Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

(1) Background: Ser/Thr protein phosphatase PPM1D is an oncogenic protein. In normal cells, however, PPM1D plays essential roles in spermatogenesis and immune response. Hence, it is necessary to develop novel PPM1D inhibitors without side effects on normal cells. Stimuli-responsive molecules are suitable for the spatiotemporal regulation of inhibitory activity. (2) Methods: In this study, we designed an ion-responsive DNA aptamer library based on G-quadruplex DNA that can change its conformation and function in response to monovalent cations. (3) Results: Using this library, we identified the PPM1D specific inhibitor M1D-Q5F aptamer. The M1D-Q5F aptamer showed anti-cancer activity against breast cancer MCF7 cells. Interestingly, the induction of the structural change resulting in the formation of G-quadruplex upon stimulation by monovalent cations led to the enhancement of the inhibitory activity and binding affinity of M1D-Q5F. (4) Conclusions: These data suggest that the M1D-Q5F aptamer may act as a novel stimuli-responsive anti-cancer agent.

DOI： 10.3390/catal10101153

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Authorship：Corresponding author   Language：English  

DOI： 10.3390/catal9100842

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Language：English   Publishing type：Research paper (scientific journal)  

The protein phosphatase PPM1D (Wip1) was originally identified as a p53 target product. Activation of PPM1D through various mechanism promotes the tumorigenic potential of various cancers by suppressing p53 and other DNA damage response proteins. New functions of PPM1D have recently been revealed in physiological processes such as cell differentiation. However, the regulatory mechanisms of signalling pathway to maintain stemness and induce cell differentiation are still unclear. Here we report that PPM1D modulates retinoic acid (RA) signalling. PPM1D knockdown resulted in decreased alkaline phosphatase activity of the human teratocarcinoma cell line NT2/D1. Inhibition of PPM1D-induced cell differentiation and decreased gene expression of the stem cell marker Oct-4 (POU5F1). RA-induced cell differentiation was promoted by reducing PPM1D activity. RA treatment elicited activation of the MEK-ERK pathway and induced rapid and transient activation of the extracellular signal-regulated kinase 1/2 (ERK-1/2). PPM1D dephosphorylated a phosphopeptide with the TEY motif in ERK-1/2 in vitro. Moreover, phosphorylation of ERK-1/2 was facilitated by PPM1D inhibition. Our study shows that PPM1D plays an important role in maintaining the undifferentiation state and a new function in RA-induced ERK regulation and cell differentiation.

DOI： 10.1093/jb/mvy119

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Authorship：Corresponding author   Language：English   Publisher：Bentham Science Publishers B.V.  

Background: Protein phosphorylation is strictly regulated by protein kinases and protein phosphatases, and disordered regulation of protein phosphorylation often causes serious diseases, such as cancer. Protein phosphatases are divided into two major groups: tyrosine (Tyr) phosphatases and serine/threonine (Ser/Thr) phosphatases. Substrate trapping mutants are frequently used to characterize Tyr phosphatases and identify their substrates
however, a rapid and simple method to identify substrates for Ser/Thr phosphatases has yet to be developed. Recently it has reported that AlF4-/AlF3 and BeF3 - form a complex with Mg2+ in the catalytic center of FCP/SCP phosphatases, and that the Mg2+-AlF4 -/AlF3 complex mimics the transition state of the hydrolysis step, while the Mg2+-BeF3 - complex mimics the aspartylphosphate intermediate. Objectives: The main objective of this study was to develop a novel methodology, termed Phosphorylation Mimic Phage Display (PMPD), to identify substrates for Ser/Thr phosphatase Scp1 using peptide phage display libraries with Mg2+ and AlF4 -. Methods: Recombinant protein of human full-length Scp1 (rScp1) expressed in E. coli system was purified by Co2+ chelated affinity column, and then confirmed by SDS-PAGE and Western-blot analysis. The Ph.D.-C7C or M12 Phage Display Libraries (New England BioLabs, Beverly, MA) were screened using purified rScp1 immobilized on ELISA plate. Then, the plate was blocked with 0.5% (w/v) BSA in maleate buffer at 4°C for 3 h, before adding approximately 1×1010 plaque-forming units (pfu) of the phages in maleate blocking AlF4 - buffer to each well. After incubating, the wells were washed with maleate AlF4 - buffer to remove unbound phages. Then, phages were eluted with Mg2+ and AlF4 - free maleate buffer or with excess rScp1. After the third round of screening, the isolated phages were sequenced and subjected to binding analyses. Results: After panning by PMPD method, 46 and 60 clones were isolated from the Ph.D. C7C and Ph.D. 12 phage libraries, respectively, as Mg2+ or/and AlF4 - -dependent binding clones. The binding analyses showed that M12-1 and Dep-3 specifically bind to Scp1 in an AlF4 --dependent manner. Notably, the Dep-3 peptide contained a Thr-Pro-Met-Ser sequence, which is similar to the Ser2-Pro3-Thr4-Ser5 (Ser/Thr-Pro-partially hydrophobic residue-Ser) sequence found in CTD, which is an endogenous substrate for Scp1. Binding analyses also showed that both BP-14 and M12-6a bound to Scp1 in a Mg2+-dependent manner. BP-14 peptide contained Ser-Thr-Tyr and Pro-Phe-Glu sequences, which are similar to the Ser-Thr-Trp and Ile-Phe-Glu sequences found in M12-6a, suggesting that one or both of these tripeptides may be the binding motif(s) recognized by Scp1. Conclusion: We developed a substrate identification method for the Ser/Thr phosphatase Scp1 using a novel phage display method with AlF4 -. Dep-3 showed a core sequence similar to that of the CTD of RNA polymerase II, an endogenous Scp1 substrate, suggesting that this method is applicable for identifying novel Scp1 substrate candidates. This method will also be applicable for other FCP/SCP-type phosphatases, allowing us to better understand the substrate recognition mechanisms of Ser/Thr phosphatases.

