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)

In cultured foreskin fibroblasts, bradykinin stimulates inositol phosphate generation, arachidonic acid release, and Na+/H+ exchange, with doses of 1-3 nM yielding half-maximal stimulation. Binding of 3H-bradykinin to these cells demonstrates a single receptor site with a Kd of 2.0 nM and a Bmax of 91 fmoles/mg protein. Bradykinin analogs of the B2 type inhibit this binding. GTP synergizes with bradykinin to stimulate phosphatidylinositol turnover in permeabilized fibroblasts and GTP-gamma-S decreases the Bmax of bradykinin binding to fibroblast membranes, indicating that a G-protein couples the receptor to phospholipase C. Pretreatment of fibroblasts with either cholera or pertussis toxin enhances bradykinin stimulation of inositol phosphate accumulation.
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PMID:Coupling of bradykinin receptors to phospholipase C in cultured fibroblasts is mediated by a G-protein. 254 33

Bradykinin inhibits vasopressin-stimulated water transport in cortical collecting tubular cells. The biochemical mechanism of this effect was explored by means of primary cultures of rabbit cortical collecting tubular cells. Bradykinin was found to produce a rapid release of calcium from intracellular stores, an increase in sn-1,2-diacylglycerol levels, and a fivefold increase in membrane-bound protein kinase C activity, consistent with stimulation of phospholipase C and activation of protein kinase C in rabbit cortical collecting tubular cells. In addition, bradykinin produced a dose-dependent 46% inhibition of vasopressin-stimulated adenosine 3',5'-cyclic monophosphate (cAMP) formation. Pretreatment with the protein kinase C inhibitors, H-7 and staurosporine, reversed the bradykinin-mediated inhibition of vasopressin-stimulated cAMP accumulation. In contrast, pretreatment with either the phospholipase A2 inhibitor, mepacrine, or pertussis toxin did not prevent the inhibitory effect of bradykinin on vasopressin-stimulated cAMP production, suggesting that the effects are not mediated by prostaglandin E2 or activation of a pertussis-toxin sensitive guanine nucleotide regulatory protein (e.g., Gi). Because bradykinin also inhibits isoproterenol-stimulated cAMP formation but does not inhibit either basal-, forskolin-, or cholera toxin-stimulated cAMP accumulation, the site of this inhibition appears to involve the hormone receptor or coupling of the receptor to the stimulatory guanine nucleotide regulatory subunit (Gs). The results demonstrate that bradykinin stimulates phospholipase C leading to activation of protein kinase C, which then inhibits vasopressin-stimulated cAMP production at the level of the hormone receptor or coupling of the receptor to Gs in cultured cortical collecting tubular cells.
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PMID:Bradykinin activates protein kinase C in cultured cortical collecting tubular cells. 255 39

Previous studies have demonstrated that bradykinin stimulates the rapid release of inositol 1,4,5 trisphosphate (IP3) from membrane phosphatidylinositol 4,5 bisphosphate (PIP2) in Madin-Darby canine kidney (MDCK) cells. Since current evidence would suggest that the activation of phospholipase C (PLC) is mediated through a guanine nucleotide-binding protein in receptor-mediated activation of PLC, we evaluated the role of guanine nucleotide proteins in receptor-mediated (bradykinin-stimulated) activation of PLC in MDCK cells. Bradykinin at 10(-7) M produced a marked increase in IP3 formation within 10 s increasing from a basal level of 46.2 to 686.6 pmol/mg cell protein a 15-fold increase. Pretreatment of MDCK cells in culture with 200 ng/ml of pertussis toxin for 4 h reduced the bradykinin-stimulated response to 205.8 pmol/mg protein. A 41-kD protein substrate in MDCK membranes was ADP ribosylated in vitro in the presence of pertussis toxin. The ADP ribosylation in vitro was inhibited by pretreatment of the cells in culture with pertussis toxin. Membranes from MDCK cells incubated in the presence of [3H]PIP2/phosphatidyl ethanolamine liposomes demonstrated hydrolysis of [3H]PIP2 with release of [3H]IP3 when GTP 100 microM or GTP gamma S 10 microM was added. Bradykinin 10(-7) M added with GTP 100 microM markedly increased the rate of hydrolysis within 10 s, thus demonstrating a similar time course of PLC activation as intact cells. These results demonstrate that bradykinin binds to its receptor and activates a membrane-associated PLC through a pertussis toxin-sensitive, guanine nucleotide protein.
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PMID:Bradykinin-activated membrane-associated phospholipase C in Madin-Darby canine kidney cells. 283 25

