• Title/Summary/Keyword: G- protein

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Regulation of a Novel Guanine Nucleotide Binding Protein Tissue Transglutaminase ($G{\alpha}_n$).

  • Im, Mie-Jae
    • BMB Reports
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    • v.34 no.2
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    • pp.95-101
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    • 2001
  • Tissue transglutaminase (TGII, $G{\alpha}h$) belongs to a family of enzymes which catalyze post-translational modification of proteins by forming isopeptides via $Ca^{2+}$-dependent reaction. Although TGII-mediated formation of isopeptides has been implicated to play a role in a variety of cellular processes, the physiological function of TGII remains unclear. In addition to this Tease activity, TGII is a guanosine triphosphatase (GTPase) which binds and hydrolyzes GTP It is now well recognized that the GTPase action of TGII regulates a receptor-mediated transmembrane signaling, functioning as a signal transducer of the receptor. This TGII function signifies that TGII is a new class of GTP-binding regulatory protein (G-protein) that differs from "Classical" heterotrimeric G-proteins. Regulation of enzyme is an important biological process for maintaining cell integrity. This review summarizes the recent development in regulation of TGII that may help for the better understanding of this unique enzyme. Since activation and inactivation of GTPase of TGII are similar to the heterotrimeric G-proteins, the regulation of heterotrimeric G-protein in the transmembrane signaling is also discussed.

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Effects of Polygalae Radix on Apotosis in PC-12 Cell (원지(遠志)물추출물이 Apoptosis에 미치는 효과)

  • Lee, Sang-Chul;Kim, Youn-Sub
    • The Korea Journal of Herbology
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    • v.30 no.1
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    • pp.59-65
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    • 2015
  • Objectives : The purpose of this study was to observe the effects of Polygalae Radix(PR) on 4-HNE-induced apoptosis in PC-12 cell. Methods : A MTT assay was conducted to observe the cytotoxicity of Polygalae Radix on the cell viability and the cytoprotective effect of Polygalae Radix against 4-HNE that causes oxidative stress-induced cytotoxicity, and then a western blot was conducted to observe the expression of $TNF-{\alpha}$, caspase-3, Bax and Bcl-2 protein that are important factors involved with apoptosis signaling pathway. Results : The Polygalae Radix water extract $25{\mu}g$, $50{\mu}g$, $100{\mu}g$ and $200{\mu}g/mL$ had no cytotoxicity on the PC-12 cell. The Polygalae Radix water extract $25{\mu}g$, $50{\mu}g$ and $100{\mu}g/mL$ had the cytoprotective effect against 4-HNE that causes cytotoxicity on the PC-12 cell. The Polygalae Radix water extract $50{\mu}g/mL$ significantly suppressed the increase in $TNF-{\alpha}$ protein expression in PC-12 cell. The Polygalae Radix water extract $25{\mu}g$ and $50{\mu}g/mL$ significantly suppressed the increase in caspase-3 protein expression in PC-12 cell. The Polygalae Radix water extract $25{\mu}g$, $50{\mu}g$ and $100{\mu}g/mL$ suppressed the increase in Bax protein expression in PC-12 cell but had no significance. The Polygalae Radix water extract $25{\mu}g$ and $100{\mu}g/mL$ significantly prevented the decrease in Bcl-2 protein expression in PC-12 cell, Conclusions : These results suggest that the Polygalae Radix water extract is effective in inhibiting apoptosis.

Nutrient Intake of Rural Housewives in Yeo-Ju Area (여주지역 농촌주부들의 영양소 섭취실태)

  • 오영주
    • Journal of Nutrition and Health
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    • v.20 no.5
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    • pp.301-308
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    • 1987
  • An attempt was made to assess nutrient intake of a group of rural housewives living in the area of Yeo-Ju, forty persons were surveyed between July 4 and 5, 1984. All foods and beverage were weighed and collected as consumed in the home over 24-hour periods and protein and ten inorganic element in the diets were assayed by laboratory analysis. 1) The average food intakes of the subject per day were 1105.7g, which consisted of vegetable food (93.1%), animal food 96.6%), and fats and oils (0.3% . The energy percentage of carbohydrate, protein, and fat were 79.5%, 13.4% and 7.1%, respectively, showing higher dependence on carbohydrate. 2) The protein intake calculated from food table was 64.98g. The contribution of animal proteins to total protein was only 18.6g, for below the recommenced allowance. 3) Analysed daily mean intake (% of RDA) of protein (g), Ca(mg), K(g), Na(g), Mg(mg), P(mg), Zn(mg), Cu (mg), Mn(mg), Fe(mg) and Cl(g) were 60.79(93.3%), 395(65.9%), 4.79(85.268%), 6.53(198-594%), 321.4(107.15%), 827.8(103.38%), 15.81(105.4%), 1.66(55-835), 5.12(102.205%), 14.12(78.44%), 9.57(188-563%), respectively.

