• Microbiology and Biotechnology Letters
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• v.42 no.1
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• pp.89-92
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• 2014

The Wnt/${\beta}$-catenin pathway plays important roles in a variety of biological processes, such as cell proliferation, differentiation, and organ development. Here, we used a cell-based reporter assay to identify bryostatin-1, a natural macrocyclic lactone, as an inhibitor of the Wnt/${\beta}$-catenin pathway. Bryostatin-1 suppressed ${\beta}$-catenin response transcription (CRT), which was activated by a Wnt3a-conditioned medium (Wnt3a-CM), through a decrease in the intracellular ${\beta}$-catenin protein levels, without affecting its mRNA level. In addition, pharmacological inhibition of proteasome abrogated bryostatin-1-mediated down-regulation of the ${\beta}$-catenin protein level. Our findings suggest that bryostatin-1 attenuates the Wnt/${\beta}$-catenin pathway through the promotion of proteasomal degradation of ${\beta}$-catenin.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.325-328
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• 2001

정상적인 뉴런의 활성전위는 외부에서 일정한 자극이 인가되었을 때 세포막을 기준으로 하여 각 이온간의 농도 차에 의해 발생한다. 최근에 관심이 되어지고 있는 쇼크에 의한 세포가 손상이 발생할 경우, 즉 신호를 받아들이고 전달하는 뉴런 중에서 축색에 이온채널이 이상증세를 발생하면 신경 전달 흐름을 흐트러지게 하여 이웃한 정상세포에게 커다란 영향을 미치게 된다. 이것은 병리학적인 중요한 역할을 하는 축색 내에 이상이 발생하였다고 가정을 하지만 이 가정을 뒷받침 해 주는 증거는 매우 적다고 보고되고 있다. 최근 연구에서 손상된 축색의 모델은 쇼크이후에 이온의 칼륨 채널에 blocking 현상이 발생하여 나트륨 이온이 다수 유입됨을 고려하고있다. 이에 본 연구에서는 쇼크나 충격에 의해 축색의 손상을 입을 경우 운동신경의 변형으로부터 병리학적인 중요한 이상결과를 일으킬 수 있는 상태를 고려하여 신경모델을 설계해 시뮬레이션 해 보았다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.175-176
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• 2000

PtdIns(4)P와 PtdIns(4,5)P$_2$등과 같은 폴리포스이노시타이드(Polyphosph-oinositide)는 여러 가지 호르몬 및 성장인자들에 의한 세포의 신호전달기작에 있어서 중요한 역할을 한다. 이들은 세포내 여러효소 및 단백질의 활성을 조절하기도 하고, cofilin(1), destrin(2), $\alpha$-actinin(3), gCap39(4) 및 CapZ등과 같은 여러 actin binding protein들의 성질을 변화시키기도 한다. (중략)

• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.363-367
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• 1994

In an effort to investigate the role of calmodulin (CaM) as a modulating molecule in the signal transduction system in plant cells, we established methods for introduction of purified CaM into cultured soybean cells. CaM was purified from bovine testis, and was labelled with fluorescein isothiocyanate (FITC). Suspension -cultured cells were healed with saponin (0.1 mg/mL) to permeabilize the plasma membrane and coincubated with FITC-CaM complex. Saponin pretreatment was found to increase the fluorescence in the suspension cultured cells, indicating that the FITC-CaM complex could be incorporated into the cytoplasm. Optimal conditions for introducing FITC-CaM complex into protoplasts by electroporation were established with various electric pulses. With increasing field strength, the fluorescence in the protoplase was increased, while the viability of the protoplase decreased. FITC-CaM complex was successfully introduced into the protoplasts by electroporation and the amount of FITC-CaM complex in the protoplase was estimated.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.355-363
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• 2009