DOI： 10.2174/0929866525666171206114913

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Lamins are thought to direct heterochromatin to the nuclear lamina (NL); however, this function of lamin has not been clearly demonstrated in vivo. To address this, we analyzed (p)olytene chromosome morphology when artificial lamin variants were expressed in Drosophila endoreplicating cells. We found that the CaaX-motif-deleted B-type lamin Dm(0), but not A-type lamin C, was able to form a nuclear envelope-independent layer that was closely associated with chromatin. Other nuclear envelope proteins were not detected in this "ectopic lamina," and the associated chromatin showed a repressive histone modification maker but not a permissive histone modification marker nor RNA polymerase II proteins. Furthermore, deletion of the C-terminal lamin-Ig-fold domain prevents chromatin association with this ectopic lamina. Thus, non-farnesylated B-type lamin Dm(0) can form an ectopic lamina and induce changes to chromatin structure and status inside the interphase nucleus.

DOI： 10.1007/s00412-016-0581-x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

An increase of nucleolar number and size has made nucleoli essential markers for cytology and tumour development. However, the underlying basis for their structural integrity and abundance remains unclear. Protein phosphatase PPM1D was found to be up-regulated in different carcinomas including breast cancers. Here, we demonstrate for the first time that PPM1D regulates nucleolar formation via inducing an increased phosphorylation of the nucleolar protein NPM. We show that PPM1D overexpression induces an increase in the nucleolar number regardless of p53 status. We also demonstrated that specific sequential phosphorylation of NPM is important for nucleolar formation and that PPM1D is a novel upstream regulator of this phosphorylation pathway. These results enhance our understanding of the molecular mechanisms that govern nucleoli formation by demonstrating that PPM1D regulates nucleolar formation by regulating NPM phosphorylation status through a novel signalling pathway, PPM1D-CDC25C-CDK1-PLK1.

DOI： 10.1038/srep33272

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

There has been considerable interest in the patterning of functionalized nanowires because of the potential applications of these materials to the construction of nanodevices. A variety of biomolecular building blocks containing amyloid peptides have been used to functionalize nanowires. However, the patterning of self-assembled nanowires can be challenging because of the difficulties associated with controlling the self-assembly of these functionalized building blocks. Herein, we present a versatile approach for the patterning of nanowires based on the combination of templated fibril growth with a versatile functionalization method using our structure-controllable amyloid peptides (SCAPs). Using this approach, we have succeeded in the formation of multi-type nanowires with tandem domain structures in high yields. Given that the mixing-SCAP method can lead to the formation of tandem fibrils, it is noteworthy that our method allowed us to control the initiation of fibril formation from the gold nanoparticles, which were attached to a short fibril as initiation points. This approach could be used to prepare a wide variety of fibril patterns, and therefore holds great potential for the development of novel self-assembled nanodevices.

DOI： 10.1038/srep31993

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

Nuclear and cytoplasmic morphological changes provide important information about cell differentiation processes, cell functions, and signal responses. There is a strong desire to develop a rapid and simple method for visualizing cytoplasmic and nuclear morphology. Here, we developed a novel and rapid method for probing cellular morphological changes of live cell differentiation process by a fluorescent probe, TAP-4PH, a 1,3a, 6a-triazapentalene derivative. TAP-4PH showed high fluorescence in cytoplasmic area, and visualized cytoplasmic and nuclear morphological changes of live cells during differentiation. We demonstrated that TAP-4PH visualized dendritic axon and spine formation in neuronal differentiation, and nuclear structural changes during neutrophilic differentiation. We also showed that the utility of TAP-4PH for visualization of cytoplasmic and nuclear morphologies of various type of live cells. Our visualizing method has no toxicity and no influence on the cellular differentiation and function. The cell morphology can be rapidly observed after addition of TAP-4PH and can continue to be observed in the presence of TAP-4PH in cell culture medium. Moreover, TAP-4PH can be easily removed after observation by washing for subsequent biological assay. Taken together, these results demonstrate that our visualization method is a powerful tool to probe differentiation processes before subsequent biological assay in live cells.

DOI： 10.1371/journal.pone.0160625

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Protein phosphatase magnesium-dependent 1 delta (PPM1D, Wip1) is a p53 inducible serine/threonine phosphatase. PPM1D is a promising target protein in cancer therapy since overexpression, missense mutations, truncating mutations, and gene amplification of PPM1D are reported in many tumors, including breast cancer and neuroblastoma. Herein, we report that a specific inhibitor, SL-176 that can be readily synthesized in 10 steps, significantly inhibits proliferation of a breast cancer cell line overexpressing PPM1D and induces G2/M arrest and apoptosis. SL-176 decreases PPM1D enzyme activity potently and specifically in vitro. These results demonstrate that SL-176 could be a useful lead compound in the development of effective anti-cancer agents. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmc.2015.08.042

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

To expand the originally developed fluorescent 1,3a, 6a-triazapentalenes as fluorescent labelling reagents, the fluorescence wavelength of the 1,3a, 6a-triazapentalenes was extended to the red color region. Based on the noteworthy correlation of the fluorescence wavelength with the inductive effect of the 2-substituent, electron-deficient 2-(2-cyano-4-methoxycarbonylphenyl)-1,3a, 6a-triazapentalene and 2-(2,6-dicyano-4-methoxycarbonylphenyl)-1,3a, 6a-triazapentalene were synthesized. The former exhibited yellow fluorescence and the latter exhibited red fluorescence, and both compounds exhibited large Stokes shifts, and the 1,3a, 6a-triazapentalene system enabled the same fluorescent chromophore to cover the entire region of visible wavelengths. The potential applications of the 1,3a, 6a-triazapentalenes as fluorescent probes in the fields of the life sciences were investigated, and the 1,3a, 6a-triazapentalene system was clearly proven to be useful as a fluorescent reagent for live cell imaging. Quantum chemical calculations were performed to investigate the optical properties of the 1,3a, 6a-triazapentalenes. These calculations revealed that the excitation involves a significant charge-transfer from the 1,3a, 6a-triazapentalene skeleton to the 2-substituent. The calculated absorption and fluorescence wavelengths showed a good correlation with the experimental ones, and thus the system could enable the theoretical design of substituents with the desired optical properties.

