• Molecules and Cells
• /
• v.42 no.7
• /
• pp.546-556
• /
• 2019

Protein phosphatase 4 (PP4) is a crucial protein complex that plays an important role in DNA damage response (DDR), including DNA repair, cell cycle arrest and apoptosis. Despite the significance of PP4, the mechanism by which PP4 is regulated remains to be elucidated. Here, we identified a novel PP4 inhibitor, protein phosphatase 4 inhibitory protein (PP4IP) and elucidated its cellular functions. PP4IP-knockout cells were generated using the CRISPR/Cas9 system, and the phosphorylation status of PP4 substrates (H2AX, KAP1, and RPA2) was analyzed. Then we investigated that how PP4IP affects the cellular functions of PP4 by immunoprecipitation, immunofluorescence, and DNA double-strand break (DSB) repair assays. PP4IP interacts with PP4 complex, which is affected by DNA damage and cell cycle progression and decreases the dephosphorylational activity of PP4. Both overexpression and depletion of PP4IP impairs DSB repairs and sensitizes cells to genotoxic stress, suggesting timely inhibition of PP4 to be indispensable for cells in responding to DNA damage. Our results identify a novel inhibitor of PP4 that inhibits PP4-mediated cellular functions and establish the physiological importance of this regulation. In addition, PP4IP might be developed as potential therapeutic reagents for targeting tumors particularly with high level of PP4C expression.

• Journal of Sasang Constitutional Medicine
• /
• v.16 no.3
• /
• pp.96-107
• /
• 2004

1. Objectives This study was carried out to investigate the effects of Gunyuljejo-tang on the $CCl_4$-induced Liver Damage in Rats. 2. Methods Sprague-Dawley rats were devided into 5 experimental groups : Normal, $NS+CCl_4$(Solid extract of $CCl_4$ injection group after Normal Saline feed), $GYJJT+CCl_4$(Solid extract of $CCl_4$ injection group after Gunyuljejo-tang feed), $CCl_4+NS$(Normal Saline feed group after $CCl_4$ injection), $CCl_4+GYJJT$(Solid extract of Gunyuljejo-tang feed group after $CCl_4$ injection). Biochemical assays for serum enzyme activities such as AST, ALT, ALP, BUN, Creatinine, Uric Acid, Total Protein, Albumin, Total Cholesterol, Triglyceride, Glucose, and mRNA Revelation of Cytochrome p450 and activities such as LPO, GSH, GST, Glutathione Reductase, Glutathione Peroxidase, SOD, Catalase, Hydroxyproline, and ${\beta}$-Glucuronidase were performed. 3. Results (1) $GYJJT+CCl_4$ showed lower revelation of Cytochrome p450. (2) $GYJJT+CCl_4$ showed higher GSH activity than $NS+CCl_4$, $CCl_4+GYJJT$ showed higher GSH activity than $CCl_4+NS$ injection significantly. (3) $GYJJT+CCl_4$ showed higher GST activity than $NS+CCl_4$. $CCl_4+GYJJT$ showed higher GST activity than $CCl_4+NS$ significantly. (4) $GYJJT+CCl_4$ showed higher Glutathione Peroxidase activity than $NS+CCl_4$, $CCl_4+GYJJT$ showed higher Glutathione Peroxidase activity than $CCl_4+NS$ significantly. (5) $CCl_4+GYJJT$ showed higher SOD activity than $CCl_4+NS$ significantly. (6) $CCl_4+GYJJT$ showed higher Catalase activity than $CCl_4+NS$ significantly. (7) $GYJJT+CCl_4$ showed lower Hydroxyproline than $NS+CCl_4$ significantly, $CCl_4+GYJJT$ showed higher Hydroxyproline than $CCl_4+NS$ significantly. (8) $GYJJT+CCl_4$ showed higher ${\beta}$-Glucuronidase activity than $NS+CCl_4$, $CCl_4+GYJJT$ showed higher ${\beta}$-Glucuronidase activity than $CCl_4+NS$ significantly. 4. Conclusions Gunyuljejo-tang has the recovering effects on the $CCl_4$-induced Liver Damage significantly.

• Journal of Food Hygiene and Safety
• /
• v.24 no.3
• /
• pp.211-216
• /
• 2009

In order to cope with risk issues of overseas on 4,4'-diaminodiphenylmethane (4,4'-MDA) known to used in the production of polyamide resins, we investigated on 4,4'-MDA migration from plastic cooking utensils. 93 samples of plastic cooking utensils were collected from the retail markets in 7 major cities of Korea during March to June, 2007 and 4,4'-MDA levels migrated to food simulants, water, 4% acetic acid, 20% ethanol and n-heptane, on plastic cooking utensils was quantified by liquid chromatography with tandem mass spectrometry (LC-MS/MS). 4,4'-MDA was detected in 14 samples, and the levels of 4,4'-MDA migrated to food simulants were in the range of $0.001{\sim}0.026$ ppm. Among them, the 4,4'-MDA migration amounts of 2 samples were above 0.01 ppm defined by the EU.

