• Journal of Ginseng Research
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• 제43권4호
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• pp.527-538
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• 2019

Background: Ginsenoside Rg1 was shown to exert ligand-independent activation of estrogen receptor (ER) via mitogen-activated protein kinase-mediated pathway. Our study aimed to delineate the mechanisms by which Rg1 activates the rapid ER signaling pathways. Methods: ER-positive human breast cancer MCF-7 cells and ER-negative human embryonic kidney HEK293 cells were treated with Rg1 ($10^{-12}M$, $10^{-8}M$), $17{\beta}$-estradiol ($10^{-8}M$), or vehicle. Immunoprecipitation was conducted to investigate the interactions between signaling protein and ER in MCF-7 cells. To determine the roles of these signaling proteins in the actions of Rg1, small interfering RNA or their inhibitors were applied. Results: Rg1 rapidly induced $ER{\alpha}$ translocation to plasma membrane via caveolin-1 and the formation of signaling complex involving linker protein (Shc), insulin-like growth factor-I receptor, modulator of nongenomic activity of ER (MNAR), $ER{\alpha}$, and cellular nonreceptor tyrosine kinase (c-Src) in MCF-7 cells. The induction of extracellular signal-regulated protein kinase and mitogen-activated protein kinase kinase (MEK) phosphorylation in MCF-7 cells by Rg1 was suppressed by cotreatment with small interfering RNA against these signaling proteins. The stimulatory effects of Rg1 on MEK phosphorylation in these cells were suppressed by both PP2 (Src kinase inhibitor) and AG1478 [epidermal growth factor receptor (EGFR) inhibitor]. In addition, Rg1-induced estrogenic activities, EGFR and MEK phosphorylation in MCF-7 cells were abolished by cotreatment with G15 (G protein-coupled estrogen receptor-1 antagonist). The increase in intracellular cyclic AMP accumulation, but not Ca mobilization, in MCF-7 cells by Rg1 could be abolished by G15. Conclusion: Ginsenoside Rg1 exerted estrogenic actions by rapidly inducing the formation of ER containing signalosome in MCF-7 cells. Additionally, Rg1 could activate EGFR and c-Src ER-independently and exert estrogenic effects via rapid activation of membrane-associated ER and G protein-coupled estrogen receptor.

• Journal of Microbiology
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• 제42권4호
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• pp.328-335
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• 2004

The human immunodeficiency virus type 1 (HIV-I) Tat protein transduction domain (PTD), which con­tains rich arginine and lysine residues, is responsible for the highly efficient transduction of protein through the plasma membrane. In addition, it can be secreted from infected cells and has the ability to enter neighboring cells. When the PTD of Tat is fused to proteins and exogenously added to cells, the fusion protein can cross plasma membranes. Recent reports indicate that the endogenously expressed Tat fusion protein can demonstrate biodistribution of several proteins. However, intercellular transport and protein transduction have not been observed in some studies. Therefore, this study exam­ined the intercellular transport and protein transduction of the Tat protein. The results showed no evi­dence of intercellular transport (biodistribution) in a cell culture. Instead, the Tat fusion peptides were found to have a significant effect on the transduction and intercellular localization properties. This sug­gests that the HIV-1 PTD passes through the plasma membrane in one direction.

• 생명과학회지
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• 제14권6호
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• pp.986-990
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• 2004

2002년 5월에서 7월사이 한국 근해로부터 총 가검물 50례 중에서 V. vulnificus은 5균주가 분리되었고, API 20E kit의동정률이 $89.4\~93.7\%$로 나타났다. V. vulnificus 16S rDNA를 증폭하여 얻은 산물을 cloning하여 염기서열을 결정하고 분석한 결과 V. vulnificus로 확인되었다. 동정된 분리균주들의 cell lysates을 SDS-PAGE로 분석하였고 표준균주로 사용된 V. vulnificus ATCC 27562와 분리 균주들을 비교해 본 결과 단백밴드pattern이 많은 차이를 보였으나 외막단백질은 V. vulnificus간에는 공통의 밴드가 확인되었으나 V. parahaemolyticus 와는 차이를 보였다.

