• BMB Reports
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• 제43권10호
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• pp.704-709
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• 2010

The Swedish mutation (K595N/M596L) of amyloid precursor protein (APP-swe) has been known to increase abnormal cleavage of cellular APP by Beta-secretase (BACE), which causes tau protein hyperphosphorylation and early-onset Alzheimer's disease (AD). Here, we analyzed the effect of APP-swe in global gene expression using deep transcriptome sequencing technique. We found 283 genes were down-regulated and 348 genes were up-regulated in APP-swe expressing H4-swe cells compared to H4 wild-type cells from a total of approximately 74 million reads of 38 base pairs from each transcriptome. Two independent mechanisms such as kinase and phosphatase signaling cascades leading hyperphosphorylation of tau protein were regulated by the expression of APP-swe. Expressions of catalytic subunit as well as several regulatory subunits of protein phosphatases 2A were decreased. In contrast, expressions of tau-phosphorylating glycogen synthase kinase $3\beta$(GSK-3$\beta$), cyclin dependent kinase 5 (CDK5), and cAMP-dependent protein kinase A (PKA) catalytic subunit were increased. Moreover, the expression of AD-related Aquaporin 1 and presenilin 2 expression was regulated by APP-swe. Taken together, we propose that the expression of APP-swe modulates global gene expression directed to AD pathogenesis.

• Molecules and Cells
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• 제43권12호
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• pp.1035-1045
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• 2020

The Drosophila genome contains four low molecular weight-protein tyrosine phosphatase (LMW-PTP) members: Primo-1, Primo-2, CG14297, and CG31469. The lack of intensive biochemical analysis has limited our understanding of these proteins. Primo-1 and CG31469 were previously classified as pseudophosphatases, but CG31469 was also suggested to be a putative protein arginine phosphatase. Herein, we present the crystal structures of CG31469 and Primo-1, which are the first Drosophila LMW-PTP structures. Structural analysis showed that the two proteins adopt the typical LMW-PTP fold and have a canonically arranged P-loop. Intriguingly, while Primo-1 is presumed to be a canonical LMW-PTP, CG31469 is unique as it contains a threonine residue at the fifth position of the P-loop motif instead of highly conserved isoleucine and a characteristically narrow active site pocket, which should facilitate the accommodation of phosphoarginine. Subsequent biochemical analysis revealed that Primo-1 and CG31469 are enzymatically active on phosphotyrosine and phosphoarginine, respectively, refuting their classification as pseudophosphatases. Collectively, we provide structural and biochemical data on two Drosophila proteins: Primo-1, the canonical LMW-PTP protein, and CG31469, the first investigated eukaryotic protein arginine phosphatase. We named CG31469 as DARP, which stands for Drosophila ARginine Phosphatase.

• 한국토양비료학회지
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• 제49권1호
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• pp.44-52
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• 2016

Plants response to phosphate starvation include the changes of activity of some enzymes, such as phosphatases, fructose-1,6-bisphosphatase, sucrose-phosphate synthase and nitrate reductase. In this study, to determine the effects of phosphate starvation on the change of activities of acid and alkaline phosphatase, fructose-1,6-bisphosphatase, sucrose-phosphate synthase, and nitrate reductase were studied in melon seedlings (Cucumis melo L.). The content of the protein and chlorophyll tended to relatively reduced in melon seedlings subjected to phosphate starvation. Acid phosphatase activity in first and second leaves of melon seedlings was relatively higher than that of third and fourth leaves of seedlings in 14 days after phosphate starvation treatment, respectively. Active native-PAGE band patterns of acid phosphatase in melon leaves showed similar to activities of acid phosphatase, whereas alkaline phosphatase activity was different from the change in the activity of acid phosphatase. Inorganic phosphate content in melon seedlings leaves was constant. The changes of Fructose-1,6-bisphosphatase and sucrose phosphate synthase activities showed similar patterns in melon seedlings leaves, and between these enzymes activities and phosphate nutrition negatively related. Fructose-1,6- bisphosphatase and sucrose phosphate synthase activities showed significant difference in second and fourth leaves, but nitrate reductase showed significant difference in first and second leaves in 14days after phosphate starvation treatment. We concluded that phosphate nutrition could affect the distribution of phosphate, carbon and nitrogen in melon seedlings.

• Journal of Yeungnam Medical Science
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• 제30권1호
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• pp.10-16
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• 2013

Background: Toll-like receptors (TLRs) are well-known pattern recognition receptors. Among the 13 TLRs, TLR2 is the most known receptor for immune response. It activates mitogen-activated protein kinases (MAPKs), which are counterbalanced by MAPK phosphatases [MKPs or dual-specificity phosphatases (DUSPs)]. However, the regulatory mechanism of DUSPs is still unclear. In this study, the effect of a TLR2 ligand (TLR2L, Pam3CSK4) on DUSP4 expression in Raw264.7 cells was demonstrated. Methods: A Raw264.7 mouse macrophage cell line was cultured in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum and 1% antibiotics (100 U/mL penicillin and 100 g/mL streptomycin) at $37^{\circ}C$ in 5% $CO_2$. TLR2L (Pam3CSK4)-mediated DUSP4 expressions were confirmed with RT-PCR and western blot analysis. In addition, the detection of reactive oxygen species (ROS) was measured with lucigenin assay. Results: Pam3CSK4 induced the expression of DUSP1, 2, 4, 5 and 16. The DUSP4 expression was also increased by TLR4 and 9 agonists (lipopolysaccharide and CpG ODN, respectively). Pam3CSK4 also induced ERK1/2 phosphorylation and ROS production, and the Pam3CSK4-induced DUSP4 expression was decreased by ERK1/2 (U0126) and ROS (DPI) inhibitors. U0126 suppressed the ROS production by Pam3CSK4. Conclusion: Pam3CSK4-mediated DUSP4 expression is regulated by ERK1/2 and ROS. This finding suggests the physiological importance of DUSP4 in TLR2-mediated immune response.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.943-947
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• 2008

A phosphate-specific and fluorescent probe was prepared for label-free phosphatase assays based on fluorescence polarization. By using the probe, dephosphorylation reactions of DNA and protein substrates by calf intestinal alkaline phosphatase (CIP) could effectively be monitored in real-time. Since this assay method does not require additional materials such as labeled substrates and phosphospecific antibodies to obtain fluorescence polarization signals, it is simple, cost-effective, and expected to be useful not only for measuring activity of phosphatases but also for high-throughput screening of phosphatase inhibitors.

