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

Changes in cytosolic calcium concentration ([Ca2+]i) have been implicated in the regulation of intracellular pH (pHi) in several cell types. In the present study we investigated the regulatory mechanism of Na+/H+ exchange induced by angiotensin II (AII) in cultured rat vascular smooth muscle cells (VSMCs). Serially passaged VSMCs from Sprague-Dawley rat thoracic aorta were grown on coverslips and loaded with the pH-sensitive fluorescent indicator 2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein (BCECF). In HCO(3-)-free Ringer solution, pH 7.40, the resting pHi was 7.21 +/- 0.02 (n = 21). A biphasic response was seen after exposure of these cells to AII: an initial transient a acidification, followed by sustained alkalization. The magnitude of alkalization was dose-dependent. AII-mediated acidification was completely inhibited by [Sar1-IIe5-Gly8]AII, but amiloride had no effect. In contrast, the alkalization induced by AII was abolished by both amiloride and Na(+)-free medium. In Ca(2+)-free medium, the AII-induced alkalization was partially blocked and verapamil also caused partial inhibition. Since AII activates phospholipase C in VSMCs, we examined whether AII would increase Na+/H+ exchange by activation of protein kinase C. An inhibitor of protein kinase C, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), partially inhibited the alkalization induced by AII. These results indicate that AII stimulates cytoplasmic alkalization via an amiloride-sensitive Na+/H+ exchange system in cultured rat VSMCs, and that this AII-stimulated Na+/H+ exchange is mediated by Ca(2+)-dependent and protein kinase C-dependent mechanisms.
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PMID:Stimulation of Na+/H+ exchange induced by angiotensin II in cultured rat vascular smooth muscle cells: role of Ca2+ and C-kinase. 154 35

In vitro effects of sodium orthovanadate on protein kinase C induced phosphorylation of rat liver cytosolic and particulate proteins were examined. Vanadate enhanced the phosphorylation of six liver cytosolic proteins (Mr 170K, 150K, 80K, 34K, 25K and 19K daltons), the probable substrates for protein kinase C. There was a 2.5-fold increase in total endogenous protein phosphorylation at 2.0 mM concentration which was abolished in the presence of protein kinase C inhibitors such as 1-(5-isoquinolinyl-sulfonyl-2-methylpiperazine (H-7), N-[2-(methylamine)-ethyl]-5-isoquinolinesulfonamide (H-8) and polymyxin B. Metavanadate showed a similar stimulatory effect whereas vanadyl sulfate was inhibitory. These differential effects of vanadium salts were also observed with the particulate fraction. The results suggest that some of the effects of vanadate could be mediated through protein kinase C-induced phosphorylation of endogenous proteins.
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PMID:Vanadate increases protein kinase C-induced phosphorylation of endogenous proteins of liver in vitro. 155 36

EL 4-6.1 cells, variants of the murine EL4 thymoma cell line, can be activated by interleukin 1 (IL-1) or phorbol 12-myristate-13-acetate (PMA), or PMA+IL-1 to secrete interleukin 2 (IL-2) and interleukin 4 (IL-4) and to express the IL-2 receptor (IL-2R). To compare the different activation pathways, we examined the effects of staurosporine (STAR) and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), two protein kinase C (PKC) inhibitors, on the induction of interleukin secretion and IL-2R expression in these cells. We report here that nanomolar concentrations of STAR strongly potentiated (20- to 30-fold) the production of IL-2 or IL-4, when EL 4-6.1 cells were induced by IL-1 alpha (or IL-1 beta) alone. By contrast, at identical concentrations, STAR dose-dependently inhibited the production of IL-2 and IL-4 resulting from PMA or PMA+IL-1 cell treatment. STAR also negatively affected the expression of IL-2R, which was dependent on PMA-sensitive PKC with either IL-1, PMA, or PMA+IL-1 stimulation. The changes in interleukin production and IL-2R expression in EL 4-6.1 activated cells were correlated with changes at the mRNA level measured by quantitative polymerase chain reaction (PCR). This finding suggests a pretranslational effect of the drug. At micromolar concentrations, H7 showed the same effects as STAR, but only increased IL-1-triggered interleukin secretions twofold. We observed that the action of PKC inhibitors did not result from modification of IL-1 receptor (IL-1R) expression in EL 4-6.1 cells. Thus, our data show that PKC inhibitors clearly distinguish between IL-1 and PMA stimulatory pathways. In addition, they suggest that the IL-1 stimulatory pathway involves PKC(s) [or other undefined kinase(s)] which regulate this pathway and differ from PKC(s) activated by PMA.
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PMID:Contrasting effects of the protein kinase C inhibitor staurosporine on the interleukin-1 and phorbol ester activation pathways in the EL4-6.1 thymoma cell line. 156 50

