Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To assess the role of calmodulin in human basophil histamine release, we triggered leukocytes with different secretagogues in the presence of putative inhibitors of calmodulin. Calcium ionophore-induced histamine release was reduced or blocked by calmidazolium, CGS 9343B, felodipine, metofenazate, and Ro 22-4839. H 186/86, a felodipine-related dihydropyridine derivative, blocked A23187-but not ionomycin-triggered histamine release, suggesting a difference in the mode of action of these ionophores. In contrast, leukocyte histamine release triggered by the purported protein kinase C (PKC) activator, 1,2-isopropylidene-3-decanoyl-sn-glycerol (IpOCOC9), was enhanced by calmidazolium, CGS 9349B and metofenazate but not affected by felodipine or Ro 22-4839, whereas the response triggered by 4 beta-phorbol 12-myristate 13-acetate (PMA) was reduced by metofenazate and Ro 22-4839 but not consistently affected by calmidazolium, CGS 9343B or felodipine. The PMA-induced histamine release was enhanced by H 186/86. Anti-IgE- and FMLP-induced responses were either unaffected or slightly enhanced by the examined calmodulin antagonists. In comparison with the calmodulin antagonists, R 59022, an inhibitor of diacylglycerol kinase, failed to reduce calcium ionophore-triggered histamine release, whereas FK506, an inhibitor of peptidyl prolyl cis-trans isomerase (PPI), reduced both anti-IgE- and ionophore-triggered responses. These results indicate that calmodulin constitutes an obligate link in signal transduction pathways leading to human leukocyte histamine release if the trigger is a calcium ionophore but not when responses are induced by anti-IgE, FMLP or PMA; a calmodulin-dependent component may rather balance responses induced by IpOCOC9.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Human basophil histamine release is differently affected by inhibitors of calmodulin, diacylglycerol kinase and peptidyl prolyl cis-trans isomerase in a secretagogue specific manner. 128 Sep 15

A mouse IgM mAb termed P1E3 was raised against resting human peripheral blood neutrophils and has been shown to recognize a cell-surface Ag with an apparent molecular mass of 155 kDa, as assessed by immunoprecipitation analysis. In addition to the main 155-kDa protein, an additional band of about 210 kDa was also recognized by P1E3 in Western blot analysis. Sequential immunoprecipitation assays showed that the Ag recognized by P1E3 differed from the CD29 and CD45 Ag. However, sequential immunoprecipitation assays carried out with two distinct anti-CD15 mAb and P1E3 showed that P1E3 reacted with CD15 or with a CD15-like Ag. P1E3 stained strongly resting human peripheral blood neutrophils, hardly reacted with peripheral blood monocytes and did not react with PBL and platelets, as assessed by immunofluorescence flow cytometry. P1E3 inhibited the respiratory burst induced by PMA or FMLP, but not the oxidative response induced by Con A or the calcium ionophores A23187 or ionomycin. Furthermore, P1E3 inhibited the activation of the Na+/H+ antiporter in response to PMA or FMLP and the phosphorylation of a protein of about 50 kDa in response to PMA. However, preincubation of neutrophils with P1E3 did not affect the increase in cytosolic free calcium concentration induced by FMLP. These data suggest that the Ag recognized by P1E3 may play a role in modulating the activation of the respiratory burst induced by PMA or FMLP, and that P1E3 seems to affect protein kinase C-mediated signal transduction mechanisms coupled to the induction of the respiratory burst.
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PMID:A monoclonal antibody that detects a specific human neutrophil antigen involved in phorbol myristate acetate- and formyl-methionyl-leucyl-phenylalanine-triggered respiratory burst. 130 67

This paper focuses on eosinophil activation and its selective inhibition. Superoxide anion (O2-) production by human eosinophils, an indicator of their activation, was induced by a variety of activators. Several compounds which are known to inhibit protein kinase C (staurosporine, K252a, sphingosine) inhibited O2- production induced by phorbol ester (PMA) but failed to inhibit O2- production induced by IgG coupled to Sepharose beads. Inhibition of O2- production by other agents (plasma-activated zymosan, fMLP, and leukotriene B4 (LTB4), was intermediate. By contrast, wortmannin, a compound which has been previously reported to inhibit O2- production in neutrophils via a protein kinase-independent pathway, potently inhibited O2- production in eosinophils which had been activated by IgG and by Platelet-Activating Factor but was virtually inactive against PMA-induced O2- production. Taken together, the results indicate that, as a minimum, there must be two pathways of induction of O2- production in eosinophils. Moreover, the intermediate levels of inhibition in cells which had been activated with serum-activated zymosan, FMLP, and LTB4 suggest that these agents may either be acting via both of these pathways or that yet other pathways may exist.
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PMID:Superoxide production by human eosinophils can be inhibited in an agonist-selective manner. 132 97

