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)

Human peripheral blood polymorphonuclear leukocytes (HPPMN) from healthy individuals are not primed and, hence, weak stimulation-dependent responses are induced by certain stimuli which bind to membrane receptors. When HPPMN were exposed to recombinant human tumor necrosis factor alpha (rHuTNF-alpha) or recombinant human granulocyte colony stimulating factor (rG-CSF), they underwent priming and the rate of superoxide anion (O.-2) generation was increased by subsequent exposure to formyl-methionyl-leucyl-phenylalanine (FMLP) or opsonized zymosan (OZ). However, the degree of enhancement was very small upon exposure to phorbol myristate acetate (PMA) or dioctanoyl glycerol (DOG). The oxygen burst induced by FMLP or OZ was inhibited by genistein and alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamamid (ST638), which are inhibitors of tyrosine kinase (TK), and was enhanced by 1-(5-isoquinoline-sulfonyl)-3-methyl-piperazine (H-7) and staurosporine, which are inhibitors of protein kinase C (PKC). Without priming, however, O.-2 generation from HPPMN by high concentrations of FMLP was not inhibited strongly by genistein or ST638. On the contrary, the oxygen burst induced by PMA or DOG was stimulated by genistein or ST638 and was inhibited by H-7 or staurosporine. Furthermore, O.-2 generation by guinea pig peritoneal neutrophils, which are already primed in vivo, was induced markedly by FMLP by a mechanism which was stimulated by a low concentration of genistein or ST638. Thus, FMLP-mediated O.-2-generation of HPPMN is coupled with rHuTNF-alpha- or rG-CSF-priming and is inhibited by TK inhibitors, whereas PMA- or DOG-induced O.-2 generation is not coupled with TNF-alpha or G-CSF-priming and is inhibited by PKC inhibitors. These results suggest that both PKC and TK play critical roles in the regulatory mechanism of priming and NADPH-oxidase activation in neutrophils.
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PMID:Modulation of TNF-alpha-priming and stimulation-dependent superoxide generation in human neutrophils by protein kinase inhibitors. 131 9

When isolated rat fat pads were incubated with vanadate, the low Michaelis-Menten constant (Km) cAMP phosphodiesterase (PDE) activity in the microsomal fraction was increased in a time- and dose-dependent manner with vanadate. 3',5'-Cyclic GMP inhibited the vanadate-stimulated PDE activity with similar profile to the insulin-stimulated one. The stimulatory effect of vanadate was inhibited by inhibitors of tyrosine kinases such as amiloride, biochanin A, and genistein to various extents. Vanadate and insulin both showed the full effect in the absence of either K+, N+, or Ca2+ in the medium, while preincubation of the fat pads with a chelator of intracellular Ca2+ inhibited the vanadate action in a dose-dependent manner. The insulin action was not inhibited by it at tested concentrations. These results suggest that the vanadate action, in contrast to the insulin one, is dependent on the intracellular level of Ca2+. Preincubation of the fat pads with inhibitors of protein kinase C such as 1-(5-isoquinoline sulfonyl)-2-methylpiperazine (H-7) and staurosporine inhibited, in part, the vanadate action but did not inhibit the insulin one. Furthermore, vanadate increased the protein kinase C activity in fat pads but insulin did not increase. H-7 and amiloride showed a significant inhibition of stimulation of protein kinase C activity by vanadate. These results suggest that vanadate stimulates, in part, the 3',5'-cyclic GMP-inhibited low Km cAMP PDE activity in the microsomal fraction of fat pads through the activation of tyrosine kinase and protein kinase C-mediated processes.
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PMID:Stimulatory effect of vanadate on 3',5'-cyclic guanosine monophosphate-inhibited low Michaelis-Menten constant 3',5'-cyclic adenosine monophosphate phosphodiesterase activity in isolated rat fat pads. 131 24