Increased oxidative stress by abnormal mitochondrial function can damage cell signal transduction and gene expression, and induce insulin resistance or diabetes. Autophagy, however, improve insulin resistance by clearance of malfunctioning mitochondria. Exercise also recovers the muscle dysfunction and degeneration by activating mitochondrial biogenesis. As it seems that exercise and autophagy might act as an orchestrated network to induce mitochondrial biogenesis, we investigated whether autophagy is involved in AMPK signal pathway stimulated by exercise or AICAR to increase mitochondrial biogenesis. And it showed that PGC-1 and mtTFA, but not autophagy marker LC3 mRNA expression were significantly increased by 6 hr of acute exercise. On the other hand, PGC-1 and mtTFA mRNA expression were upregulated by AICAR treatment to C2C12 myotube. However these genes were not inhibited by LC3 siRNA transfection. These results provide the evidence that autopahgy affects on mitochondrial biogenesis through different signal pathway from AMPK signal transduction.

• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.73-80
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• 2009

G protein-coupled receptors(GPCRs) family is a cell membrane protein, and plays an important role in a signaling mechanism which transmits external signals through cell membranes into cells. But, GPCRs each are known to have various complex control mechanisms and very unique signaling mechanisms. Structural features, and family and subfamily of GPCRs are well known by function. and accordingly, the most fundamental work in studies identifying the previous GPCRs is to classify the GPCRs with given protein sequences. Studies for classifying previously identified GPCRs more easily with mathematical models have been mainly going on. In this paper Considering that functions of proteins are determined by their stereoscopic structures, the present paper proposes a method to compare secondary structures of two GPCRs having different amino acid sequences, and then detect an unknown GPCRs assumed to have a same function in databases of previously identified GPCRs.

• KSBB Journal
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• v.17 no.1
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• pp.110-113
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• 2002

Studies were made to examine the various effects of jasmonic acid and benzoic acid on ginsenoside production in suspension cultures of Panax ginseng C. A. Meyer. Jasmonic acid increased the ginsenoside production when it was dosed at the concentration of 50 $\mu$M or higher. The cell growth, however, was reduced with jasmonic acid. When benzoic acid was dosed simultaneously with iasmonic acid, the ginsenoside production increased 9.6 folds. It was 2.2 times higher than the result of single dose of jasmonic acid.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.3
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• pp.254-261
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• 2000

The present study has attempted to look into the mechanism of ras-induced carcinogenesis in a human epithelial cell system. Human epithelial cells immortalized with Ad12-SV40 hybrid virus were used to assess carcinogenic potential of the ras-oncogene. Cells transfected with pSV2-ras showed characteristics of cellular transformation. The transformation parameters such as cell density, soft-agar colony formation, and cell aggregation were significantly increased in the cells expressing ras oncoprotein. In addition, the duration required for the appearance of foci was shortened in the ras-transfected cells. Consistent with other reports, our results demonstrated an evidence that the ras-oncogene induced the cellular transformation of human epithelial cell system. When a high concentration of glucocorticoid was added into the media, transformation process was accelerated. It is speculated that glucocorticoid may provide an advantageous environment for the proliferation of the transformed cells. The induction of the intracellular free calcium concentrations following agonist treatment was significantly lower in the transformed cells than in the control cells. These effects were more manifested in the presence of extracellular cacium, indicating that the transformation process may alter the influx pathway of extracellular calcium. The induction of $IP_3$ following agonist treatment was also lower in the transformed cells than in the control cells. Thus, it is suggested that phospholipase C-coupled pathway was down-regulated in the process of the ras-induced transformation. While the levels of $TGF-{\beta}_1$ and PAI-2 mRNAs were decreased, the level of fibronectin mRNA was increased. The results indicate that mechanism of the ras-induced transformation may be associated with the altered expressions of growth regulatory factors. The present study demonstrates an evidence that the ras-induced cellular transformation may be associated with alteration of signal transduction and growth regulatory factors. The study will contribute to improve the understanding of molecular mechanism of epithelium-derived cancers including oral cancer.

