• Journal of Microbiology and Biotechnology
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• 제32권8호
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• pp.982-988
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• 2022

Licorice (Glycyrrhiza) has been used as preventive and therapeutic material for hyperpigmentation disorders. Previously, we isolated noble compounds including dehydroglyasperin C (DGC), dehydroglyasperin D (DGD) and isoangustone A (IAA) from licorice hexane/ethanol extracts. However, their anti-melanogenic effects and underlying molecular mechanisms are unknown. The present study compared effects of DGC, DGD and IAA on pigmentation in melan-a melanocytes and human epidermal melanocytes (HEMn). DGD exerted the most excellent anti-melanogenic effect, followed by DGC and IAA at non-cytotoxic concentrations. In addition, DGD significantly inhibited tyrosinase activity in vitro cell-free system and cell system. Western blot result showed that DGD decreased expression of microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase-related protein-1 (TRP-1) in melan-a cells and HEMn cells. DGD induced phosphorylation of MITF, ERK and Akt signal pathway promoting MITF degradation system. However, DGD did not influence p38 and cAMP-dependent protein kinase (PKA)/CREB signal pathway in melan-a cells. These result indicated that DGD inhibited melanogenesis not only direct regulation of tyrosinase but also modulating intracellular signaling related with MITF level. Collectively, these results suggested a protective role for DGD against melanogenesis.

• 환경생물
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• 제40권3호
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• pp.255-266
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• 2022

갑각류에서 탈피는 ecdysteroid와 juvenile hormone (JH) 신호 경로에 관여하는 유전자의 상호작용에 의해 조절된다. Ecdysteroid와 달리, 탈피 과정에서 JH 신호 경로 유전자의 역할은 부유성 갑각류에서는 잘 알려져 있지 않다. 본 연구는 기수산 물벼룩(Diaphanosoma celebensis)의 JH 신호경로에서 JH 합성, 수용체, 분해 등에 관여하는 3종의 유전자(JHAMT, Met, JHEH)의 염기서열 분석과 계통 분석을 실시하였다. 또한 탈피 주기에서 이들 유전자의 mRNA 발현양상을 분석하였다. D. celebensis의 JH 관련 유전자는 잘 보존된 domain을 가지고 있었으며, 아미노산 서열 분석과 계통 분석 결과는 이들 단백질이 곤충 및 다른 갑각류의 해당 단백질과 기능적으로 유사한 특징을 나타낸다. 또한 탈피 주기에 따른 유충 호르몬( JH) 신호전달경로 관련 유전자의 발현변화 결과를 통해 이들 유전자가 JH의 합성 및 분해에 관여함으로써 D. celebensis에서 성공적인 탈피에 기여할 것임을 제시하였다. 본 연구는 지각류에서 탈피 주기에서 JH 경로 유전자의 역할을 이해하는 데 도움이 될 것이다.

• BMB Reports
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• 제52권2호
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• pp.119-126
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• 2019

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) initiates the extrinsic apoptotic pathway through formation of the death-inducing signaling complex (DISC), followed by activation of effector caspases. TRAIL receptors are composed of death receptors (DR4 and DR5), decoy receptors (DcR1 and DcR2), and osteoprotegerin. Among them, only DRs activate apoptotic signaling by TRAIL. Since the levels of DR expressions are higher in cancer cells than in normal cells, TRAIL selectively activates apoptotic signaling pathway in cancer cells. However, multiple mechanisms, including down-regulation of DR expression and pro-apoptotic proteins, and up-regulation of anti-apoptotic proteins, make cancer cells TRAIL-resistant. Therefore, many researchers have investigated strategies to overcome TRAIL resistance. In this review, we focus on protein regulation in relation to extrinsic apoptotic signaling pathways via ubiquitination. The ubiquitin proteasome system (UPS) is an important process in control of protein degradation and stabilization, and regulates proliferation and apoptosis in cancer cells. The level of ubiquitination of proteins is determined by the balance of E3 ubiquitin ligases and deubiquitinases (DUBs), which determine protein stability. Regulation of the UPS may be an attractive target for enhancement of TRAIL-induced apoptosis. Our review provides insight to increasing sensitivity to TRAIL-mediated apoptosis through control of post-translational protein expression.