• Journal of Microbiology and Biotechnology
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• 제31권12호
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• pp.1615-1623
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• 2021

Picropodophyllotoxin (PPT), an epimer of podophyllotoxin, is derived from the roots of Podophyllum hexandrum and exerts various biological effects, including anti-proliferation activity. However, the effect of PPT on colorectal cancer cells and the associated cellular mechanisms have not been studied. In the present study, we explored the anticancer activity of PPT and its underlying mechanisms in HCT116 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to monitor cell viability. Flow cytometry was used to evaluate cell cycle distribution, the induction of apoptosis, the level of reactive oxygen species (ROS), assess the mitochondrial membrane potential (Δψm), and multi-caspase activity. Western blot assays were performed to detect the expression of cell cycle regulatory proteins, apoptosis-related proteins, and p38 MAPK (mitogen-activated protein kinase). We found that PPT induced apoptosis, cell cycle arrest at the G1 phase, and ROS in the HCT116 cell line. In addition, PPT enhanced the phosphorylation of p38 MAPK, which regulates apoptosis and PPT-induced apoptosis. The phosphorylation of p38 MAPK was inhibited by an antioxidant agent (N-acetyl-L-cysteine, NAC) and a p38 inhibitor (SB203580). PPT induced depolarization of the mitochondrial inner membrane and caspase-dependent apoptosis, which was attenuated by exposure to Z-VAD-FMK. Overall, these data indicate that PPT induced G1 arrest and apoptosis via ROS generation and activation of the p38 MAPK signaling pathway.

• 한국자기공명학회논문지
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• 제18권2호
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• pp.58-62
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• 2014

Human transmembrane proteins (hTMPs) are closely related to transport, channel formation, signaling, cell to cell interaction, so they are the crucial target of modern medicinal drugs. In order to study the structure and function of these hTMPs, it is important to prepare reasonable amounts of proteins. However, their preparation is seriously difficult and time-consuming due to insufficient yields and low solubility of hTMPs. We tried to produce large amounts of Syndecan-4 transmembrane domain (Syd4-TM) that is related to the healing wounds and tumor for a long time. In this study, we performed the structure determination of Syd4-TM combining the Polarity Index at Slanted Angle (PISA) wheel pattern analysis based on $^{15}N-^1H$ 2D SAMPI-4 solid-state NMR of expressed Syd4-TM and Molecular Dynamics (MD) simulation using Discovery Studio 3.1.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.28-37
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• 2016

Numerous plants have been documented to contain phenolic compounds. Thymol is one among these phenolic compounds that possess a repertoire of pharmacological activities, including anti-inflammatory, anticancer, antioxidant, antibacterial, and antimicrobial effects. Despite of the plethora of affects elicited by thymol, its activity profile on gastric cancer cells is not explored. In this study, we discovered that thymol exerts anticancer effects by suppressing cell growth, inducing apoptosis, producing intracellular reactive oxygen species, depolarizing mitochondrial membrane potential, and activating the proapoptotic mitochondrial proteins Bax, cysteine aspartases (caspases), and poly ADP ribose polymerase in human gastric AGS cells. The outcomes of this study displayed that thymol, via an intrinsic mitochondrial pathway, was responsible for inducing apoptosis in gastric AGS cells. Hence, thymol might serve as a tentative agent in the future to treat cancer.

• Biomolecules & Therapeutics
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• 제22권6호
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• pp.519-524
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• 2014

We have previously shown that 2,4,3',5'-tetramethoxystilbene (TMS), a trans-stilbene analogue, induces apoptosis in human cancer cells. However, the detailed mechanisms of mitochondria-dependent apoptosis induced by TMS are not fully understood. In the present study, the possible roles of annexin A5 in TMS-mediated apoptosis were investigated in MCF7 human breast cancer cells. Quantitative real-time PCR analysis and Western blot analysis showed that the expression of annexin A5 was strongly increased in TMS-treated cells. TMS caused a strong translocation of annexin A5 from cytosol into mitochondria. Confocal laser scanning microscopic analysis clearly showed that TMS induced translocation of annexin A5 into mitochondria. TMS increased the expression and oligomerization of voltage-dependent anion channel (VDAC) 1, which may promote mitochondria-dependent apoptosis through disruption of mitochondrial membrane potential. When cells were treated with TMS, the levels of Bax, and Bak as well as annexin A5 were strongly enhanced. Moreover, we found that the cytosolic release of apoptogenic factors such as cytochrome c, or apoptosis-inducing factor (AIF) in mitochondria was markedly increased. Annexin A5 depletion by siRNA led to decreased proapoptotic factors such as Bax, Bak, and annexin A5. Taken together, our results indicate that annexin A5 may play an important role in TMS-mediated mitochondrial apoptosis through the regulation of proapoptotic proteins and VDAC1 expression.

