• Biodesign
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• v.6 no.4
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• pp.84-91
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• 2018

Spo0F is a response regulator that modulates sporulation, undergoes phosphorylation for phosphorelay signal transduction, and interacts with various regulatory proteins; however, the mechanisms through which phosphorylation induces structural changes and regulates interactions with binding partners remain unclear. Here, we determined the unphosphorylated crystal structure of Spo0F from the psychrophilic bacterium Paenisporosarcina sp. TG-14 (PaSpo0F) and established a phosphorylation-state structural model. We found that PaSpo0F underwent structural changes (Lys54 and Lys102) by phosphorylation and generated new interactions (Lys102/Gln10 and Lys54/Glu84) to stabilize the ${\beta}4/{\alpha}4$ and ${\beta}1/{\alpha}1$ loop structures, which are important target-protein binding sites. Analysis of Bacillus subtilis Spo0 variants revealed movement by BsSpo0F Thr82 and Tyr84 residues following interaction with BsSpo0B, providing insight into the movement of corresponding residues in PaSpo0F (Thr80 and Tyr82), with further analysis of BsSpo0F/BsRapH interaction revealing alterations in the ${\beta}4/{\alpha}4$ loop region. These results suggest that phosphorylation-induced structural rearrangement might be essential for PaSpo0F activation and expand the understanding of Spo0F-specific activation mechanisms during sporulation.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.48-49
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• 2001

The carcinogens 2-amino-3-methylimidazo［4, 5-f］quinoline (IQ) and 1, 2-dimethylhydrazine (DMH) induce colon tumors in the Fisher 344 rat that contain mutations in Ctnnbl, the gene for b-catenin, but the pattern of mutation differs from that found in human colon cancers. In both species, mutations affect the glycogen synthase kinase 3$\beta$ (GSK-3$\beta$) consensus region of $\beta$-catenin, but whereas they directly substitute critical Ser/Thr phosphorylation sites in human colon cancers, the majority of mutations cluster around Ser$_{33}$ in the rat tumors.(omitted)d)

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10b
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• pp.5-6
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• 2001

The carcinogens 2-arnioo-3-methylimidazo［4,5-f］quinoline (IQ) and 1,2-dimethylhydrazine (DMH) induce colon tumors in the Fisher 344 rat that contain mutations in Ctnnb1, the gene for b-catenin, but the pattern of mutation differs from that found in human colon cancers. in both species, mutations affect the glycogen synthase kinase 3$\beta$ (GSK-3$\beta$) consensus region of $\beta$-catenin, but whereas they directly substitute critical Ser/Thr phosphorylation sites in human colon cancers, the majority of mutations cluster around Ser$^{33}$ in the rat tumors.(omitted)

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.1
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• pp.1-8
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• 2018

The objective of this study was to purify and characterize the ${\beta}-secretase$ inhibitor from enzymatic hydrolysates of blackfin flounder muscle, for development of a novel anti-dementia agent that may be used in the drug or functional food industries. ${\beta}-secretase$ inhibitory peptide was purified from various enzymatic hydrolysates of blackfin flounder muscle. Among six enzymatic hydrolysates, the Alcalase hydrolysate revealed highest ${\beta}-secretase$ inhibitory activity. Consecutive purification of the blackfin flounder muscle hydrolysate using Sephadex G-25 column chromatography and octadecylsilane C18 reversed phase HPLC techniques were used to isolate a potent ${\beta}-secretase$ inhibitory peptide composed of 5 amino acids, Leu-Thr-Gln-Asp-Trp (MW: 526.7 Da). The $IC_{50}$ value of purified ${\beta}-secretase$ inhibitory peptide was $126.93{\mu}M$. Results of this study suggest that peptides derived from blackfin flounder muscle may be beneficial as anti-dementia compounds in functional foods or as pharmaceuticals.

