• 방사선산업학회지
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• 제5권1호
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• pp.15-20
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• 2011

Protein kinases are the most important drug targets for the treatment of numerous diseases. The involvement of protein kinase C (PKC) in many biological processes such as development, memory, cell differentiation, and proliferation has been demonstrated. PKC is recognized as an important player in carcinogenesis. Thus, a variety of PKC inhibitors have been investigated. Among them, flavonoids have been demonstrated to affect the activity of many mammalian in vitro enzyme systems. The recent investigation was performed to evaluate the inhibitory effects of hesperidin, which is a flavonoid, on the proliferation and carcinogenesis of many cancers. In this study, an efficient kinase assay based on a biochip using radio-phosphorylation was established and performed for an examination of the inhibitory effects of hesperidin on PKC activity at different concentrations of 50, 200, 500 nM. It was found that hesperidin shows inhibitory potency on PKC, and that the biochip can be used to rapidly screen kinase inhibitors resulting in the therapeutic agents.

• 한국동물학회지
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• 제35권3호
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• pp.277-286
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• 1992

개구리의 난자로 부터 maturation promoting factor(MPF)를 추출, 부분 분리하여 이들의 활성을 조사하고 이 물질의 생성과 protein kinase C(반KC)와의 관계를 조사하SB다. 성숙된 난자를 분쇄한 후 초원심분리과정을 거쳐 MPF의 crude extract(CE)를 얻은 다음 ultrafiltration (UF)과 고속액체크로마토그라피를 거쳐서 3종류의 분획 (peak 1, 11, and 111)을 얻었다. 이들 분획을 in nitro assay와 autoradiDgraphy를 사용하여 확인한 결과 분획 11에서 MPF 활성이 있는 것을 알았다. 분리 단계에 따라 MPF의 정제도를 Hl histone kinase assay로 조사한 결깍 UF를 거친 것은 CE보다 약 3배로, 분획 11에서는 약 117배로 증가한 것을 확인하였다. 또한 MPF분획의 인산화를 autoradiography로 조사한 결과 45 KD 단백질을 포함한 수종의 난자 단백질이 강하게 인산화되었음을 알 수 있었다. PKC의 활성화가 난자내 MPF의 생성을 유도하는가를 보기 위하여 PKC의 활성제인 12-0-tetradecanoyl phorbol 13 acetate(TPA)를 처리한 난자의 세포질 추출물을 미세주입 법으로 조사한 결과 TPA 처리 후 6시간부터 난자내 MPF의 활성이 나타나는 것을 알 수 있었다. 이러한 결과들은 PKC의 활성화가 MPF의 생성을 유도하고, MPF의 활성화와 함께 일부 단백질들의 인산화를 통하여 궁극적으로 난자 성숙을 촉진했음을 시사한다.

• 한국미생물·생명공학회지
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• 제21권1호
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• pp.54-58
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• 1993

미생물 대사산물로부터 phorbol ester에 의해 유도되는 K562 세포 표면의 소포형성 및 Protein kinase C(PKC)에 대한 저해제를 탐색하여 방선균 분리주 No.2007-18로 부터 용매추출 및 크로마토그래피의 기법을 이용하여 MT-2007을 분리하였다. MT-2007는 503.9MuM의 농도에서 phorbol 12,13-dibutylate에 의해 유도된 K562 세포표면의 bleb형성을 완전히 저해하였고, PKC 효소의 IC50 값은 31.4 MuM 이었다.

• The Korean Journal of Physiology and Pharmacology
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• 제12권5호
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• pp.259-265
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• 2008

$[Ca^{2+}]_i$ transients by reverse mode of cardiac $Na^+/Ca^{2+}$ exchanger (NCX1) were recorded in fura-2 loaded BHK cells with stable expression of NCX1. Repeated stimulation of reverse NCX1 produced a long-lasting decrease of $Ca^{2+}$ transients ('rundown'). Rundown of NCX1 was independent of membrane $PIP_2$ depletion. Although the activation of protein kinase C (PKC) was observed during the $Ca^{2+}$ transients, neither a selective PKC inhibitor (calphostin C) nor a PKC activator (PMA) changed the degrees of rundown. By comparison, a non-specific PKC inhibitor, staurosporine (STS), reversed rundown in a dose-dependent and reversible manner. The action of STS was unaffected by pretreatment of the cells with calphostin C, PMA, or forskolin. Taken together, the results suggest that the stimulation of reverse NCX1 by STS is independent of PKC and/or PKA inhibition.

