared to levels found in animals given either antibiotic separately. The lack of potentiation of nephrotoxicity in newborns administered a combination of vancomycin and gentamicin may be due to decreased accumulation of either antibiotic in kidney.
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PMID:Gentamicin-induced renal metabolic alterations in newborn rat kidney: lack of potentiation by vancomycin. 252 10

Heparan sulfate proteoglycans (HSPG) of rat liver are associated with the plasma membrane in a hydrophobic intrinsic and a hydrophilic extrinsic form. We were interested in determining whether or not these two forms could be detected in the Golgi apparatus, the subcellular site of addition of oligosaccharides and sulfate to HSPG. In vivo and in vitro radiolabeled HSPG from rat liver Golgi apparatus membranes could only be solubilized with detergents that disrupt the membrane lipid bilayer, suggesting that they are solely associated via hydrophobic interactions. Both forms of HSPG were detected in plasma membranes of rat liver and isolated rat hepatocytes. The detergent-solubilized HSPG bound to octyl-Sepharose columns, whereas the hydrophilic form did not; this latter form, however, was released from the membrane by heparin. The hydrophobic anchor of HSPG in the Golgi and plasma membranes was insensitive to treatment with phosphatidylinositol-specific phospholipase C under conditions in which alkaline phosphatase was sensitive; this suggests that the hydrophobic anchor of HSPG is the core protein itself. Preliminary experiments suggest that the subcellular site of processing of the hydrophobic to the hydrophilic form of HSPG is the plasma membrane. A specific processing activity, probably a protease of the plasma membrane not present in serum or the endoplasmic reticulum membrane, converted hydrophobic HSPG of the Golgi membrane to the hydrophilic form. In addition, pulse-chase experiments with [35S]Na2SO4 in rats demonstrated that at short times, the bulk of the radiolabeled cellular HSPG was in the Golgi apparatus; later on, the bulk of the radioactivity was found in the plasma membrane, the only subcellular site where the hydrophilic form of HSPG was detected.
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PMID:Differential association of rat liver heparan sulfate proteoglycans in membranes of the Golgi apparatus and the plasma membrane. 252 26

Since our previous experiments suggested that glycosylation-inhibiting factor (GIF) is a phosphorylated derivative of a phospholipase inhibitory protein, we determined whether other well-known phospholipase inhibitors may have similar biological activities. The results showed that phospholipase A2 (PLA2) inhibitors, such as recombinant human lipocortin I and ONO-RS-082, could switch T cell hybridoma 12H5 cells from the formation of glycosylated IgE-binding factors (IgE-BF) to the formation of unglycosylated IgE-BF, whereas neomycin, a phospholipase C inhibitor, failed to affect the nature of IgE-BF formed by the cells. The minimum concentrations of lipocortin I and ONO-RS-082 required for switching the 12H5 cells to the formation of unglycosylated IgE-BF were comparable to or less than IC50 of the inhibitors for PLA2. The ability of partially purified GIF to switch the 12H5 cells to the formation of unglycosylated IgE-BF was markedly enhanced by treatment of the preparation with alkaline phosphatase. It was also found that lipocortin I and ONO-RS-082, but not neomycin, facilitated the generation of GIF-producing T cells. When spleen cells of ovalbumin (OVA)-primed BDF1 mice were stimulated with homologous antigen and the activated T cells were propagated by recombinant IL-2 in the presence of GIF, lipocortin I, or ONO-RS-082, T cells obtained in the cultures constitutively produced their own GIF. Antigenic stimulation of the T cells induced the formation of unglycosylated IgE-BF and GIF with an affinity for OVA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of phospholipase A2 inhibitors on mouse T lymphocytes. I. Phospholipase A2 inhibitors exert similar immunological activities as glycosylation inhibiting factor. 253 36

1. We have compared the effect of phosphatidyl inositol specific phospholipase C (PI-PLC) on the attachment of both 5'-nucleotidase and alkaline phosphatase to the liver plasma membrane from different species. 2. Our results demonstrate differences in the susceptibilities of both enzymes to PI-PLC treatment in relation to their origin. 3. These results were confirmed by immunoblotting using polyclonal anti-5'-nucleotidase antibodies. 4. In addition, in a single animal, susceptibility of both enzymes to PI-PLC treatment is different from one tissue to another. 5. The different percentages of released enzymes could be explained either by a polymorphism in the anchoring of these proteins at the cell surface membrane, or by a different steric hindrance or environment at the cleavage site itself.
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PMID:Differences in the release of 5'-nucleotidase and alkaline phosphatase from plasma membrane of several cell types by PI-PLC. 254 47