Phorbol ester (TPA) and retinoic acid (RA) are two potent immunomodulatory agents whose actions are mediated through distinct signal transduction pathways involving protein kinase C (PKC) and nuclear RA receptors, respectively. We have investigated the interactions between these two pathways in the regulation of expression of the inflammatory cytokine IL-8 in human skin fibroblasts. TPA (as previously reported) and RA both induced IL-8 mRNA and protein in a time- and dose-dependent manner. IL-8 mRNA induction by TPA (10 nM) was maximal (15-fold) within 6 h, and returned to baseline within 24 h of treatment, although maximal induction (10-fold) by RA (1 microM) did not occur until 24 h posttreatment. Induction of IL-8 by TPA was blocked by 1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine, which inhibits PKC and cAMP-dependent protein kinases (PKA), but not by N-(2-ganidinoethyl)-5-isoquinoline sulfonamide, which preferentially inhibits PKA, consistent with the participation of PKC in the induction of IL-8 by TPA. In contrast, induction of IL-8 by RA was inhibited by both 1-(5-isoquinoline sulfonamide and N-(2-gamidinoethyl)-5-isoquinoline sulfonamide, suggesting the participation of PKA in the induction of IL-8 by RA. However, activation of PKA by addition of cAMP analogues was not sufficient to induce IL-8 expression. Induction of IL-8 by RA also did not appear to be mediated indirectly through induction of IL-1, because addition of IL-1R antagonist did not block IL-8 induction by RA. RA and TPA added in combination synergistically enhanced expression of IL-8 mRNA, measured at 6 (2-fold) and 24 h (10-fold) posttreatment. To investigate the mechanism of this synergy, the effect of TPA and RA on fibroblast PKC activation and PKC isozyme levels were determined. TPA, either alone or together with RA, but not RA alone, stimulated phosphorylation of an endogenous 80-kDa PKC substrate. Dermal fibroblasts expressed three PKC isozymes (alpha, (delta, and (epsilon). TPA, but not RA, down-regulated PKC-alpha, neither TPA or RA affected the level of PKC-delta, and both TPA and RA down-regulated PKC-epsilon. This latter effect was enhanced 2-fold by addition of RA and TPA together. These data suggest that modulation of PKC-epsilon may be a common participant in the regulation of IL-8 expression by TPA and RA.
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PMID:Retinoic acid and phorbol ester synergistically up-regulate IL-8 expression and specifically modulate protein kinase C-epsilon in human skin fibroblasts. 132 13

1. Na+ influx into cultured vascular smooth muscle cells (VSMC) obtained from spontaneously hypertensive rats (SHR) and from Wistar-Kyoto rats (WKY) was measured. Na+ influx via the Na+/H+ exchange system was measured as the rate of 22Na+ influx into cultured VSMC sensitive to ethylisopropylamiloride (EIPA), a specific inhibitor of the exchange system. 2. The total 22Na+ influx rate in SHR was significantly higher than in WKY (6.08 +/- 0.16 vs 4.13 +/- 0.09 nmol/min per mg protein; P less than 0.001; n = 14). The EIPA (1 X 10(-4) mol/L)-sensitive 22Na+ influx rate in SHR was significantly higher than that in WKY (4.32 +/- 0.27 vs 2.17 +/- 0.14 nmol/min per mg protein; P less than 0.001; n = 14). There was no difference in EIPA-insensitive 22Na+ influx between SHR and WKY. The EIPA-sensitive 22Na+ influx rate into VSMC was significantly decreased in SHR but not in WKY by the addition of 1 X 10(-4) mol/L 1-(5-isoquinoline-sulfonyl)-methylpiperazine (H-7), an inhibitor of protein kinase C (PK-C). 3. These results suggest that the increase in Na+ influx in SHR may be due to elevation of the Na+/H+ exchange activity, and possible involvement of PK-C in the increased Na+/H+ exchange activity in VSMC from SHR.
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PMID:Increased Na+/H+ exchange activity in vascular smooth muscle cells of spontaneously hypertensive rats and possible involvement of protein kinase C. 132 79

1. A giant patch method was used to study the stimulatory effect of cytoplasmic MgATP on outward Na(+)-Ca2+ exchange current in inside-out cardiac membrane patches (1-10 G omega seals with 14-24 microns pipette tip diameters) excised from guinea-pig, rabbit and mouse myocytes. 2. To establish the validity of the method with respect to structure, bleb formation was examined with electron microscopy and with confocal fluorescence light microscopy. The blebs, which form as the sarcolemma detaches, excluded intracellular organelles and transverse tubules. The blebbed cells contained normal sarcomeres, sarcoplasmic reticulum, triads and diads. 3. To further establish the validity of the method for ion transport studies, measurements of Na(+)-K+ pump currents and charge movements are described briefly which demonstrate (i) free access to the cytoplasmic membrane side, (ii) MgATP dependence comparable to reconstituted pump (Kd, 94 microns), (iii) fast, rigorous concentration control and (iv) Na(+)-K+ pump densities in the range of whole-cell densities. 4. Stimulation of outward Na(+)-Ca2+ exchange current by MgATP attenuated exchange current decay during step increments of cytoplasmic sodium, shifted the secondary activation of outward exchange current by cytoplasmic calcium to lower free calcium concentrations and, particularly in mouse cardiac sarcolemma, induced cytoplasmic calcium-independent current. 5. Upon removal of MgATP the stimulatory effect usually decayed with a t50 (half-time) of about 3 min. However, the reversal took place much more rapidly (t50, 5-20 s) in patches from individual guinea-pig and rabbit myocyte batches. When decay was rapid, secondary activation by cytoplasmic calcium was shifted to higher free cytoplasmic calcium concentrations (Kd, 10-65 microns-free calcium). 6. With repeated applications of MgATP the rate and magnitude of the stimulatory effect progressively decreased. 7. The Kd for MgATP of the initial rate of stimulation of outward exchange current was 3 mM or greater. When decay was rapid, the steady-state dependence of exchange current on MgATP also had a Kd of 3 mM or greater. 8. Stimulation of Na(+)-Ca2+ exchange current by MgATP occurred in the absence of cytoplasmic calcium with 9 mM-EGTA. 9. The stimulatory effect of 2 mM-MgATP was not inhibited by up to 200 microM of the protein kinase inhibitor 1-(5-isoquinoline sulphonyl)-2-methylpiperazine (H7), or by peptide inhibitors of cyclic AMP-dependent protein kinase, protein kinase C and calcium-calmodulin-dependent protein kinase II.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The giant cardiac membrane patch method: stimulation of outward Na(+)-Ca2+ exchange current by MgATP. 133 2