• Horticultural Science & Technology
• /
• v.28 no.5
• /
• pp.810-817
• /
• 2010

We observed abnormal morphology of cotyledons occurring in seedlings derived from open-pollinated and cross-pollinated tetraploid grapes and selected aneuploids, especially hypo- and hyper-tetraploid in seedlings with abnormal morphology of cotyledons. Five types of morphologically abnormal cotyledons were observed. In open-pollination of four tetraploid grapes, the frequency of abnormal cotyledons was 1.6% (49 of 3029 seeds). Percentage of aneuploids in the seedlings of abnormal cotyledons was 20.4% (10 of 49 seedlings). Aneuploids in open-pollination consisted of three (4n = 4x-2), four (4n = 4x-1), and three (4n = 4x+1) seedlings. In cross-pollination of tetraploids, the frequency of abnormal cotyledons was 3.4% (59 of 1729 seeds). Percentage of aneuploids in the seedlings with abnormal cotyledons was 22.0% (13 of 59 seedlings). Aneuploids from cross-pollination of tetraploids consisted of two (4n = 4x-2), nine (4n = 4x-1), one (4n = 4x+1), and one (4n = 4x+3) seedlings. According to the results, although the abnormal cotyledon morphology of seedlings obtained from crossing between tetraploid grapes appeared at low rate (2.3%), aneuploid seedlings occurred at high rate (22.0%); therefore, it indicated that this selection strategy might be very efficient in the initial seedling stage.

• Journal of the Korean Chemical Society
• /
• v.43 no.3
• /
• pp.302-306
• /
• 1999

The 1,3-dipolar cycloaddition reaction of the quinoxaline 4-oxide 10 with 2-chloroacrylonitrile gave the 2,3-dihydro-lH-1,2-diazepino[3,4-blquinoxalines lla, b, respectively, which were converted into the 2,3,4,6-tetrahydro-lH-l,2-diazepino[3,4-b]quinoxaline 12. The reaction of compound lla with selenium dioxide in acetic acid/water resulted in ring transformation to give the 1,4-dihydro-4-oxopyridazino[3,4-blquinoxaline 13.

• Journal of the Korean Chemical Society
• /
• v.41 no.11
• /
• pp.586-589
• /
• 1997

1,2,3,4,5,6-Hexaalkyl-1,4-dibora-2-cyclohexene was not produced by the general preparation method in our laboratory because of difficulties in the preparation of $B_2Cl_4.$ 2,3-Dietyl-1,4,5,6-tetramethyl-1,4-dibora-2-cyclohexene, 2 was synthesized by the reduction-oxidation reaction of potassium and methyliodide from 1,4-dimethyl-2,3-diethyl-1,4-dibora-2-cyclohexene, 1 as a substrate. Cobalt sandwich-complexes, 6, 7 and 8 were synthesized by the reaction of 2,3-diethyl-1,4,5,6-tetramethyl-1,4-dibora-2-cyclohexene with $({\eta}5-C_5H_5Co(C_2H_4)_2.$.

• Journal of Life Science
• /
• v.18 no.2
• /
• pp.264-272
• /
• 2008

The lactate dehydrogenase (EC 1.1.1.27, LDH) isozymes in tissues from Acanthogobius hasta were characterized by biochemical, immunochemical and kinetic methods. The activities of LDH in skeletal muscle and eye tissues were 65.30 and 53.25 units, but LDH activities in heart and liver tissues were very low. LDH/CS (EC 4.1.3.7, citrate synthase) in skeletal muscle was the highest as 22.29. Specific activities of LDH in brain, eye and skeletal muscle were 56.45, 38.04 and 11.0 units/mg, respectively. The LDH isozymes in tissues were separated by polyacrylamide gel electrophoresis after immunoprecipitation with antiserum against $A_4,\;B_4$ eye-specific $C_4$ and liver-specific $C_4$. LDH $AC_4$ isozymes were detected predominantly in skeletal muscle, brain and eye tissues, and $B_4$ isozyme was detected in heart. Anodal eye-specific $C_4$ and cathodal liver-specific $C_4$ were coexpressed in A. hasta. The eye-specific $C_4$ isozyme showed higher activity in eye tissue, but liver-specific $C_4$ isozyme showed lower activity in liver. As a result, one part of molecular structures in $A_4\;and\;C_4,\;A_4\;and\;B_4$, and eye-specific $C_4$ and liver-specific $C_4$ were similar, but in $B_4\;and\;C_4$ were different with each other. Therefore the subunit A may be conservative in evolution, and the evolution of subunit B seems to be faster than that of subunit A. The LDH $A_4$ isozyme of skeletal muscle was purified in the fraction from elution with NAD+ containing buffer of affinity chromatography and eye-specific $C_4$ isozyme was eluted right after $A_4$, so the structure of eye-specific $C_4$ isozyme is similar to $A_4$. And LDH activity remained 35.22-43.47% as a result of the inhibition by pyruvate, the Michaelis-Menten constant values for pyruvate was 0.080-0.098 mM, and Vmax were 153.85 units, 35.09 units in skeletal muscle and eye, respectively. Also the $B_4$ isozyme was the thermo-stablest and $C_4$ was stabler than $A_4$ isozyme. The optimum pH of LDH was 6.5. The results mentioned above indicate that isozymes in tissues showed the properties between LDH $A_4\;and\;B_4$ isozyme as A. hasta was adapted to hypoxic conditions. Also LDH seems to function more effectively under anaerobic condition because LDH in skeletal muscle and eye tissues have high affinity for pyruvate.

