• BMB Reports
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• 제32권3호
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• pp.311-316
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• 1999

Studies in adipocytes indicate that secretion of active lipoprotein lipase (LPL) was strictly regulated by a quality control system in the endoplasmic reticulum (ER). However, there has been no report about the ER chaperones participating in the folding and assembly of LPL. Many chaperones are known to bind unfolded proteins and dissociate from them through the ATP-hydrolyzing reaction. In this study, putative ER chaperones for LPL were determined by affinity chromatography using denatured LPL as an affinity ligand and elution with ATP. BiP, grp94, calreticulin, and another 50 kDa K-D-E-L protein in the ER of rat adipose tissue were bound to denatured LPL and eluted by ATP. Calnexin was bound to denatured LPL; however, it was not eluted by ATP but by acetic acid. These results indicate that, at least, BiP, grp94, calreticulin, calnexin, and the unidentified 50 kDa protein might act as putative chaperones for the proper folding and assembly of LPL in ER.

• 대한의생명과학회지
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• 제14권1호
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• pp.59-62
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• 2008

This experiment was performed to study the effect of TSH (thyroid-stimulating hormone) on the expression of endoplasmic reticulum (ER) chaperones in the rat thyrocytes FRTL-5 cells. Although the expressions of ER membrane kinases (ATF6, IRE1 and PERK) were specially enhanced under absence of TSH, no remarkable up- or down regulations of ER chaperones (BiP, CHOP and Calnexin) were detected by TSH. We firstly report here that TSH by dose up-regulated expression of ER membrane kinases in FRTL-5 culture thyrocytes.

• 생명과학회지
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• 제23권9호
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• pp.1104-1108
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• 2013

에틸렌 글리콜(ethylene glycol)은 자동차 부동액 주성분으로 우리 실생활에 널리 쓰이고 있다. 접근이 용이하고 달콤한 맛 때문에 자살목적이나 보관 및 사용 시 의도적으로 또는 실수로 인한 오용사고가 자주 발생한다. 에틸렌 글리콜은 그 자체로는 인체의 독성이 낮지만 생체에서 대사과정을 거치면서 독성이 높아진 유기산을 만들어 다양한 조직에서 광범위한 세포손상을 유발한다. 다양한 세포 스트레스가 소포체(ER) 샤페론과 소포체 스트레스 센서의 유전자 발현을 유도하는 것은 이미 알려져 있다. 본 연구에서는 rat 조직에서 소포체 샤페론과 소포체 스트레스 센서 유전자의 발현 조절이 에틸렌 글리콜에 의해 유도되고, 조직학적 변화도 H&E 염색 및 면역 형광염색에 의해 확인하였다.

• Journal of Life Science
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• 제12권2호
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• pp.53-56
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• 2002

The baculovirus expression vector system (BEVS) is one of the powerful heterologous protein expression systems using insect cells. As a result this has become a hot issue in the fleld of biotechnology. The advantage of the BEVS is that the large-scale production of heterologous proteins, which undergo posttranslational modification in the endoplasmic reticulum (ER), can be accomplished. Altrough posttranslational modification of heterologous proteins in insect cells is more similar to mammalian cells than yeast, it is not always identical. Therefore, aggregation and degradation can sometimes occur in the ER. To produce a high level of bioactive heterologous proteins using BEVS in insect cells, the prerequisite is to completely understand the posttranslational conditions that determine how newly synthesized polypeptides are folded and assembling with ER chaperones in the ER lumen. Here, we provide information on current BEVS problems and the possibility of successful heterologous protein production from mammalian cells.

• The Plant Pathology Journal
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• 제31권4호
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• pp.323-333
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• 2015

As sessile organisms, plants are exposed to persistently changing stresses and have to be able to interpret and respond to them. The stresses, drought, salinity, chemicals, cold and hot temperatures, and various pathogen attacks have interconnected effects on plants, resulting in the disruption of protein homeostasis. Maintenance of proteins in their functional native conformations and preventing aggregation of non-native proteins are important for cell survival under stress. Heat shock proteins (HSPs) functioning as molecular chaperones are the key components responsible for protein folding, assembly, translocation, and degradation under stress conditions and in many normal cellular processes. Plants respond to pathogen invasion using two different innate immune responses mediated by pattern recognition receptors (PRRs) or resistance (R) proteins. HSPs play an indispensable role as molecular chaperones in the quality control of plasma membrane-resident PRRs and intracellular R proteins against potential invaders. Here, we specifically discuss the functional involvement of cytosolic and endoplasmic reticulum (ER) HSPs/chaperones in plant immunity to obtain an integrated understanding of the immune responses in plant cells.