DOI： 10.1039/c4sc02780a

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Language：Japanese  

DOI： 10.14952/SEIKAGAKU.2015.870531

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Other Link： http://search.jamas.or.jp/link/ui/2016055242

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Wnt signaling regulates a variety of cellular processes during embryonic development and in the adult. Many of these activities are mediated by the Frizzled family of seven-pass transmembrane receptors, which bind Wnts via a conserved cysteine-rich domain (CRD). Secreted Frizzled-related proteins (sFRPs) contain an amino-terminal, Frizzled-like CRD and a carboxyl-terminal, heparin-binding netrin-like domain. Previous studies identified sFRPs as soluble Wnt antagonists that bind directly to Wnts and prevent their interaction with Frizzleds. However, subsequent observations suggested that sFRPs and Frizzleds form homodimers and heterodimers via their respective CRDs, and that sFRPs can stimulate signal transduction. Here, we present evidence that sFRP1 either inhibits or enhances signaling in the Wnt3a/beta-catenin pathway, depending on its concentration and the cellular context. Nanomolar concentrations of sFRP1 increased Wnt3a signaling, while higher concentrations blocked it in HEK293 cells expressing a SuperTopFlash reporter. sFRP1 primarily augmented Wnt3a/beta-catenin signaling in C57MG cells, but it behaved as an antagonist in L929 fibroblasts. sFRP1 enhanced reporter activity in L cells that were engineered to stably express Frizzled 5, though not Frizzled 2. This implied that the Frizzled expression pattern could determine the response to sFRP1. Similar results were obtained with sFRP2 in HEK293, C57MG and L cell reporter assays. CRDsFRP1 mimicked the potentiating effect of sFRP1 in multiple settings, contradicting initial expectations that this domain would inhibit Wnt signaling. Moreover, CRDsFRP1 showed little avidity for Wnt3a compared to sFRP1, implying that the mechanism for potentiation by CRDsFRP1 probably does not require an interaction with Wnt protein. Together, these findings demonstrate that sFRPs can either promote or suppress Wnt/beta-catenin signaling, depending on cellular context, concentration and most likely the expression pattern of Fzd receptors. Published by Elsevier Inc.

DOI： 10.1016/j.cellsig.2013.09.016

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Amyloid peptides have great potential as building blocks in the creation of functional nanowires due to their natural ability to self-assemble into nanofibrillar structures and because they can be easily modified with various functional groups. However, significant modifications of an amyloid peptide generally alter its self-assembly property, making it difficult to construct functionalized fibrils with a desired structure and function. In this study, a very effective method to overcome this problem is demonstrated by using our structure-controllable amyloid peptides (SCAPs) terminated with a three-amino-acid-residue cap. The method consists on mixing two or more structurally related amyloid peptides with a fraction of modified SCAPs which co-assemble into a fibril. This SCAP-mixing method provides remarkable control over the self-assembly process both on the small oligomers level and the macroscopic fibrils level. Furthermore, it is shown that the modified peptides imbedded in the resulting fibril can subsequently be functionalized to generate nanowires with the desired properties, highlighting the importance of this SCAP method for nanotechnology applications. Copyright © 2013 WILEY-VCH Verlag GmbH &amp
Co. KGaA, Weinheim.

DOI： 10.1002/adfm.201300577

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Histone deacetylase (HDAC) inhibitors belong to a new class of potential anticancer agents. It may be possible to reduce some of the toxicity by specifically targeting only the HDAC isoform. Here, stereoisomeric HDAC inhibitors containing fluoroalkene were analyzed for their specificity toward HDAC isoforms. Z-Form 1(Z) showed high affinity to HDACs whereas E-isoform 1(E) had lower affinity to HDAC1 and HDAC4. These data suggested that introduction of alkene with E/Z configuration to HDAC inhibitor can be a new strategy to develop the isoform-selective HDAC inhibitors.

DOI： 10.1246/cl.130243

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Tumor suppressor protein p53 induces cell cycle arrest, apoptosis, and senescence in response to cellular stresses. The p53 tetramer formation is essential for its functions. Despite of these crucial functions of p53 for integrity of genome, activation of the p53 signal pathway causes low induced pluripotent stem (iPS) cell generation efficiency. In this study, we report transient inhibition of p53-dependent transcription using a p53 tetramerization domain peptide that contains cell penetrating and nuclear localization signals. The peptide was efficiently introduced into cells and inhibited p21 expression via hetero-tetramerization with endogenous p53 protein. This method can be applied towards safe and efficient iPS cell generation. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2012.02.085

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

PPM1D is a p53-inducible Ser/Thr protein phosphatase. PPM1D gene amplification and overexpression have been reported in a variety of human tumors, including breast cancer and neuroblastoma. Because the phosphatase activity of PPM1D is essential for its oncogenic role, PPM1D inhibitors should be viable anti-cancer agents. In our current study, we showed that SPI-001 was a potent and specific PPM1D inhibitor. SPI-001 inhibited PPM1D phosphatase activity in PPM1D-overexpressing human breast cancer cells and increased phosphorylation of p53. Furthermore, SPI-001 suppressed cell proliferation by inducing apoptosis. Our present study suggested that SPI-001 was a potential lead compound in developing anti-cancer drugs. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2011.10.084

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

Protein phosphorylation plays central roles in a wide variety of signal transduction pathways and most phosphorylated proteins contain multi-phosphorylated sites. PPM1 type Ser/Thr protein phosphatase family is known to show rigid substrate specificity unlike other Ser/Thr phosphatase PPP family including PP1, PP2A and PP2B. PPM1 type phosphatases are reported to play important roles in growth regulation and in cellular stress signalling. In this study, we developed a phosphatase assay of PPM1D using phosphatase motif-specific antibody. PPM1D is a member of PPM1 type Ser/Thr phosphatase and known to dephosphorylate Ser(P)-Gln sequence. The gene amplification and overexpression of PPM1D were reported in many human cancers. We generated the monoclonal antibody specific for the Ser(P)-Gln sequence, named 3G9-H11. The specificity of this method using ELISA enables the convenient measurement of the dephosphorylation level of only PPM1D target residues of substrate peptides with multiple phosphorylated sites in the presence of multiple phosphatases. In addition, the antibody was applicable to immunoblotting assay for PPM1D function analysis. These results suggested that this method should be very useful for the PPM1D phosphatase assay, including high-throughput analysis and screening of specific inhibitors as anti-cancer drugs. The method using phosphatase motif-specific antibody can be applied to other PPM1 phosphatase family.

