• Proceedings of the Korean Biophysical Society Conference
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• 1998.06a
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• pp.40-41
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• 1998

Acetylcholine-activated $K^{＋}$ ($K_{ACh}$) channels has been introduced as a typical G protein ( $G_{K}$)-coupled inwardly rectifying $K^{＋}$ (GIRK) channel, which constructs with four subunit composed of two types of GIRK isoforms, GIRK1 and GIRK4 (or CIR) for the atrial $K_{ACh}$ channel.(omitted)d)d)d)

• BMB Reports
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• v.50 no.4
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• pp.158-159
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• 2017

MicroRNAs (miRNAs) regulate gene expression by guiding the Argonaute (Ago)-containing RNA-induced silencing complex (RISC) to specific target mRNA molecules. It is well established that miRNAs are stabilized by Ago proteins, but the molecular features that trigger miRNA destabilization from Ago proteins remain largely unknown. To explore the molecular mechanisms of how targets affect the stability of miRNAs in human Ago (hAgo) proteins, we employed an in vitro system that consisted of a minimal hAgo2-RISC in HEK293T cell lysates. Surprisingly, we found that miRNAs are drastically destabilized by binding to seedless, non-canonical targets. We showed that miRNAs are destabilized at their 3' ends during this process, which is largely attributed to the conformational flexibility of the L1-PAZ domain. Based on these results, we propose that non-canonical targets may play an important regulatory role in controlling the stability of miRNAs, instead of being regulated by miRNAs.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.36-36
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• 2002

In the present study, we investigated effects of extracellular zinc (Zn$\^$2＋/) on T-type Ca$\^$2＋/ channel isoforms (${\alpha}$lG, ${\alpha}$lH, and ${\alpha}$lI) stably expressed in HEK 293 cells. Ca$\^$2＋/ currents were measured using 10 mM Ca$\^$2＋/ as a charge carrier under whole cell-ruptured patch configuration. Zn$\^$2＋/ blocked the ${\alpha}$lH currents with a 100- and 200-fold higher potency (IC$\sub$50/ = 2.5 ${\mu}$M) when compared with those for blockade of the ${\alpha}$1G and ${\alpha}$1I currents, respectively.(omitted)

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.53-58
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• 2011

Cysteine and histidine-capped water-dispersible ZnS:Mn nanocrystals (ZnS:Mn-Cys and ZnS:Mn-His) were synthesized and their effects on E. coli and human cells were investigated. Particle sizes of these nanocrystals were found from HR-TEM images to be 3.5 nm and 4.0 nm, respectively. Their solution photoluminescence spectra showed identical broad emission peaks at 580 nm. ZnS:Mn-His significantly suppressed the growth of E. coli at $100{\mu}g/mL$ and 1 mg/mL concentrations, something not observed with ZnS:Mn-Cys. Consistent with this, greater inhibition of cell proliferation and viability were observed in HEK293 and IMR90 cells in ZnS:Mn-His at $100{\mu}g/mL$ and 1 mg/mL concentrations.

• BMB Reports
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• v.44 no.6
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• pp.381-386
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• 2011

In the present study, we characterized the function of HS1-binding protein 3 (HS1BP3), which is mutated in essential tremor and may be involved in lymphocyte activation. We found that HS1BP3 localized to the mitochondria and endoplasmic reticulum partially. Overexpression of HS1BP3 induced apoptosis in HEK293T and HeLa cell lines. When these cell lines were transfected with HS1BP3, they exhibited nuclear DNA condensation, externalization of phosphatidylserine (PS), and cleavage of poly ADP ribose polymerase (PARP). Furthermore, suppression of HS1BP3 or HS1 expression attenuates HS1BP3 induced apoptosis. In addition, HS1BP3 enhanced activator protein 1 (AP-1)-mediated transcription in a dose-dependent manner. Therefore, we conclude that HS1BP3 regulates apoptosis via HS1 and stimulates AP-1-mediated transcription.

• Mass Spectrometry Letters
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• v.4 no.3
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• pp.41-46
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• 2013

The goal of this study is to find an experimental condition which enables us to perform enzymatic studies on the cellular behavior of PTEN (phosphatase and tensine homolog) through identification of molecular species of phosphatidylinositol 3,4,5-trisphosphates and their quantitative analysis in a mammalian cell line using mass spectrometry. We initially exployed a two-step extraction process using HCl for extraction of phosphatidylinositol 3,4,5-trisphosphates from two mammalian cell lines and further analyzed the extracted phosphatidylinositol 3,4,5-trisphosphates using tandem mass spectrometry for the identification of them. We finally quantified the concentration of phosphatidylinositol 3,4,5-trisphosphates using internal standard calibration. From these observation, we found that HEK 293-T cells is a good model to examine the enzymatic behavior of PTEN in a cell, and the minimum amount of phosphatidylinositol 3,4,5-trisphosphates is more than 50 pmol for quantification in a mass spectrometer. These results suggest that the well-optimized experimental conditions are required for the investigation of the cellular PTEN in terms of the catalytic mechanism and further for the detailed identification of cellular substrates.

