• Molecules and Cells
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• v.38 no.7
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• pp.597-603
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• 2015

Biosynthesis of the phytohormone ethylene is under tight regulation to satisfy the need for appropriate levels of ethylene in plants in response to exogenous and endogenous stimuli. The enzyme 1-aminocyclopropane-1-carboxylic acid synthase (ACS), which catalyzes the rate-limiting step of ethylene biosynthesis, plays a central role to regulate ethylene production through changes in ACS gene expression levels and the activity of the enzyme. Together with molecular genetic studies suggesting the roles of post-translational modification of the ACS, newly emerging evidence strongly suggests that the regulation of ACS protein stability is an alternative mechanism that controls ethylene production, in addition to the transcriptional regulation of ACS genes. In this review, recent new insight into the regulation of ACS protein turnover is highlighted, with a special focus on the roles of phosphorylation, ubiquitination, and novel components that regulate the turnover of ACS proteins. The prospect of cross-talk between ethylene biosynthesis and other signaling pathways to control turnover of the ACS protein is also considered.

• BMB Reports
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• v.49 no.9
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• pp.459-473
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• 2016

Neurodegenerative diseases (NDs) often involve the formation of abnormal and toxic protein aggregates, which are thought to be the primary factor in ND occurrence and progression. Aged neurons exhibit marked increases in aggregated protein levels, which can lead to increased cell death in specific brain regions. As no specific drugs/therapies for treating the symptoms or/and progression of NDs are available, obtaining a complete understanding of the mechanism underlying the formation of protein aggregates is needed for designing a novel and efficient removal strategy. Intracellular proteolysis generally involves either the lysosomal or ubiquitin-proteasome system. In this review, we focus on the structure and assembly of the proteasome, proteasome-mediated protein degradation, and the multiple dynamic regulatory mechanisms governing proteasome activity. We also discuss the plausibility of the correlation between changes in proteasome activity and the occurrence of NDs.

• The Microorganisms and Industry
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• v.20 no.2
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• pp.33-40
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• 1994

미생물에 대한 유전자 재조합법 등의 개발로 동물세포에서만 합성되던 단백질들을 미생물을 통하여 생산하는 기술이 확립되어 있으나, 동물 세포내에서만 정확하게 실행되어지는 단백질 분자의 folding과 post-translational modification 등이 미생물에서는 불완전하게 이루어져 활성을 잃게 되는 단점이 있고, pyrogen과 같이 미생물로부터 유래한 endotoxin이 생산물에 섞여 있을수도 있으며, 미생물로부터 생산되는 각종 단백질로부터 원하는 유용 단백질을 분리하기 어려운것 등, 현실적으로 많은 어려움을 가지고 있기 때문에 미생물을 이용하기보다 동물 세포 배양을 통하여 위와 같은 제재들을 생산하려 하고 있다. 유전자 재조합 기술은, 현재 미생물뿐만 아니라, 동,식물 세포에 대하여도 적용되어 있어서 각종 유용생산물을 동,식물세포의 유전자 조작을 통해 얻을 수 있는 단계에 와 있으며, 이는 유전자 치료(gene therapy)와 같은 의료분야에까지 확장될 수 있게 되었다. 표 2에서는 동물 세포를 배양할 때와 미생물을 이용할 때의 각각의 특징을 보여주고 있다.

• KSBB Journal
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• v.8 no.4
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• pp.405-408
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• 1993

Absidia zychae NRIC 1199 produced two forms of carboxypeptidase(CPZ-1 and CPZ-2) which were distinguished in their isoelectric points but had almost identical properties(1). The amino acid sequences for the N-terminal of both enzymes were the same (Tyr-Thr-Ser-Pro-Lys-Leu-Xaa-Asp-Pro-Asp-Val) and any significant difference was not observed between amino acid compositions of the two enzymes. The ouchterlony double diffusion technique using antibody raised against the CPZ-2 protein demonstrated a good cross-reaction between CPZ-1 and CPZ-2 Genomic Southern analysis showed only one gene encoding CPZ in the genome of Absidia zychae. However, a significant difference between two enzymes was observed on peptide map using Staphylococcus aureus V8 protease, distinguishable only one band, indicating that multiple forms of CPZ are caused by post-translational modification, such as deamidation.

• Journal of the Korean Magnetic Resonance Society
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• v.12 no.1
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• pp.40-50
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• 2008

Ghrelin is a unique peptide hormone that releases growth factor and it stimulates appetite. It comes from pre pro-ghrelin by the post translational modification process and its innate functions are known as food up-take and the growth hormone regulation. Therefore, the structural information of ghrelin precursor is of importance in understanding it function. From our results, we found that the solution structure of ghrelin is mostly random coil conformation at neutral pH value and the structural population changes with pH environments. Data from circular dichroism in different TFE concentrations revealed that the secondary structure changes from random coil to a-helix and the isodichroic point is observed at 202nm, implying that two equilibrium states exist between random coil and helical structure.