• 약학회지
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• 제43권2호
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• pp.263-273
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• 1999

When glutamate was infected intrathecally, the result is similar to those produced by TPA injected. The involvement of protein kinase C (PKC) in the nociceptive responses in rat dorsal horn neurons of lumbar spinal cord was studied. In test with formalin, a PKC inhibitor (chelerythrine) inhibited dose-dependently the formalin-induced behavior response. Neomycin also inhibited it significantly. But, a PKC activator (12-O-tetradecanoylphorbol-13-ester, TPA) showed reverse effect. When gluatamate was injected intrathecally, we observed the result is smilar to those produced by TPA injection. On the other hand, intrathecal injection of glutamate induced thermal and mechanical hyperalgesia. In Tail-flick test, we examined the involvement of PKC on the glutamate-indeced thermal hyperalgesia. Chelerythrine showed an inhibitory effect and TPA enhanced thermal response. Glutamate decreased the mechanical threshold significantly. A pretreatment of chelerythrine and neomycin inhibited glutamate-induced mechanical hyperalgesia, but the effect of neomycin was not significant. TPA had little effect on the mechanical nociceptive response. These results suggest that the PKC activation through metabotropic receptor at postsynaptic region of spinal cord dorsal horn neurons may influence on the persistent nociception produced by chemical stimulation with formalin, thermal and mechanical hyperalgesia induced by glutamate.

• 대한수의학회지
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• 제39권6호
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• pp.1073-1080
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• 1999

Previous studies suggested that the inhibition of thyroxine ($T_4$) release by ${\alpha}_1$-adrenoceptor and muscarinic receptor stimulation results in activated protein kinase C (PKC) from mouse and guinea pig thyroids. In the present study, the effect of carbachol, methoxamine, phorbol myristate acetate (PMA), and R59022 on the release of $T_4$ from the mouse, rat, and guinea pig thyroids was compared to clarify the role of PKC in the regulation of the release of $T_4$. The thyroids were incubated in the medium containing the test agents, samples of the medium were assayed for $T_4$ by EIA kits. Forskolin, an adenylate cyclase activator, chlorophenylthio-cAMP sodium, a membrane permeable analog of cAMP, and isobutyl-methylxanthine, a phosphodiesterase inhibitor, like TSH (thyroid stimulating hormone), enhaced the release of $T_4$ from the mouse, rat, and guinea pig thyroids. Methoxamine, an ${\alpha}_1$-adrenoceptor agonist, inhibited the TSH-stimulated release of $T_4$ in mouse, but not rat and guinea pig thyroids. In contrast, carbachol, a muscarinic receptor agonist, inhibited the release of $T_4$ in guinea pig, but not mouse and rat thyroids. These inhibition were reversed by prazosin, an ${\alpha}_1$-adrenoceptor antagonist or atropine, a muscarinic antagonist or $M_1$- and $M_3$-muscarinic antagonists, in mouse or guinea pig thyroids. In addition, staurosporine, a PKC inhibitor, reversed methoxamine or carbachol inhibition of TSH stimulation. Furthermore, PMA, a PKC activator, and R59022, a diacylglycerol (DAG) kinase inhibitor, inhibited the TSH-stimulated release of $T_4$ in mouse, rat, and guinea pig thyroids. These inhibition were blocked by staurosporine. These findings suggest that the activation of receptor or DAG inhibits TSH-stimulated $T_4$ release through a PKC-dependent mechanism in thyroid gland.

• 대한수의학회지
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• 제38권3호
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• pp.508-517
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• 1998

There is evidence that the sympathetic nervous system exerts a control on thyroid function via an adrenergic innervation of thyroid cells. Although it is clear that the inhibitory effects of catecholamines result from an activation of ${\alpha}_1$-adrenoceptors, the mechanisms involved in ${\alpha}_1$-stimulation are not fully understood. The effects of methoxamine and protein kinase C (PKC) activator on the release of thyroxine ($T_4$) from mouse thyroid were studied to clarify the role of PKC in the regulation of $T_4$ release in vitro. The glands were incubated in the medium, samples of the medium were assayed for $T_4$ by EIA kits. Methoxamine inhibited the TSH-stimulated $T_4$ release. This inhibition was reversed by prazosin, an ${\alpha}_1$-adrenergic antagonist. Futhermore, the inhibitory effect of methoxamine on the $T_4$ release stimulated by TSH was prevented by chloroethylclonidine, an ${\alpha}_{1b}$-adrenoceptor antagonist, but not by WB4101, an ${\alpha}_{1a}$-adrenoceptor antagonist. Also methoxamine inhibited the forskolin-, cAMP- or IBMX-stimulated $T_4$ release. These inhibition were reversed by PKC inhibitors, such as staurosporine and $H_7$. PMA, a PKC activator, completely inhibited the TSH-stimulated $T_4$ release, and its inhibition was reversed by staurosporine and $H_7$, but not by chelerythrine. R59022 (a diacylglycerol kinase inhibitor), like methoxamine, also inhibited the TSH-stimulated $T_4$ release, and its inhibition was also reversed by staurosporine. The present study suggests that methoxamine inhibition of $T_4$ release from mouse thyroid can be induced by activation of the ${\alpha}_{1b}$-adrenoceptors and that it is mediated through the ${\alpha}_1$-adrenoceptor-stimulated PKC formation.

