• Biomolecules & Therapeutics
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• 제1권1호
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• pp.121-124
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• 1993

To elucidate the effect of antipsychotics and antidepressants on phosphoinositide(Pl) second massenger system, we studied the dose-dependent inhibition of the phosphoinositide-specific phospholipase C(PLC) isozymes, ${\beta}_1,\;{\gamma}_1$ and${\delta}_1,$ by fluphenazine and haloperidol as antipsychotics, and amitriptyline, maprotiline and mianserin as antidepressants. All the antipsychotics and antidepressants tested showed inhibition on at least one of the PLC isozymes with $IC_{50}$ at the concentration between 25 and $250 {\mu}M.$ Maprotiline, mianserin and amitriptyline inhibited 80 to 90% of the activities of all three PLC isozymes at the concentration of $250{\mu}M,$ while haloperidol and fluphenazine inhibited PLC ${\beta}_1$ and${\gamma}_1$ But baclofen didn't inhibit any PLC isozyme. These results suggested that PLC isozymes are inhibited by antipsychotics and antidepessants even though the concentration is high, and these drugs may affect PI signal transduction system by direct inhibition of PLC isozymes.

• The Korean Journal of Physiology and Pharmacology
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• 제1권4호
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• pp.385-392
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• 1997

The phospholipase C (PLC)-mediated intracellular signal transduction pathway is considered to be involved in the regulation of blood pressure. However, little information is available concerning the distributional and functional significance of PLC in the genetic hypertensive rats. As the first step of knowing the role of PLC on hypertension, we investigated the distribution of 6 PLC isozymes $(PLC-{\beta}1,\;-{\beta}3,\;-{\beta}4,\;-{\gamma}1,\;-{\gamma}2\;and\;-{\delta}1)$ in the heart and brain, which are concerned with hypertension, in the normotensive Wistar-Kyoto rat (WKY) and spontaneously hypertensive rat (SHR) using the western blotting and immunocytochemistry. The immunoreactivities of PLC isozymes in brain were detected, but there were no distributional and quantitative differences between the WKY and SHR. In the heart, but the immunoreactivities to $PLC-{\beta}1$ and $-{\gamma}2$ in the SHR were higher than those in WKY. In immunocytochemistry to confirm these western blotting data, $PLC-{\beta}1$ and $-{\gamma}2$ were localized in cardiac myocytes and the intensities of immunoreactivity in SHR were stronger than that in WKY. These results suggest that $PLC-{\beta}1$ and $-{\gamma}2$ would have possibility to concern with the establishment of spontaneous hypertension.

• 한국응용과학기술학회지
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• 제16권3호
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• pp.263-271
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• 1999

We checked the presence of phospholipase $A_2(PLA)_2$ which could split the ester bond at the position 2 in the glycerol backbone of glycerophospholipids, in the cells of hyperthermophiles of Pyrococcus horikoshii and Sulfolobus acidocaldarius. The results obtained are as follows; (1). Pyrococcus horikoshii cells were grown in obligate anaerobic conditions at $95^{\circ}C$ and they needed sulfur as energy source instead of oxygen, while Sulfolobus acidocaldarius species grew well in the aerobic medium (pH 2.5) containing yeast and sucrose at $75^{\circ}C$. (2). Pyrococcus horikoshii cells produced phospholipase $A_2$ in the cell culture media although this species did not show lipase activity at least in the pH range of 1.5 ${\sim}$ 3.5. Sulfolobus acidocaldarius cells produced lipase hydrolyzing triacylglycerols such as triolein, but did not split any kind of phospholipids used as substates. (3). The compound of 1-decanoyl-2-(p-nitrophenylglutaryl) phosphatidylcholine was not suitable for a substrate in this experiment, though frequently used as a subtrate for checking presence of phospholipase $A_2$, for its decomposi-tion in this experiment. The L-${\alpha}$-phosphatidylcholine-${\beta}$-[N-7-nitrobenz-2-oxa-1, 3-diazol]aminohexanoyl-${\gamma}$-hexadecanoyl labelled with a fluorescent material, did not show any migration of acyl chains in the molecule during the reaction with phospholipase $A_2$ under a hot condition. (4). Phospholipase $A_2$ in the cells of Pyrococcus horikoshii, showed the optimum activity at $pH6.7{\sim}7.2$ and $95{\sim}105^{\circ}C$, respectively, and was activated by addition of calcium chloride solution. Andthe phospholipase $A_2$ specifically hydrolyzed glycero-phospholipids such as phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl serine and phosphatidyl inositol, but could not split phospholipid containing ether bonds in the molecule such as DL -${\alpha}$-phosphatidylcholine-${\beta}$-palmitoyl-${\gamma}$-O-hexadecyl, DL-${\alpha}$-phosphati- dylcholine-${\beta}$- oleoyl-${\gamma}$-O-hexadecyl, DL-phosphatidylcholine-dihexadecyl.