• Biomolecules & Therapeutics
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• v.25 no.3
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• pp.321-328
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• 2017

Steroid sulfatase (STS) is an enzyme responsible for the hydrolysis of aryl and alkyl sulfates. STS plays a pivotal role in the regulation of estrogens and androgens that promote the growth of hormone-dependent tumors, such as those of breast or prostate cancer. However, the molecular function of STS in tumor growth is still not clear. To elucidate the role of STS in cancer cell proliferation, we investigated whether STS is able to regulate the integrin signaling pathway. We found that overexpression of STS in HeLa cells increases the protein and mRNA levels of integrin ${\beta}1$ and fibronectin, a ligand of integrin ${\alpha}5{\beta}1$. Dehydroepiandrosterone (DHEA), one of the main metabolites of STS, also increases mRNA and protein expression of integrin ${\beta}1$ and fibronectin. Further, STS expression and DHEA treatment enhanced phosphorylation of focal adhesion kinase (FAK) at the Tyr 925 residue. Moreover, increased phosphorylation of ERK at Thr 202 and Tyr 204 residues by STS indicates that STS activates the MAPK/ERK pathway. In conclusion, these results suggest that STS expression and DHEA treatment may enhance MAPK/ERK signaling through up-regulation of integrin ${\beta}1$ and activation of FAK.

• Molecules and Cells
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• v.28 no.1
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• pp.25-30
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• 2009

${\beta}$-Arrestins turn off G protein-mediated signals and initiate distinct G protein-independent signaling pathways. We previously demonstrated that angiotensin $AT_1$ receptorbound ${\beta}$-arrestin 1 is cleaved after $Phe^{388}$ upon angiotensin II stimulation. The mechanism and signaling pathway of angiotensin II-induced ${\beta}$-arrestin cleavage remain largely unknown. Here, we show that protein Tyr phosphatase activity is involved in the regulation of ${\beta}$-arrestin 1 cleavage. Tagging of green fluorescent protein (GFP) either to the N-terminus or C-terminus of ${\beta}$-arrestin 1 induced conformational changes and the cleavage of ${\beta}$-arrestin 1 without angiotensin $AT_1$ receptor activation. Orthovanadate and molybdate, inhibitors of protein Tyr phosphatase, attenuated the cleavage of C-terminal GFP-tagged ${\beta}$-arrestin 1 in vitro. The inhibitory effects of okadaic acid and pyrophosphate, which are inhibitors of protein Ser/Thr phosphatase, were less than those of protein Tyr phosphatase inhibitors. Cell-permeable pervanadate inhibited angiotensin II-induced cleavage of ${\beta}$-arrestin 1 in COS-1 cells. Our findings suggest that Tyr phosphorylation signaling is involved in the regulation of angiotensin II-induced ${\beta}$-arrestin cleavage.

• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.826-835
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• 1999

Background : The $\beta_2$ adrenergic receptor ($\beta_2$ AR) polymorphisms occurring at amino acid position 16 (Arg to Gly), 27 (Gln to Glu), 34 (Val to Met), and 164 (Thr to Ile) are known to be functionally relevant and also disease-modifying in subjects with asthma. However the contribution of these polymorphisms to the development of the asthmatic phenotype or other markers for allergic disease remains to be established. Methods : 109 patients with bronchial asthma and 42 healthy person were included. Serum total IgE, allergen specific IgE, and skin prick test were performed to all of the subjects. $\beta_2$ AR polymorphisms were checked by mutated allele specific amplification (MASA) method. Results : The results were as follows. The frequencies of $\beta_2$ AR polymorphisms in asthmatic patients and healthy person were not statistically different(p>0.05). There was no association between $\beta_2$ AR polymorphisms of amino acid position 16, 27, 34 and the existence of atopy among asthmatic patients(p>0.05). Between asthmatic patients with or without elevated IgE level and $\beta_2$ AR polymorphisms of amino acid position 16, 27, 34, there was no statistically significant association(p>0.05). Conclusion : There was no difference in frequency of the $\beta_2$ AR polymorphism between asthmatic patients and healthy person. In the bronchial asthma, association of $\beta_2$ AR polymorphism and atopy/serum total IgE was not found.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.465-471
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• 1997

