Lipophilic fraction of Panax ginseng induces neuronal differentiation of PC12 cells and promotes neuronal survival of rat cortical neurons by protein kinase C dependent manner

SummaryTissue factor (TF) is a transmembrane receptor which, in association with factors VII and Vila, activates factor IX and X, thereby activating the coagulation protease cascades. In response to bacterial lipopolysaccharide (LPS) monocytes transcribe, synthesize and express TF on their surface. We investigated whether LPS-induced TF in human monocytes is mediated by protein kinase C (PKC) activation. The PKC agonists phorbol 12- myristate 13-acetate (PMA) and phorbol 12, 13 dibutyrate (PdBu) were both potent inducers of TF in human monocytes, whereas 4 alpha-12, 13 didecanoate (4 a-Pdd) had no such effect. Both LPS- and PMA-induced TF activity were inhibited, in a concentration dependent manner, by three different PKC inhibitors: H7, staurosporine and calphostin C. TF antigen determination confirmed that LPS-induced cell-surface TF protein levels decreased in parallel to TF functional activity under staurosporine treatment. Moreover, Northern blot analysis of total RNA from LPS- or PMA-stimulated monocytes showed a concentration-dependent decrease in TF mRNA levels in response to H7 and staurosporine. The decay rate of LPS-induced TF mRNA evaluated after the arrest of transcription by actinomycin D was not affected by the addition of staurosporine, suggesting that its inhibitory effect occurred at a transcriptional level. We conclude that LPS-induced production of TF and its mRNA by human monocytes are dependent on PKC activation.

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The Lack of a Role for Protein Kinase C in Neurite Extension and in the Induction of Ornithine Decarboxylase by Nerve Growth Factor in PC12 Cells

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)94099-8 ◽

1989 ◽

Vol 264 (6) ◽

pp. 3538-3544 ◽

Cited By ~ 1

Author(s):

D S Reinhold ◽

K E Neet

Keyword(s):

Protein Kinase C ◽

Nerve Growth Factor ◽

Growth Factor ◽

Protein Kinase ◽

Pc12 Cells ◽

Ornithine Decarboxylase ◽

Nerve Growth ◽

Neurite Extension ◽

Kinase C

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Tamoxifen inhibits phorbol ester stimulated osteoclastic bone resorption: An effect mediated by calmodulin

Biochemistry and Cell Biology ◽

10.1139/o00-084 ◽

2000 ◽

Vol 78 (6) ◽

pp. 715-723 ◽

Cited By ~ 8

Author(s):

John P Williams ◽

Margaret A McKenna ◽

Allyn M Thames III ◽

Jay M McDonald

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Bone Resorption ◽

Phorbol Ester ◽

Phorbol Esters ◽

Fold Increase ◽

Dependent Manner ◽

Osteoclast Activity ◽

Kinase C ◽

Protein Kinase Cα

Tamoxifen inhibits bone resorption by disrupting calmodulin-dependent processes. Since tamoxifen inhibits protein kinase C in other cells, we compared the effects of tamoxifen and the phorbol ester, phorbol myristate acetate, on osteoclast activity. Phorbol esters stimulate bone resorption and calmodulin levels four-fold (k0.5 = 0.10.3 µM). In contrast, tamoxifen inhibited osteoclast activity ~60% with an IC50 of 1.5 µM, had no apparent effect on protein kinase C activity in whole-cell lysates, and reduced protein kinase Cα recovered by immunoprecipitation 75%. Phorbol esters stimulated resorption in a time-dependent manner that was closely correlated with a similar-fold increase in calmodulin. Protein kinase Cα, β, δ, ε, and ζ were all down-regulated in response to phorbol ester treatment. Tamoxifen and trifluoperazine inhibited PMA-dependent increases in bone resorption and calmodulin by 85 ± 10%. Down-regulation of protein kinase C isoforms by phorbol esters suggests that the observed increases in bone resorption and calmodulin levels are most likely due to a mechanism independent of protein kinase C and dependent on calmodulin. In conclusion, the data suggest that protein kinase C negatively regulates calmodulin expression and support the hypothesis that the effects of both phorbol esters and tamoxifen on osteoclast activity is mediated by calmodulin.Key words: osteoclast, calmodulin, tamoxifen, osteoporosis, protein kinase C.

