• Biomolecules & Therapeutics
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• v.21 no.1
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• pp.21-28
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• 2013

Microglia play a role in maintaining and resolving brain tissue homeostasis. In pathological conditions, microglia release pro-inflammatory cytokines and cytotoxic factors, which aggravate the progression of neurodegenerative diseases. Autophagy pathway might be involved in the production of pro-inflammatory cytokines and cytotoxic factors in microglia, though details of the mechanism remain largely unknown. In the present study, we examined the role of the autophagy pathway in activated BV2 microglia cells. In BV2 cells, rapamycin treatment activated the formation of anti-LC3-labeled autophagosomes, whereas the ATG5 depletion using siRNA-ATG5 prevented the formation of LC3-labeled autophagosomes, indicating that BV2 cells exhibit an active classical autophagy system. When treated with LPS, BV2 cells expressed an increase of anti-LC3-labeled dots. The levels of LC3-labeled dots were not suppressed, instead tended to be enhanced, by the inhibition of the autophagy pathway with siRNA-ATG5 or wortmannin, suggesting that LPS-induced LC3-labeled dots in nature were distinct from the typical autophagosomes. The levels of LPS-induced expression of iNOS and IL6 were suppressed by treatment with rapamycin, and conversely, their expressions were enhanced by siRNA-ATG5 treatment. Moreover, the activation of the autophagy pathway using rapamycin inhibited cell death of LPS-stimulated microglia. These results suggest that although microglia possess a typical autophagy pathway, the glial cells express a non-typical autophagy pathway in response to LPS, and the activation of the autophagy pathway suppresses the expression of iNOS and IL6, and the cell death of LPS-stimulated microglia.

• Genomics & Informatics
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• v.7 no.4
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• pp.203-207
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• 2009

The target of rapamycin (TOR) signaling pathway conserved from yeast to human plays critical roles in regulation of eukaryotic cell growth. It has been shown that TOR pathway is involved in several cellular processes, including ribosome biogenesis, nutrient response, autophagy and aging. However, due to the functional diversity of TOR pathway, we do not know yet some key effectors of the pathway. To find unknown effectors of TOR signaling pathway, we took advantage of a green fluorescent protein (GFP)-tagged collection of budding yeast Saccharomyces cerevisiae. We analyzed protein abundance changes by measuring the GFP fluorescence intensity of 4156 GFP-tagged yeast strains under inhibition of TOR pathway. Our proteomic analysis argues that 83 proteins are decreased whereas 32 proteins are increased by treatment of rapamycin, a specific inhibitor of TOR complex 1 (TORC1). We found that, among the 115 proteins that show significant changes in protein abundance under rapamycin treatment, 37 proteins also show expression changes in the mRNA levels by more than 2-fold under the same condition. We suggest that the 115 proteins indentified in this study may be directly or indirectly involved in TOR signaling and can serve as candidates for further investigation of the effectors of TOR pathway.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.33-33
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• 2019

The AKT signaling pathway is a highly regulated cell signaling system that forms a network with other cell signaling pathways. Hence, the AKT signaling pathway mediates several important cellular functions that include cell survival, proliferation, cell migration, and et cetera. Irregularities that led overactive AKT signaling have been linked to many diseases such as cancer and metabolic-associated diseases. Hence, modulating the overactive AKT signaling pathway via inhibitor is a tantalizing prospect for treatment of cancer and metabolic-associated diseases. Two inhibitors of the AKT signaling pathway will be presented in this symposium: 1) Bisleuconothine A (BisA), a bisindole alkaloid that inhibit autophagy and 2) Ceramicine B (CerB), a limonoid that inhibit adipogenesis. The first topic is on a bisindole alkaloid, BisA and its mechanism in inducing autophagosome formation in lung cancer cell line, A549.(1) Since most autophagy inducing agents generally induce apoptosis, we found that BisA does not induce apoptosis even in high dose. BisA up-regulation of LC3 lipidation is achieved through mTOR inactivation. The phosphorylation of PRAS40, a mTOR repressor was suppressed by BisA. This observation suggested that BisA inactivates mTOR via suppression of PRAS40 phosphorylation. Interestingly, the phosphorylation of AKT, an upstream regulator of PRAS40 phosphorylation was also down-regulated by BisA. These findings suggested that Bis-A induces autophagosomes formation by interfering with the AKT-mTOR signaling pathway. The second topic is on CerB and its mechanism in inhibiting adipogenesis in preadipocytes cell line, MC3T3-G2/PA6.(2,3) CerB inhibits the phosphorylation of protein kinase B (AKT) at the Thr308 position but not the Ser473. Consequently, the phosphorylation of FOXO3 which is located downstream of AKT is also inhibited. Considering that FOXO3 is an important regulator of PPARγ which is a key factor in adipogenesis, CerB may inhibit adipogenesis via the AKT-FOXO3 signaling pathway. Taken together, both BisA and CerB highlighted the potential of AKT signaling pathway modulation as an approach to induce autophagy and inhibit the formation of fat cells, respectively.

• Molecules and Cells
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• v.39 no.3
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• pp.169-178
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• 2016

Although $N{\alpha}$-terminal acetylation (Nt-acetylation) is a pervasive protein modification in eukaryotes, its general functions in a majority of proteins are poorly understood. In 2010, it was discovered that Nt-acetylation creates a specific protein degradation signal that is targeted by a new class of the N-end rule proteolytic system, called the Ac/N-end rule pathway. Here, we review recent advances in our understanding of the mechanism and biological functions of the Ac/N-end rule pathway, and its crosstalk with the Arg/N-end rule pathway (the classical N-end rule pathway).