The cyclodextrin glycosyltransferase (CGTase, EC 3.2.1.19) from Bacillus brevis CD162 was purified by precipitating with ammonium sulfate, DEAE-Sepharose CL-6B column chromatography and Sephadex G-150 column chromatography. The molecular mass and pI of the purified enzyme were estimated to be 74,000 and 6.3 by SDS-PAGE and isoelectric focusing, respectively. The purified enzyme was clearly identified as the CGTase by zymogram after SDS-PAGE. The optimum pH and temperature for the enzyme activity were 8.0 and $55^{\circ}C$, respectively. The enzyme was stable at the range of pH $5.5{\sim}9.0$, and up to $50^{\circ}C$. The amino acid sequence from the $NH_2-terminal$ of the purified CGTase was Ser-Val-Thr-Asn-Lys-Val-Asn-Tyr-Ser-Lys-Asp-Val-Ile-Tyr-Gln. The yields of the products from starch as the substrate were 1.3% for ${\alpha}-$, 33.9% for ${\beta}-$, and 9.7% for ${\gamma}-cyclodextrin$.

• Animal cells and systems
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• v.9 no.3
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• pp.161-171
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• 2005

Integrin-linked kinase 1 (ILK1) regulates several protein kinases, including PKB/Akt kinase and glycogen synthase kinase ${\beta}$. ILK1 is also involved distinctively in the cell morphological and structural functions by interacting with the components of the extracellular matrix or integrin. According to the information of serum- and glucocorticoid-induced kinase 1 (SGK1) substrate specificity (R-X-R-X-X(S/T)-${\phi};{\phi}$ indicates a hydrophobic amino acid), two putative phosphorylation sites, $Thr^{181}\;and\;Ser^{246}$, were found in ILK1. We showed that ILK1 fusion protein and two fluorescein-labeled ILK1 peptides, $FITC-^{174}RTRPRNGTLN^{183}$ and $FITC-^{239}CPRLRIFSHP^{248}$, were phosphorylated by SGK1 in vitro. We also identified that 14-3-3 ${\theta}\;{\varepsilon}\;and\;{\xi}$, among several 143-3 isotypes $({\beta},\;{\gamma},\;{\varepsilon},\;{\eta},\;{\sigma},\;{\theta},\;{\tau}\;and\;{\xi})$ formed protein complex with ILK1 in COS-1 cells. Furthermore, the phosphorylation of $Ser^{246}$ by SGK1 induced the binding with 14-3-3. It was also demonstrated that 14-3-3-bound ILK1 has reduced kinase activity. Thus, these data suggest that SGK1 phosphorylates $Thr^{181}\;and\;Ser^{246}$ of ILK1 and the phosphorylation of its $Ser^{246}$ makes ILK1 bind to 14-3-3, resulting in the inhibition of ILK1 kinase activity.

• BMB Reports
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• v.40 no.6
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• pp.1058-1068
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• 2007

The post-translational modifications of Ser and Thr residues by O-linked $\beta$-N-acetylglucosamine (O-GlcNAc), i.e., O-GlcNAcylation, is considered a key means of regulating signaling, in a manner analogous to protein phosphorylation. Furthermore, it has been suggested that the increased flux of glucose through the hexosamine biosynthetic pathway (HBP) stimulates O-GlcNAcylation, and that this may be responsible for many of the manifestations of type 2 diabetes mellitus. To determine whether excessive O-GlcNAcylation of target proteins results in pancreatic $\beta$ cell dysfunction, we increased nucleocytoplasmic protein O-GlcNAcylation levels in $\beta$ cells by exposing them to streptozotocin and/or glucosamine. Streptozotocin and glucosamine co-treatment increased O-GlcNAcylated proteomic patterns as assessed by immunoblotting, and these increases in nuclear and cytoplasmic protein O-GlcNAcylations were accompanied by impaired insulin secretion and enhanced apoptosis in pancreatic $\beta$ cells. This observed $\beta$cell dysfunction prompted us to examine Akt and Bcl-2 family member proteins to determine which proteins are O-GlcNAcylated under conditions of high HBP throughput, and how these proteins are associated with $\beta$ cell apoptosis. Eventually, we identified ten new O-GlcNAcylated proteins that were expressed during $\beta$ cell apoptosis, and analyzed the functional implications of these proteins in relation to pancreatic $\beta$ cell dysfunction.