• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.714-718
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• 2014

Apoptosis is the process of programmed cell death executed by specific proteases, the caspases, which mediate the cleavage of various vital proteins. Elucidating the consequences of this endoproteolytic cleavage is crucial to understanding cell death and other related biological processes. Although a number of possible roles for caspase-6 have been proposed, the identities and functions of proteins that interact with caspase-6 remain uncertain. In this study, we established a cell line expressing tandem affinity purification (TAP)-tagged caspase- 6 and then used LC-MS/MS proteomic analysis to analyze the caspase-6 interactome. Eight candidate caspase-6-interacting proteins were identified. Of these, five proteins (hnRNP-M, DHX38, ASPP2, MTA2, and UACA) were subsequently examined by co-immunoprecipitation for interactions with caspase-6. Thus, we identified two novel members of the caspase-6 interactome: hnRNP-M and MTA2.

• The Journal of Internal Korean Medicine
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• v.32 no.1
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• pp.33-42
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• 2011

Background : Despite recent advances in cancer management, prognosis of ovarian cancer is poor. Anticancer effects of herbal medicine, such as Euonymus alatus Sieb, Oldenlandia diffusa (Willd.) Roxburgh, and Orostachys japonicus A. Berger, have been reported in treatment of ovarian and cervical cancers, but the systematic approaches to explain their molecular mechanism(s) have not yet been established. Objectives : To establish a basis of understanding for anti-cancer mechanisms of herbal medicine, we profiled protein expression in human ovarian and cervical cancer cells treated with the extracts from Euonymus alatus Sieb, Oldenlandia diffusa (Willd.) Roxburgh and Orostachys japonicus A. Berger. Methods : Human ovarian cancer cell line NIH:OVCAR-3, and human cervical cancer cell line HeLa were employed in the present study. Whole protein was obtained from the cells harvested at 48 hours after the treatment with herbal water-extract, and analyzed by 2DE-based proteomic approach. Results : Various changes of protein expression induced by the herbal treatment were monitored : down-regulation of molecular chaperone (calreticulin variant), glycolytic enzymes (D-3-phosphoglycerate dehydrogenase, glyceraldehyde 3-phosphate dehydrogenase and alpha-enolase), RNA processing molecules (hnRNP A2/B1), and antioxidant protein (peroxiredoxin 1). Conclusions : Repression of glycolysis has been accepted as the mechanism to increase anticancer reagent's effect. Thus, down-regulation of glycolytic enzymes by the herbal extracts suggested a possible synergistic effect of herbs in the presence of platinum-based therapeutics. In further study, as well as the synergistic effect of the herbs, it has to be further validated whether artificial regulation of hnRNP A2/B1 in ovarian cancer cells affects various cancer survival factors, since RNA processing can be interrupted by deranged expression of hnRNP subtypes, and it results in an inhibition of cancer cell growth.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.198.1-198
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• 2000

No Abstract, See Full Text

• BMB Reports
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• v.50 no.9
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• pp.466-471
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• 2017

The results of this study show that c-Jun N-terminal kinase (JNK) activation was associated with the enhancement of docetaxel-induced cytotoxicity by simvastatin in DU145 human prostate cancer cells. To better understand the basic molecular mechanisms, we investigated simvastatin-regulated targets during simvastatin-induced cell death in DU145 cells using two-dimensional (2D) proteomic analysis. Thus, vimentin, Ras-related protein Rab-1B (RAB1B), cytoplasmic hydroxymethylglutaryl-CoA synthase (cHMGCS), thioredoxin domain-containing protein 5 (TXNDC5), heterogeneous nuclear ribonucleoprotein K (hnRNP K), N-myc downstream-regulated gene 1 (NDRG1), and isopentenyl-diphosphate Delta-isomerase 1 (IDI1) protein spots were identified as simvastatin-regulated targets involved in DU145 cell death signaling pathways. Moreover, the JNK inhibitor SP600125 significantly inhibited the upregulation of NDRG1 and IDI protein levels by combination treatment of docetaxel and simvastatin. These results suggest that NDRG1 and IDI could at least play an important role in DU145 cell death signaling as simvastatinregulated targets associated with JNK activation.