This study has investigated the role of protein kinase C (PKC) activation in IgG-mediated phagocytosis by human monocytes. Incubation of monocytes with IgG-opsonized targets increased membrane-associated PKC approximately 2-fold. Kinetic studies showed that the translocation of PKC to membrane occurred before significant ingestion took place. The pharmacologic PKC inhibitor H7 inhibited IgG-dependent ingestion with ID50 of 20 microM, while the structurally related isoquinoline sulfonamide HA1004 had no effect at this concentration. Staurosporine and calphostin C, PKC inhibitors which have different mechanisms of actions than H7, also inhibited ingestion. Depletion of PKC by prolonged incubation with phorbol esters also inhibited phagocytosis, and dose-response curves showed a strong correlation between the extent of PKC depletion and the extent of inhibition of ingestion. Finally, phagosomes were isolated by sucrose density centrifugation of cells disrupted 5 min after the initiation of phagocytosis. Measurement of PKC activity and immunoreactivity in the phagosomes showed that PKC was concentrated in the phagosome membrane approximately 5-fold compared to the uninvolved plasma membrane. Together, these data suggest that PKC activation is an early, essential step in the efficient ingestion of IgG-opsonized targets by monocytes.
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PMID:Immunoglobulin-mediated phagocytosis by human monocytes requires protein kinase C activation. Evidence for protein kinase C translocation to phagosomes. 137 16

The ability of human tumor necrosis factor-alpha (TNF-alpha) and human granulocyte colony stimulating factor (G-CSF) to induce phosphorylation of protein tyrosyl residues in human peripheral neutrophils (PMN) was investigated by Western blot analysis with antiphosphotyrosine antibody. Both TNF-alpha and G-CSF increased the tyrosyl phosphorylation of various proteins, such as species of 54-, 63-, 72-, 83-, 98-, 108-, and 115-kDa proteins. The ligand-stimulated tyrosyl phosphorylation of the 115-kDa protein was time- and concentration-dependent. When the 115-kDa protein was phosphorylated, it was recovered from membrane fractions. The phosphorylation of the 115-kDa protein was inhibited by genistein and alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamamide (ST 638), inhibitors of tyrosine kinase (TK), and was enhanced by 1-(5-isoquinoline-sulfonyl) methyl-piperazine dihydrochloride (H-7) and staurosporine, inhibitors of Ca(2+)- and phospholipid-dependent protein kinase (PKC). Similar inhibition by the TK inhibitors and stimulation by the PKC inhibitors were also observed with formylmethionyl-leucyl-phenylalanine (FMLP)-induced superoxide (O2.-) generation by TNF-alpha- or G-CSF-primed PMN. Phosphorylation of the 115-kDa protein occurred in parallel with the ligand-dependent generation of O2.-. These and other observations suggested that substrate proteins for tyrosine kinase, such as the 115-kDa protein, might play critical roles in the mechanism for priming of neutrophils. This is the first report describing that tyrosyl phosphorylation is involved in the priming of neutrophils by G-CSF and TNF-alpha.
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PMID:Role of tyrosyl phosphorylation in neutrophil priming by tumor necrosis factor-alpha and granulocyte colony stimulating factor. 138 35

We searched for a possible role for protein kinase C in the growth of human erythroid progenitor cells, using pharmacologic approaches. Two protein kinase C inhibitors, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) and staurosporine, dose-dependently inhibited the growth of immature erythroid progenitor cells (BFU-E) induced by interleukin 3 (IL-3) plus erythropoietin (Ep) or granulocyte macrophage colony-stimulating factor (GM-CSF) plus Ep whereas a weaker analog of H-7, N-(2-guanidinoethyl)-5-isoquinoline sulfonamide (HA-1004), had no effect on the number of BFU-E. These three compounds had no effect on the growth of mature erythroid progenitor cells (CFU-E) stimulated by Ep. The culture of accessory cell-depleted bone marrow demonstrated that the effects of these compounds on colony formation do not appear to be mediated by accessory cells. The potential of these compounds to inhibit the GM-CSF-dependent growth of KG-1 cells correlated well with the extent of their inhibitor of protein kinase C activities from KG-1 cells. Thus, the protein kinase C system is apparently involved in the growth of BFU-E, supported by IL-3 or GM-CSF. The growth signal for CFU-E transduced by Ep may be achieved through other systems.
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PMID:A role for protein kinase C in the growth of human erythroid progenitor cells. 154 67