• Animal cells and systems
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• v.15 no.2
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• pp.123-130
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• 2011

Transient receptor potential melastatin 7 (TRPM7) channels are novel $Ca^{2+}$-permeable non-selective cation channels that are ubiquitously expressed. Activation of TRPM7 channels has been shown to be involved in the survival of gastric cancer cells. Here we show evidence suggesting that TRPM7 channels play an important role in $Zn^{2+}$- mediated cellular injury. Using a combination of electrophysiology, pharmacological analysis, small interfering RNA (siRNA) methods and cell death assays, we showed that activation of TRPM7 channels augmented $Zn^{2+}$-induced apoptosis of AGS cells, the most common human gastric adenocarcinoma cell line. The $Zn^{2+}$-mediated cytotoxicity was inhibited by the non-specific TRPM7 blockers $Gd^{3+}$ or 2 aminoethoxydiphenyl borate (2-APB) and TRPM7 specific siRNA. In addition, we showed that overexpression of TRPM7 channels in HEK293 cells increased $Zn^{2+}$- induced cell injury. Thus, TRPM7 channels may represent a novel target for physiological disorders where $Zn^{2+}$ toxicity plays an important role.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.23-23
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• 2018

In this study, new titanium alloys were prepared by adding elements such as tantalum (Ta), zirconium (Zr) and the like to complement the biological, chemical and mechanical properties of titanium alloys. The Ti-40Ta-xZr ternary alloy was formed on the basis of Ti-40Ta alloy with the contents of Zr in the contents of 0, 3, 7 and 15 wt. %. Plasma electrolytic oxidation (PEO), which combines high-voltage sparks and electrochemical oxidation, is a novel method to form ceramic coatings on light metals such as Ti and its alloys. These oxide film produced by the electrochemical surface treatment is a thick and uniform porous form. It is also composed of hydroxyapatite and calcium phosphate-based phases, so it has the characteristics of bone inorganic, non-toxic and very high bioactivity and biocompatibility. Ti-40Ta-xZr alloys were homogenized in an Ar atmosphere at $1050^{\circ}C$ for 1 hour and then quenched in ice water. The electrochemical oxide film was applied by using a power supply of 280 V for 3 minutes in 0.15 M calcium acetate monohydrate ($Ca(CH_3COO)_2{\cdot}H_2O$) and 0.02 M calcium glycerophosphate ($C_3H_7CaO_6P$) electrolyte. A small amount of 0.0075M zinc acetate and magnesium acetate were added to the electrolyte to enhance the bioactivity. The mechanical properties of the coated surface of Ti-40Ta-xZr alloys were evaluated by Vickers hardness, roughness test, and elastic modulus using nano-indentation, and the surface wettability was evaluated by measuring the contact angle of the coated surface. In addition, cell activation and differentiation were examined by cell culture of HEK 293 (Human embryonic kidney 293) cell proliferation. Surface properties of the alloys were analyzed by scanning electron microscopy(FE-SEM), EDS, and X-ray diffraction analysis (XRD).

• Korean Journal of Medicinal Crop Science
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• v.15 no.6
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• pp.411-416
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• 2007

This study was performed to investigate the reduction of toxicity and improvement of anticancer activities from R. sachalinensis by ultra high pressure extracts process. The cytotoxicity on human kidney cell (HEK293) and human lung cell (HEL299) was showed below 20.4% and 21.6% as compare to normal extracts in adding 1.0 $mg/m{\ell}$ concentration. This showed that toxic materials through ultra high pressure processing is broken or degraded. Because bond such as hydrogen bond, electrostatic bond, Van der waals bond, the hydrophobic bond, can be broken by high pressure. The anticancer activity was also increased in over 7% by high pressure processing in A549, AGS, MCF-7 and Hep3B cells. The result showed that extraction by high pressure have low cytotoxicity and high anticancer activity. So, the high pressure extraction technology can play an important role in eruption of new material with high biological activity.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.509-515
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• 2021

In this study, poly lactic-co-glycolic acid (PLGA) nanoparticles (PNP) were prepared through double (w/o/w) emlusion and emulsifying solvent-evaporation technique using PLGA, which has biocompatibility and biodegradability. To maximize stability and bioavailability of the particles, chitosan-coated PLGA nanoparticles (CPNP) were prepared by charge interaction between PNP and chitosan. We demonstrated that CPNP can be utilized as a drug carrier of oral administration. The chemical structure of CPNP was analyzed by ¹H-NMR and FT-IR, and all characteristic peaks appeared, confirming that it was successfully prepared. In addition, particle size and zeta potential of CPNP were analyzed using dynamic light scattering (DLS) while morphological images were obtained using transmission electron microscope (TEM). Thermal decomposition behavior of CPNP was observed through thermogravimetric analysis (TGA). In addition, the cytotoxicity of CPNP was confirmed by MTT assay at HEK293 and L929 cell lines, and it was proved that there is no toxicity confirmed by the cell viability of above 70% at all concentrations. These results suggest that the CPNP developed in this study may be used as an oral drug delivery carrier.