• IMMUNE NETWORK
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• v.13 no.2
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• pp.55-62
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• 2013

Swiprosin-1 exhibits the highest expression in $CD8^+$ T cells and immature B cells and has been proposed to play a role in lymphocyte biology through actin remodeling. However, regulation of swiprosin-1 gene expression is poorly understood. Here we report that swiprosin-1 is up-regulated in T cells by PKC pathway. Targeted inhibition of the specific protein kinase C (PKC) isotypes by siRNA revealed that $PKC-{\theta}$ is involved in the expression of swiprosin-1 in the human T cells. In contrast, down-regulation of swiprosin-1 by A23187 or ionomycin suggests that calcium-signaling plays a negative role. Interestingly, swiprosin-1 expression is only reduced by treatment with $NF-{\kappa}B$ inhibitors but not by NF-AT inhibitor, suggesting that the $NF-{\kappa}B$ pathway is critical for regulation of swiprosin-1 expression. Collectively, these results suggest that swiprosin-1 is a $PKC-{\theta}$-inducible gene and that it may modulate the late phase of T cell activation after antigen challenge.

• Journal of Life Science
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• v.22 no.1
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• pp.87-91
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• 2012

Phorbol 12-myristate 13-acetate (PMA), a known tumor-promoting phorbol ester, activates the signal transduction enzyme protein kinase C (PKC) in animal cells. We investigated the effect of PMA on the regulation of gravitropism via ethylene production in primary roots of maize. PMA stimulated root growth and the gravitropic response in a concentration-dependent manner at $10^{-6}$ M and $10^{-4}$ M over 8 hrs. These effects were prevented by treatment with staurosporine (STA), a potent inhibitor of PKC. These results support the possibility that the gravitropic response might be regulated through protein kinases that are involved in the signal transduction system. Ethylene is known to play a role in the regulation of root growth and gravitropism. Ethylene production was increased by about 26% and 37% of the control rate in response to $10^{-6}$ M and $10^{-4}$ M PMA, respectively. PMA also stimulated the activity of ACC synthase (ACS), which converts the S-adenosyl-L-methionine (AdoMet) to 1-aminocyclopropane-1-carboxylic acid (ACC) in the ethylene production pathway. These effects on ethylene production were also prevented by STA treatment. These results suggest that the root gravitropic response in maize is regulated through protein kinases via ethylene production.

• Toxicological Research
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• v.28 no.2
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• pp.107-112
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• 2012

Polychlorinated biphenyls (PCBs) are persistent and bioaccumulative environmental pollutants. Recently, it is suggested that neurotoxic effects such as motor dysfunction and impairment in memory and learning have been associated with PCB exposure. However, structure relationship of PCB congeners with neurotoxic effects remains unknown. Since PKC signaling pathway is implicated in the modulation of motor behavior as well as learning and memory and the role of PKC are subspecies-specific, we attempted to study the effects of structurally distinct PCBs on the total PKC activity as well as subspecies of PKC in cerebellar granule cell culture model. Cells were exposed to 0, 25 and 50 ${\mu}M$ of PCB-126, PCB-169, PCB-114, PCB-157, PCB-52 and PCB-4 for 15 min. Cells were subsequently analyzed by [$^3H$] phorbol ester binding assay or immunoblotted against PKC-${\alpha}$ and -${\varepsilon}$ monoclonal antibodies. While non-dioxin-like-PCB (PCB-52 and PCB-4) induced a translocation of PKC-${\alpha}$ and -${\varepsilon}$ from cytosol to membrane fraction, dioxin-like PCBs (PCB-126, -169, -114, -157) had no effects. [$^3H$] Phorbol ester binding assay also revealed structure-dependent increase similar to translocation of PKC isozymes. While PCB-4 induced translocation of PKC-${\alpha}$ and -${\varepsilon}$ was inhibited by ROS inhibitor, the pattern of translocation was not affected in presence of AhR inhibitor. It is suggested that PCB-4-induced PKC activity may not be mediated via AhR-dependent pathway. Taken together, our findings suggest that chlorination of ortho-position in PCB may be a critical structural moiety associated with neurotoxic effects, which may be preferentially mediated via non-AhR-dependent pathway. Therefore, the present study may contribute to understanding the neurotoxic mechanism of PCBs as well as providing a basis for establishing a better neurotoxic assessment.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.6
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• pp.503-510
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• 2001