We investigated the effects of seven isoquinoline derivatives in overcoming resistance to vinblastine in Adriamycin-resistant mouse leukemia P388/ADR cells and human myelogeneous leukemia K562/ADR cells. N-(2-Methylpiperazyl)-5-isoquinoline-sulfonamide (H-7), N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide (H-8), and N-(2-aminoethyl)-5-isoquinolinesulfonamide (H-9) did not reverse resistance to vinblastine in these resistant cells. N-[2-[N-[3-(4-Chlorophenyl)-2-propenyl]amino]ethyl]-5- isoquinolinesulfonamide (H-86) and N-[2-[N-[3-(4-chlorophenyl)-1-methyl-2-propenyl]- amino]ethyl]-5-isoquinolinesulfonamide (H-87) caused significant accumulation of intracellular vinblastine and marked reversal of the resistance to vinblastine in both resistant cell lines. Addition of a formyl group at the terminal amino group of H-86 (H-85) or addition of an aminoethyl group to the nitrogen atom at the sulfonamide group of H-86 (W-66) reduced those activities. The activity on vinblastine accumulation seems to correlated with the hydrophobicity of the compounds. The compounds that effectively reversed resistance to vinblastine inhibited [3H]vinblastine efflux and photoaffinity labeling of P-glycoprotein with a photosensitive analogue of vinblastine, N-(p-azido-(3-[125I]iodo)-salicyl)-N'-beta-aminoethylvindesine. Although these isoquinoline derivatives inhibited protein kinase A and protein kinase C with various potencies, these inhibitory activities did not correlate with the reversal of drug resistance. These results indicate that hydrophobic isoquinoline derivatives reverse multidrug resistance due to the suppression of drug binding to P-glycoprotein, without involvement of their activities on protein kinase A and protein kinase C.
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PMID:Overcoming of vinblastine resistance by isoquinolinesulfonamide compounds in adriamycin-resistant leukemia cells. 161 7

We have previously shown that after peripheral nerve lesion the synthesis of NGF is induced in cells of the nerve sheath (Heumann et al., 1987a). Further analysis led to the identification of growth factors and intracellular mechanisms responsible for this induction in sciatic fibroblasts (Lindholm et al., 1988; Hengerer et al., 1990). The present work aimed at the elucidation of the regulation of NGF synthesis in Schwann cells. A variety of cytokines and peptide growth factors, including interleukin-1 (IL-1) and platelet-derived growth factor (PDGF), which are known to increase NGF-mRNA in fibroblasts and astrocytes, failed to do so in Schwann cell cultures. Forskolin (FK), an activator of adenylate cyclase, increased the level of NGF-mRNA eightfold within 3 hr of incubation. The effect of FK on NGF-mRNA was mimicked by analogs of cAMP but not by dideoxyforskolin, an FK derivative not activating adenylate cyclase. Application of norepinephrine and isoproterenol also augmented the NGF-mRNA content. Pretreatment of Schwann cells with N-[2-(methylamino)ethyl]-5-isoquinoline sulfonamide dihydrochloride (H-8), an inhibitor of cyclic-nucleotide-dependent protein kinases, decreased both basal and elevated levels of NGF-mRNA. Ionomycin, a Ca2+ ionophore, and phorbol 12-myristate 13-acetate (TPA), an activator of protein kinase C, potentiated the effect of FK in an H-8-sensitive manner. We show that the action of FK is independent of changes in mRNA stability and of protein synthesis. Thus, in cultured Schwann cells upregulation of NGF-mRNA expression seems to be mainly achieved by a cAMP-triggered transcriptional activation of the NGF gene. Another striking difference between various glial cell types was revealed by application of transforming growth factor beta-1 (TGF-beta 1), which is the strongest inducer of NGF-mRNA in cultured astrocytes (Lindholm et al., 1990). Schwann cells responded to TGF-beta 1 by decreasing basal as well as FK-induced NGF-mRNA levels. Together with previously published work, our results show that cell-type-specific mechanisms not only account for the different control of NGF expression in neurons as compared to glial cells, but also reveal a surprising specificity of regulatory mechanisms in different non-neuronal cell types, even those derived from the same tissue such as fibroblasts and Schwann cells of peripheral nerves.
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PMID:Cell-type-specific regulation of nerve growth factor (NGF) synthesis in non-neuronal cells: comparison of Schwann cells with other cell types. 165 45


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