Bradykinin-stimulated prostaglandin synthesis was investigated in Swiss albino 3T3 fibroblasts (Swiss 3T3 cells) and bovine pulmonary artery endothelial cells (CPAE). Previous studies have indicated that bradykinin stimulates arachidonic acid release in Swiss 3T3 cells by activating phospholipase A2 and by activating phosphatidylcholine-specific phospholipase C in CPAE cells. The dose-response for bradykinin-stimulated prostaglandin synthesis was similar in Swiss 3T3 cells and CPAE cells. Marked differences were found in the effects of several bradykinin analogs in Swiss 3T3 cells and CPAE cells. des-Arg9-bradykinin was a partial agonist in CPAE cells whereas it was completely inactive in Swiss 3T3 cells. [p-chloro-D-Phe6-D-Pro7]-Bradykinin was a full agonist in Swiss 3T3 cells, but only a partial agonist, exhibiting a bell-shaped curve, in CPAE cells. The bradykinin antagonist, [D-Arg0-Hyp3-D-Phe7]-bradykinin, was a several-fold more potent antagonist in Swiss 3T3 cells, compared to CPAE cells. The effects of these bradykinin analogs on prostaglandin synthesis do not fit the previously described BK1, BK2 bradykinin receptor classification. These findings suggest that there are at least two bradykinin receptors which stimulate prostaglandin synthesis. Previous studies have indicated that these two bradykinin receptors may be coupled to different transduction pathways for the release of arachidonate.
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PMID:Distinct bradykinin receptors mediate stimulation of prostaglandin synthesis by endothelial cells and fibroblasts. 289 57

Proteins encoded by ras genes have recently been reported to couple certain growth factor receptors to phospholipase C, the enzyme catalyzing phosphatidylinositol breakdown. To investigate this hypothesis, the normal and the transforming Ha-, Ki-, and N-ras genes were each transfected into Rat-1 fibroblasts under the control of strong promoters. Several cell lines, both normal and transformed, were selected that expressed high levels of p21ras. Phosphatidylinositol turnover was measured in these cells in response to a wide variety of peptide factors; bradykinin was found to have a greatly enhanced effect on the p21ras overexpressors relative to the parental and control cells. Bradykinin receptor numbers were measured in these lines and found to be up to 40-fold higher in the p21ras overexpressors than in the parental cells. This was found to be the case for both normal and transforming forms of all three varieties of ras genes. Receptor number correlated well with the bradykinin-dependent phosphatidylinositol turnover response in all cases. These data indicate that the effects of p21ras on cellular responses to the peptide hormone bradykinin are due to changes in receptor number rather than to direct coupling by p21ras between the receptor and phospholipase C.
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PMID:p21ras-induced responsiveness of phosphatidylinositol turnover to bradykinin is a receptor number effect. 290 Oct 87

The addition of bradykinin to NG108-15 cells results in a transient hyperpolarization followed by prolonged cell depolarization. Injection of inositol 1,4,5-trisphosphate or Ca2+ into the cytoplasm of NG108-15 cells also elicits cell hyperpolarization followed by depolarization. Tetraethylammonium ions inhibit the hyperpolarizing response of cells to bradykinin or inositol 1,4,5-trisphosphate. Thus, the hyperpolarizing phase of the cell response may be due to inositol 1,4,5-trisphosphate-dependent release of stored Ca2+ into the cytoplasm, which activates Ca2+-dependent K+ channels. The depolarizing phase of the cell response to bradykinin is due largely to inhibition of M channels, thereby decreasing the rate of K+ efflux from cells and, to a lesser extent, to activation of Ca2+-dependent ion channels and Ca2+ channels. In contrast, injection of inositol 1,4,5-trisphosphate or Ca2+ into the cytosol did not alter M channel activity. Incubation of NG108-15 cells with pertussis toxin inhibits bradykinin-dependent cell hyperpolarization and depolarization. Bradykinin stimulates low Km GTPase activity and inhibits adenylate cyclase in NG108-15 membrane preparations but not in membranes prepared from cells treated with pertussis toxin. Reconstitution of NG108-15 membranes from cells treated with pertussis toxin with nanomolar concentrations of a mixture of highly purified No and Ni [guanine nucleotide-binding proteins that have no known function (No) or inhibit adenylate cyclase (Ni)] restores bradykinin-dependent activation of GTPase and inhibition of adenylate cyclase. These results show that [bradykinin . receptor] complexes interact with No or Ni and suggest that No and/or Ni mediate the transduction of signals from bradykinin receptors to phospholipase C and adenylate cyclase.
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PMID:Bradykinin-activated transmembrane signals are coupled via No or Ni to production of inositol 1,4,5-trisphosphate, a second messenger in NG108-15 neuroblastoma-glioma hybrid cells. 308 91