• BMB Reports
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• v.47 no.3
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• pp.167-172
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• 2014

Reactivating the p53 pathway in tumors is an important strategy for anticancer therapy. In response to diverse cellular stresses, the tumor suppressor p53 mediates apoptosis in a transcription-independent and transcription-dependent manner. Although extensive studies have focused on the transcription-dependent apoptotic pathway of p53, the transcription-independent apoptotic pathway of p53 has only recently been discovered. Molecular interactions between p53 and Bcl-2 family proteins in the mitochondria play an essential role in the transcription-independent apoptosis of p53. This review describes the structural basis for the transcription-independent apoptotic pathway of p53 and discusses its potential application to anticancer therapy.

• Journal of Plant Biology
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• v.16 no.1_2
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• pp.6-11
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• 1973

The utilization of acetate by Dunaliella tertiolecta was examined, and the detections and assays of the enzymes of the tricarboxylic acid cycle and the glyoxylate pathway were described. Acetate could not be utilized as a sole carbon source for the growth. The carboxyl carbon of acetate was incorporated more rapidly into CO2 than the methyl carbon. It was identified that malate, succinate, citrate and etc., were accumulated whne [U-14C] acetate was supplied to the cell free homogenate. The following enzyme activities were measured; acetothiokinase, isocitrate dehydrogenase, fumarase, malate dehydrogenase and aconitase. Though isocitratase, malate synthetase, succinate dehydrogenase and oxoglutarate dehydrogenase could not be detected, 14C from succinate was easily contributed to CO2 and cell component. The evidence suggested that the glyoxylate pathway was not operative and showed that the TCA cycle was the all important pathway in the oxidation of acetate to CO2 in Dunaliella.

• Korean Journal of Microbiology
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• v.25 no.1
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• pp.28-33
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• 1987

Celluloytic bacteria, -Gram positive, Gram negative and actionmycetes-were used to study their catabolic pathways of carbohydrate. It was found that Embden-Meyerhof-Parnas(EMP) pathway and hexose monophosphate(MHP) shunt were operated in Cellulomonase sp. CS1-1, C. flavigena, and Pseudomonas fluorescens subsp. cellulosa when they were cultured in a glucose containing medium, whilst gluconate was catabolised mainly via Entner-Doudoroff(ED) pathway, and to some extend through HMP shunt. Enzymes of ED pathway in the orgamisms were induced by gluconate. On the other hand Nocardia cellulans catabolised glucose and gluconate via EMP pathway and HMP shunt. The growth rate of N. Cellulans on gluconate were much slower than that on glucose.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.109-111
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• 1998

The effect of dissolved oxygen concentration on the metabolism of glucose in Pseudomonas putida BM014 was investigated. Glucose was completely converted to 2-ketogluconate via extracellular oxidative pathway and then taken up for cell growth under the condition of sufficient dissolved oxygen concentration. On the other hand, oxygen limitation below dissolved oxygen tension (DOT) value of 20% of air saturation caused the shift of glucose metabolism from the extracellular oxidative pathway to the intracellular phosphorylative pathway. Specific activities of hexokinase and gluconate kinase in intracellular phosphorylation pathway decreased as the DOT increased, while 2-ketogluconokinase activity in extracellular oxidative pathway increased under the same condition. This result can be usefully applied to microbial transformation of glucose to 2-ketogluconate, the synthetic precursor for iso-vitamine C, with almost 100% yield via extracellular oxidation by simple DOT control.

• Genomics & Informatics
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• v.16 no.4
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• pp.39.1-39.3
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• 2018

The rapid increase in genetic dataset volume has demanded extensive adoption of biological knowledge to reduce the computational complexity, and the biological pathway is one well-known source of such knowledge. In this regard, we have introduced a novel statistical method that enables the pathway-based association study of large-scale genetic dataset-namely, PHARAOH. However, researcher-level application of the PHARAOH method has been limited by a lack of generally used file formats and the absence of various quality control options that are essential to practical analysis. In order to overcome these limitations, we introduce our integration of the PHARAOH method into our recently developed all-in-one workbench. The proposed new PHARAOH program not only supports various de facto standard genetic data formats but also provides many quality control measures and filters based on those measures. We expect that our updated PHARAOH provides advanced accessibility of the pathway-level analysis of large-scale genetic datasets to researchers.

• International Journal of Oral Biology
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• v.46 no.2
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• pp.81-84
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• 2021

Salivary glands are exocrine glands that secrete saliva into the oral cavity, and secreted saliva plays essential roles in oral health. Therefore, maintaining the salivary glands in an intact state is required for proper production and secretion of saliva. To investigate a specific signaling pathway that might affect the maintenance of mouse submandibular gland (SMGs), RNA sequencing was performed. In SMGs, downregulated expression patterns of Rho-associated protein kinase (ROCK) signaling pathway-related genes, including Rhoa, Rhob, Rhoc, Rock1, and Rock2, were observed. Gene expression profiling analyses of these genes indicate that the ROCK signaling pathway is a potential signal for SMG maintenance.