• 생명과학회지
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• 제9권1호
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• pp.76-83
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• 1999

Endoplasmic reticulum (ER)내에 단백질의 folding과 안정화에 관여하는 단백질을 molecular cha-perone이라고 한다. GRP94 역시 ER내에 존재하는 molecular chaperone으로 알려지고 있지만 갑상선세포에서 단백질의 folding에 관여한다는 증거는 아직 불충분하다. 본 설험은 molecular chaperone을 세포내에서 overexpression시킬 수 있는 system을 확립하였다. 그 중에서 GRP94가 단백질의 folding에 직접적으로 관여한다는 증거를 얻기 위하여, endogenous GRP94를 code한 cDNA를 overexpression vector에 의해서 forced expression시킴으로 신생thyroglobulin의 folding에 직접적으로 관여하는 증거를 immun-oprecipitation으로 증명하였다.

• Biomolecules & Therapeutics
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• 제20권3호
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• pp.346-351
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• 2012

Cells show various stress signs when they are challenged with severe physiological problems. Majority of such cellular stresses are conveyed to endoplasmic reticulum (ER) and unfolded protein response (UPR) serves as typical defense mechanism against ER stress. This study investigated an interaction between ER stress agents using macropage cell line Raw 264.7. When activated by lipopolysaccharide (LPS), the cell lines showed typical indicators of ER stress. Along with molecular chaperones, the activation process leads to the production of additional inflammatory mediators. Following activation, the macrophage cell line was further treated with TUN and characterized in terms of chaperone expression and cytokine secretion. When treated with TUN, the activated macrophage cell leads to increased secretion of IL-6 although expression of ER stress markers, GRP94 and GRP78 increased. The secretion of cytokines continued until the addition of BFA which inhibits protein targeting from ER to Golgi. However, secretion of cytokines was ceased upon dual treatments with BFA and TG. This result strongly implies that cells may differently deal with various polypeptides depending on the urgency in cellular function under ER stress. Considering IL-6 is one of the most important signal molecules in macrophage, the molecule might be able to circumvent ER stress and UPR to reach its targeting site.

• International Journal of Industrial Entomology and Biomaterials
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• 제7권2호
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• pp.133-137
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• 2003

Cells respond to an accumulation of unfolded proteins in the endoplasmic reticulum (ER) by increasing transcription of genes encoding molecular chaperones and folding enzymes. The information is transmitted from the ER lumen to the nucleus by intracellular signaling pathway, called the unfolded protein response (UPR). In Saccharomyces cerevisiae, such induction is mediated by the cis-acting unfolded response element (UPRE) which has been thought to be recognized by Hac1p transcription factor. We cloned the ATFC gene showing similarity with Hac1p, and then examined to determine whether ATFC gene product specifically binds to UPRE by electrophoretic mobility shift assays. ATFC gene product displayed appreciable binding ${to ^{32}}P-labelled$ UPRE. Therefore, we concluded that ATFC represents a major component of the putative transcription factor responsible for the UPR leading to the induction of ER-localized stress proteins.

• 생명과학회지
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• 제22권8호
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• pp.1132-1136
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• 2012

많은 종류의 세포스트레스는 unfolded protein response (UPR)관련인자의 유전자발현을 조절한다. 본 연구결과 부동스트레스(immobilization stress)는 세포의 소포체스트레스(ER stress)와 관련된 유전자발현의 변화를 유도한다; Heart, spleen, thymus, kidney, testis에서는 유전자발현 변화가 없었지만 adrenal gland, liver, lung에서는 유의할만한 상승변화가 있었다. 그러나 muscle에서는 다른 것들과 대조적으로 발현이 감소되었다. 이 결과는 부동스트레스도 다른 종류의 세포스트레스와 같이 세포수준에서 UPR을 조절할 수 있다는 최초의 보고이다.

• Animal cells and systems
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• 제10권3호
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• pp.115-120
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• 2006

Parkinson's disease (PD) is a neurodegenerative disease caused by selective degeneration of dopaminergic neurons in the substantia nigra. Mutations in ${\alpha}$-synuclein have been causally linked to the pathogenesis of hereditary PD. In addition, it is a major component of Lewy body found in the brains of sporadic cases as well. In the present study, we examined whether overexpression of wild type or PD-related mutant ${\alpha}$-synuclein induces unfolded protein response (UPR) and triggers the known signaling pathway of the resulting endoplasmic reticulum (ER) stress in SH-SY5Y cells. Overexpression of wild type, A30P, and A53T ${\alpha}$-synuclein all induced XBP-1 mRNA splicing, one of the late stage UPR events. However, activation of ER membrane kinases and upregulation of ER or cytoplsmic chaperones were not detected when ${\alpha}$-synuclein was overexpressed. However, basal level of cytoplsmic calcium was elevated in ${\alpha}$-synuclein-expressing cells. Our observation suggests that overexpression of ${\alpha}$-synuclein induces UPR independent of the known ER membrane kinase-mediated signaling pathway and induces ER stress by disturbing calcium homeostasis.