On the basis of its distribution pattern in embryos of the axolotl (Ambystoma mexicanum), we recently identified alkaline phosphatase as a molecule potentially involved in guiding the migration of the pronephric duct. Alkaline phosphatase is a cell surface protein anchored to cell membranes via a covalent linkage to a phosphatidylinositol glycan (PI-G). The enzyme phosphatidylinositol-specific phospholipase C (PIPLC) specifically releases from cell surfaces molecules anchored by the PI-G linkage. In order to test the possibility that a PI-G anchored protein is involved in directing pronephric duct cell migration, PIPLC was applied to axolotl embryos. The enzyme was introduced into embryos through the use of a novel slow-release bead material, hydrolysed polyacrylamide. PIPLC blocked pronephric duct cell migration without interfering with somite fissure formation, a concurrent, neighbouring morphogenetic cell rearrangement which occurs with little if any alkaline phosphatase present. In addition, alkaline phosphatase activity was markedly diminished in the vicinity of the implanted beads. These observations suggest that at least one protein anchored to the cell membrane by a PI-G linkage, possibly alkaline phosphatase, is involved in guiding or promoting pronephric duct cell migration.
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PMID:Axolotl pronephric duct cell migration is sensitive to phosphatidylinositol-specific phospholipase C. 255 84

Daily sc injection of gentamicin (100 mg/kg) for 4 days produced a significant decrease in the activities of renal cortical Na+,K+-ATPase and alkaline phosphatase. The observed reduction in renal functional enzymatic markers was associated with significant elevation in sphingomyelin, phosphatidylserine, phosphatidylglycerol, phosphatidylinositol, phosphatidylcholine, and total phospholipid. Gentamicin significantly decreased the activity of renal phospholipase C. Nitrendipine (25 mg/kg/day) for 7 days po for 4 days alone did not markedly alter the activities of kidney phospholipase C, alkaline phosphatase, and Na+,K+-ATPase or tissue phospholipid levels. Daily administration of nitrendipine for 3 days followed by concurrent treatment of nitrendipine and gentamicin failed to prevent antibiotic-induced renal histopathologic changes, phospholipidosis, or decrease in alkaline phosphatase. However, in rats simultaneously given nitrendipine and gentamicin the activity of Na+,K+-ATPase returned to control values, indicating a selective blocking action for nitrendipine. The inability of nitrendipine to prevent gentamicin-induced renal phospholipidosis or decreases in enzymatic function markers was associated with significantly elevated tissue aminoglycoside levels when compared to values seen in rats given only the antibiotic. Evidence suggests that nitrendipine is not effective in lowering the concentration of gentamicin in renal cortex. The effectiveness of an agent in providing protection against aminoglycoside nephrotoxicity may be associated with the ability of the drug to lower renal gentamicin content.
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PMID:Inability of nitrendipine to protect against gentamicin nephrotoxicity in the rat. 255 58

The effect of endothelin-1 (ET), a novel vasoactive peptide derived from endothelial cells, on osteoblastic MC3T3-E1 cells was studied. ET specifically binds to a single class of high-affinity receptors in MC3T3-E1 cells and induces phospholipase C activation with the production of two second messengers, inositol trisphosphate and 1,2-diacylglycerol, and a biphasic increase in intracellular free Ca2+ concentration ([Ca2+]i), which consists of an initial transient increase and an ensuing sustained plateau, as measured with a fluorescent indicator, fura-2. The second plateau phase but not the initial transient increase in [Ca2+]i induced by ET is abolished by removal of extracellular Ca2+ but not by either nicardipine, verapamil, or diltiazem. The ET-stimulated production of inositol trisphosphate is not abolished by removal of extracellular Ca2+, indicating that ET-stimulated phospholipase C activation is not a consequence of an increase in Ca2+ influx across the plasma membrane. ET causes stimulation of DNA synthesis and reduction of alkaline phosphatase activity in MC3T3-E1 cells. A protein kinase C activator phorbol 12,13-dibutyrate mimics these effects of ET. The results demonstrate that ET activates the inositol lipid signaling pathway and induces mobilization of Ca2+ from both extra- and intracellular pools and activation of protein kinase C in osteoblastic MC3T3-E1 cells.
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PMID:Endothelin-1 activates phospholipase C and mobilizes Ca2+ from extra- and intracellular pools in osteoblastic cells. 255 72