• Journal of the Korean Chemical Society
• /
• v.46 no.3
• /
• pp.213-218
• /
• 2002

(${\eta}$5-Cyclopentadienyl)(${\eta}$6-1,2,3,4-tetramethyl-1,4-dibora-2,5-cyclohexadiene)Ni (5) was synthe-sizedas a main product by the reaction of cyclopentadienyl(carbonyl)nickel dimer and 1,2,3,4-tetramethyl-1,4-di-bora-2-cyclohexene (1). Di-allyl nickel reacted with 2,3-diethyl-1,4-di-methyl-1,4-dibora-2-cyclohexene (2) at -20$^{\circ}C$ to give bis(${\eta}$6-2,3-diethyl- 1,4-dimethyl-1,4-dibora-2,5-cyclohexadiene)nickel (6) in the yield of 15%. By the reaction of di-allyl nickel and 2,3-dimethyl-1,4-diethoxy-1,4-di- bora-2-cyclohexene (3) at -20$^{\circ}C$ bis[${\eta}$6-2,3-dim-ethyl-1,4-diethoxy-1,4-di- bora-2,5-cyclohexadiene]nickel (7) was obtained in 22% yield. These double-decker complexes were difficult to separate because of their unstabilities and were identified by ESR, NMR, MS and ele-mental analysis, etc.

• Journal of Life Science
• /
• v.28 no.10
• /
• pp.1132-1139
• /
• 2018

The stability of diverse cellular proteins in eukaryotes is regulated via ubiquitination. Moreover, E3 ligase plays a crucial role in determining substrate specificity and transfers ubiquitins into the substrates during the ubiquitination process. As a type of multi-subunit E3 ligase, cullin4 (CUL4)-based E3 ligase (CRL4) complex is involved in a variety of cellular processes, such as hormonal and stress responses in plants. In spite of several reports on the versatile roles of CRL4 in various signalings in Arabidopsis, CRL4's function in rice has been poorly known. To learn about CRL4-mediated cellular processes in rice in more detail, OsCUL4 that exhibits the highest homology with Arabidopsis CUL4 was isolated, and its expression patterns in various tissues and in response to plant hormones and abiotic stresses were monitored. Exogenous application of ABA or cytokinin increased the transcript levels of the OsCUL4 gene. Moreover, OsCUL4 was significantly upregulated in response to drought and salt stresses. These findings imply that OsCUL4 may be functionally related to ABA- and/or cytokinin-mediated cellular responses. OsCUL4 directly interacted with OsDDB1, an adaptor protein of CRL4, indicating that OsCUL4 can act as a scaffold protein of CRL4. An expression study on the OsCUL4 gene from this report could be used as a starting point to elucidate cellular responses in which a CRL4-mediated ubiquitination process is involved in rice.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2002.05d
• /
• pp.618-621
• /
• 2002

MPEG-4 컨텐츠는 비디오, 오디오 파일을 비롯하여 다양한 타입의 미디어로 구성되는 복합 멀티미디어 데이터이다. 본 논문에서는 MPEG-4 컨텐츠 생산을 위해서 저작 환경을 제공하고 이를 MPEG-4 파일로 생성하는 MPEG-4 컨텐츠 저작 도구를 제안한다. 특히 제안하는 MPEG-4 저작 도구는 AVI 형태의 동영상 자료를 입력 받아, MPEG-4 오디오, 비디오 데이터로 변환하고 이를 MPEG-4 장면 저작에 이용할 수 있다. MPEG-4 컨텐츠는 MPEG-4 파일로 구성되며, 장면 구성이 배제된 오디오, 비디오로만 구성된 MPEG-4 파일과 전체 미디어 데이터가 하나의 장면으로 생성된 MPEG-4 파일이 될 수 있다.