DOI： 10.1093/jb/mvr056

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Stabilization of protein structures and protein protein interactions are critical in the engineering of industrially useful enzymes and in the design of pharmaceutically valuable ligands. Hydrophobic interactions involving phenylalanine residues play crucial roles in protein stability and protein-protein/peptide interactions. To establish an effective method to explore the hydrophobic environments of phenylalanine residues, we present a strategy that uses pentafluorophenylalanine (F(5)Phe) and cyclohexylalanine (Cha). In this study, substitution of F(5)Phe or Cha for three Phe residues at positions 328, 338, and 341 in the tetramerization domain of the tumor suppressor protein p53 was performed. These residues are located at the interfaces of p53 p53 interactions and are important in the stabilization of the tetrameric structure. The stability of the p53 tetrameric structure did not change significantly when F(5)Phe-containing peptides at positions Phe328 or Phe338 were used. In contrast, the substitution of Cha for Phe341 in the hydrophobic core enhanced the stability of the tetrameric structure with a T(m) value of similar to 100 degrees C. Phe328 and Phe338 interact with each other through pi-interactions, whereas Phe341 is buried in the surrounding alkyl side-chains of the hydrophobic core of the p53 tetramerization domain. Furthermore, high pressure-assisted denaturation analysis indicated improvement in the occupancy of the hydrophobic core. Considerable stabilization of the p53 tetramer was achieved by filling the identified cavity in the hydrophobic core of the p.5.3 tetramer. The results indicate the status of the Phe residues, indicating that the "pair substitution" of Cha and F(5)Phe is highly suitable for probing the environments of Phe residues. (C) 2011 Wiley Periodicals, Inc. Biopolymers 95: 410-419, 2011.

DOI： 10.1002/bip.21594

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Secreted frizzled-related protein (sFRP)-1 is a Wnt antagonist that inhibits breast carcinoma cell motility, whereas the secreted glycoprotein thrombospondin-1 stimulates adhesion and motility of the same cells. We examined whether thrombospondin-1 and sFRP-1 interact directly or indirectly to modulate cell behavior. Thrombospondin-1 bound sFRP-1 with an apparent K(d) = 48 nM and the related sFRP-2 with a K(d) = 95 nM. Thrombospondin-1 did not bind to the more distantly related sFRP-3. The association of thrombospondin-1 and sFRP-1 is primarily mediated by the amino-terminal N-module of thrombospondin-1 and the netrin domain of sFRP-1. sFRP-1 inhibited alpha 3 beta 1 integrin-mediated adhesion of MDA-MB-231 breast carcinoma cells to a surface coated with thrombospondin-1 or recombinant N-module, but not adhesion of the cells on immobilized fibronectin or type I collagen. sFRP-1 also inhibited thrombospondin-1-mediated migration of MDA-MB-231 and MDA-MB-468 breast carcinoma cells. Although sFRP-2 binds similarly to thrombospondin-1, it did not inhibit thrombospondin-1-stimulated adhesion. Thus, sFRP-1 binds to thrombospondin-1 and antagonizes stimulatory effects of thrombospondin-1 on breast carcinoma cell adhesion and motility. These results demonstrate that sFRP-1 can modulate breast cancer cell responses by interacting with thrombospondin-1 in addition to its known effects on Wnt signaling. Published by Elsevier Inc.

DOI： 10.1016/j.abb.2011.03.004

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Other Link： http://orcid.org/0000-0002-0580-0125

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Li-Fraumeni syndrome, a hereditary disorder characterized by familial clusters of early-onset multiple tumors, is caused by mutation of the TP53 gene, which encodes the p53 tumor suppressor protein. Mutation of Arg337 to histidine in the tetramerization domain of p53 is most frequently observed in Li-Fraumeni syndrome. This mutation is reported to destabilize the tetrameric structure of p53. We designed and synthesized calix[6] arene derivatives, which have six imidazole or pyrazole groups at the upper rim. In this study, we report, for the first time, the enhancement of the in vivo transcriptional activity of the most common Li-Fraumeni p53 mutant by imidazole-calix[6] arene through stabilization of the oligomer formation. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmcl.2010.06.053

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BENTHAM SCIENCE PUBL LTD  

We report that the addition of amino acids to the amyloid peptide dramatically affected the structure and the rate of formation of amyloid fibrils. The attachment of three lysines to A beta(10-35) gave the formation of remarkably long fibrils, while three glutamates resulted in a faster formation rate of the fibrils.

