• The Korean Journal of Zoology
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• v.30 no.4
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• pp.325-340
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• 1987

근세포 융합에 있어서 당단백질의 역할을 세포내 glycosylation의 저해제인 tunicamycin을 이용하여 검토하였다. 근세포가 읖합하기 전 여러 시기에 tunicamycin을 0.04091m숙 농도로 처리하면 세포내 glycosylation과 근세포 융합은 크게 감소되지만, 단백질 합성률과 creatine kinase 활성은 별로 변하지 않는 점으로 미루어 보아 근세포 표면의 당단백질은 세포간의 recognition과 adhesion에 관여하는 것으로 추정할 수있었다. 따라서, 표지된 Con A 염색법을 써서 근세포 원형질막의 당단백질의 변화를 검토해 본 결과 tunicamycin을 처리한 경우 원형질막 당단백질의 대부분이 감소됨을 볼 수 있었으며, 아울러 근세포내 단백질의 분해속도는 증가하고 fibronectin은 감소하는 현상을 관찰할 수 있었다. 한편, fibronectin(20 ug/ml) 을 tunicamycin과 같이 처리한 경우에는 융합이 억제되지 않았다. 이상의 결과들은 tunicamycin이 근세포가 adhesion하는데 필요한 세포막표면의 fibronectin의 유용성을 감소시킴으로써 근세포의 융합을 억제할 가능성을 제시하는 것이다.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.1004-1011
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• 2010

This study was designed to evaluate the protective effects of Dodamtanggami-bang (DDTG) on tunicamycin induced cell death by ER stress in C6 glial cells. Cell viability was measured by MTT assay and LDH release. Apoptosis was determined by caspase activity and flow cytometry in C6 glial cells. Expression of ER stress mediators including, GRP78 and CHOP proteins were measured by Western blot analysis. Tunicamycin induced the apoptosis of C6 glial cells, which was characterized as nucleic acid and caspase-3 activation, PARP cleavage, and sub-G0/G1 fraction of cell cycle increase. However, pretreatment with DDTG protected C6 glial cells from tunicamycin. Treatment with tunicamycin resulted in the increased the expression of GRP78 and CHOP protein and produced ROS generation. However, pretreatment with DDTG inhibited the ER stress pathway, including increase of the expression of GRP78, CHOP proteins in C6 glial cells treated with tunicamycin. Taken together, these data suggest that DDTG is able to protect C6 glial cells from tunicamycin with marked inhibition of ER stress.

• Molecules and Cells
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• v.46 no.6
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• pp.337-344
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• 2023

N-glycosylation, a common post-translational modification, is widely acknowledged to have a significant effect on protein stability and folding. N-glycosylation is a complex process that occurs in the endoplasmic reticulum (ER) and requires the participation of multiple enzymes. GlcNAc-1-P-transferase (GPT) is essential for initiating N-glycosylation in the ER. Tunicamycin is a natural product that inhibits N-glycosylation and produces ER stress, and thus it is utilized in research. The molecular mechanism by which GPT triggers N-glycosylation is discussed in this review based on the GPT structure. Based on the structure of the GPT-tunicamycin complex, we also discuss how tunicamycin reduces GPT activity, which prevents N-glycosylation. This review will be highly useful for understanding the role of GPT in the N-glycosylation of proteins, as well as presents a potential for considering tunicamycin as an antibiotic treatment.

• The Korean Journal of Zoology
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• v.35 no.2
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• pp.183-193
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• 1992

흰쥐 정자의 성숙과정중에 일어나는 부정소 상피세포, 내강 및 정자 사이의 상호관계를 알아보기 위하여 각 실험군 별로 웅성호르몬 투여에 따른 탄수화물 관기의 함량 변화를 측정하였고, tunicamycin 투여 후 hexosamine의 할량 변화를 살펴봄으로써 glycosylation되는 장소를 확인하였다. 부정소두와 부정소이 상피세포내의 hexose 함량은 거세 후 5일군부터 유의성있게 감소하였고, testosterone 투여시는 각각 5일 , 10일군부터 유의하게 증가하였으며 , hexosamine과 sialic acid의 경우도 통계적으로 유의하게 변화하는 시기는 달랐으나 hexose와 유사하게 증가와 감소하는 경향이 나타났으므로 이러한 하나하나의 탄수화물 관기의 함량 변화는 웅성호르몬에 의존적임을 알 수 있었다. Tunicamycin을 투여하여 hexosamine의 함량 변화를 측정하였을 때 투여 기간에 따라 상피세포와 내강액에서 유의하게 감소하였으나, 정자에서는 일관성있게 감소되지 않았으므로 정자가 직접 hexosamine또는 여러 당단백질 합성에 관여하는 것은 아니며 부정소상피세포나 내장에 의하여 영향받을 수 있다는 가능성을 확인하였다.