• Molecules and Cells
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• 제41권7호
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• pp.622-630
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• 2018

Leukocyte common antigen-related protein tyrosine phosphatases (LAR-RPTPs) are cellular receptors of heparan sulfate (HS) and chondroitin sulfate (CS) proteoglycans that regulate neurite outgrowth and neuronal regeneration. LAR-RPTPs have also received particular attention as the major presynaptic hubs for synapse organization through selective binding to numerous postsynaptic adhesion partners. Recent structural studies on LAR-RPTP-mediated trans-synaptic adhesion complexes have provided significant insight into the molecular basis of their specific interactions, the key codes for their selective binding, as well as the higher-order clustering of LAR-RPTPs necessary for synaptogenic activity. In this review, we summarize the structures of LAR-RPTPs in complex with various postsynaptic adhesion partners and discuss the molecular mechanisms underlying LAR-RPTP-mediated synaptogenesis.

• Biodesign
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• 제6권4호
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• pp.79-83
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• 2018

Mitogen-activated protein kinases (MAPKs) are one of the most important enzymes in various cellular activities, and the MAPK signaling pathway is implicated in many disorders. MAPK phosphatases (MKPs) are regulators that contain a MAPK-binding domain (MBD) for MAPK recognition, and a catalytic domain (CD), for dephosphorylation and inactivation of MAPKs. Due to their crucial role in regulating the MAPK pathway, MKPs are regarded as a potential drug target in various diseases. Attempts have also been made to regulate the MAPK pathway by reducing the MKP activity. For drug development, it is important to understand the key features of MAPK-MKP complex formation. This review summarizes the studies on MAPK-MKP complexes, mainly focusing on their selective recognition and catalytic activation.

• BMB Reports
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• 제47권10호
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• pp.593-598
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• 2014

RNA polymerase II carboxyl-terminal domain (RNAPII CTD) phosphatases are responsible for the dephosphorylation of the C-terminal domain of the small subunit of RNAPII in eukaryotes. Recently, we demonstrated the identification of several interacting partners with human small CTD phosphatase1 (hSCP1) and the substrate specificity to delineate an appearance of the dephosphorylation catalyzed by SCP1. In this study, using the established cells for inducibly expressing hSCP1 proteins, we monitored the modification of ${\beta}$-O-linked N-acetylglucosamine (O-GlcNAc). O-GlcNAcylation is one of the most common post-translational modifications (PTMs). To gain insight into the PTM of hSCP1, we used the Western blot, immunoprecipitation, succinylayed wheat germ agglutinin-precipitation, liquid chromatography-mass spectrometry analyses, and site-directed mutagenesis and identified the $Ser^{41}$ residue of hSCP1 as the O-GlcNAc modification site. These results suggest that hSCP1 may be an O-GlcNAcylated protein in vivo, and its N-terminus may function a possible role in the PTM, providing a scaffold for binding the protein(s).

• 한국응용곤충학회지
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• 제34권2호
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• pp.95-99
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• 1995

무당벌레(Harmonia axyridis)의 중장 내에서 먹이 단백질이 소화되는 과정을 연구하기 위하여 진딧물과 생간의 AP를 모델 단백질로 이용하였다. 천역 먹이인 긴꼬리볼록진딧물(Megoura crassicauda)과 인공먹이인 닭의 생간은 각각 고유의 acid phosphatase(AP)를 가지고 있으며, 무당벌레의 중장 내부로 들어온 후에도 활성을 나타내었다. 무당벌레의 장에서 자체적으로 생성하여 중장 내부로 분비하는 AP는 관찰되지 않았다. 무당벌레의 단백질 소화력은 먹이의 종류에 따라 차이를 나타내는 경향을 보였다. 생간의 AP는 무당벌레 중장내에서 12시간이 지나면 거의 활성을 잃어 버리나 긴꼬리볼록 진딧물의 AP는 24시간이 경과하여도 강한 활성을 나타내었다.

• BMB Reports
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• 제36권6호
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• pp.597-602
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• 2003

Acid phosphatases (APases) play a role in the release of phosphate in organic complexes in soil. We investigated tissue- and isoform-specific responses of APases to phosphorus (P) deficiency in three rice genotypes; Dasan-byeo, Sobi-byeo, and Palawan. The levels of shoot APase activity per protein were similar in the three genotypes. They significantly decreased with P deprivation that was longer than seven days. Root APase activity per protein was two- to three-fold higher in Dasan than in Sobi and Palawan. In all genotypes the APase activity increased in P-deficient plants, but the increase was higher in Sobi and Palawan. After 21 days of P deprivation, secreted APase activity increased more than eight-fold in Dasan and two-fold in Sobi and Palawan. Isoform profiles of shoot and root APases were most diverse in Dasan. The activities of the major isoforms in P-deficient shoots decreased in all three genotypes. Depending on the genotypes, further increases in constitutive isoforms and new induction of one to four isoforms occurred in P-deficient roots. The results indicate that tissue and genotype differences in the response of APase to P deficiency are primarily facilitated by the different responses of the isoforms.