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Post-transcriptional regulation of apolipoprotein E expression in mouse macrophages by phorbol ester

Biochemical Journal ◽

10.1042/bj2920105 ◽

1993 ◽

Vol 292 (1) ◽

pp. 105-111 ◽

Cited By ~ 15

Author(s):

L Dory

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Apolipoprotein E ◽

Phorbol Ester ◽

Mrna Levels ◽

Dependent Manner ◽

Kinase C ◽

Protein Kinase C Activity ◽

Mouse Macrophages ◽

Apoe Expression

Phorbol ester-mediated differentiation of THP-1 cells (a human monocytic cell line) into mature macrophages is associated with a transcriptional induction of apolipoprotein E (apoE) expression [Auwerx, Deeb, Brunzell, Peng and Chait (1988) Biochemistry 27, 2651-2655]. Endotoxin, on the other hand, which may also act through activation of protein kinase C, is a potent inhibitor of apoE expression in mouse macrophages [Werb and Chin (1983) J. Biol. Chem. 258, 10642-10648]. The present experiments examine the effect of phorbol ester, an activator of protein kinase C, on the apoE expression in mouse thioglycollate-elicited peritoneal macrophages. Phorbol ester inhibits apoE expression in a specific, time- and dose-dependent manner. A 75% inhibition in the rate of apoE secretion, but not that of total protein, was observed following a 4.5 h incubation with 160 nM phorbol ester, although nearly full inhibition was obtained with 40 nM. The changes in apoE secretion were paralleled by similar changes in apoE synthesis, indicating synthesis as the primary site of action. The decreased rates of apoE synthesis are shown not to be due to increased apoE degradation. The profound inhibition of apoE synthesis was not accompanied by significant changes in apoE mRNA levels at any concentration of phorbol ester (up to 16 microM), or length of treatment (up to 24 h), suggesting a post-transcriptional locus of regulation of apoE expression. Although the early changes in apoE synthesis correlate with increased microsomal protein kinase C activity, the suppression of apoE expression persists even during conditions of nearly complete (> 95%) loss of protein kinase C activity, suggesting that the direct or indirect effect of protein kinase C on apoE expression is mediated by a stable phosphorylated protein, or that the observed effects are mediated through a protein kinase C species that is not readily downregulated by phorbol esters. The presented studies clearly demonstrate the potential importance of the translational regulation of apoE expression through the protein kinase C signal transduction pathway.

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Regulation of protein kinase C activity in neuronal differentiation induced by the N-ras oncogene in PC-12 cells

Molecular and Cellular Biology ◽

10.1128/mcb.10.6.2983-2990.1990 ◽

1990 ◽

Vol 10 (6) ◽

pp. 2983-2990

Author(s):

J C Lacal ◽

A Cuadrado ◽

J E Jones ◽

R Trotta ◽

D E Burstein ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Neuronal Differentiation ◽

Phorbol Esters ◽

Ras Oncogene ◽

Intact Cells ◽

Pc 12 Cells ◽

Kinase C ◽

Ras P21

Expression of the N-ras oncogene under the control of the glucocorticoid-responsive promoter in the pheochromocytoma cell line UR61, a subline of PC-12 cells, has been used to investigate the differentiation process to neuronal cells triggered by ras oncogenes (I. Guerrero, A. Pellicer, and D. E. Burstein, Biochem. Biophys. Res. Commun. 150:1185-1192, 1988). Using ras-inducible cell lines, we observed that expression of the oncogenic N-ras p21 protein interferes with the ability of phorbol esters to induce downregulation of protein kinase C. This effect was associated with the appearance of immunologically detectable protein kinase C as well as the activity of the enzyme as analyzed either by binding of [3H]phorbol-12,13-dibutyrate in intact cells or by in vitro kinase activity. These results indicate a relationship between ras p21 and protein kinase C in neuronal differentiation in this model system. Comparison to the murine fibroblast system suggests that this relationship may be functional.