• Journal of Life Science
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• v.27 no.2
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• pp.233-240
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• 2017

Previously, we have shown that Schisandra chinensis (Turcz.) Baill. (S. chinensis) has a protective effect against endoplasmic reticulum (ER) stress-induced hepatic steatosis. Gomisin A is a bioactive phytoestrogen derived from S. chinensis. In the present study, the in vitro and in vivo effects of gomisin A on ER stress and hepatic steatosis were investigated. We quantified the expression of markers of ER stress, including glucose regulated protein 78 (GRP78), C/EBP homolog protein (CHOP), and X-box-binding protein-1 (XBP-1), in HepG2 cells treated with tunicamycin or palmitate. Tunicamycin treatment in HepG2 cells induced the expression of markers of ER stress, including GRP78, CHOP, and XBP-1c. However, treatment with gomisin A reduced the expression of markers of ER stress. These inhibitory effects were also observed in palmitate-incubated HepG2 cells. The in vivo inhibitory effects of gomisin A were assessed in mice injected with tunicamycin or fed with a high fat diet (HFD). Gomisin A reduced the expression of markers of ER stress and decreased triglyceride levels in the livers of mice after tunicamycin injection or HFD feeding. Furthermore, gomisin A decreased the expression of inflammatory genes in palmitate-incubated HepG2 cells and the liver of HFD-fed obese mice. These results suggest that gomisin A inhibits ER stress and ameliorates hepatic steatosis induced by ER stress.

• BMB Reports
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• v.44 no.11
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• pp.735-740
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• 2011

Tunicamycin, an endoplasmic reticulum (ER) stress inducer, specifically inhibits N-glycosylation. The cyclic AMP (cAMP) response element-binding protein H (CREBH) was previously shown to be regulated by UPR-dependent proteolytic cleavage in the liver. On the other hand, the role of CREBH in other tissues is unknown. In the present study, tunicamycin increased the level of CREBH activation (cleavage) as well as mRNA expression in osteoblast cells. Adenoviral (Ad) overexpression of CREBH suppressed BMP2-induced expression of alkaline phosphatase (ALP) and osteocalcin (OC). Interestingly, the BMP2-induced OASIS (structurally similar to CREBH, a positive regulator of osteoblast differentiation) expression was also inhibited by CREBH overexpression. In addition, inhibition of CREBH expression using siRNA reversed the tunicamycin-suppressed ALP and OC expression. These results suggest that CREBH inhibited osteoblast differentiation via suppressing BMP2-induced ALP, OC and OASIS expression in mouse calvarial derived osteoblasts.

• Biomolecules & Therapeutics
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• v.17 no.2
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• pp.162-167
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• 2009

Adipocytes undergo adipocyte stress in the excessive presence of lipid. Adipocyte stress accompanies the typical signs of endoplasmic reticulum (ER) stress: unfolded protein response and overexpression of molecular chaperones. Apoptotic induction in adipocytes is known as a good strategy for treating obesity. The drug "tunicamycin" was tested for its therapeutic potential in inducing apoptosis on differentiating adipocytes of 3T3-L1. When the 3T3-L1 cells, stimulated for adipogenesis, were treated with tunicamycin, they showed typical ER stress symptoms. Despite progression in ER stress, however, the differentiated 3T3-L1 hardly proceeded to apoptosis based on the CHOP protein expression and FACS analysis. This is very different from C2C12, the myogenic counterpart of 3T3-L1, which showed significant apoptosis along with ER stress. This study also characterizes a potential mechanism whereby adipocyte may avoid apoptosis to sustain the pathological state of obesity. The level of GRP94 expression significantly upholds in 3T3-L1 under tunicamycin treatment compared to preadipocytes and C2C-12. When GRP94 expression was inhibited by siRNA, 3T3-L1 showed a higher level of CHOP expression compared to C2C12 cells. In conclusion, adipocytes exert an anti-apoptotic mechanism under ER stress caused by tunicamycin; thus, apoptotic induction in adipocyte is not a viable anti-obesity option. The unusual level of GRP94 may serve as a key role whereby adipocytes reach to the obesity level circumventing the apoptosis.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.95-102
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• 2019