Long-term treatment of cultured bovine adrenal medullary chromaffin (BAMC) cells with arachidonic acid $(100\;{\mu}M),$ angiotesnin II (100 nM), prostaglandin $E_2\;(PGE_2;\;10\;{\mu}M),$ veratridine $(2\;{\mu}M)$ or KCl (55 mM) for 24 hrs increased both norepinephrine and epinephrine levels in the supernatant. Pretreatment with staurosporine (10 nM), a protein kinase C (PKC) inhibitor, completely blocked increases of norepinephrine and epinephrine secretion induced by arachidonic acid, angiotensin II, $PGE_2,$ veratridine or KCl. In addition, K252a, another PKC inhibitor whose structure is similar to that of staurosporine, effectively attenuated both norepinephrine and epinephrine secretion induced by arachidonic acid. However, K252a did not affect the catecholamine secretion induced by angiotensin II, $PGE_2,$ veratridine or KCl. Our results suggest that staurosporine may inhibit long-term catecholamine secretion induced by various secretagogues in a mechanism other than inhibiting PKC signaling. Furthermore, long-term secretion of catecholamines induced by arachidonic acid may be dependent on PKC pathway.

• Animal cells and systems
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• v.13 no.4
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• pp.391-397
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• 2009

The house dust mite (Dermatophagoides pteronissinus) is an important factor in triggering allergic diseases. The function of eosinophils, particularly in the production of cytokine or chemokine, is critical in understanding the pathogenesis of inflammatory diseases. In this study, we examined whether D. pteronissinus extract (DpE) induces the expression of monocyte chemotactic protein 1 (MCP-1)/CCL2, IL-8/CXCL8, and IL-6 that mediate in the infiltration and activation of immune cells and in its signaling mechanism in the human eosinophilic cell line, EoL-1. DpE increased the mRNA and protein expression of MCP-1, IL-8, and IL-6 in a time- and dose-dependent course in EoL-1 cells. In our experiments using signal-specific inhibitors, we found that the increased expression of MCP-1, IL-8, and IL-6 due to DpE is associated with Src family tyrosine kinase and protein kinase C $\delta$ (PKC $\delta$). In addition, the activation of extracellular signal-regulated kinase (ERK) is required for MCP-1 and IL-8 expression while p38 mitogen-activated protein kinase (MAPK) is involved in IL-6 expression. DpE induced the phosphorylation of ERK and p38 MAPK. PP2, an inhibitor of Src family tyrosine kinase, and rottlerin, an inhibitor of PKC $\delta$, blocked the activation of ERK and p38 MAPK. DpE induces the activation of ERK and p38 MAPK via Src family tyrosine kinase and PKC $\delta$ for MCP-1, IL-8, or IL-6 production. Increased cytokine release due to the house dust mite and the characterization of its signal transduction may be valuable in understanding the eosinophil-related pathogenic mechanism of inflammatory diseases.

