• Journal of the Korean Magnetic Resonance Society
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• v.24 no.2
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• pp.43-46
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• 2020

Huntington's disease (HD) is an inherited neurodegenerative disease caused by abnormal polyglutamine (polyQ) expansion in the huntingtin protein (Htt). There is no cure for HD so far. Although exact molecular mechanism of HD pathogenesis is still elusive, fibril formation of the expanded Htt is linked to the toxicity. In this study, we prepared the expanded Htt containing 46 glutamines, and induced the fibrillation by proteolytic cleavage. Fibrillation of the pathogenic Htt has been monitored by time course NMR experiment. The NMR-based monitoring method could be widely used to screen the candidates to inhibit the fibrillation of the pathogenic Htt.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.313.3-314
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• 2002

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in response to a variety of cytokines and other proinflammatory stimuli. It has been known that aberrant up-regulation of COX-2 is associated with resistance to apoptosis. Contrary to the above notion. treatment of MCF10A-ras cells with the anti-tumor agent ET -18-O-$CH_3$ caused increased expression of COX-2 and its mRNA transcript. while inducing apoptosis as revealed by proteolytic cleavage of poly(ADP-ribose)polymerase. caspase-3 activation, and positive TUNEL staining. (omitted)

• Biomedical Science Letters
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• v.20 no.3
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• pp.168-172
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• 2014

It has recently been shown that hypothermia treatment improves brain ischemia injury and is being increasingly considered by many clinicians. However, the precise roles of hypothermia for brain ischemia are not yet clear. In the present study we demonstrated firstly that hypothermia induced beta-catenin-interacting protein 1 (CTNNBIP1) gene expression and its expression was dramatically decreased under ischemic conditions. It was also demonstrated that hypothermia activated endoplasmic reticulum (ER) stress sensors especially both, the phosphorylation of $eIF2{\alpha}$, and ATF6 proteolytic cleavage. However, the factors of apoptosis and autophagy were not associated with hypothermia. These findings suggested that hypothermia controlled CTNNBIP1 gene expression under ischemia, which may provide a clue to the development of treatments and diagnostic methods for brain ischemia.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.80-80
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• 2002

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in response to a variety of cytokines. The presence of oncogenic ras has been associated with sustained induction of COX-2, which confers resistance to apoptosis. Contrary to the above notion, we found that MCF10A-ras cells treated with an anti-tumor agent, ET-18-O-$CH_3$, underwent apoptosis as revealed by proteolytic cleavage of poly(ADP-ribose)polymerase, pro-caspase 3 activity, and TUNEL staining, while the same treatment caused an increased expression of COX-2 as well as the elevated production of prostaglandin E$_2$(PGE$_2$).(omitted)

• Korean Journal of Medicinal Crop Science
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• v.11 no.4
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• pp.264-267
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• 2003

Korean medicinal plants were screened for their inhibitory activity against HIV-1 protease. The inhibitory activity of protease was determined by incubating the extracts in reaction mixtures containing protease and substrate $His-Lys-Ala-Arg-Val-Leu-(p-NO_{2}-Phe)-Glu-Ala-Nle-Ser-NH_{2}$ to perform proteolytic cleavage reactions. In this study the twenty six extracts from medicinal plants were investigated. Of the extracts tested, the extracts from the stem of Morus alba. exhibited the strongest activity with inhibition of 81% at a concentration of $100{\mu}g/ml$. The extracts of the flower of Saxjfraga stolonifera, and stems of Euonymus japonica and Castanea crenata showed appreciable inhibitory activity (>50%) against HIV-1 protease at same concentration.

• Archives of Pharmacal Research
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• v.27 no.12
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• pp.1253-1257
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• 2004

6-Methoxydihydrosanguinarine (6ME), a benzophenanthridine alkaloid derived from the methanol extracts of Hylomecon hylomeconoides, showed a dose-dependent effect at 1-10 ${\mu}M$ on causing apoptotic cell death in HT29 colon carcinoma cells $(IC_{50} = 5.0{\pm}0.2 {\mu}M)$. Treatment of HT-29 cells with 6ME resulted in the formation of internucleosomal DNA fragmentation. Treatment of the cells with 6ME caused activation of caspase-3, -8 and 9 protease and subsequent proteolytic cleavage of poly(ADP-ribose)polymerase. 6ME increased the expression of p53 and Bax and decreased the expression of Bid. These results indicate that p53 and proapoptotic Bcl-2 family proteins might participate in the antiproliferative activity of 6ME in HT29 cells.