Endoplasmic reticulum (ER) stress is mediated by disturbance of $Ca^{2+}$ homeostasis. The store-operated calcium (SOC) channel is the primary $Ca^{2+}$ channel in non-excitable cells, but its participation in agent-induced ER stress is not clear. In this study, the effects of tunicamycin on $Ca^{2+}$ influx in human umbilical vein endothelial cells (HUVECs) were observed with the fluorescent probe Fluo-4 AM. The effect of tunicamycin on the expression of the unfolded protein response (UPR)-related proteins BiP and CHOP was assayed by western blotting with or without inhibition of Orai1. Tunicamycin induced endothelial dysfunction by activating ER stress. Orai1 expression and the influx of extracellular $Ca^{2+}$ in HUVECs were both upregulated during ER stress. The SOC channel inhibitor SKF96365 reversed tunicamycin-induced endothelial cell dysfunction by inhibiting ER stress. Regulation of tunicamycin-induced ER stress by Orai1 indicates that modification of Orai1 activity may have therapeutic value for conditions with ER stress-induced endothelial dysfunction.

• Applied Biological Chemistry
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• v.24 no.4
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• pp.252-259
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• 1981

The effects of tunicamycin (TM) on the growth and ${\alpha}-amylase$ productivity of B. amyloliquefaciens K were studied. The minimal growth inhibitory concentration was $0.25{\mu}\textrm{g}/m\ell$ and its ${\alpha}-amylase$ was stable up to $50^{\circ}C$. When the saking culture with $1{\mu}\textrm{g}/m\ell$ of Tunicamycin caused the change of cell shape from form rod to irregular circular form and the mycelium lysis. the grow th of His-, $TM^{\tau}$ mutant obtained by treatment of TM and ultraviolet ray was similar to that of the parent strain, but the productivity of ${\alpha}-amylase$, protease, and RNase was lower than that of the parent.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2004.11a
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• pp.124-128
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• 2004

We have assessed amyloid ${\beta}-peptide$ $(A{\beta})-induced$ neurotoxicity in primary neurons and organotypic hippocampal slice cultures (OHC) in rat. Exposing cultured hippocampal and cerebellar granule neurons to $A{\beta}$ resulted in a decrease of MTT reduction, and in destruction of neuronal integrity. Treatment of these neurons with tunicamycin, an inhibitor of N-glycosylation in the endoplasmic reticulum (ER), also decreased MTT reduction in these neurons. S-allyl-L-cysteine (SAC), an active organosulfur compound in aged garlic extract, protected hippocampal but not cerebellar granule neurons against $A{\beta}$- or tunicamycin-induced toxicity. In the hippocampal neurons, protein expressions of casapse-12 and GRP 78 were significantly increased after $A{\beta}_{25-35}$ or tunicamycin treatment. The increase in the expression of caspase-12 was suppressed by simultaneously adding $1{\mu}M$ SAC in these neurons. In contrast, in the cerebellar granule neurons, the expression of caspase-12 was extremely lower than that in the hippocampal neurons, and an increase in the expression by $A{\beta}_{25-35}$ or tunicamycin was not detected. In OHC, ibotenic acid (IBO), a NMDA receptor agonist, induced concentration-dependent neuronal death. When $A{\beta}$ was combined with IBO, there was more intense cell death than with IBO alone. SAC protected neurons in the CA3 area and the dentate gyrus (DG) from the cell death induced by IBO in combination with $A{\beta}$, although there was no change in the CA1 area. Although protein expression of casapse-12 in the CA3 area and the DG was significantly increased after the simultaneous treatment of AI3 and IBO, no increase in the expression was observed in the CA1 area. These results suggest that SAC could protect against the neuronal cell death induced by the activation of caspase-12 in primary cultures and OHC. It is also suggested that multiple mechanisms may be involved in neuronal death induced by AI3 and AI3 in combination with IBO.