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Drug Resistance Effects of Ribosomal Protein L24 Overexpression in Hepatocellular Carcinoma HepG2 Cells

  • Guo, Yong-Li;Kong, Qing-Sheng;Liu, Hong-Sheng;Tan, Wen-Bin
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.22
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    • pp.9853-9857
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    • 2014
  • Background: The morbidity and mortality rate of liver cancer continues to rise in China and advanced cases respond poorly to chemotherapy. Ribosomal protein L24 has been reported to be a potential therapeutic target whose depletion or acetylation inhibits polysome assembly and cell growth of cancer. Materials and Methods: Total RNA of cultured amycin-resistant and susceptible HepG2 cells was isolated, and real time quantitative RT-PCR were used to indicate differences between amycin-resistant and susceptible strains of HepG2 cells. Viability assays were used to determine amycin resistance in RPL24 transfected and control vector and null-transfected HepG2 cell lines. Results: The ribosomal protein L24 transcription level was 7.7 times higher in the drug-resistant HepG2 cells as compared to susceptible cells on quantitative RT-PCR analysis. This was associated with enhanced drug resistance as determined by methyl tritiated thymidine (3H-TdR) incorporation. Conclusions: The ribosomal protein L24 gene may have effects on drug resistance mechanisms in hepatocellular carcinoma HepG2 cells.

Development of piezoelectric immunosensor for the rapid detection of marine derived pathogenic bacteria, Vibrio vulnificus

  • Hong, Suhee;Jeong, Hyun-Do
    • Journal of fish pathology
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    • v.27 no.2
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    • pp.99-105
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    • 2014
  • Biosensors consist of biochemical recognition agents like antibodies immobilized on the surfaces of transducers that change the recognition into a measurable electronic signal. Here we report a piezoelectric immunosensor made to detect Vibrio vulnificus. A 9MHz AT-cut piezoelectric wafer attached with two gold electrodes of 5mm diameter was used as the transducer of the QCM biosensor with a reproducibility of ${\pm}0.1Hz$ in frequency response. We have tried different approaches to immobilize antibody on the sensor chip. Concerning the orientation of antibody for the best antigen binding capacity, the antibody was immobilized by specific binding to protein G or by cross-linking through hydrazine. In addition, protein G was cross-linked on glutaraldehyde activated immine layer (PEI) or EDC/NHS activated sulfide monolayer (MPA). PEI was found to be more effective to immobilize protein G following glutaraldehyde activation than MPA. However, hydrazine chip showed a better capability to immobilize more IgG than protein G chip and a higher sensitivity. The sensor system was able to detect V. vulnificus in dose dependent manner and was able to detect bacterial cells within 5 minutes by monitoring frequency shifts in real time. The detection limit can be improved by preincubation to enrich the bacterial cell number.

A Study on Calculation Methods and Amounts Changes of Recommended Protein Intake in the Recommended Dietary Allowances for Koreans and Dietary Reference Intakes for Koreans (한국인의 단백질 섭취권장량 산출방법과 단백질 섭취권장량 변화 - 한국인 영양권장량과 한국인 영양섭취기준을 중심으로 -)

  • Kim, Young-Nam
    • Journal of Korean Home Economics Education Association
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    • v.24 no.2
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    • pp.51-62
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    • 2012
  • This research examined the method and amount changes of recommended protein intakes(RPI) for male and female adult, and pregnant lactating women from 1962's Recommended Dietary Allowances for Korean(KRDA) to 2010's Dietary Reference Intakes for Koreans(KDRIs) revised. As male and female adult's RPI calculation, factorial method was applied until 1989 KRDA, after that nitrogen balance study was applied. Basal factor in factorial method was standard protein(egg or milk protein) requirement or obligatory nitrogen(protein) loss. On the other hand, basal factor in nitrogen balance study was minimum dietary protein requirement to maintain nitrogen equilibrium balance(nitrogen intake = nitrogen excretion). Adjusting factors of RPI were stress and/or protein requirement difference among people. The RPI of male adults were 50~80 g/day, that of female adults were 45~70 g/day. The additional RPI of pregnant women were 10~30 g/day, were calculate based upon the extra protein needs caused by unborn child development. The pregnant women's additional RPI of 2010's KDRIs revised in the periods of first, second, and third trimester were 0, 15, 30 g/day, respectively. The additional RPI of lactation women were 20~30 g/day, were calculated based upon the extra protein needs caused by maternal milk secretion.