• BMB Reports
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• 제42권9호
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• pp.552-560
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• 2009

Cyclooxygenases (COX-1 and COX-2) are ER-resident proteins that catalyze the committed step in prostanoid synthesis. COX-1 is constitutively expressed in many mammalian cells, whereas COX-2 is usually expressed inducibly and transiently. Abnormal expression of COX-2 has been implicated in the pathogenesis of chronic inflammation and various cancers; therefore, it is subject to tight and complex regulation. Differences in regulation of the COX enzymes at the posttranscriptional and posttranslational levels also contribute significantly to their distinct patterns of expression. Rapid degradation of COX-2 mRNA has been attributed to AU-rich elements (AREs) at its 3’UTR. Recently, microRNAs that can selectively repress COX-2 protein synthesis have been identified. The mature forms of these COX proteins are very similar in structure except that COX-2 has a unique 19-amino acid (19-aa) segment located near the C-terminus. This C-terminal 19-aa cassette plays an important role in mediation of the entry of COX-2 into the ER-associated degradation (ERAD) system, which transports ER proteins to the cytoplasm for degradation by the 26S proteasome. A second pathway for COX-2 protein degradation is initiated after the enzyme undergoes suicide inactivation following cyclooxygenase catalysis. Here, we discuss these molecular determinants of COX-2 expression in detail.

• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1179-1183
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• 2011

In this study, the chromosome-encoded pcuRCAXB genes that are required for p-cresol degradation have been identified by using a newly constructed green fluorescent protein (GFP)-based promoter probe transposon in the long-chain alkylphenol degrader Pseudomonas alkylphenolia. The deduced amino acid sequences of the genes showed the highest identities at the levels of 65-93% compared with those in the databases. The transposon was identified to be inserted in the pcuA gene, with the promoterless gfp gene being under the control of the pcu catabolic gene promoter. The expression of GFP was positively induced by p-cresol and was about 10 times higher by cells grown on agar than those in liquid culture. In addition, p-hydroxybenzoic acid was detected during p-cresol degradation. These results indicate that P. alkylphenolia additionally possesses a protocatechuate ortho-cleavage route for p-cresol degradation that is dominantly expressed in colonies.

• Archives of Pharmacal Research
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• 제15권1호
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• pp.41-47
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• 1992

In order to obtain acetaminophen, a popular analgesic-antipyretic, though microbial p-hydroxylation and N-acetylation of aniline, various Streptomyces strains were screened. Aniline N-acetylation activity was rather ubiquitous but-hydroxylation activity was selective. Microbial conversion pathway of aniline to acetaminophen was considered to be through N-acetylation and p-hydroxylation or vice versa. However, depending on species used, o-hydroxylation and its degradation activity (S. fradiae) and acetaminophen degradation activity (S. coelicolar) were also detected. Among the screened Streptomyces strains, S fradiae NRRL 2702 showed the highest acetanilide p-hydroxylation activity (203% conversion rate). Furthermore, in S. fradiae carbon source and its concentration, phosphate ion concentration and pH of growth medium were found to play the crucial roles in p-hydroxylation activity. Through the proper combination of factors mentioned above, the ten times more activity (26-30% conversion rate) was attained.

• 대한의생명과학회지
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• 제27권3호
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• pp.182-186
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• 2021

Parkinson disease (PD) is becoming one of the most neurodegenerative disorder worldwide. The deposited aggregates have been connected in the pathophysiology of PD, which are degraded either by ubiquitin-proteasomal system (UPS) or autophagy-lysosomal pathway (ALP). Leucin-rich repeat kinase 2 (LRRK2), one of the neurodegenerative proteins of PD is also stringently controlled by both UPS and ALP degradation as well. However, the polyubiquitination pattern of LRRK2 aggregates is largely unknown. Here, we found that K63-linked polyubiquitinations of G2019S mutant, most familial variant for PD, is highly enhanced compared to those of wild type LRRK2 (WT). In addition, in the presence of overexpressed p62/SQSTM-1, ubiquitination of LRRK2 WT or D1994A was reduced, whereas G2019S mutant was not diminished significantly. Therefore, we propose that degradation of G2019S via UPS is more involved with K63-linked ubiquitination than K48-linked ubiquitination, and overexpressed p62/SQSTM-1 does not enhance degradative effect on G2019S variant.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2001년도 추계학술대회
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• pp.157-163
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• 2001