Compromised neutrophil function has been found in a number of patients with localized juvenile periodontitis (LJP), although the pathogenic mechanism is unknown. Since infection with Actinobacillus actinomycetemcomitans is frequently found in patients with LJP, we have evaluated in vitro the effect of a bacterial extract of A. actinomycetemcomitans on the development of the respiratory burst by neutrophils. Pre-incubation of neutrophils with bacterial extract increased H2O2 induced by FMLP and zymosan in a dose-dependent fashion. Substitution of FMLP for bacterial extract produced similar results. Moreover, FMLP and bacterial extract had an additive effect on superoxide production following phagocytosis of zymosan. In contrast, bacterial extract significantly decreased PMA-stimulated H2O2, but pre-incubation with FMLP instead of bacterial extract failed to decrease PMA-stimulated H2O2. Bacterial extract did not change the percentage of cells activated by FMLP, opsonized zymosan, or PMA. Heat-treated bacterial extract induced effects similar to non-treated extract. Bacterial extract treated with proteinase K or phenol extraction increased FMLP or zymosan stimulated H2O2 equivalent to non-treated bacterial extract. In contrast, proteinase K or phenol extraction abolished the inhibitory effect of bacterial extract on PMA-stimulated H2O2 production. The bacterial extract component(s) that inhibits PMA-stimulated H2O2 is therefore a protein(s), resistant to 56 degrees C, and is not endotoxin. The partially activated state of PMNs exposed to A. actinomycetemcomitans extract, combined with their reduced ability to respond to a protein kinase C-dependent stimulus, may partially explain the abnormalities noted in LJP patients.
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PMID:Neutrophil modulation by Actinobacillus actinomycetemcomitans. II. Phagocytosis and development of respiratory burst. 132 89

Flow cytometry and the fluorescent dyes DCF and R123 were used to examine oxygen metabolite production in human leukocytes and T-lymphoblastoid Jurkat cells, activated by PMA or by FMLP. When unseparated leukocytes were activated by PMA, oxidative products were generated not only in PMN and monocytes but also to a lower extent in lymphocytes. These responses were correlated with protein kinase C activation. PMA did not, however, induce the synthesis of reactive oxygen species in isolated lymphocytes. FMLP did not affect lymphocyte oxidative metabolism when added to the whole leukocyte mixture, but activated only the phagocyte populations. Similarly, Jurkat cells which alone were unresponsive to PMA, became strongly fluorescent when they were mixed with PMN and treated with this activator. In all cases, they did not respond to FMLP. Superoxide dismutase and catalase addition did not prevent the lymphoid cell response in the presence of phagocytes, whereas Desferal did. These data indicate that under physiological conditions, activated lymphocytes are capable of oxidative metabolism and also evidence some close relation between the leukocyte populations. We discuss the putative mechanism of oxygen metabolite generation in lymphocytes and the role of these metabolites in the immune response.
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PMID:Increased oxidative metabolism in PMA-activated lymphocytes: a flow cytometric study. 151 80

Recruitment of inflammatory cells to the lung capillaries has been proposed as an important step in the sequence of events that lead to acute lung injury. Frequently, in the clinical setting, bacteremia and sepsis syndrome precede the acute lung failure and endotoxin priming may represent a comparable paradigm, useful for experimental pursuit. Following addition of the chemotactic tripeptide FMLP (10(-9) to 10(-6) M) to the cell-free, salt solution perfusate of isolated rat lungs, only a small degree of vasoconstriction was observed. However, in lungs isolated from rats that received 2 mg/kg intraperitoneal Salmonella enteritidis endotoxin 2 h before lung perfusion, FMLP dose dependently caused a large, transient pulmonary pressor response, edema formation, and release of large amounts of thromboxane and leukotriene B4. Since in vitro priming with endotoxin, direct vascular injury by neutrophil elastase, nor direct stimulation with FMLP of pulmonary artery rings from endotoxin-pretreated rats, mimicked the effects of in vivo endotoxin priming, we conclude that the presence of inflammatory cells in the lung capillaries accounted for the large amount of eicosanoids produced by the lungs after FMLP stimulation. In fact, by retrograde lavage of the lung circulation with a collagenase solution, previously adherent cell clumps were mobilized and identified. These cell clumps, composed of red blood cells, neutrophils, and platelets, were not seen in the vascular lavage sediment obtained from unprimed control lungs. Indomethacin, a thromboxane antagonist, AA861, a 5-lipoxygenase inhibitor, and WEB 2086, a platelet-activating factor (PAF) antagonist, reduced the thromboxane synthesis and release after FMLP (10(-7) M) in in vivo endotoxin-primed lungs. None of the inhibitors employed exclusively inhibited only one particular eicosanoid mediator but rather affected the release of several mediators, suggesting a close link between the different synthetic arachidonic acid pathways. An inhibitor of phospholipase C (2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate), NCDC, but not an inhibitor of phospholipase D (Wortmannin) or of protein kinase C (staurosporine) inhibited the FMLP-stimulated pulmonary pressure rise and eicosanoid release in endotoxin-primed lungs in vivo. Our data suggest that eicosanoids (in particular thromboxane) released from cells trapped in the lung circulation, but not from constitutive lung cells, contribute to vasoconstriction and edema formation caused by the chemoattractant FMLP in endotoxin-primed lungs.
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PMID:FMLP causes eicosanoid-dependent vasoconstriction and edema in lungs from endotoxin-primed rats. 154 53