• The Korean Journal of Zoology
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• v.36 no.4
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• pp.439-451
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• 1993

Protein kinase C isozymes in a human prostate adenocarcinoma PC-3 cell line were characterized. Immunoreactive bands and immunocytochemical stains were obsenred in PC-3 cells with antibodies raised against protein kinase C ${\alpha}$, ${\beta}$, ${\gamma}$, $\delta$, $\varepsilon$, and ζ types, respectively. Protein kinase C ${\alpha}$ corresponded to a immunoreactive band at a molecular weight of 80,000-dalton, whereas molecular weights of other immunoreactive isozvmes of protein kinase C were detected at 68,000-dalton. Protein kinHse C $\delta$ and ζ antibodies detected additional bands at 55,000-dalton and 80,000-dalton, respectively Immunocvtochemical study confirmed the results of the immunoblotting experiments qualitatively: all six protein kinase C isozymes were detected in the cytoplasm of PC-3 cells. Translocation of protein kinase C in PC-3 cells were also examined with phorbol 12-myristate 13-acetate (PMA), bryostatin 2, diolein, and 1-oleoyl-2-acetyl glycerol (OAG). Differential reactions of protein kinase C isozvmes to these activators were obsenred. When PC-3 cells were treated with 10mM bryostatin 2, protein kinase C isozyme u was translocated into the nucleus, whereas s type was translocated into the plasma membrane and the nucleus. Protein kinase C ${\alpha}$ and ζ types were translocated into the nucleus following the treatment with 101M diolein, whereas protein kinase C ${\alpha}$, ${\beta}$, ${\gamma}$, and $\varepsilon$ types were translocated into the nucleus by the treatment with 10mM OAG. Protein kinase C ${\alpha}$ and $\varepsilon$ types were translocated into the nucleus in the presence of 100nM PMA. Protein kinase C $\delta$ type was translocated to the nuclear membrane by these activators, however, only PMA-induced translocation was inhibited by protein kinase C inhibitor, 1-(5-isoquinolinesulfonyll-2-methvlpiperazine dihvdrochloride (H7) . H7 inhibited translocation of protein kinase C ${\alpha}$ type induced by PMA, ${\beta}$ type by OAG and s type by PMA and OAG, whereas it did not affect translocations induced by bryostatin and diolein, respectively. These results suggest that there exist six isoformes of protein kinase C (${\alpha}$, ${\beta}$, ${\gamma}$, $\delta$, $\varepsilon$ and ζ types) in PC-3 cells and that each of these isozvmes distinctivelv reacts to bryostatin, diolein, OAG and PMA, in part due to an altered molecular size and conceivably discrete binding site(s).

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.1
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• pp.11-18
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• 1999

Nuclear factor $_{\kappa}B\;(NF-_{\kappa}B)$ activation is modulated by various protein kinases. Activation of $NF-_{\kappa}B$ is known to be important in the regulation of cell viability. The present study investigated the effect of inhibitors of protein tyrosine kinase (PTK), protein kinase C (PKC) and protein kinase A (PKA) on $NF-_{\kappa}B$ activity and the viability of bovine cerebral endothelial cells (BCECs). In serum-deprivation-induced BCEC death, low doses of $TNF{\alpha}$ showed a protective effect. $TNF{\alpha}$ induced $NF-_{\kappa}B$ activation within 4 h in serum-deprivation. PTK inhibitors (herbimycin A and genistein) and PKC inhibitor (calphostin C) prevented $NF-_{\kappa}B$ activation stimulated by $TNF{\alpha}.$ Likewise, these inhibitors prevented the protective effect of $TNF{\alpha}.$ In contrast to $TNF{\alpha}-stimulated\;NF-_{\kappa}B$ activity, basal $NF-_{\kappa}B$ activity of BCECs in media containing serum was suppressed only by calphostin C, but not by herbimycin A. As well BCEC death was also induced only by calphostin C in serum-condition. H 89, a PKA inhibitor, did not affect the basal and $TNF{\alpha}-stimulated\;NF-_{\kappa}B$ activities and the protective effect of $TNF{\alpha}$ on cell death. These data suggest that modulation of $NF-_{\kappa}B$ activation could be a possible mechanism for regulating cell viability by protein kinases in BCECs.