DOI： 10.2174/092986610790963618

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Inhibitors of histone deacetylases (HDAC) are emerging as a promising class of anti-cancer agents. The mercaptoacetoamide-based inhibitors are reported to be less toxic than hydroxamate and are worthy of further consideration. Therefore, we have designed a series of analogs as potential inhibitors of HDACs, in which the mercaptoacetamide group was replaced by (mercaptomethyl) fluoroalkene, and their HDAC inhibitory activity was evaluated. Subnanomolar inhibition was observed for all synthetic compounds. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmc.2009.12.005

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

The tumor suppressor protein p53 is a tetrameric phosphoprotein that. induces cell cycle, development, and differentiation by regulating the expression of target genes. The tetramerization of p53 is essential for its tumor suppressor functions. It has been known that oxidation of proteins affects their structure and function. A methionine residue (Met340) is located at the hydrophobic core tit p53 tetramerization domain. Here, we demonstrated that Met340 residue can be oxidized to methionine sulfoxide under oxidative conditions and investigated effects of-the oxidation of p53 tetramerization domain oil its stability and oligomerization state by CD measurement and gel filtration. The oxidation of Met340 drastically induced destabilization of the p53 tetramer by 22.8 kJ/mol of Delta Delta G (TM), while retaining the identical conformation as that of the wild-type peptide. Trypsin digestion experiments also showed that oxidation of Met340 allowed the peptide to form locally loose structure and become more sensitive to enzyme degradation. Tit(tetrameric structure may be destabilized because the oxidation of Met340 induces charge repulsion and/or steric hindrance between the sulfoxide groups. These results taken together suggested that oxidation of methionine residues tit the p53 protein might lie one of the inactivation mechanism of p53 transcriptional function under conditions of oxidative stress. (C) 2008 Periodicals, Inc. Biopolymers 91: 78-84, 2009.

DOI： 10.1002/bip.21084

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

PPM1D is a PPM1 type protein phosphatase and is induced in response to DNA damage. PPM1D-deficient mice show defects in spermatogenesis and lymphoid cell functions but the mechanisms underlying these phenotypes remain unknown. In our current study, we identify and characterize an alternative splicing variant (denoted PPM1D430) of human PPM1D at both the mRNA and protein level. PPM1D430 comprises the common 420 residues of the known PPM1D protein (PPM1D605) and contains a stretch of PPM1D430-specific 10 amino acids. Semi-quantitative reverse transcriptionpolymerase chain reaction (RTPCR) analysis revealed that PPM1D430 mRNA is also induced in response to the genotoxic stress in a p53-dependent manner. In vitro phosphatase analysis and PPM1D430-specific RNA interference analysis further indicated that PPM1D430 can dephosphorylate Ser15 of human p53 both in vitro and in vivo. On the other hand, expression profiling of this gene by RTPCR analysis of a human tissue cDNA panel revealed that PPM1D430 is expressed exclusively in testes and in leucocytes whereas PPM1D605 is ubiquitous. In addition, PPM1D430 shows a different subcellular localization pattern and protein stability when compared with PPM1D605 under some conditions. Our current findings thus suggest that PPM1D430 may exert specific functions in immune response and/or spermatogenesis.

DOI： 10.1093/jb/mvn135

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DOI： 10.1007/978-0-387-73657-0_249

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：BENTHAM SCIENCE PUBL LTD  

Protein phosphatase magnesium-dependent 1, delta (PPM1D) is a member of the PPM1 (formerly PP2C) protein phosphatase family, and is induced in response to DNA damage. The overexpression of PPM1D is thought to exert oncogenic effects through the inhibition of tumor suppressor proteins. PPM1D shows high selectivity for the primary sequence in its substrates when compared with other phosphatases, but the mechanisms underlying substrate recognition by this enzyme is not clearly known. In our present study we wished to identify the active center and further elucidate the substrate preference of PPM1D, and to this end performed sequence alignments among the human PPM1 type phosphatases. The results of this analysis clearly showed that the putative active site residues of PPM1D are highly conserved among the PPM1 family members. Phosphatase analyses using PPM1D mutants further identified the metal-chelating residues and a phosphate binding residue. In kinetic analyses using a series of phosphorylated p53 peptide analogs, the introduction of acidic residues into the region flanking the sites of dephosphorylation enhanced their affinity with PPM1D. Homology modeling of PPM1D also revealed that PPM1D contains two characteristic loops, a Pro-residue rich loop on the opposite side of the active site and a basic-residue rich loop in the vicinity of the active site in the catalytic domain. Interestingly, nonhydrolyzable AP4-3E peptides derived from the acidic p53 peptide analogs very effectively blocked PPM1D activity in an uncompetitive manner, suggesting that AP4-3E peptides may be useful lead compounds in the development of novel inhibitors of PPM1D.

DOI： 10.2174/092986608785849236

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

Histone acetyltransferases form crucial links in transducing extrinsic signals to actual initiation of transcription. A multitude of stress signal integrations occur through the interaction of p300 with p53 phosphorylated at different residues of the transactivation domain. How such interactions activate different gene expression programs remains largely unknown. p300 contains at least five domains that are known to interact with p53, but their role in transcription regulation is not known. We measured the binding affinity of various phosphorylated transactivation. domains towards several p53 binding domains of p300 by fluorescence anisotropy. The binding affinities of different phosphorylated transactivation domains of p53 towards different domains of p300 vary by several orders of magnitude, indicating that interactions of different post-translationally modified forms of p53 may occur through different domains of p300. Thus, different post-translationally modified p53 fragments may form transcription-initiating complexes of different configurations, leading to the activation of different promoters and pathways. (C) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jmb.2007.11.082

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Endogenous opioid peptides consist of a conserved amino acid residue of Phe 3 and Phe 4, although their binding modes for opioid receptors have not been elucidated in detail. Endomorphin-2, which is highly selective and specific for the mu opioid receptor, possesses two Phe residues at the consecutive positions 3 and 4. In order to clarify the role of Phe 3 and Phe 4 in binding to the It receptor, we synthesized a series of analogs in which Phe 3 and Phe 4 were replaced by various amino acids. It was found that the aromaticity of the Phe-p-phenyl groups of Phe 3 and Phe 4 is a principal determinant of how strongly it binds to the receptor, although better molecular hydrophobicity reinforces the activity. The receptor binding subsites of Phe 3 and Phe 4 of endomorphin-2 were found to exhibit different structural requirements. The results suggest that [Trp 3]endomorphin-2 (native endomorphin-1) and endomorphin-2 bind to different receptor subclasses. (C) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.bmc.2007.03.009