In the present study, we first investigated which of the factors, protein kinase C (PKC) or Ca2+, plays an important role in activation of phospholipase D (PLD) of rabbit peritoneal neutrophils stimulated by the chemoattractant FMLP. PLD activity was assessed by measuring [3H]phosphatidylethanol ([3H]PEt), the unambiguous marker of PLD, generated by [3H]lyso platelet-activating factor-prelabeled neutrophils in the presence of ethanol. PKC inhibitors, staurosporine and 1-(5-isoquinolinesulfonyl-2-methylpiperazine dihydrochloride, augmented the plateau level of [3H]PEt produced in FMLP-stimulated cells, although they had no effect on the initial rate of the formation. Furthermore, it was found that the FMLP-stimulated [3H]PEt formation was inhibited by pretreatment of cells with PMA, a PKC activator, and exposure of cells to staurosporine before PMA pretreatment moderately blocked the PMA inhibition. Ca2+ ionophore ionomycin, as well as FMLP, stimulated [3H]PEt formation, accompanied by a decrease in [3H]phosphatidylcholine, in a time- and concentration-dependent manner. Both FMLP and ionomycin absolutely required extracellular Ca2+ to increase [3H]PEt formation. These results imply that elevated intercellular Ca2+ by FMLP stimulation is the major factor for PLD activation and that PKC rather negatively regulates the enzyme activity. Interestingly, a calmodulin inhibitor, N-(6-aminohexyl)-5-chloro-1- naphthalenesulfonamide, and a myosin L chain kinase inhibitor, 1-(5-iodonaphthalene-1-sulfonyl)-1H-h exahydro-1,4-diazepine hydrochloride, both inhibited the ionomycin- and FMLP-stimulated [3H]PEt formation in a concentration-dependent manner. Results obtained in this study suggest that, in FMLP-stimulated rabbit peritoneal neutrophils, increased intracellular Ca2+ activates PLD through calmodulin/myosin L chain kinase pathway and, thereafter, the enzyme activation is turned off by simultaneously activated PKC.
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PMID:Calcium rather than protein kinase C is the major factor to activate phospholipase D in FMLP-stimulated rabbit peritoneal neutrophils. Possible involvement of calmodulin/myosin L chain kinase pathway. 162 5

Exposure to the phorbol ester, phorbol 12-myristate, 13-acetate (PMA, 100nM) for 10 minutes enhanced cyclic AMP accumulation in human neutrophils under basal conditions and in response to the beta-adrenergic receptor agonist isoproterenol (ISO), 1 microM) and the adenylate cyclase activator forskolin (FSK, 10mM). Potentiation of responses to ISO by PMA was dose-dependent between 0.1 and 100nM PMA. The diacylglycerol analogue, 1-oleoyl-2-acetylglycerol (OAG) (50 microM) also elevated beta-receptor responses, but 4 beta-phorbol (100nM), lacking the capacity to activate PMA, was ineffective. Short-term exposure (12 seconds) to the peptide n-formylmethionine leucyl-phenylalanine (FMLP, 1 microM) also elevated neutrophil cyclic AMP accumulation. All potentiating effects of PMA on cyclic AMP production were inhibited by the protein kinase inhibitor 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine (H7). Elevation of cyclic AMP by FMLP was insensitive to H7. PMA had no apparent effect on beta-receptor agonist-affinity, distribution between cell-surface and internalised compartments, or the capacity of ISO to induce beta-receptor internalisation. Responses to FSK or ISO in terms of fold-stimulation of basal cyclic AMP accumulation in the presence of PMA were not elevated by PMA. These findings indicate that PMA exerts a potentiating effect on neutrophil adenylate cyclase responses through protein kinase C activation. FMLP elevation of neutrophil cyclic AMP in the absence of other stimuli, appears however, to be insensitive to protein kinase inhibition.
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PMID:Neutrophil beta-adrenergic receptor responses are potentiated by acute exposure to phorbol ester without changes in receptor distribution or coupling. 165 46

