• ALGAE
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• v.19 no.3
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• pp.271-276
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• 2004

One hundred and fifty four micro algal strains, newly isolated from nationwide freshwaters in Korea, were screened for their anticancer, ant diabetic, and antibiotic activities. The micro algal strains were cultured with different nutritional conditions that were divided into 4 groups as follows; a normal Allen medium, nitrogen (N)-limited medium, phosphorus (P)-limited medium, and N and P-limited medium. Algal biomass was extracted with a mixture of acetone:H₂O (1:1, v:v) and the extracts were used for the screening of bioactive materials. Anticancer, ant diabetic, and antibiotic materials were screened by the methods of vaccinia Hl-related protein tyrosine phosphates (VHR DS-PTPase) inhibition, protein tyrosine phosphates 1B (PTP1B) inhibition, and paper disk. The inhibition activity of VHR DS-PTPase was observed in 18 strains, having a maximum 79% inhibition from Anabaena affinis and the inhibition activity of PTP1B was observed in 9 strains, having a maximum 97% from Sphaerocystis schroeteri. Microcystis aeruginosa incubated in an N and P-limited medium showed antibiotic activity in 8 species out of 13 pathogenic bacteria. As a whole, it seemed that the stressed condition such as N and/or P limitation increased the production of bioactive materials in micro algae.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2883-2884
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• 2011

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.189.1-189
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• 1994

• Bulletin of the Korean Chemical Society
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• v.18 no.7
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• pp.691-692
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• 1997

• Journal of Microbiology and Biotechnology
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• v.29 no.4
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• pp.645-650
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• 2019

Brown adipocytes have an important role in the regulation of energy balance through uncoupling protein-1 (UCP-1)-mediated nonshivering thermogenesis. Although brown adipocytes have been highlighted as a new therapeutic target for the treatment of metabolic diseases, such as obesity and type II diabetes in adult humans, the molecular mechanism underlying brown adipogenesis is not fully understood. We recently found that protein tyrosine phosphatase receptor type B (PTPRB) expression dramatically decreased during brown adipogenic differentiation. In this study, we investigated the functional roles of PTPRB and its regulatory mechanism during brown adipocyte differentiation. Ectopic expression of PTPRB led to a reduced brown adipocyte differentiation by suppressing the tyrosine phosphorylation of VEGFR2, whereas a catalytic inactive PTPRB mutant showed no effects on differentiation and phosphorylation. Consistently, the expression of brown adipocyte-related genes, such as UCP-1, $PGC-1{\alpha}$, PRDM16, $PPAR-{\gamma}$, and CIDEA, were significantly inhibited by PTPRB overexpression. Overall, these results suggest that PTPRB functions as a negative regulator of brown adipocyte differentiation through its phosphatase activity-dependent mechanism and may be used as a target protein for the regulation of obesity and type II diabetes.

• Biomolecules & Therapeutics
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• v.8 no.2
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• pp.153-159
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• 2000

A novel serine/threonine protein phosphatase with EF-hand motif, which belongs to PPEF family was partially cloned from rat brain cDNA by employing RT-PCR method. The size of the amplified clone was 1.6kbp. The amplified DNA was subcloned into pGEM-T-Easy vector and the resulting plasmid was maned as pGEM-rPPEF2. The nucleuotide sequence is shared by 88% with that of mouse PPEF-2 cDNA, and the deduced amino acid sequence reveal 92% homology with that of mouse PPEF-2 cDNA. The N-terminal region of the cloned rat brain PPEF contains a putative phosphatase catalytic domain (PP domain) and the C-terminal region contains multiple $Ca^{2+}$ binding sites (EF region). The putative catalytic domin (PP) and the EF-hand motif (EF) regions were subcloned into pGEX4T-1 and were overexpressed in E. coli DH5 as glutathione-S-transferase (GST) fusion proteins. Expression of the desired fusion protein was identified by SDS-PAGE and also by immunoblot analysis using monoclonal antibody against GST. The recombinant proteins were purified by glutathione-agarose chromatography. This report is first to demonstrate the cloning of PPEF family from rat brain tissues. The clone reported here would be invaluable for the investigation of the role of this new type-phosphatase in rat brain.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.275-277
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• 2012

• Journal of Life Science
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• v.12 no.1
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• pp.113-119
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• 2002

The cloning and expression of Phosphotyrosine Protein Phosphatase into E. coli provides important tools of understanding of its functions and signal transduction mechanisms. The abundant soluble protein of the Phosphotyrosine Protein Phosphatase A (PtpA) and the active site mutant PtpA(C9S) were produced using the expression vector pET26 in E. coli and pIJ6021 with the thiostrepton in S. lividans. The enzyme activity of both proteins extracted by Ni-NTA column had same results from the expression vector pET26 and pIJ6021. The enzyme activity of phosphatase was found in the protein of PtpA, but not in that of C9S. The western blot detected by penta His-tag antibody resulted in the inducer, thiostrepton was not a good trigger to induce a large amount of PtpA protein. The overexpression of both proteins had no significantly different effect on the A factor cascade related to the secondary metabolite and mycelium formation between PtpA and C9S. However, overproduction of PtpA protein using pIJ6021 in S. lividans brought about a dramatic decrease in the amount of phosphotyrosine proteins (p200, p90, and p65), but no significantly phenotypic variation in S. lividans. This indicates that PtpA has an important proteome role in signal transduction mechanism of producing massive amount of phosphotyrosine protein in Streptomyces sp.

• BMB Reports
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• v.31 no.2
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• pp.135-138
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• 1998

A previous study on a yeast protein tyrosine phosphatase, YPTP1, using synthetic phosphotyrosine-containing peptides with various sequences as substrates revealed that DADEpYDA exhibits high affinity ($K_m=4{\mu}M$) toward the enzyme. A modified version of this peptide, GDADEpmFDA, immobilized on a resin, was used in this study as an affinity ligand for the purification of YPTP1. Phosphonomethyl-phenylalanine (pmF) was used as a nonhydrolyzable analog of the phosphotyrosine (pY) residue, with properties similar to pY. A protected form of pmF, $Fmoc-pmF(^{t}Bu)_{2}-OH$, was chemically synthesized and introduced during solid-phase peptide sythesis. YPTP1 was onrexpressed in an E. coli strain carrying a plasmid pT7-7-ptpl. Affinity chromatography of the crude lysate afforded PTPI (39 kDa) of about 50% purity.

• BMB Reports
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• v.46 no.6
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• pp.289-294
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• 2013

To maintain cellular homeostasis against the demands of the extracellular environment, a precise regulation of kinases and phosphatases is essential. In cell cycle regulation mechanisms, activation of the cyclin-dependent kinase (CDK1) and cyclin B complex (CDK1:cyclin B) causes a remarkable change in protein phosphorylation. Activation of CDK1:cyclin B is regulated by two auto-amplification loops-CDK1:cyclin B activates Cdc25, its own activating phosphatase, and inhibits Wee1, its own inhibiting kinase. Recent biological evidence has revealed that the inhibition of its counteracting phosphatase activity also occurs, and it is parallel to CDK1:cyclin B activation during mitosis. Phosphatase regulation of mitotic kinases and their substrates is essential to ensure that the progression of the cell cycle is ordered. Outlining how the mutual control of kinases and phosphatases governs the localization and timing of cell division will give us a new understanding about cell cycle regulation.