We used electronic cell sizing and Cl- efflux measurements in guinea pig jejunal enterocytes to study activation of Cl- conductance under two experimental conditions, regulatory volume decrease (RVD) after passive hypotonic swelling and volume regulation during Na(+)-alanine cotransport. RVD after a hypotonic (0.5 x isotonic) challenge was not affected by the protein kinase C (PKC) inhibitor 100 microM 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7). Volume decrease after cell swelling in response to L-Ala (25 mM) was prevented by H-7 (P less than 0.05) or the more potent PKC inhibitor 10 nM staurosporine (P less than 0.001). L-Ala stimulated biphasic 36Cl efflux, a rapid efflux over 60 s which was inhibited by H-7 (P less than 0.01) and the Cl(-)-channel blocker anthracene-9-carboxylic acid (9-AC) (P less than 0.005). In contrast, after hypotonic dilution the rate of 36Cl efflux increased (P less than 0.005); H-7 had no effect but 9-AC inhibited the increase (P less than 0.01). Gramicidin (0.5 microM) added to cells maximally swollen by L-Ala in Cl(-)-containing medium caused 2 degree swelling (P less than 0.001), but 10 nM staurosporine reduced this 2 degree swelling (P less than 0.001). Addition of phorbol ester or synthetic diacylglycerol to villus cells under isotonic conditions, after gramicidin addition, caused cell swelling (P less than 0.005) that was inhibited by staurosporine (P less than 0.05). We concluded that PKC does not activate Cl- conductance for hypotonic RVD but that Na(+)-nutrient cotransport is a physiological stimulus for PKC to activate Cl- conductance necessary for volume regulation.
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PMID:Effect of protein kinase C inhibitors on Cl- conductance required for volume regulation after L-alanine cotransport. 156 20

We have recently established ME-1, a human myelomonocytic leukaemia cell line derived from acute myelomonocytic leukaemia with eosinophilia (M4E0). When ME-1 cells were cultured in serum-free medium, they stopped proliferating and began to differentiate morphologically, functionally and phenotypically to mature granulocyte-like cells. The protein kinase inhibitor, 1-(5-isoquinolinyl-sulphonyl)-2-methylpiperazine (H-7) enhanced this differentiation dose-dependently. Upon addition of fetal calf serum (FCS) to the serum-free medium, the differentiation of ME-1 cells into granulocyte-like cells was inhibited and they resumed cell growth. We have recently reported that the differentiation of ME-1 cells into macrophage-like cells induced by IL-3 and GM-CSF involved the activation of protein kinase C. The present results indicate that ME-1 is a bipotential cell line that can differentiate into granulocyte-like cells or macrophage-like cells, and that protein kinase C is closely related to each form of differentiation.
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PMID:Granulocytic differentiation of the human myelomonocytic leukaemia cell line ME-1 in serum-free culture. 158 Dec 9

It is shown that the intracellular glutathione (GSH) concentration of neuroblastoma-2a cells in culture increases with a maximum at 24 h after starting treatment with 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), an inhibitor of protein kinase C (PKC). Other inhibitors of this and other protein kinases, e.g. sphingosine, staurosporine, and HA 1004, at the concentrations tested, had a less marked or negligible effect on intracellular GSH concentration. 12-O-Tetradecanoylphorbol-13-acetate (TPA) was also tested and showed no significant effect 24 h after addition.
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PMID:H7, a protein kinase C inhibitor, increases the glutathione content of neuroblastoma cells. 159 9