The effects of carbobenzyloxy-leucine-tyrosine-chloromethylketone (zLYCK), an inhibitor of chymotrypsin, were investigated on the activation pathways of the human neutrophil respiratory burst. At 10 microM zLYCK, a parallel inhibition was observed of superoxide production stimulated with the chemo-attractant FMLP and of chymotrypsin-like activity of human neutrophils. By contrast, superoxide production induced by PMA was minimally affected by zLYCK. The known transduction pathways triggered by FMLP were analyzed. zLYCK did not affect either the FMLP-induced cytosolic free calcium transient, inositol 1,4,5 trisphosphate formation, nor the PMA-induced phosphorylation of the 47-kDa substrate of protein kinase C. zLYCK did not affect the activity of protein kinase C extracted from neutrophils. In Ca(2+)-depleted cells, in which phosphatidylinositol 4,5-biphosphate breakdown does not occur, zLYCK inhibited the FMLP-induced respiratory burst in cells primed by low doses of PMA. The activity of the NADPH oxidase tested with active membranes from stimulated neutrophils or in a cell-free system was not inhibited by zLYCK. We conclude that: 1) zLYCK inhibits superoxide production through the inhibition of a chymotrypsin-like protease of the neutrophil, 2) zLYCK inhibits FMLP-induced activation of NADPH oxidase through a pathway independent of PtdInsP2 breakdown and cytosolic free calcium, and 3) zLYCK may prove a useful probe for the characterization of its target protease in neutrophil activation.
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PMID:The chymotrypsin inhibitor carbobenzyloxy-leucine-tyrosine-chloromethylketone interferes with the neutrophil respiratory burst mediated by a signaling pathway independent of PtdInsP2 breakdown and cytosolic free calcium. 165 5

Activation of the respiratory burst in the monocytic cell line U937 by cross-linking human 40-kDa FcR for IgG (Fc gamma RII) with the IgG1 mAb, CIKM5, is dependent on the maturation state of the cell. Addition of anti-Fc gamma RII to undifferentiated cells does not activate the respiratory burst but differentiation with human rIFN-gamma (200 U/ml) for 13 to 15 days results in maximal stimulation by this agonist, with half-maximal responses in cells incubated for 10 to 12 days. During maturation the development of responsiveness to cross-linking Fc gamma RII occurs later than the development of responsiveness to the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (maximal responses at 7 to 9 days), or the chemotactic peptide FMLP (half-maximal responses at 7 to 9 days). The late development of maximal Fc gamma RII responses is not associated with either increased Fc gamma RII expression, enhanced calcium mobilization induced by anti-Fc gamma RII, changes in protein kinase C activity (PKC) or a switch in PKC isotype expression. Activation of the respiratory burst via Fc gamma RII may not be mediated by activation of PKC as the kinase inhibitors 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride and N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride inhibited the Fc gamma RII response by less than 20% at concentrations which inhibit the 12-O-tetradecanoylphorbol-13-acetate-induced respiratory burst by more than 80%. IFN-gamma U937 cells did not metabolize incorporated arachidonate into eicosanoids when stimulated with anti-Fc gamma RII, suggesting that eicosanoids do not mediate activation of the respiratory burst, and this was confirmed by the lack of inhibition by the specific 5'-lipoxygenase and glutathione S-transferase inhibitor, piriprost, and the cyclo-oxygenase inhibitor, indomethacin. In addition there was no significant release of radiolabeled arachidonate in response to anti-Fc gamma RII. The response to anti-Fc gamma RII is inhibited by pertussis toxin, suggesting that signal transduction is via a GTP-binding protein. Agents that elevate intracellular cAMP increased the magnitude of the cAMP transients stimulated by anti-Fc gamma RII and also inhibited the respiratory burst. FMLP responses showed a similar pattern of sensitivity to this range of inhibitors, suggesting that both Fc gamma RII and FMLP receptor share common regulatory mechanisms. However, the termination of the respiratory burst activated via Fc gamma RII and FMLP receptor is independently regulated, in that after FMLP-induced activation there is no subsequent inhibition of the Fc gamma RII-mediated response and vice versa.
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PMID:Differentiation-linked activation of the respiratory burst in a monocytic cell line (U937) via Fc gamma RII. A study of activation pathways and their regulation. 165 5


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