The mechanism of bradykinin-induced contraction in rabbit urinary detrusor was investigated using an anti-inflammatory drug, tiaramide. The contraction as well as prostaglandin (PG) E2 release induced by bradykinin was abolished by treatment with indomethacin, indicating that the contraction was mediated by PGs. The accumulation of inositol phosphates (IP) by bradykinin was partly inhibited by treatment with indomethacin, suggesting that part of the IP accumulation was due to PGs. Although the remaining accumulation of IPs induced by bradykinin in the presence of indomethacin should elicit contraction in smooth muscle cells, indomethacin abolished bradykinin-induced contraction. The dissociation between indomethacin-induced inhibition of IP accumulation and contraction induced by bradykinin might be explained by the existence of PG-generating cells in addition to smooth muscle cells. Bradykinin stimulates phospholipase C, which leads to an increase in intracellular free Ca++, activation of phospholipase A2 and release of PGs in the PG-generating cells. The released PGs act on smooth muscle cells to elicit contractions via phospholipase C activation and Ca++ mobilization. Tiaramide inhibited the PGE2 release and contraction induced by bradykinin by reducing the arachidonic acid release from membrane phospholipid but did not have a direct effect on cyclo-oxygenase. Tiaramide reduced IP accumulation induced by bradykinin to an extent similar to indomethacin. However, tiaramide had no effect on IP accumulation induced by PGE2, although it potently inhibited the contraction induced by PGE2, which elicits contractions without affecting phospholipase A2. The rise in intracellular free Ca++ induced by PGE2 as well as bradykinin was inhibited by tiaramide.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Bradykinin-induced contraction is inhibited by tiaramide, an anti-inflammatory drug, with an inhibition of increase in intracellular free calcium. 313 43

The release of eicosanoids and endothelium-derived relaxing factor (EDRF) from endothelial cells is thought to involve a calcium-dependent step. Using cultured bovine aortic endothelial cells as a model system, we have examined the relation between agonist-induced changes in inositol polyphosphates and calcium levels within the endothelial cells and extracellular calcium on EDRF release. In a superfusion-cascade system, EDRF was detected by the relaxation of a rabbit aortic ring without endothelium suspended beneath a column of cultured endothelial cells. Endothelial cell stimulation by bradykinin or melittin induced dose-dependent relaxation of the bioassay ring. In addition, bradykinin and melittin stimulated an increase in intracellular calcium concentration in fura-2 loaded endothelial cells and an increase in inositol 1,4,5-trisphosphate (Ins[1,4,5]P3) in cells prelabeled with 3H-myoinositol. Bradykinin stimulation produced transient increases in Ins(1,4,5)P3, fura-2 fluorescence and transient EDRF release. Melittin stimulation induced more prolonged release of EDRF from the endothelial cell column, which was correlated with sustained increases in the fura-2 signal and the level of Ins(1,4,5)P3. Omission of calcium from the cell superfusate attenuated, but did not eliminate, bradykinin-induced EDRF release and the calcium transient, whereas the melittin-induced responses were only slightly attenuated. Endothelial cells clearly demonstrate receptor-activation of phospholipase C and release of sequestered calcium from subcellular sites in response to Ins(1,4,5)P3. These results imply that EDRF release is correlated with increased intracellular calcium levels seen in the absence of extracellular calcium. However, sustained release of EDRF does require influx of extracellular calcium via an undefined mechanism.
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PMID:Endothelium-derived relaxing factor release associated with increased endothelial cell inositol trisphosphate and intracellular calcium. 326 34