• Biomolecules & Therapeutics
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• 제27권1호
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• pp.41-47
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• 2019

The apoptotic effects of shikonin (5,8-dihydroxy-2-[(1R)-1-hydroxy-4-methylpent-3-enyl]naphthalene-1,4-dione) on the human colon cancer cell line SNU-407 were investigated in this study. Shikonin showed dose-dependent cytotoxic activity against SNU-407 cells, with an estimated $IC_{50}$ value of $3{\mu}M$ after 48 h of treatment. Shikonin induced apoptosis, as evidenced by apoptotic body formation, sub-G_1$ phase cells, and DNA fragmentation. Shikonin induced apoptotic cell death by activating mitogen-activated protein kinase family members, and the apoptotic process was mediated by the activation of endoplasmic reticulum (ER) stress, leading to activation of the $PERK/elF2{\alpha}/CHOP$ apoptotic pathway, and mitochondrial $Ca^{2+}$ accumulation. Shikonin increased mitochondrial membrane depolarization and altered the levels of apoptosis-related proteins, with a decrease in B cell lymphoma (Bcl)-2 and an increase in Bcl-2-associated X protein, and subsequently, increased expression of cleaved forms of caspase-9 and -3. Taken together, we suggest that these mechanisms, including MAPK signaling and the ER- and mitochondria-mediated pathways, may underlie shikonin-induced apoptosis related to its anticancer effect.

• BMB Reports
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• 제56권3호
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• pp.172-177
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• 2023

BEST family is a class of Ca²⁺-activated Cl- channels evolutionary well conserved from bacteria to human. The human BEST paralogs (BEST1-BEST4) share significant amino acid sequence homology in the N-terminal region, which forms the transmembrane helicases and contains the direct calcium-binding site, Ca²⁺-clasp. But the cytosolic C-terminal region is less conserved in the paralogs. Interestingly, this domain-specific sequence conservation is also found in the BEST1 orthologs. However, the functional role of the C-terminal region in the BEST channels is still poorly understood. Thus, we aimed to understand the functional role of the C-terminal region in the human and mouse BEST1 channels by using electrophysiological recordings. We found that the calcium-dependent activation of BEST1 channels can be modulated by the C-terminal region. The C-terminal deletion hBEST1 reduced the Ca²⁺-dependent current activation and the hBEST1-mBEST1 chimera showed a significantly reduced calcium sensitivity to hBEST1 in the HEK293 cells. And the C-terminal domain could regulate cellular expression and plasma membrane targeting of BEST1 channels. Our results can provide a basis for understanding the C-terminal roles in the structure-function of BEST family proteins.

• Journal of Yeungnam Medical Science
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• 제3권1호
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• pp.41-48
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• 1986

사람의 적혈구막으로부터 Band 3를 분리정제하고 이를 liposome 내로 도입시켜 그 결과를 관찰하였다. 적혈구를 약알칼리 저장액으로 용혈시켜 막을 분리한 후, 저이온강도 용액으로 처리하여 Band 4를 추출하였다. Triton X-100 추출액에 p-chloromercuribenzoate를 가하고 sucrose density gradient ultracentrifugation후 fractionation하여 Band 3를 정제하였다. phosphatidyl L-serine과 cholesterol을 1 : 1 molar ratio로 섞고 진공회전 증발기를 사용하여 chloroform을 제거한 후 Triton X-100을 제거한 Band 3용액을 가하고 sonication함으로 liposome(reverse-phase evaporation vesicle)을 만들면서 Band 3를 도입 시켰다 Band 3의 분리정제 및 liposome에 도입되었음은 sodium dodecyl sulfate-polyacrylamide gel 전기영 동 후 coomassie brilliant blue 염색으로 확인할 수 있었다.