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Intake/Balance of Dietary Protein in Korean College Student (한국인 대학생에게 식이성 단백질의 흡수 및 평형)

  • 이영희;오승호
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.23 no.5
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    • pp.711-717
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    • 1994
  • This study was conducted to obtain accurate data on intake, apparent digestibility and nitrogen balance of dietary protein which the korean take in habitually. Subjects were 8 male college students, aged from 20 to 26, and maintained their menu and life pattern as usual during a 4-week study. The same amount of diet that the subjects had consumped, and feces and urine were collected and measured to extract their nitrogen content data by Kjeldahl method. From above data, the apparent digestibility and the body nitrogen balance were estimated by determining daily protein intake and excretion. The daily protein intake measured by Jjeldahil method was 88.3$\pm$ 0.9g(1.45/kg of body weight /day) which marked 8.3% higher than that estimatd by food analysis table. The proportional of animal protein against total protein intake was 50.4$\pm$ 2.3%. Daily fecal protein loss was 14.3$\pm$0.6g and the apparent digestibility was 83.8$\pm$ 0.7%. The urinary nitrogen excretion was 10.30$\pm$0.19g. The nitrogen balance considering nitrogen excretion from feces indicated positive balance of 1.06$\pm$0.20g.

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Molecular Cloning and Expression of a cDNA Encoding Putative Chemosensory Protein from the Mole Cricket, Gryllotalpa orientalis

  • Kim, Iksoo;Lee, Kwang-Sik;Ryu, Kang-Sun;Kim, Jin-Woo;Ahn, Mi-Young;Lee, Heui-Sam;Sohn, Hung-Dea;Jin, Byung-Rae
    • International Journal of Industrial Entomology and Biomaterials
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    • v.6 no.1
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    • pp.87-92
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    • 2003
  • We describe here the cloning, expression and characterization of a cDNA encoding a putative chemosensory protein (CSP) from the mole cricket, Gryllotalpa orientalis. The G. orientalis chemosensory protein cDNA sequences comprised of 384 bp with 128 amino acid residues. The G. orientalis chemosensory protein showed 75.4% protein sequence identity to the Locusta migratoria CSP, Northern blot analysis revealed that signal was stronger in head than leg and cuticle, indicating that the head part containing antennae is a main site for G. orientalis chemosensory protein synthesis. The cDNA encoding G. orientalis chemosensory protein was expressed as approximately 12 kDa polypeptide in baculovirus-infected insect cells.

Effect of Glucose, Starch, Sucrose on the Protein Utilization In Weanling Rats (흰쥐에 있어 탄수화물의 종류에 따른 단백질의 체내 이용에 관한 연구)

  • Hong, Myoung-Bock;Kim, Mi-Kyung
    • Journal of Nutrition and Health
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    • v.13 no.4
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    • pp.167-176
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    • 1980
  • This study was conducted to compare effects of various types of dietary carboh ydrates fed with different levels of protein on the protein utilization in weanling rats. Sixty male Sprague-Dawley rats weighing $60{\pm}1.3grams$ were adapted for 1 week with 77% starch-15% casein diet. Then the animals divided into 12 groups according to body weight and fed each experimental diet for two weeks. Carbodydrates used were glucose, starch, and sucrose and the amount of protein given were 0g, 1g, 3g, 5g casein/day. Protein portion of the diet was fed in two seperate feedings per day while nonprotein portion was fed ad libitum. It seemed that there was no significant difference in the protein utilization by using the different kinds of carbohydrate, but in P.E.R., N.P.U., weights of organs and protein and lipid in total carcass, glucose groups were tended to be slightly lower than starch and sucrose groups. The larger the amount of casein given, the higher were the value of body weight gain, F.E.R., weights of organs, total lipid in carcass and the amount of nitrogen retention. On the while, the larger the amount of casein given, the lower were the value of the intake of non-protein portion, P.E.R., N.P.U, and the percentage of nitrogen retention.

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G-Proteins Expressed in the Ocellus of the Hydromedusan, Spirocodon saltatrix.

  • Iwasa, Tatsuo;Shimazaki, Yumiko;Yamamoto, Masamichi;Ohtsu, Kohzoh
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.278-280
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    • 2002
  • We have cloned a hydromedusan opsin cDNA and showed that the deduced amino acid sequence of the cytoplasmic loop between helices 5 and 6 (loop 5-6) was clearly different from that reported so far. The amino acid sequence of the loop 5-6 is important on determination of the specificity for the coupled G- protein. To clarify which class of G-protein mediates the phototransduction system in the ocellus of the hydromedusan, we investigated G-proteins expressed in the ocellus. By PCR against the cDNA of the ocellus with primers designed according to the conserved amino acid sequence in G-protein a subunit, we obtained three kinds of cDNA fragments. Based on the sequence similarities, ttwo of them (JGI and JG3) were classified as $G_{i}$ and $G_{q}$, respectively. The other one (JG2) was a new subtype within $G_{*}$ class. Electron microscopic immunocytochemistry with the antiserum against the C-terminal sequence of $G_{q}$ or $G_{t}$ revealed the presence. of the both classes in the ocellus. The similarity of the C-terminal sequence of the JG2 with that of bovine $G_{t}$ suggests that the anti- $G_{t}$ antiserum would bind to JG2. These results suggest the possibility that the hydromedusan rhodopsin decides the specificity for the coupled G-protein by the other domain than the loop 5-6.oop 5-6.5-6.

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