In this study, we report that the isoquinolinesulfonamide inhibitors of protein kinase C (PKC), H-7 [1-(5-isoquinolinesulfonyl)-2-methylpiperazine] and its related derivatives H-8 and HA-1004, in addition to staurosporine cause depletion and reorganization of microfilament bundles of porcine aortic endothelial cells in both low-density and confluent monolayer cultures. Concomitantly, significant loss of cell adhesion was noted following treatment with H-7. The effects of these compounds were found to be reversible upon wash-out, with restoration of the microfilament network. In addition, longer term incubation with phorbol myristate acetate (PMA) carried out to deplete PKC results in depletion of microfilaments as well. After 24 hr of PMA incubation, however, addition of H-7 or staurosporine is associated with further loss of the remaining microfilaments, suggesting that these agents act, at least in part, through a PKC-independent mechanism.
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PMID:Disruption of endothelial actin microfilaments by protein kinase C inhibitors. 160 36

In this report we showed that calmodulin antagonists chlorpromazine (CPZ) and W-7 (N-[6-aminohexyl]-5-chloro-1-naphtalenesulfonamide), when added to fibroblast cell cultures, gave rise to a time- and dose-dependent decrease of sphingomyelinase activity. CPZ and W-7 also significantly inhibited LDL- and non-LDL-dependent cholesterol esterification. Addition of these drugs to cell culture medium mimicked what is observed in the genetic disease Niemann-Pick type C. H-7 (1-[5-isoquinonylsulfonyl]-2-methylpiperazine), an inhibitor of protein kinase C and cyclic nucleotide-dependent kinases, had no effect on sphingomyelinase and cholesterol ester formation. Thus the possibility of a modulation of cell sphingomyelin and cholesterol esters by a calmodulin-dependent second messenger system must be considered.
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PMID:Calmodulin antagonists chlorpromazine and W-7 inhibit exogenous cholesterol esterification and sphingomyelinase activity in human skin fibroblast cultures. Similarities between drug-induced and Niemann-Pick type C lipidoses. 161 24

Subconfluent cultures of LLC-PK1 cells were incubated for 1 h in Krebs-Henseleit buffer (KHB) of pH 7.4 or 6.8 to investigate the signal transduction events associated with prostaglandin F2 alpha (PGF2 alpha) inhibition of ammonia metabolism. Exposure of these cultures to PGF2 alpha (0.1 ng/ml) inhibited the acute low pH stimulation of ammonia production and to a lesser degree alanine formation in a manner analogous to the response exhibited with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Pretreatment with an inhibitor of protein kinase C [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, i.e., H-7] or utilization of cultures with downregulated protein kinase C activity abolished the inhibitory response to PGF2 alpha. Exposure to PGF2 alpha for 10 min in KHB of pH 6.8 resulted in an activation of protein kinase C, as demonstrated by a significant increase in membrane-bound enzyme activity. Incubation of the cells with PGF2 alpha in KHB of pH 6.8 also resulted in a significant increase in inositol trisphosphate formation. Treatment of the cultures with verapamil in calcium-containing medium or removal of calcium from the incubating medium resulted in a significant loss of the PGF2 alpha inhibitory response on both ammonia and alanine production. Furthermore, under conditions of calcium-free incubation, PGF2 alpha had no significant effect on protein kinase C activity. Because both PGF2 alpha- and TPA-induced inhibition of ammoniagenic response to acute acidosis was prevented by amiloride, the underlying mechanism may involve protein kinase C-mediated changes in intracellular pH. These results indicate that the activation of protein kinase C plays a key role in mediating PGF2 alpha inhibition of ammoniagenesis.
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PMID:Signal transduction events whereby PGF2 alpha inhibits the ammoniagenic response to acute acidosis. 162 19

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


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