• Journal of Life Science
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• v.22 no.3
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• pp.428-436
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• 2012

Protein phosphorylation is a universal mechanism that regulates cellular activities. The brassinosteroid (BR) signal transduction pathway is a relay of phosphorylation and dephosphorylation cascades. It starts with the BR-induced activation of the membrane receptor kinase brassinosteroid insensitive 1 (BRI1), resulting in the dephosphorylation of transcription factors such as BZR1/BES2 and BZR2/BES1 followed by BR-induced gene expression. Brassinosteroid signal transduction research has progressed rapidly by identifying the phosphorylation/dephosphorylation site(s) of the BR-regulated kinase and phosphatase substrates with a simultaneous pursuit of mutant phenotypes. Autophosphorylation, transphosphorylation, and serine/threonine and tyrosine phosphorylation of the receptor protein kinases BRI1 and BRI1-associated kinase (BAK1) have increased the understanding of the regulatory role of those kinases during physiological and developmental processes in plants. The phosphorylation event initiated by BR is also found in the regulation of receptor-mediated endocytosis and the subsequent degradation of the receptor. However, the basic molecular links of the BR signal transduction pathway are not well understood regarding this phosphorylation/dephosphorylation event. This review summarizes the current state of BR signal transduction research to uncover the phosphorylation/dephosphorylation networks and suggests directions for future research on steroid signal transduction to gain a more comprehensive understanding of the process.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.274-274
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• 1994

본 연구에서는 토끼신장 근위세뇨관 일차배양세포에서 브라디키닌의 생리작용이 phospholipase D (PLD)에 의해 매개되는지를 살펴 보기위해 PLD 효소반응의 특이한 성질인 transphosphatidylation 반응의 생성물인 phosphatidylethanol (PEth) 의 세포내 양을 측정함으로 PLD 효소의 관련성을 규명할 수 있었다. 시간경과에 따른 phosphatidic acid (PA) 및 diacylglycerol (DAG) 의 생성을 살펴본 결과 PA가 DAG보다 먼저 생성되어 최고치 (30초)에 도달하였고 DAG는 1분이후부터 5분까지 서서히 생성되는 양상을 나타내었다. 또한 0.5에서 5％까지의 에탄올 존재하에 PA 및 PE소 생성량을 비교해본 결과 에탄올량이 증가함에 따라 PA는 감소하는 반민 PEth 의 생성은 계속 증가하였다. 한편 브라디키닌 농도 변화 실험에서는 브라디키닌농도가 증가함에 따라 PA 및 PEth 둘다 생성이 증가되었다. 이러한 결과로부터 토끼신장 근위세뇨관 세포막에 존재하는 브라디키닌수용체는 브라디키닌에 의해 activation 시 PLD를 직접적으로 활성화시켜 그들의 작용을 세포내로 전달한다는 사실을 알 수 있었다. 또한 PLD 효소활성의 activator로 수용체효능 제외에 칼슘이온, protein kinase C (PKC) 등이 몇몇 다른 실험에 의해 밝혀져 있고, G protein 역시 PLD 효소 활성을 조절하는 역할이 있음이 알려졌다. calcium ionophore 및 칼슘채널길항제인 verapamil을 이용한 실험에서 우리는 브라디키닌의 PLD 활성화는 칼슘이온에 의존적인 경로 및 비의존적인 경로가 같이 존재함을 알수 있었다. 또한 브라디키닌의 PLD 활성화기전이 PKC 의존적인지를 살펴보기위해 PKC activator(PMA) 및 inhibitor (staurosporine)를 이용한 실험에서 브라디키닌은 신장세포에서 PKC를 통하여 PLD를 활성화시킴으로 신호전달을 하는 것으로 추측되었다. 마지막으로 가수분해안되는 G protein 유도체인 GTPrS 및 G protein 활성물질 NaF, 백일해독소등을 이용한 실험에서 G protein 의 PLD 조절활성을 확인할 수 있었다.