• Proceedings of the PSK Conference
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• 2003.10b
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• pp.135.2-135.2
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• 2003

Plasma membrane blebs are observed in many types of apoptotic cells, but their processes of formation remain to be clarified. In the present study, we investigated whether there is a relationship between change of intracellular phosphotyrosine levels and biochemical apoptotic events in Jurkat T cells undergoing apoptosis by agonistic anti-Fas antibody. When Jurkat cells were treated with Fas-antibody in the presence or absence of pretreatment with sodium orthovanadate ($Na_3${VO}_4$), a phosphotyrosine phosphatase (PTPase) inhibitor, membrane blebs disappeared in orthovanadate-treated cells. (omitted)

• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.69-78
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• 1996

This study was done to investigate the enzyme-histochemical localization and characteristics of alkaline and acid phosphatase related with metabolism in sparganum and adult of Spirometrn erinacei. By the enzyme-histochemical assay, the alkaline and acid phosphatases were localized in the tegument and subtegumental musculature of sparganum and adult, but not in the parenchyma. The activities of alkaline phosphatase were stronger in the tegument than in the subtegumental musculature, and activities of acid phosphatase were stronger in the tegument of adults than those of sparganum. The 2 isozymes of alkaline and acid phosphatases were separated from s-sparganum (from snake) and r-sparganum (from experimentaly infected rats) respectively but 4 isozymes of Alp and 3 isoxymes of Acp were separated from adult worms by electrophoresis. In isogyme Alp, the 661)a was the common isozyme, but 130 kDa isozyme of Acp was the common isozyme in spargana and adult worms. By isoelectrofocusing, 4 isozymes (PI 7.9, 7.7, 6.5 and 6.3) and 2 isozymes (PI 7.9 and 7.7) of alkaline phosphatase were separated from adults and spargana respectively. In the stability against heat, activity of alkaline phosphatase was denatured perfectly after heating at 90℃ for 40 seconds. The optimum pH and temperature for activity of alkaline phosphatase were about pH 10 and 50℃, respectively. The maximum activity (unit) of alkaline phosphatase was 22.0 in s- sparganum,25.0 in r-sparganum and 215.0 in adult worms, so that the maximum activity was revealed higher in adults than spargana. As the result from above, we observed that alkaline and acid phosphatases were functioned mainly in the tegument and subtegumental musculature , and the isoxymes of phosphatase were activated differently according to habitat of the parasites. The spargana and adult worms carry out the pafasitism by adapting thenlselves to parasitic circumstance loth these emxymes.

• Biomedical Science Letters
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• v.5 no.1
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• pp.119-129
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• 1999

This study was aimed to investigate the enzyme-histochemical localization and characteristics of alkaline and acid phosphatase extracted from adult of Echinostoma hortense. Using the Gomori calcium stain and the Gomori lead nitrate satin method, we found that the alkaline and acid phosphatases were localized mostly in the intestine, vitellaria and pharynx of Echinostoma hortense. The three isozymes of alkaline phosphatase and two isozymes of acid phosphatase were separated from Echinostoma hortense by electrophoresis. The isozymes of alkaline phosphatase were 145.9, 207.5, 220.8 kDa and the isozymes of acid phosphatase were 179.5 and 209.4 kDa. The activity of alkaline phosphatase was denatured completely after heating at 9$0^{\circ}C$ for 12 seconds. The optimum pH and temperature for activity of alkaline phosphatase were about pH 9 and 4$0^{\circ}C$, while the optimum pH for activity of acid phosphatase was about pH 5. The maximum activity of alkaline phosphatase was at 189 unit, but maximum activity of acid phosphatase was at 71 unit As the result from above, we observed that alkaline and acid phosphatases funtion mainly in the alimentary tract and vitellaria. Echinostoma hortense performs the parasitism in the intestine of host by using proper isozyme of phosphatase.

• BMB Reports
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• v.30 no.3
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• pp.222-228
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• 1997

Protein phosphatase 2C (PP2C) is one of the four major serine/threonine phosphatases which is dependent on $Mg^{2+}$ for its activity. PP2C was purified from rat liver cytosol and its characteristics were investigated. The substrate employed for routine assay was $[^{32}P]casein$ phosphorylated by PKA. The purification process involved DEAE chromatography, ammonium sulfate fractionation, phenyl sepharose chromatography, sephacryl 5-200 gel filtration, and histone agarose chromatography. The SDS-PAGE of PP2C showed one major single protein band at a position corresponding to a molecular mass of 43 kd and the purification fold was 637. The enzyme showed a pH optimum of 8 and $K_M$ value was $1.9\;{\mu}M$. However, when the substrate was changed to $[^{32}P]histone$, the pH optimum was shifted to 7 and $K_M$ value was $2.3\;{\mu}M.\;Mg^{2+}$ was essential to the enzyme activity and okadaic acid did not exert any inhibitory effect on the enzyme. To examine residue in the active site of PP2C effects of some protein-modifying reagents were tested.

• BMB Reports
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• v.43 no.2
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• pp.127-132
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• 2010

Phosphatidylinositol (3,4,5)-triphosphate ($PIP_3$) is a lipid second messenger that employs a wide range of downstream effector proteins for the regulation of cellular processes, including cell survival, polarization and proliferation. One of the most well characterized cytoplasmic targets of $PIP_3$, serine/threonine protein kinase B (PKB)/Akt, promotes cell survival by directly interacting with nucleophosmin (NPM)/B23, the nuclear target of $PIP_3$. Here, we report that nuclear $PIP_3$ competes with Akt to preferentially bind B23 in the nucleoplasm. Mutation of Arg23 and Arg25 in the PH domain of Akt prevents binding to $PIP_3$, but does not disrupt the Akt/B23 interaction. However, treatment with phosphatases PTEN or SHIP abrogates the association between Akt and B23, indicating that nuclear $PIP_3$ regulates the Akt/B23 interaction by controlling the concentration and subcellular dynamics of these two proteins.