• BMB Reports
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• 제33권2호
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• pp.97-102
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• 2000

Phosphoinositide-specific phospholipase C-${\gamma}1$ (PLC-${\gamma}1$) is a pivotal mediator in the signal transduction cascades induced by many growth factors. Using a yeast two-hybrid system, heat-shock protein 90 (Hsp90) was identified as a PLC-${\gamma}1$-binding protein. A co-immunoprecipitation experiment, using anti-PLC-${\gamma}1$ antibody, demonstrated an in vivo interaction between Hsp90 and PLC-${\gamma}1$ in the NIH-3T3 cells. The interaction in NIH-3T3 was unaffected by the PDGF treatment, inducing phosphorylation and activation of PLC-${\gamma}1$. Direct interaction between Hsp90 and PLC-${\gamma}1$ was confirmed by in vitro binding experiments using purified Hsp90 and PLC-${\gamma}1$. Furthermore, Hsp90 increased the $PIP_2$-hydrolyzing activity of PLC-${\gamma}1$ up to 2-fold at $0.1{\mu}M$ in vitro. Taken together, we show for the first time, the interaction of PLC-${\gamma}1$ with Hsp90, both in vivo and in vitro. We suggest that Hsp90 may play a role in PLC-${\gamma}1$-mediated signal transduction.

• Journal of Microbiology and Biotechnology
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• 제22권1호
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• pp.50-57
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• 2012

Phospholipase C-${\gamma}l$ (PLC-${\gamma}l$) expression is associated with cellular transformation. Notably, PLC-${\gamma}$ is up-regulated in colorectal cancer tissue and breast carcinoma. Because exotoxins released by Clostridium botulinum have been shown to induce apoptosis and promote growth arrest in various cancer cell lines, we examined here the potential of Clostridium difficile toxin A to selectively induce apoptosis in cells transformed by PLC-${\gamma}l$ overexpression. We found that PLC-${\gamma}l$-transformed cells, but not vector-transformed (control) cells, were highly sensitive to C. difficile toxin A-induced apoptosis and mitotic inhibition. Moreover, expression of the proapoptotic Bcl2 family member, Bim, and activation of caspase-3 were significantly up-regulated by toxin A in PLC-${\gamma}l$-transformed cells. Toxin A-induced cell rounding and paxillin dephosphorylation were also significantly higher in PLC-${\gamma}l$-transformed cells than in control cells. These findings suggest that C. difficile toxin A may have potential as an anticancer agent against colorectal cancers and breast carcinomas in which PLC-${\gamma}l$ is highly up-regulated.

• 생명과학회지
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• 제16권4호
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• pp.612-617
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• 2006