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Protein kinase C-ζ modulates thromboxane A2-mediated apoptosis in adult ventricular myocytes via Akt

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2002.282.1.h320 ◽

2002 ◽

Vol 282 (1) ◽

pp. H320-H327 ◽

Cited By ~ 12

Author(s):

Yukitaka Shizukuda ◽

Peter M. Buttrick

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Cardiac Myocytes ◽

Ventricular Myocytes ◽

Kinase Assay ◽

Dependent Manner ◽

Adult Rat ◽

Kinase C ◽

Adult Cardiac Myocytes ◽

Pkc Ζ

We hypothesized that thromboxane A2 (TxA2) receptor stimulation directly induces apoptosis in adult cardiac myocytes. To investigate this, we exposed cultured adult rat ventricular myocytes (ARVM) to a TxA2 mimetic [1S-[1α,2α(Z),3β(1E,3S*),4α]]-7-[3-[3-hydroxy-4-(4-iodophenoxy)-1-butenyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid (I-BOP) for 24 h. Stimulation with I-BOP induced apoptosis in a dose-dependent manner and was completely prevented by a TxA2 receptor antagonist, SQ-29548. We further investigated the role of protein kinase C (PKC) in this process. TxA2 stimulation resulted in membrane translocation of PKC-ζ but not PKC-α, -βII, -δ, and -ε at 3 min and 1 h. The activation of PKC-ζ by I-BOP was confirmed using an immune complex kinase assay. Treatment of ARVM with a cell-permeable PKC-ζ pseudosubstrate peptide (ζ-PS) significantly attenuated apoptosis by I-BOP. In addition, I-BOP treatment decreased baseline Akt activity and its decrease was reversed by treatment with ζ-PS. The inhibition of phosphatidylinositol 3-kinase upstream of Akt by wortmannin or LY-294002 abolished the antiapoptotic effect of ζ-PS. Therefore, our results suggest that the activation of PKC-ζ modulates TxA2 receptor-mediated apoptosis at least, in part, through Akt activity in adult cardiac myocytes.

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Sequestration of phosphoinositides by mutated MARCKS effector domain inhibits stimulated Ca2+mobilization and degranulation in mast cells

Molecular Biology of the Cell ◽

10.1091/mbc.e11-07-0614 ◽

2011 ◽

Vol 22 (24) ◽

pp. 4908-4917 ◽

Cited By ~ 26

Author(s):

Deepti Gadi ◽

Alice Wagenknecht-Wiesner ◽

David Holowka ◽

Barbara Baird

Keyword(s):

Plasma Membrane ◽

Protein Kinase C ◽

Protein Kinase ◽

Time Course ◽

Fluorescent Protein ◽

Immunoglobulin E ◽

Dependent Manner ◽

Effector Domain ◽

Granule Exocytosis ◽

Kinase C

Protein kinase C β (PKCβ) participates in antigen-stimulated mast cell degranulation mediated by the high-affinity receptor for immunoglobulin E, FcεRI, but the molecular basis is unclear. We investigated the hypothesis that the polybasic effector domain (ED) of the abundant intracellular substrate for protein kinase C known as myristoylated alanine-rich protein kinase C substrate (MARCKS) sequesters phosphoinositides at the inner leaflet of the plasma membrane until MARCKS dissociates after phosphorylation by activated PKC. Real-time fluorescence imaging confirms synchronization between stimulated oscillations of intracellular Ca2+concentrations and oscillatory association of PKCβ–enhanced green fluorescent protein with the plasma membrane. Similarly, MARCKS-ED tagged with monomeric red fluorescent protein undergoes antigen-stimulated oscillatory dissociation and rebinding to the plasma membrane with a time course that is synchronized with reversible plasma membrane association of PKCβ. We find that MARCKS-ED dissociation is prevented by mutation of four serine residues that are potential sites of phosphorylation by PKC. Cells expressing this mutated MARCKS-ED SA4 show delayed onset of antigen-stimulated Ca2+mobilization and substantial inhibition of granule exocytosis. Stimulation of degranulation by thapsigargin, which bypasses inositol 1,4,5-trisphosphate production, is also substantially reduced in the presence of MARCKS-ED SA4, but store-operated Ca2+entry is not inhibited. These results show the capacity of MARCKS-ED to regulate granule exocytosis in a PKC-dependent manner, consistent with regulated sequestration of phosphoinositides that mediate granule fusion at the plasma membrane.

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