• BMB Reports
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• v.53 no.12
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• pp.611-621
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• 2020

Bacterial endoribonuclease toxins belong to a protein family that inhibits bacterial growth by degrading mRNA or rRNA sequences. The toxin genes are organized in pairs with its cognate antitoxins in the chromosome and thus the activities of the toxins are antagonized by antitoxin proteins or RNAs during active translation. In response to a variety of cellular stresses, the endoribonuclease toxins appear to be released from antitoxin molecules via proteolytic cleavage of antitoxin proteins or preferential degradation of antitoxin RNAs and cleave a diverse range of mRNA or rRNA sequences in a sequence-specific or codon-specific manner, resulting in various biological phenomena such as antibiotic tolerance and persister cell formation. Given that substrate specificity of each endoribonuclease toxin is determined by its structure and the composition of active site residues, we summarize the biology, structure, and substrate specificity of the updated bacterial endoribonuclease toxins.

• The Korean Journal of Zoology
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• v.26 no.4
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• pp.235-251
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• 1983

Several approaches have been made to access the mechanism of fusion in chick myoblast in vitro. Lactoperoxidase-catalyzed iodination was applied to labell cell surface proteins during myogenesis. Quantitative as well as qualitative changes were observed in $^131$I surface components of prefusion and postfusion cells. Two proteins with a molecular weight of 165K and 93K daltons were observed to appear at the onset of fusion as compared to prefusion stage. At the same time, 245K dalton protein decreased whereas the low molecular weight proteins increased consistently. The decrease of high molecular weight proteins appears to be associated with the cell cycle of myoblast during differentiation. The increased appearance of low molecular weight proteins might be due to the proteolytic cleavage of the high molecular weight proteins. Examination of intracellulr cAMP levels during fusion has revealed that a large but transient increase in cAMP occurs before the onset of fusion. This result suggests a causal relationship between the increase of cAMP and the onset of fusion, and further, that differentiating myoblasts are synthronized to a high degree. During the course of myoblast differentiation, at least four lowe molecular weight proteins, which different from major surface proteins iodinated, were identifiable in the culture medium. These proteins could be ascribed to be released from the membrane by proteolytic cleavage of surface proteins in the course of myoblast fusion. The significance of cell surface alterations and the released proteins during the fusion, the involvement of cAMP in the onset of fusion and the possibility that fusion is promoted by external factor(s) are discussed.

• Toxicological Research
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• v.19 no.2
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• pp.91-98
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• 2003

Alkylating agents form alkylated base adducts in the DNA and cause DNA lesions leading to cell killing. In this study, we investigated the mechanism of apoptosis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in PC-3 and DU145 human prostate carcinoma cell lines. MNNG treatment resulted in the inhibition of cell proliferation in a concentration-dependent manner to a similar extent in both cell lines. This anti-proliferative effect of PC-3 and DU145 cells by MNNG was associated with morphological changed such as membrane shrinking, cell rounding up and formation of apoptotic bodies. MNNG treatment also induced a proteolytic cleavage of specific target proteins such as poly(ADP-ribose) polymerase (PARP) and $\beta$-catenin proteins in DU145 cells but in PC-3 cells. Furthermore, we observed an increase of proapoptotic protein Bax family expression and a decrease of antiapoptotic protein Bcl-2 family by MNNG treatment in a concentration-dependent manner MNNG also induced a proteolytic activation of caspase-3 and -9, which is believed to play a central role in the apoptotic signaling pathway.

• Journal of Microbiology and Biotechnology
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• v.28 no.12
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• pp.2079-2094
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• 2018

Sunflower trypsin inhibitor (SFTI) is a 14-amino-acid bicyclic peptide that contains a single internal disulfide bond. We initially constructed chimeras of SFTI with N-terminal secretion signals from the Escherichia coli OmpA and Pseudomonas aeruginosa ToxA, but only detected small amounts of protease inhibition resulting from these constructs. A substantially higher degree of protease inhibition was detected from a C-terminal SFTI fusion with E. coli YebF, which radiated more than a centimeter from an individual colony of E. coli using a culture-based inhibitor assay. Inhibitory activity was further improved in YebF-SFTI fusions by the addition of a trypsin cleavage signal immediately upstream of SFTI, and resulted in production of a 14-amino-acid, disulfide-bonded SFTI free in the culture supernatant. To assess the potential of the secreted SFTI to protect the ability of a cytotoxic protein to kill tumor cells, we utilized a tumor-selective form of the Pseudomonas ToxA (OTG-PE38K) alone and expressed as a polycistronic construct with YebF-SFTI in the tumor-targeted Salmonella VNP20009. When we assessed the ability of toxin-containing culture supernatants to kill MDA-MB-468 breast cancer cells, the untreated OTG-PE38K was able to eliminate all detectable tumor cells, while pretreatment with trypsin resulted in the complete loss of anticancer cytotoxicity. However, when OTG-PE38K was co-expressed with YebF-SFTI, cytotoxicity was completely retained in the presence of trypsin. These data demonstrate SFTI chimeras are secreted in a functional form and that co-expression of protease inhibitors with therapeutic proteins by tumor-targeted bacteria has the potential to enhance the activity of therapeutic proteins by suppressing their degradation within a proteolytic environment.