• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.152-159
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• 2014

The regulation of protein tyrosine phosphorylation is mediated by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) and is essential for cellular homeostasis. Co-expression of PTKs with PTPs in Pichia pastoris was used to facilitate the expression of active PTKs by neutralizing their apparent toxicity to cells. In this study, the gene encoding phosphatase PTP1B with or without a blue fluorescent protein or peroxisomal targeting signal 1 was cloned into the expression vector pAG32 to produce four vectors. These vectors were subsequently transformed into P. pastoris GS115. The tyrosine kinases EGFR-2 and $PDGFR{\beta}$ were expressed from vector pPIC3.5K and were fused with a His-tag and green fluorescent protein at the N-terminus. The two plasmids were transformed into P. pastoris with or without PTP1B, resulting in 10 strains. The EGFR-2 and $PDGFR{\beta}$ fusion proteins were purified by $Ni^{2+}$ affinity chromatography. In the recombinant P. pastoris, the PTKs co-expressed with PTP1B exhibited higher kinase catalytic activity than did those expressing the PTKs alone. The highest activities were achieved by targeting the PTKs and PTP1B into peroxisomes. Therefore, the EGFR-2 and $PDGFR{\beta}$ fusion proteins expressed in P. pastoris may be attractive drug screening targets for anticancer therapeutics.

• 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.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.1029-1033
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• 2012

A number of evidence have been accumulated that the regulation of reversible tyrosine phosphorylation, which can be regulated by the combinatorial activity of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs), plays crucial roles in various biological processes including differentiation. There are a total of 107 PTP genes in the human genome, collectively referred to as the "PTPome." In this study, we performed PTP profiling analysis of the HIB-1B cell line, a brown preadipocyte cell line, during brown adipogenesis. Through RT-PCR and real-time PCR, several PTPs showing differential expression pattern during brown adipogenesis were identified. In the case of PTP-RE, it was shown to decrease significantly until 4 days after brown adipogenic differentiation, followed by a dramatic increase at 6 days. The overexpression of PTP-RE led to decreased brown adipogenic differentiation via reducing the tyrosine phosphorylation of the insulin receptor, indicating that PTP-RE functions as a negative regulator at the early stage of brown adipogenesis.

• 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

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1769-1776
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• 2014

Binding modes of a series of catechol derivatives such as protein tyrosine phosphatase 1B (PTP1B) inhibitors were identified by molecular modeling techniques. Docking, molecular dynamics simulations and free energy calculations were employed to determine the modes of these new inhibitors. Binding free energies were calculated by involving different energy components using the Molecular Mechanics-Poisson-Boltzmann Surface Area and Generalized Born Surface Area methods. Relatively larger binding energies were obtained for the catechol derivatives compared to one of the PTP1B inhibitors already in use. The Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) free energy decomposition analysis indicated that the hydroxyl functional groups and biphenyl ring system had favorable interactions with Met258, Tyr46, Gln262 and Phe182 residues of PTP1B. The results of hydrogen bound analysis indicated that catechol derivatives, in addition to hydrogen bonding interactions, Val49, Ile219, Gln266, Asp181 and amino acid residues of PTP1B are responsible for governing the inhibitor potency of the compounds. The information generated from the present study should be useful for the design of more potent PTP1B inhibitors as anti-diabetic agents.

• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1303-1304
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• 2004

• BMB Reports
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• v.45 no.3
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• pp.141-146
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• 2012

Protein tyrosine phosphatase 1B (PTP1B) is important in the regulation of metabolic diseases and has emerged as a promising signaling target. Previously, we reported the PTP1B inhibitory activity of Rheum undulatum (RU). In the present study, we investigated the metabolic regulatory effects of RU in a high-fat diet (HFD) model. RU treatment significantly blocked body weight gain, which was accompanied by a reduction of feed efficiency. In addition, it led to a reduction of liver weight mediated by overexpression of PPAR${\alpha}$ and CPT1 in the liver, and an increase in the expression of adiponectin, aP2, and UCP3 in adipose tissue responsible for the reduction of total and LDL-cholesterol levels. Chrysophanol and physcion from RU significantly inhibited PTP1B activity and strongly enhanced insulin sensitivity. Altogether, our findings strongly suggest that 2 compounds are novel PTP1B inhibitors and might be considered as anti-obesity agents that are effective for suppressing body weight gain and improving lipid homeostasis.

• Proceedings of the KSCN Conference
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• 2004.05a
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• pp.437.1-437
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• 2004

The protein, called PTP1B (protein tyrosine phosphatase 1B), joins a list of enzymes that mice are associated with obesity. The purpose of this study was to investigate the effects of PTP1B inhibitors and taurine on blood lipid profiles in adolescents obesity model rats. Three week-old thirty-six male Sprague-Dawley rats were randomly assigned to six groups (high fat diet group; HFD group, high fat diet ＋ taurine group; HF＋TR group, high fat diet＋PTP1B inhibitor A group; HF＋A group, high fat diet＋PTP1B inhibitor B; HF＋B group, high fat diet＋PTP1B inhibitor A＋taurine group; HF＋A＋TR group, high fat diet ＋ PTP1B inhibitor B＋taurine group; HF＋B＋TR group).(omitted)

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.2
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• pp.109-115
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• 2008

The comparative molecular field analyses(CoMFA) models between the substituents with changing groups($R_1{\sim}R_4$) of $3{\beta}$-hydroxy-12-oleanen-28-oic acid derivatives as substrate molecule and their inhibitory activities($pI_{50}$) against protein tyrosine phosphatase(PTP)-1B were derived and discussed quantitatively. The optimized CoMFA F1 model have best predictability and fitness($r^2_{cv.}=0.654$ and $r^2_{ncv.}=0.995$). The order of contribution ratio (%) with CoMFA fields on the inhibitory activities was a steric field(53.0%), electrostatic field(36.2%) and hydrophobic field(10.8%). From the analytical results of CoMFA contour maps, the inhibitory activities were dependent on the R4 group in substrate molecules. Particularly, the new active compounds(P1 & P2) with the inhibitory activity against melanin synthesis were expected.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.31-32
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• 2011