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-LISS  

Pigment-dispersing factor (PDF) is an 18-mer peptide that acts as a principal neurotransmitter of the insect circadian clock. Our previous study, utilizing anti-Uca beta-PDH polyclonal antibody (pAb) to immunolabel the optic lobe of the cricket Gryllus bimaculatus, suggested the existence of an alternative PDF-like peptide in the outer cells of the first neuropile, or lamina (La), which were much less immunoreactive than the inner cells of the second neuropile, the medulla (Me). To obtain structural information about such a PDF-like peptide, we prepared 10 anti-Gryllus PDF monoclonal (mAb) and pAb antibodies and analyzed their detailed epitope specificities. The PDFMe and PDFLa inner cells and their axonal projections were clearly immunoreactive to all these antibodies, revealing the widespread immunocytochemical organization of the PDF system in the optic lobe, as seen previously with anti-Uca beta-PDH pAb and anti-Gryllus PDF mAb, the epitope structures of which were also clarified in this study. The lamina outer cells, which we found lacked a target pdf mRNA, displayed specific immunoreactivities, indicating that the cells contain a distinct PDF-like peptide possessing both N- and C-terminal structures. These cells were not immunolabeled by some other monoclonal antibodies, however, implying that the PDFLa outer cells have a PDF isoform peptide devoid of Asn at positions 6 and 16. This isoform was also identified in a varicose arborization in the lamina. These results suggest not only the structure of the peptide, but also the possibility of additional functions of this novel PDF isoform.

DOI： 10.1002/cne.21112

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC  

We converted Ser-207, located in helix 5 of the beta(2)-adrenergic receptor, into all other natural amino acids. To quantify receptor activation as a receptor number-independent parameter and directly related to G(s) activation, we expressed the mutants in a G alpha(s)-tethered form. GTP exchange in such constructs is restricted to the fused alpha-subunit and is a linear function of the receptor concentration. Except S207R, all other mutants were expressed to a suitable level for investigation. All mutations reduced the binding affinities of the catechol agonists, epinephrine and isoproterenol, and the extent of reduction was unrelated to the residue ability to form hydrogen bonds. Instead, both enhancements and reductions of affinity were observed for the partial agonist halostachin and the antagonist pindolol. The mutations also enhanced and diminished ligand-induced receptor activation, but the effects were strictly ligand-specific. Polar residues such as Asp and His exalted the activation by full agonists but suppressed that induced by the partial agonists halostachin and dichloroisoproterenol. In contrast, hydrophobic residues such as Ile and Val augmented partial agonist activation. Only Ile and Lys produced a significant increase of constitutive activity. The effects on binding and activity were not correlated, nor did such parameters show any clear correlation with up to 78 descriptors of amino acid physicochemical properties. Our data question the idea that Ser-207 is exposed to the polar crevice in the unbound receptor. They also suggest that the active receptor form induced by a full agonist might be substantially different from that caused by constitutive activation.

DOI： 10.1074/jbc.M502901200

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Secreted Frizzled-related proteins (sFRPs) bind Wnts and modulate their activity. To identify putative sFRP-1 binding motifs, we screened an M 13 phage displayed combinatorial peptide library. A predominant motif, LN-VDGRW-L/V, was present in similar to70% of the phage that bound sFRP-1. Use of peptide/alkaline phosphatase chimeras and alanine scanning confirmed that the conserved motif was important for sFRP-1 recognition. The dissociation constant for a peptide/sFRP-1 complex was 3.9 muM. Additional analysis revealed that DGR was the core of the binding motif. Although Wnt proteins lack this sequence, other proteins possessing the DGR motif may function as novel binding partners for sFRP-1. Published by Elsevier Inc.

DOI： 10.1016/j.peptides.2004.07.010

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC BONE & MINERAL RES  

We determined that sFRP-1 mRNA was differentially expressed by osteoblast/stromal cell lines and that sFRP-1 neutralizing antibodies and siRNA complementary to sFRP-1 coding sequence enhanced, while recombinant sFRP-1 inhibited, osteoclast formation. In studying the mechanism of action for sFRP-1, we found that sFRP-1 could bind recombinant RANKL. These results suggest potential cross-talk between Wnt and RANKL pathways.

DOI： 10.1359/JBMR.040807

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ZOOLOGICAL SOC JAPAN  

The molecular basis of the circadian clock is an autoregulatory feedback loop in which the PAS domain-containing protein PERIOD periodically inhibits its own transcription. In the present study on PERIOD of the silk moth Bombyx mori, we have cloned two distinct period mRNA homologues with different PAS domain sequences either with or without the pentapeptide GTQEK. A period cDNA fragment first amplified by PCR exhibited a 15 bp-deleted nucleotide sequence in the PAS domain, compared with the database sequence. A possible alternative splicing mechanism was examined by PCR analyses, and a 15 bp-inserted clone was also amplified. The entire sequences of these period a and period P isoforms were then determined by the 3' and 5' RACE methods. Isoform period a consists of a 3,324 bp oligonucleotide encoding 1,108 amino acid residues, whereas isoform period P comprises 3,309 bp corresponding to 1,103 amino acids. Isoforms period a and period P were found to be exactly identical except for the 15 bp deletion/insertion site. Such a pair of isoforms with a deletion/insertion sequence, namely two splice variants, has previously been reported only for the PERIOD proteins of the two honeybees, Apis mellifera and A. cerana. The occurrence of an alternative splicing mechanism in the a mori period gene was hypothesized based on the genome structure recently clarified. Bombyx mori PERIOD a and P proteins are the isomers that reveal firstly the different PAS domain sequences.