• Molecules and Cells
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• v.39 no.1
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• pp.72-76
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• 2016

Cell death pathways such as apoptosis can be activated in response to oxidative stress, enabling the disposal of damaged cells. In contrast, controlled intracellular redox events are proposed to be a significant event during apoptosis signaling, regardless of the initiating stimulus. In this scenario oxidants act as second messengers, mediating the post-translational modification of specific regulatory proteins. The exact mechanism of this signaling is unclear, but increased understanding offers the potential to promote or inhibit apoptosis through modulating the redox environment of cells. Peroxiredoxins are thiol peroxidases that remove hydroperoxides, and are also emerging as important players in cellular redox signaling. This review discusses the potential role of peroxiredoxins in the regulation of apoptosis, and also their ability to act as biomarkers of redox changes during the initiation and progression of cell death.

• 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.

• BMB Reports
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• v.41 no.8
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• pp.587-592
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• 2008

Cotesia vestalis is an endoparasitoid of Plutella xylostella larvae and injects a polydnavirus (CvBV) into its host during oviposition. In this report we characterize the gene, CvBV3307, and its products. CvBV3307 is located on segment S33 of the CvBV genome, is 517 bp, and encodes a putative protein of 122 amino acids, including a serine-rich region. The expression pattern of CvBV3307 in parasitized larvae and the subcellular localization of CvBV3307 only in granulocytes indicated that it might be involved in early protection of parasitoid eggs from host cellular encapsulation and in manipulating the hormone titer and developmental rhythm of host larvae. Western blot analysis showed that the size of the immunoreactive protein (about 55 kDa) in parasitized hosts at 48 hours post parasitization (h p.p.) is much larger than the predicted molecular weight of 13.6 kDa, which suggests that CvBV3307 undergoes extensive post-translational modification in hosts.

• Journal of Life Science
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• v.28 no.3
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• pp.376-387
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• 2018

Among a variety of environmental stresses heat, cold, chilling, high salt, drought, and so on exposed to plants, drought stress has been reported as a crucial factor to adversely affect the growth and productivity of plants. Therefore, to understand the mechanism for the drought stress signal transduction pathway in plants is more helpful to develop useful crops that display the enhanced tolerance against drought stress, and to expand crop growing areas. The signal transduction pathway for the drought stress in plants is largely categorized into two types; ABA-dependent pathway and ABA-independent pathway. It has been reported that two transcription factors, AREB/ABF and DREB2, play predominant roles in ABA-dependent and ABA-independent pathways, respectively. In addition to transcriptional regulation mediated by AREB/ABF and DREB2 transcription factors, post-translational modification (such as phosphorylation and ubiquitination) and epigenetic control are importantly involved in the signal transduction for drought stress. In this paper, we review current understanding of signal transduction pathway on drought stress in plants, especially focusing on the biological roles of a variety of signaling components related to drought stress response. Further understanding the mechanism of drought resistance in plants through this review will be useful to establish theoretical basis for developing drought tolerant crops in the future.

• The Journal of Natural Sciences
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• v.17 no.1
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• pp.13-29
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• 2006

Most redox-active proteins have thiol-bearing cysteine residues that are sensitive to oxidation. Cysteine thiols oxidized to sulfenic acid are generally unstable, either forming a disulfide with a nearby thiol or being further oxidized to a stable sulfinic acid, which have been viewed as an irreversible protein modification. However, recent studies showed that cysteine residues of certain thiol peroxidases (Prxs) undergo reversible oxidation to sulfinic acid and the reduction reaction is catalyzed by sulfiredoxin (Srx1). Specific Cys residues of various other proteins are also oxidized to sulfinic acid ($Cys-So_2H$). Srxl is considered one of the oxidant proteins with a role in signaling through catalytic reduction of oxidative modification like in the reduction of glutathionylation, a post-translational, oxidative modification that occurs on numerous proteins. In this study, the role of sulfiredoxin in cellular processes, was investigated by studying its interaction with other proteins. Through the yeast two-hybrid system (Y2HS) technique, we have found that Ams1 is a potential and novel interacting protein partner of Srxl. $\alpha$-mannosidase (Ams1) is a resident vacuolar hydrolase which aids in recycling macromolecular components of the cell through hydrolysis of terminal, non-reducing $\alpha$-D-mannose residues. It forms an oligomer in the cytoplasm and under nutrient rich condition and is delivered to the vacuole by the Cytoplasm to Vacuole (Cvt) pathway. Aside from the role of Srxl as a catalyst in the reduction of cysteine sulfenic acid groups, it may play a completely new function in the cellular process as indicated by its interaction with Ams1 of the yeast Saccharomyces cerevisiae.