• Archives of Pharmacal Research
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• 제23권5호
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• pp.518-524
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• 2000

We examined the modulation of protein kinase C (PKC) subtypes during apoptosis induced by ginsenoside Rh2 (G-Rh2) in human neuroblastoma SK-N-Bl(2) and rat glioma C6Bu-1 cells. Apoptosis induced by C-Rh2 in both cell lines was confirmed, as indicated by DNA fragmentation and in situ strand breaks, and characteristic morphological changes. During apoptosis induced by G-Rh2 in SK-N-BE(2) cells, PKC subtypes $\alpha$, $\beta$ and $\gamma$ were progressively increased with prolonged treatment, whereas PKC $\delta$ increased transiently at 3 and 6 h and PKC $\varepsilon$ was gradually down-regulated after 6 h following the treatment. On the other hand, PKC subtype $\beta$ markedly increased at 24 h when maximal apoptosis was achieved. In C6Bu-l cells, no significant changes in PKC subtypes $\alpha$, $\gamma$, $\delta$, $\varepsilon$ and $\beta$ were observed during apoptosis induced by G-Rh2. These results suggest the evidence for a possible role of PKC subtype in apoptosis induced by G-Rh2 in SK-N-BE(2) cells but not in C6Bu-1 cells, and raise the possibility that G-Rh2 may induce apoptosis via different pathways interacting with or without PKC in different cell types.

• Asian-Australasian Journal of Animal Sciences
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• 제19권7호
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• pp.958-963
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• 2006

The effect of ginsenosides (GS) on germ cell proliferation was evaluated with a chicken ovarian germ-somatic cell coculture model and the mechanism involving protein kinase C (PKC) pathway was investigated. Ovarian cells were cultured in serum-free McCoy's 5A medium and challenged with GS alone or in combinations with PKC activator (phorbol 12-myristate 13-acetate, PMA) or inhibitor ($H_7$) for 48 h. The number of germ cells was counted and the proliferating cells were identified by immunocytochemistry of proliferating cell nuclear antigen (PCNA). Results showed that GS significantly increased germ cell proliferation and this stimulating effect was further increased by PMA, but inhibited by H7, in a dose-dependent manner. Moreover, GS-elevated PCNA expression and the PCNA -labeling index of germ cells displayed similar changes with the increased numbers of germ cells. These results indicated that GS stimulated proliferation of ovarian germ cells with involvement of the PKC-mediated system.

• 대한의생명과학회지
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• 제14권2호
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• pp.69-76
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• 2008

${\gamma}$-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system, and its actions are mediated by subtypes of GABA receptors named as $GABA_A$, $GABA_B,\;and\;GABA_C,\;GABA_A$, receptor consisting of ${\alpha},\;{\beta},\;{\gamma}\;and\;{\delta}$ subunits is a heterooligomeric ligand-gated chloride channel. This study was performed to investigate regulation of $GABA_A$ receptor by protein kinase C(PKC). Ion currents were recorded using gramicidine-perforated patch and whole cell patch clamp. mRNA encoding the subunits of PKC expressed in major pelvic ganglion (MPG) neurons was detected by using RT-PCR. The GABA-induced inward current was increased by PKC activators and decreased by PKC inhibitors, respectively. These effects were not associated with intracellular $Ca^{2+}$ and GAG (1-oleoyl-2-acetyl-sn-glycerol), a membrane permeable diacylglycerol (DAG) analogue. These results mean that the subfamily of PKC participating in activation of $GABA_A$ receptor would be an atypical PKC (aPKC). Among theses, ${\xi}$ isoform of aPKC was detected by RT-PCR. Taking together, we suggest that excitable $GABA_A$ receptor in sympathetic MPG neuron seemed to be regulated by aPKC, particular in ${\xi}$ isoform. The regulatory roles of PKC on excitatory $GABA_A$ receptors in sympathetic neurons of MPG may be an important factor to control the functional activity of various pelvic organs such as bowel movement, micturition and erection.