DOI： 10.2108/zsj.21.903

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS LTD  

Pigment-dispersing factor (PDF), an 18-amino acid neuropeptide, is a principal circadian neurotransmitter for the circadian rhythms of the locomotor activity in flies. Recently, two completely different types of PDF precursor were clarified; that of the cricket Gryllus bimaculatus and that of the last-summer cicada Meimuna opalifera. The G. bimaculatus PDF precursor is extraordinarily short and comprises a nuclear localization signal (NLS), while the M. opalifera PDF precursor is of ordinary length, comparable to that seen for the precursors of crustacean beta-PDH homologues. Although their PDF peptide regions were exactly the same, the regions containing a signal peptide combined with a PDF-associated peptide (PAP) were remarkably different from each other. Such a grouping suggested a fundamental role for the PAP peptide in the circadian clock, perhaps associated with PDF function. In the present study, the cDNA cloning of PDF from the adult brains of the housefly Musca domestica was carried out and it was found that an isolated clone (527 bp) encodes a PDF precursor protein of ordinary length. The PDF peptide shows a high sequence identity (78%-94%) and similarity (89%-100%) to insect PDFs and also to the crustacean beta-PDH peptides. In particular, there is only a single amino acid difference between the PDFs of Musca and Drosophila; at position 14 Ser for Musca PDF and Asn for Drosophila PDF. A characteristic Ser(10) in Drosophila was retained in Musca, indicating the presence of a structural profile unique to these PDFs. The results of sequence analyses suggest that Musca and Drosophila PDFs are to be considered members of a single group that has evolved structurally. When the primary structure of the PAP regions was compared, the Musca PDF precursor also belonged to the same group as that to which the Drosophila PDF precursor belongs. Copyright (C) 2003 European Peptide Society and John Wiley Sons, Ltd.

DOI： 10.1002/psc.511

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DOI： 10.1007/BF02442573

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ZOOLOGICAL SOC JAPAN  

Pigment-dispersing factor (PDF), an 18-amino acid neuropeptide, is a principal circadian neuromodulator functioning downstream of the insect brain's circadian.clock, modulating daily rhythms of locomotor activity. Recently, we found that PDF precursors of the cricket Gryllus bimaculatus comprise a nuclear localization signal (NLS). Moreover, the nuclear localization of PDF immunoreactivity and the translocation of GFP-fused PDF precursor into the nucleus have both been demonstrated. These suggest a fundamental role for PDF peptide in the circadian clock system within the nucleus, in addition to its role in downstream neural events. In the present study, we carried out the cDNA cloning of PDF from adult brains of the last-summer cicada Meimuna opalifera, and found that an isolated clone (545 bp) encodes an ordinary PDF precursor protein. PDF peptide itself shows a high sequence identity (78-94%) and similarity (89-100%) to insect PDFs and also to the crustacean beta-PDH peptides. The computer-assisted sequence analysis of PDF precursor revealed a possible translocation into the nucleus, despite the lack of a definite NLS-like sequence. Using immunocytochemistry, the optic lobes of M. opalifera revealed PDF-immunoreactive neurons in both the medulla and lamina neuropiles. All these PDF cells exhibited prominent immunolabeling of both their perikarya and axons, but not their nuclei. Our results provide the first structural and immunocytochemical identification of PDF neurons in Hemiptera.

DOI： 10.2108/zsj.19.821

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE BIOCHEMICAL SOC  

Pigment-dispersing factor (PDF) was recently reported to be a principal circadian neuromodulator involved in transmitting circadian rhythms of daily locomotion in insects. In Drosophila, PDF functions in some of the neurons expressing the clock genes period, timeless, Clock, and cycle, and those clock genes in turn regulate pdf gene expression. In the present study, we cloned a cDNA encoding PDF in the brain of a nocturnal insect, the cricket Gryllus bimaculatus, and found that an isolated clone (310 bp) codes for an extraordinarily short precursor protein with no definite signal sequence, but a nuclear localization signal (NLS)-like sequence instead. The cricket PDF exhibits high sequence identity (78-94%) and similarity (89-100%) to insect PDFs and also to crustacean beta-PDH peptides. In the optic lobes of G. bimaculatus there are PDF-immunoreactive neurons in both the medulla and lamina neuropiles. Among the strongly immunoreactive lamina PDF neurons, on electron microscopy we identified cells exhibiting distinct staining that is not only cytoplasmic but also nuclear. When GFP-fused PDF precursor proteins were expressed in COS-7 cells, distinct translocation of the fusion protein into the nucleus was observed. This is the first finding of PDF peptide in the nucleus, which suggests a fundamental role of PDF peptide per se in the circadian clock system.

DOI： 10.1093/oxfordjournals.jbchem.a003180

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Deltorphin II is a peptide ligand specific for the delta opioid receptor. In order to elucidate the role of Phe(3) in binding to the delta opioid receptor, we synthesized a series of analogs in which Phe(3) was replaced by various amino acids such as Ala, cyclohexylalanine (Cha), fluorophenylalanines, and other alkyl-side chain amino acids (Val, Leu, and norleucine (Nle)). It was found that [Cha(3)]deltorphin II and [Nle(3)]deltorphin II retain almost a full receptor binding affinity. The results indicated that the Phe(3)-phenyl group of deltorphin II can be substituted by the alkyl groups such as cyclohexyl and propyl in the interaction with the delta receptor.

DOI： 10.1246/bcsj.73.2549

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC  

One of the structural characteristics of a neuropeptide nociceptin is the existence of Arg-Lys (RK) residues at positions 8-9 and 12-13; both RKs have been suggested to bind to the acidic amino acid cluster in the second extracellular loop of the seven transmembrane domain receptor ORL1. With a design strategy of attempting to obtain an analog that binds moire strongly to the receptor's acidic cluster, we synthesized a series of nociceptin analogs in which the RK dipeptide unit was placed at positions 6-7, 10-11, or 14-15 adjacent to the parent RKs. Among these nociceptin analogs containing the RK triple repeat, [Arg-Lys(6-7)]. and [Arg-Lys(10-11)]nociceptins exhibited weak activities (6-9 and 60-90% of nociceptin, respectively) both in the receptor binding assay and in the [S-35]GTP gammaS binding functional assay. In contrast, [Arg-Lys(14-15)]nociceptin was found to be very potent in both assays (3-fold in binding and 17-fold in GTP gammaS functional assay). [Arg-Lys(14-15)]nociceptin was the first peptide analog found to be stronger than the parent nociceptin, and structure-activity studies have suggested that the incorporated Arg-Lys(14-15) interacts with either the receptor acidic amino acid cluster or the receptor aromatic aminoacidresidues. (C) 2000 Academic Press.