포스포리파제 C-감마1$(phospholipase\;C-{\gamma}\;1;\;PLC-{\gamma}\;1)$은 활성화될 경우 세포 내의 이차전령인 inositol 1,4,5-trisphosphate$(IP_3)$와 diacylglycerol(DG)을 생성하는 중요한 세포 신호전달 분자이다. 튜불린은 미세소관과 방추사의 주요 구성 단백질로서 알파형과 베타형의 두 가지 동위형이 있는데 이들은 모든 진핵세포에 존재하면서 이형 이합체를 형성한다. 이 중 베타형 튜불린은 사람의 경우 6종의 또 다른 동위형이 존재하는 것으로 밝혀졌는데 이들은 각 조직에서 그 발현양상이 서로 다르게 나타난다. 이전의 연구에서 우리들은 $PLC-{\gamma}\;1$과 4종의 베타튜불린 동위형 즉, ${\beta}1$, ${\beta}2$, ${\beta}3$ 및 ${\beta}6$이 세포 내에서 서로 결합할 수 있으며 또한 외부의 자극이 전달될 경우 이들 4종의 동위형이 $PLC-{\gamma}\;1$을 활성화시켜 준다는 사실을 보고한 바 있다. 이번 실험에서는 이전의 연구에서 조사하지 못하였던 베타 튜불린의 나머지 두 가지 동위형 즉, ${\beta}4$및 ${\beta}5$가 $PLC-{\gamma}\;1$에 결합하여 $PLC-{\gamma}\;1$의 활성을 증가시켜줌으로서 세포 내에서의 신호전달계를 조절하고 있음을 확인하였다. 이 결과는 이전의 연구결과와 연관 지워볼 때, 6종의 모든 베타형 튜불린은 세포 외부의 자극이 있을 경우 $PLC-{\gamma}\;1$을 활성화시켜줌을 시사한다.

• BMB Reports
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• 제28권5호
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• pp.387-391
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• 1995

In order to investigate whether phospholipase C (PLC) activity in oat celIs is regulated by Gprotein, we have characterized PLC in plasma membranes of oat tissues. To identify the purified plasma membrane, $K^+$-stimulated, $Mg^{2+}$-dependent ATPase activity was measured. The activity of ATPase was shown to be proportional to the concentration of membrane protein. To examine the PLC activity regulated by G-protein, we used the inside-out and outside-out plasma membrane mixture isolated from the oat cells. The plasma membrane mixture showed higher PLC activity than the one of the outside-out plasma membrane. This suggests that PLC activity is located at the cytoplasmic surface of plasma membrane. PLC activity in plasma membrane mixture was dependent on $Ca^{2+}$ with maximum activity at 100 ${\mu}m$ $Ca^{2+}$ and it was inhibited by 1 mM EGTA. Using Sep-pak $Accell^{TM}$ Plus QMA chromatography, we found that inositol 1,4,5-trisphosphate ($IP_3$) was produced in the presence of 10 ${\mu}m$ $Ca^{2+}$. The PLC activity in the membrane was enhanced by an activator of G-protein ($GTP{\gamma}S$) and not by an inhibitor ($GDP{\beta}S$). This indicates that a G-protein is involved in the activation of PLC in the plasma membrane of oat cells.

• 한국동물학회:뉴스레터
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• 제12권2호
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• pp.95.1-95
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• 1995

No Abstract, See Full Text

• 한국동물학회:학술대회논문집
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• 한국동물학회 1995년도 한국생물과학협회 학술발표대회
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• pp.223.1-223
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• 1995

No Abstract, See Full Text

• Biomolecules & Therapeutics
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• 제23권5호
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• pp.421-427
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• 2015

Imperatorin has been known to exert many biological functions including anti-inflammatory activity. In this study, we investigated the inhibitory effects of imperatorin on the production of inflammatory mediators in mouse bone marrow-derived mast cells (BMMC). Imperatorin inhibited degranulation and the generation of eicosanoids (leukotriene $C_4$ ($LTC_4$) and prostaglandin $D_2$ ($PGD_2$) in IgE/antigen (Ag)-stimulated BMMC. To elucidate the molecular mechanism involved in this process, we investigated the effect of imperatorin on intracellular signaling in BMMC. Biochemical analyses of the IgE/Ag-mediated signaling pathway demonstrated that imperatorin dramatically attenuated degranulation and the production of 5-lipoxygenase-dependent $LTC_4$ and cyclooxygenase-2-dependent $PGD_2$ through the inhibition of intracellular calcium influx/phospholipase $C{\gamma}1$, cytosolic phospholipase $A_2$/mitogen-activated protein kinases and/or nuclear factor-${\kappa}B$ pathways in BMMC. These results suggest that the effects of imperatorin on inhibition of degranulation and eicosanoid generation through the suppression of multiple steps of IgE/Ag-mediated signaling pathways would be beneficial for the prevention of allergic inflammation.