• Journal of Nutrition and Health
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• v.37 no.9
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• pp.763-770
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• 2004

This study was designed to compare the anti-carcinogenic effect of conjugated linoleic acid isomers on tumor incidence, cell proliferation and the levels of thromboxane (TX) B$_2$, prostaglandin (PG) E$_2$ and 1,2-diacylglycerol (DAG), and the related enzyme expression of cyclooxygenase (COX)-2 and protein kinase C (PKC) in colonic mucosa of 1,2-dimethy- lhydrazine (DMH) -treated rats. One hundred eight male Sprague Dawley rats were randomly divided into 3 groups depending on the types of CLA isomers, i.e. control group (no CLA contained), c9t11 group (cis-9, trans-11 CLA contained), and t10c12 group (trans-10, cis-12 CLA contained). The experimental diet was composed of protein at 20%, carbohydrate at 56.2%, and fat at 14.5% including 1.0% CLA isomers by weight. The experimental diet was fed for 30 weeks with the initiation of intramuscular injection of DMH, which was injected twice a week for 6 weeks to give total dose of 180 mg per kg body weight. Two CLA isomers (c9, t11, t10, c12) significantly reduced tumor incidence and cell proliferation by reducing the protein expression of COX-2 and PKC, and the level of TXB$_2$, PGE$_2$, and DAG in colonic mucosa. However, there was no significant difference in anti-carcinogenic effect between c9t11-CLA and t10c12-CLA.

• BMB Reports
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• v.31 no.5
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• pp.468-474
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• 1998

Membrane depolarization in PC12 cells induces calcium influx via an L-type voltage-sensitive calcium channel (L-VSCC) and increases intracellular free calcium, which leads to tyrosine phosphorylation of epidermal growth factor (EGF) receptor and the associated adaptor protein, She. This activated EGF receptor complex then can activate mitogen-activated protein (MAP) kinase, as in nerve growth factor (NGF) receptor activation. In the present study, we investigated the role of EGF receptor in the signaling pathway initiated by membrane depolarization of PC12 cells. Prolonged membrane depolarization induced phosphorylation of extracellular signal-regulated kinase (ERK) within 1 min in undifferentiated PC12 cells. Pretreatment of PC12 cells with the calcium chelator EGTA abolished depolarization-stimulated ERK phosphorylation, but NGF-induced phosphorylation of ERK was not affected. The chronic treatment of phorbol ester, which down-regulated the activity of protein kinase C (PKC), did not affect the phosphorylation of ERK upon depolarization. In the presence of an inhibitor of EGF receptor, neither depolarization nor calcium ionophore increased the level of ERK phosphorylation. These data imply that the EGF receptor is functionally necessary to activate ERK and neurite outgrowth in response to the prolonged depolarization in PC12 cells, and also that PKC is apparently not involved in this signaling pathway.

• Molecules and Cells
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• v.19 no.1
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• pp.60-66
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• 2005

Low density lipoproteins (LDL) play important roles in the pathogenesis of atherosclerosis. Diabetes is associated with accelerated atherosclerosis leading to cardiovascular disease in diabetic patients. Although LDL stimulates the proliferation of arterial smooth muscle cells (SMC), the mechanisms are not fully understood. We examined the effects of native LDL and glycated LDL on the extracellular signal-regulated kinase (ERK) pathway. Addition of native and glycated LDL to rat aorta SMCs (RASMCs) stimulated ERK phosphorylation. ERK phosphorylation was not affected by exposure to the $Ca^{2+}$ chelator BAPTA-AM but inhibition of protein kinase C (PKC) with GF109203X, inhibition of Src kinase with PP1 ($5{\mu}M$) and inhibition of phospholipase C (PLC) with U73122/U73343 ($5{\mu}M$) all reduced ERK phosphorylation in response to glycated LDL. In addition, pretreatment of the RASMCs with a cell-permeable mitogen-activated protein kinase kinase (MEK) inhibitor (PD98059, $5{\mu}M$) markedly decreased ERK phosphorylation in response to native and glycated LDL. These findings indicate that ERK phosphorylation in response to glycated LDL involves the activation of PKC, PLC, and MEK, but is independent of intracellular $Ca^{2+}$.