• Parasites, Hosts and Diseases
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• v.39 no.2
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• pp.151-160
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• 2001

Randomly selected 435 clones from Acanthamoeba healyi cDNA library were sequenced and a total of 387 expressed sequence tags (ESTs) had been generated. Based on the results of BLAST search, 130 clones (34.4%) were identified as the genes enconding surface Proteins , enzymes for DNA, energy Production or other metabolism, kinases and phosphatases, protease, proteins for signal transduction, structural and cytoskeletal proteins, cell cycle related proteins, transcription factors, transcription and translational machineries, and transporter proteins. Most of the genes (88.5%) are newly identified in the genus Acanthamoeba. Although 15 clones matched the genes of Acanthamoeba located in the public databases, twelve clones were actin gene which was the most frequently expressed gene in this study. These ESTs of Acanthamoeba would give valuable information to study the organism as a model system for biological investigations such as cytoskeleton or cell movement, signal transduction, transcriptional and translational regulations. These results would also provide clues to elucidate factors for pathogenesis in human granulomatous amoebic encephalitis or keratitis by Acanthamoeba.

• Korean Journal of Microbiology
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• v.23 no.2
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• pp.90-100
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• 1985

The present study was designed to investigate cellular regulation of phosphate metabolism between catabolically repressed and derepressed states in yeast (Saccharomyces uvarum). The activities of various phospatases and the contents of phosphate compounds were detected according to the culture phase and various phosphate concentrations. As the results, Saccharomyces uvarum derepressed many phosphate metabolizing enzymes such as alkaline phosphatase, acid phosphatase and ATPase more than ten fold simultaneously during catabolic repression (phospgate and sugar starvation). At the same state, the amounts of orthophosphate, nucleotidic labile phosphate and acid soluble polypgosphate were increased, compared to basal levels of normally cultivated cells. $Mg^{++}-stimulated$ type among all phospatases was appeared to have most of the enzyme activity. It could be postulated that $K^+ -stimulated$ alkaline phosphatase was directly or indirectly correlated with the synthesis of acid insoluble polyphosphate $Mg^{++}-stimulated$ phosphatase with the degradation of polyphosphates. In case of cultivation in the medium supplemented with sugar and phosphate (catabolic derepression), phospgatase activities except for alkaline phosphatase were decreased rapidly through the progressive batch culture, After 12 hrs culture, at early exponential phase, the cellular accumulation of acid insoluble polyphosphate increased about 5 fold, compared to those of the starved cells. Under catabolic repression, it could be postulated that intracellular phosphate metabolism was regulated by derepressions of phosphatases. The function of polyphosphate system was shown to compensate the ATP/ADP system as phosphate donor and energy source especially during catabolic repression.

• Journal of Applied Biological Chemistry
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• v.48 no.4
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• pp.183-186
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• 2005

Arabidopsis AHL gene encodes a 3'(2')-phosphoadenosine 5'-phosphate (PAP)-specific phosphatase that plays a role in the sulfate activation pathway. We complemented E. coli cysQ mutant defective in cysteine biosynthesis with the AHL gene. AHL cDNA was cloned into the prokaryotic expression vector pKK388-1 and transformed into the bacterial mutant. Since cysQ mutant is a leaky cysteine auxotroph only under aerobic conditions, the bacteria were grown in liquid media with vigorous shaking to provide more aeration. In cysteine-free medium, cysQ mutant and the mutant harboring empty vector did not grow well, whereas cells harboring AHL cDNA exhibited significantly improved growth with doubling time of approximately 3 h. cysQ is known to encode a 3'(2'),5'-diphosphonucleoside 3'(2')-phosphohydrolase (DPNPase). However, our data suggest that cysQ protein has PAP-specific phosphatase activity in addition to DPNPase activity. Microbial complementation procedure described in this paper is useful for structure-activity studies of PAP-specific phosphatases identified from microbes and plants.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.2
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• pp.129-135
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• 2020

SHP2 is an unusual protein phosphatase that functions as an activator for several signaling pathways, including the RAS pathway, while most other phosphatases suppress their downstream signaling cascades. The physiological and pathophysiological roles of SHP2 have been extensively studied in the field of cancer research. Mutations in the PTPN11 gene which encodes SHP2 are also highly associated with developmental disorders, such as Noonan syndrome (NS), and cognitive deficits including learning disabilities are common among NS patients. However, the molecular and cellular mechanism by which SHP2 is involved in cognitive functions is not well understood. Recent studies using SHP2 mutant mice or pharmacological inhibitors have shown that SHP2 plays critical role in learning and memory and synaptic plasticity. Here, we review the recent studies demonstrating that SHP2 is involved in synaptic plasticity, and learning and memory, by the regulation of the expression and/or function of glutamate receptors. We suggest that each cell type may have distinct paths connecting the dots between SHP2 and glutamate receptors, and these paths may also change with aging.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.31-36
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• 1994

From the pSKH201 plasmid which had been previously cloned in our laboratory, a 3.0kbp insert DNA encoding the alkaline phosphatase of Kluyveromyces fragilis was cleaved with several restriction endonucleases and ligated int the appropriate sites of M13mp18/19 vectors and sequenced by Sanger's dideoxy chain termination method. The sequence contained a 1,638 bp open reading frame(ORP) whose similarities in nucleotide, when compared with those of Saccharomyces cerevisiae and Escherichia coli by GENETYX program, were found to be 61% and 46%, respectively. The deduced amino acid sequence consists of 546 amino acids and contains several homologous regions in the alkaline phosphatases of E. coli, S.cerevisiae and human placenta.