Mycolic acid-containing gram-positive bacteria, so called nocardioform actinomycetes, have become a great interest to environmental microbiologists due to their metabolic versatility, multidegradative capacity and potential for bioremediation of priority pollutants. For example, Rhodococcus rhodochrous N75 was able to metabolize 4-methy1catechol via a modified $\beta$-ketoadipate pathway whereby 4-methylmuconolactone methyl isomerase catalyzes the conversion of 4-methylmuconolactone to 3-methylmuconolactone in order to circumvent the accumulation of the 'dead-end' metabolite, 4-methylmuconolactone. R. rhodochrous N75 has also shown the ability to transform a range of alkyl-substituted catechols to the corresponding muconolactones. A novel 3-methylmuconolactone-CoAsynthetase was found to be involved in the degradation of 3-methylmuconolactone, which is not mediated in a manner analogous to the classical $\beta$-ketoadipate pathway but activated by the addition of CoA prior to hydrolysis of lactone ring, suggesting that the degradative pathway for methylaromatic compounds by gram-positive bacteria diverges from that of proteobacteria. Mycobacterium sp. Strain PYR-l isolated from oil-contaminated soil was capable of mineralizing various polyaromatic hydrocarbons (PAHs), such as naphthalene, phenanthrene, pyrene, fluoranthrene, 1-nitropyrene, and 6-nitrochrysene. The pathways for degradation of PAHs by this organism have been elucidated through the isolation and characterization of chemical intermediates. 2-D gel electrophoresis of PAH-induced proteins enabled the cloning of the dioxygenase system containing a dehydrogenase, the dioxygenase small ($\beta$)-subunit, and the dioxygenase large ($\alpha$)-subunit. Phylogenetic analysis showed that the large a subunit did not cluster with most of the known sequences except for three newly described a subunits of dioxygenases from Rhodococcus spp. and Nocardioides spp. 2-D gel analysis also showed that catalase-peroxidase, which was induced with pyrene, plays a role in the PAH metabolism. The survival and performance of these bacteria raised the possibility that they can be excellent candidates for bioremediation purposes.

• Molecules and Cells
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• 제22권3호
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• pp.353-359
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• 2006

The bone morphogenetic protein (BMP) family has been implicated in control of cartilage development. Here, we demonstrate that BMP-2 promotes chondrogenesis by activating p38 mitogen-activated protein kinase (MAPK), which in turn downregulates $Wnt-7a/{\beta}$-catenin signaling responsible for proteasomal degradation of Sox9. Exposure of mesenchymal cells to BMP-2 resulted in upregulation of Sox9 protein and a concomitant decrease in the level of ${\beta}$-catenin protein and Wnt-7a signaling. In agreement with this, the interaction of Sox9 with ${\beta}$-catenin was inhibited in the presence of BMP-2. Inhibition of the p38 MAPK pathway using a dominant negative mutant led to sustained Wnt-7a signaling and decreased Sox9 expression, with consequent inhibition of precartilage condensation and chondrogenic differentiation. Moreover, overexpression of ${\beta}$-catenin caused degradation of Sox9 via the ubiquitin/26S proteasome pathway. Our results collectively indicate that the increase in Sox9 protein resulting from downregulation of ${\beta}$-catenin/Wnt-7a signaling is mediated by p38 MAPK during BMP-2 induced chondrogenesis in chick wing bud mesenchymal cells.

• Molecules and Cells
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• 제47권1호
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• pp.100001.1-100001.8
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• 2024

In eukaryotes, a primary protein quality control (PQC) process involves the destruction of conformationally misfolded proteins through the ubiquitin-proteasome system. Because approximately one-third of eukaryotic proteomes fold and assemble within the endoplasmic reticulum (ER) before being sent to their destinations, the ER plays a crucial role in PQC. The specific functions and biochemical roles of several E3 ubiquitin ligases involved in ER-associated degradation in mammals, on the other hand, are mainly unknown. We identified 2 E3 ligases, ubiquitin protein ligase E3 component N-recognin 1 (UBR1) and ubiquitin protein ligase E3 component N-recognin 2 (UBR2), which are the key N-recognins in the N-degron pathway and participate in the ER stress response in mammalian cells by modulating their stability. Cells lacking UBR1 and UBR2 are hypersensitive to ER stress-induced apoptosis. Under normal circumstances, these proteins are polyubiquitinated through Lys48-specific linkages and are then degraded by the 26S proteasome. In contrast, when cells are subjected to ER stress, UBR1 and UBR2 exhibit greater stability, potentially as a cellular adaptive response to stressful conditions. Although the precise mechanisms underlying these findings require further investigation, our findings show that cytoplasmic UBR1 and UBR2 have anti-ER stress activities and contribute to global PQC in mammals. These data also reveal an additional level of complexity within the mammalian ER-associated degradation system, implicating potential involvement of the N-degron pathway.