In the mouse neuroblastoma x dorsal root ganglion hybrid cell line F-11, bradykinin receptor stimulation induced the release of inositol-1,4,5-trisphosphate (IP3) and inositol-1,4-bisphosphate (IP2). Maximal stimulation of [2-3H]IP3 and [2-3H]IP2 release by bradykinin in the absence of LiCl occurred at 7 (or less) and 15 s, respectively, with average levels of 5.7-(IP3) and 3.4-(IP2) fold of control values. The EC50 for bradykinin was 33 +/- 5 nM. IP3 and IP2 concentrations returned to basal levels approximately 1 min after bradykinin addition. Bradykinin-induced IP3 release was blocked by several novel bradykinin analogues. In particular, [D-Arg0]-Hyp3-Thi5,8-[D-Phe7]-bradykinin [Hyp, hydroxyproline; Thi, beta-(2-thienyl)-L-alanine] blocked IP3 production in a dose-dependent fashion. Several of these analogues alone showed little or no agonist activity. The bradykinin receptor may be coupled to phospholipase C via a GTP-sensitive protein (Gi or Go), as preincubation for 18-20 h with pertussis toxin decreased IP3 concentrations by 45%. Bradykinin is also known to modulate the concentrations of other second messengers in neurons, increasing the concentrations of Ca2+, diacylglycerol (DG), and cyclic GMP and decreasing the concentration of cyclic AMP. These second messengers modulated bradykinin-dependent IP3 release to varying degrees. A23187, a Ca2+ ionophore, produced a 37% decrease in IP3 concentration. 12-O-Tetradecanoylphorbol-13-acetate, which mimics the effects of DG and activates protein kinase C, inhibited IP3 release by 80%. Dibutyryl cyclic GMP produced little or no inhibition of IP3. [D-Ala2,D-Leu5]Enkephalin (DADLE), an opioid peptide that decreases cyclic AMP concentrations, likewise had no effect.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Modulation of bradykinin-induced inositol trisphosphate release in a novel neuroblastoma x dorsal root ganglion sensory neuron cell line (F-11). 349 4

Bradykinin stimulation of inositol polyphosphate production was followed using [3H]inositol-labeled porcine aortic endothelial cells grown in culture. Bradykinin stimulated a significant increase in inositol trisphosphate (IP3) production within 15 s. This increase reached a maximum value of 5-fold above control at 30 s and returned toward baseline by 90 s. Production of inositol bisphosphate increased with time reaching 4-fold by 60 s. Bradykinin stimulated the production of IP3 and inositol biphosphate in a dose-dependent manner with an EC50 of 9 X 10(-9) M. Labeled pools of phosphatidylinositol-4,5-bisphosphate (PIPP) decreased by 50% within 30 s, corresponding to the rise in IP3, while labeled lysophosphatidylinositol pools increased 3-fold by 60 s. Pertussis toxin, a protein which ribosylates GTP-binding proteins, did not inhibit bradykinin-stimulated inositol polyphosphate production. Incubation of labeled cells in the absence of extracellular Ca2+ also did not affect bradykinin-stimulated inositol polyphosphate production. Further, A23187, a Ca2+ ionophore, failed to stimulate PIPP metabolism. Finally, Ca2+ influx into cell monolayers occurred with a time course which paralleled rather than preceded the increase in IP3 levels. These data suggest that bradykinin stimulates phospholipase C metabolism of PIPP to IP3 by a mechanism which does not contain a pertussis toxin sensitive GTP-binding protein. Also, this receptor-linked phospholipase C activity does not appear to be activated by extracellular Ca2+ influx. The results support the proposal that IP3 production initiates Ca2+ mobilization and suggest that the calcium-dependent step in arachidonate release is distal to IP3 production.
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PMID:Bradykinin stimulation of inositol polyphosphate production in porcine aortic endothelial cells. 377 75


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