• Molecules and Cells
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• v.38 no.2
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• pp.163-170
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• 2015

Lipoteichoic acid (LTA) is a major component of the cell wall of Gram-positive bacteria. Its effects on living organisms are different from those of lipopolysaccharide (LPS) found in Gram-negative bacteria. LTA contributes to immune regulatory effects including anti-aging. In this study, we showed that LTA isolated from Lactobacillus plantarum (pLTA) inhibited melanogenesis in B16F10 mouse melanoma cells. pLTA reduced the cellular activity of tyrosinase and the expression of tyrosinase family members in a dose-dependent manner. The expression of microphthalmia- associated transcription factor (MITF), a key factor in the synthesis of melanin, was also decreased by pLTA. Further, we showed that pLTA activated melanogenesis signaling, such as extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinse (PI3K)/AKT. In addition, the expression of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and HuR, which are important RNA-binding proteins (RBPs), was reduced. pLTA likely degrades MITF via regulation of melanogenic signaling and RNA stability of melanogenic proteins, resulting in the reduction of melanin. Thus, our data suggest that pLTA has therapeutic potential for treating hyperpigmentation disorders and can also be used as a cosmetic whitening agent.

• Molecules and Cells
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• v.41 no.10
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• pp.909-916
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• 2018

In pancreatic ${\beta}$ cells, glucose stimulates the biosynthesis of insulin at transcriptional and post-transcriptional levels. The RNA-binding protein, polypyrimidine tract-binding protein 1 (PTBP1), also named hnRNP I, acts as a critical mediator of insulin biosynthesis through binding to the pyrimidine-rich region in the 3'-untranslated region (UTR) of insulin mRNA. However, the underlying mechanism that regulates its expression in ${\beta}$ cells is unclear. Here, we report that glucose induces the expression of PTBP1 via the insulin receptor (IR) signaling pathway in ${\beta}$ cells. PTBP1 is present in ${\beta}$ cells of both mouse and monkey, where its levels are increased by glucose and insulin, but not by insulin-like growth factor 1. PTBP1 levels in immortalized ${\beta}$ cells established from wild-type (${\beta}IRWT$) mice are higher than levels in ${\beta}$ cells established from IR-null (${\beta}IRKO$) mice, and ectopic re-expression of IR-WT in ${\beta}IRKO$ cells restored PTBP1 levels. However, PTBP1 levels were not altered in ${\beta}IRKO$ cells transfected with IR-3YA, in which the Tyr1158/1162/1163 residues are substituted with Ala. Consistently, treatment with glucose or insulin elevated PTBP1 levels in ${\beta}IRWT$ cells, but not in ${\beta}IRKO$ cells. In addition, silencing Akt significantly lowered PTBP1 levels. Thus, our results identify insulin as a pivotal mediator of glucose-induced PTBP1 expression in pancreatic ${\beta}$ cells.

• BMB Reports
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• v.42 no.4
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• pp.232-237
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• 2009

Sterol regulatory element-binding protein (SREBP)-1c plays a crucial role in the regulation of lipogenic enzymes in the liver. We previously reported that an X-chromosome-linked RNA binding motif (RBMX) regulates the promoter activity of Srebp-1c. However, still unknown was how it regulates the gene expression. To elucidate this mechanism, we screened the cDNA library from mouse liver by yeast two-hybrid assay using RBMX as bait and identified scaffold attachment factor B1 (SAFB1). Immunoprecipitation assay demonstrated binding of SAFB1 to RBMX. Chromatin immunoprecipitation assay showed binding of both SAFB1 and RBMX to the upstream region of Srebp-1c gene. RNA interference of Safb1 reduced the basal and RBMX-induced Srebp-1c promoter activities, resulting in reduced Srebp-1c gene expression. The effect of SAFB1 overexpression on Srebp-1c promoter was found only in the presence of RBMX. These results indicate a major role for SAFB1 in the activation of Srebp-1c through its interaction with RBMX.

• Journal of Life Science
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• v.30 no.6
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• pp.570-579
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• 2020

Pre-mRNA splicing is a crucial step for the expression of information encoded in eukaryotic genomes. Alternative splicing occurs when splice sites are differentially recognized and more than one transcript and potentially multiple proteins are generated from the same pre-mRNA. The decision on which splice sites are selected under particular cellular conditions is determined by the interaction of proteins, globally designated as splicing factors, that guide spliceosomal components, and thereby the spliceosome, to their respective splice sites. Abiotic stresses such as heat, cold, salt, drought, and hypoxia markedly alter alternative splicing patterns in plants, and these splicing events implement changes in gene expression for adaptive responses to adverse environments. Alteration of the expression or activity of splicing factors results in alternative splicing under cold, heat, salt, or drought conditions, and alternatively spliced isoforms respond distinctly in several aspects such as expression in different tissues or degradation via nonsense-mediated decay. Spliced isoforms may vary in their subcellular localization or have different biological functions under stress conditions. Despite numerous studies, functional analyses of alternative splicing have been limited to particular abiotic stresses; the molecular mechanism of alternative splicing in abiotic stress response remains uncovered which suggests that further studies are needed in this area.