Release of PI-anchoring enzymes and other effects of phosphatidylinositol-specific phospholipase C from Bacillus thuringiensis on TN-368 cells from a moth ovary. Toxicon 27, 637-645, 1989.--The effect of phosphatidylinositol-specific phospholipase C(PIPLC) from Bacillus thuringiensis was investigated on TN-368 cells, derived from the ovary of a moth, Trichoplusia ni. Quantitative analysis of lipids showed that phosphatidylinositol (PI) was contained as one of the major phospholipids in TN-368 cells, whereas sphingomyelin and cholesterol were minor lipid components. When TN-368 cells were treated with PIPLC, significant amounts of alkaline phosphatase, 5'-nucleotidase and beta-glucosidase were released from these cells. Thus, these enzymes were shown to be PI-anchoring proteins in the plasma membrane of these cells. In the presence of 4.2 units of PIPLC, the cell growth of TN-368 was inhibited by 50%. In contrast with normal cells, the cells cultured in the presence of PIPLC became swollen and globular, losing their protoplasmic extensions. Also, there was degeneration of the interior of TN-368 cells cultivated in the presence of PIPLC. Mitochondria became swollen with a decrease in number of granules while the crista turned transparent. Also, an increase in lysosomes was observed and vacuoles seemingly derived from smooth endoplasmic reticula appeared.
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PMID:Release of PI-anchoring enzymes and other effects of phosphatidylinositol-specific phospholipase C from Bacillus thuringiensis on TN-368 cells from a moth ovary. 274 61

The larval midgut epithelial cell of the silkworm, Bombyx mori, has two forms of alkaline phosphatase and trehalase, soluble and membrane-bound. Alkaline phosphatase and trehalase of the latter form are found in the brush border membrane and the basolateral membrane, respectively. In this work we studied the membrane anchors of these membrane-bound enzymes. Alkaline phosphatase was solubilized by phosphatidyl-inositol-specific phospholipase C, but not by papain. Conversely, trehalase was released from the membrane by papain, but not by phosphatidylinositol-specific phospholipase C. Both enzymes were solubilized in an amphiphilic form with 0.5% Triton X-100 plus 0.5% sodium deoxycholate (pH 7.0). The detergent-solubilized alkaline phosphatase and trehalase were converted to hydrophilic form on incubation with phosphatidylinositol-specific phospholipase C and papain, respectively. The effects of papain on solubilization and conversion of trehalase were completely inhibited by leupeptin. These results suggest that, in the silkworm larvae, alkaline phosphatase is anchored in the brush-border membrane via a glycosyl-phosphatidylinositol, while trehalase is associated with the basolateral membrane through a hydrophobic segment of the polypeptide.
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PMID:Membrane anchors of alkaline phosphatase and trehalase associated with the plasma membrane of larval midgut epithelial cells of the silkworm, Bombyx mori. 276 26

Isolation of two membrane-bound alkaline phosphatase (AP) species from avian growth plate cartilage matrix vesicle (MV) fractions is described. AP was first released from the membranes by phosphatidylinositol-specific phospholipase C (PIase C), followed by chromatography on DEAE-Bio-Gel A and Reactive-Red agarose. Two AP species having apparent Mr of 81.5 and 77 kDa by SDS-PAGE were purified in high yield and specific activity by this simple method. Treatment with neuraminidase to remove sialic acid residues reduced their size slightly, but did not diminish the difference in Mr between the two species. Digestion with N-glycanase, however, decreased both AP species to a common size of 59 kDa. This reveals that both enzymes are highly glycosylated and suggests that the two forms may result from differences in degree of glycation. The amino acid compositions of the two avian enzyme forms are very similar, but are markedly enriched in serine, glycine and glutamate when compared to those reported for mammalian liver-kidney-bone AP. Possible differences in amino acid sequence between the two avian forms have not been excluded. The cross-reactivity of polyclonal antibodies to these enzymes with bovine kidney, but not intestinal AP, indicate that the avian cartilage APs are of the liver-kidney-bone isozyme type.
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PMID:Isolation of two glycosylated forms of membrane-bound alkaline phosphatase from avian growth plate cartilage matrix vesicle-enriched microsomes. 280 49


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