DOI： 10.1006/bbrc.2000.3822

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

In accordance with detection of a few phospholipase A(2) (PLA(2)) isozyme genes by Southern blot analysis, only two cDNAs, named NnkPLA-I and NnkPLA-II, encoding group I PLA(2)s, NnkPLA-I and NnkPLA-II, respectively, were isolated from the venom gland cDNA library of Elapinae Naja naja kaouthia of Malaysia. NnkPLA-I and NnkPLA-II showed four amino acid substitutions, all of which were brought about by single nucleotide substitution. No existence of clones encoding CM-II and CM-III, PLA(2) isozymes which had been isolated from the venom of N. naja kaouthia of Thailand, in Malaysian N. naja kaouthia venom gland cDNA library was verified by dot blot hybridization analysis with particular probes. NnkPLA-I and NnkPLA-II differed from CM-II and CM-III with four and two amino acid substitutions. respectively, suggesting that their molecular evolution is regional. The comparison of NnkPLA-I, NnkPLA-II and cDNAs encoding other group I snake venom gland PLA(2)s indicated that the 5'- and 3'-untranslated regions are more conserved than the mature protein-coding region and that the number of nucleotide substitutions per nonsynonymous site is almost equal to that per synonymous sire in the protein-coding region, suggesting that accelerated evolution has occurred in group I venom gland PLA(2)s possibly to acquire new physiological functions. (C) 1999 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0041-0101(99)00165-8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

A pair of 35 kDa polypeptides (TAO1/TAO2) are expressed in more than 90% of all primary lung adenocarcinomas but not in other major malignancies. Mass spectrometry of tryptic peptides showed that TAO1/TAO2 is identical to napsin A, a recently described member of the aspartic proteinase family. The site of processing of pronapsin A to the mature form was located, Napsin expression was detected in human lung adenocarcinoma tumors, compatible with the marker nature of TAO1/TAO2 in the diagnosis of primary lung adenocarcinoma. This is important since identification of markers which can distinguish primary lung adenocarcinomas from distant metastases is desirable. Northern blot analysis showed expression of napsin also in normal lung and kidney tissue, and in situ hybridization showed expression in type II alveolar cells of the lung. This protease is concluded to have a specific functional role in the normal alveolar epithelium and is a candidate protease for the proteolytic processing of surfactant precursors. (C) 1999 Federation of European Biochemical Societies.

DOI： 10.1016/S0014-5793(99)01493-3

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Language：English   Publisher：The Japanese Biochemical Society  

A ligand containing an SNpys group, i.e. 3-nitro-2-pyridinesulfenyl linked to a mercapto (or thiol) group, can bind covalently to a free mercapto group to form a disulfide bond via the thiol-disulfide exchange reaction. This SNpys chemistry has been successfully applied to the discriminative affinity labeling of μ and δ opioid receptors with SNpys-containing enkephalins. In order to explore the mercapto groups conserved at or near the ligand binding sites of three opioid receptor subtypes, we synthesized two Cys(Npys)-containing analogs of dynorphin A, namely, [D-Ala2,Cys(Npys)8] dynorphin A-(1-9) amide (1) and Co-Ala2,Cys(Npys)12] dynorphin A-(1-13) amide (2). When rat (μ and δ) or guinea pig (χ) brain membranes were incubated with these Cys(Npys)-containing dynorphin A analogs and then assayed for inhibition of the binding of DAGO (μ), deltorphin II (δ), and U-69593 (χ), the number of receptors decreased sharply, depending upon the concentrations of these Cys(Npys)- containing dynorphin A analogs. It was found that dynorphin A analogs 1 and 2 effectively label μ receptors (EC50= 27-33 nM), but also label δ receptors fairly well (160-180 nM). However, for χ receptors they showed drastically different potencies as to affinity labeling; i.e., EC50= 210 nM for analog 1, but 10,000 nM for analog 2. Analog 2 labeled χ receptors about 50 times more weakly than analog 1. These results suggested that dynorphin A analog 1 labels the Cys residues conserved in μ, δ, and χ receptors, whereas analog 2 only labels the Cys residues conserved in μ, and δ receptors.

DOI： 10.1093/oxfordjournals.jbchem.a022430

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPRINGER  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

A part of the 3'-flanking region of BP-II gene, which is one of Trimeresurus flavoviridis venom gland phospholopase A(2) (PLA(2)) isozyme genes, has a region homologous to avian chicken repeat 1 (CR1)-element. In the present study, ten CR1-like elements were further identified in T. gramineus venom gland PLA(2) isozyme genes, T. flavoviridis PLA(2) inhibitor (PLI) genes, and T. flavoviridis and T. gramineus TATA-box binding protein (TBP) genes. Southern blot analysis using a probe for CR1 showed that Crotalinae snake genomes contain a number of CR1-like elements. (C) 1998 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0041-0101(97)00104-9

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS AUST  

Four different stereoisomers of cyclopropylphenylalanine (VPhe) were incorporated into [D-Ala(2),Leu(5)]enkephalin at the position 4. These conformationally restricted enkephalin analogs were evaluated for their binding characteristics to mu and delta opioid receptors in rat brain. A striking finding is that the E-(2R,3S)-isomer binds to a novel class of delta receptors and discriminates this receptor from the ordinary delta receptor. This new type of delta receptor suspected to be a receptor which suppresses the thermal analgesia mediated through mu receptor. The Z-(2R,3R)-isomer was very potent with several times more enhanced affinity to delta receptors than to mu receptors, but could not differentiate the delta receptors. The Z-(2S,3S)-isomer was weak, and E-(2S,3R)-isomer was almost inactive.

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Other Link： http://id.nii.ac.jp/1141/00037103/

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Other Link： http://search.jamas.or.jp/link/ui/2001073487

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Event date： 2021.6

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Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Tokyo  

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Venue：Lindau (Germany)  

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Application no：特願2007-511193, PCT/JP2006/306921 

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Application no：特願2008-262646, PCT出願PCT/JP2009/005128 

Publication no：WO2010041401 A1 

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