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TPR鞋用材料  [PDF]
郑玉婴
福州大学学报(自然科学版) , 2001,
Abstract: 分析了TPR鞋用材料的配方、工艺、性能 .实验结果表明 ,该材料具有高弹性、耐低温、粘结强度牢等特点 ,适用于生产中高档运动鞋和旅游鞋鞋底 .
Investigación cinética de óxidos no estequiométricos de níquel por reducción termoprogramada  [cached]
María M. Romero-Ramírez,Julio C. Llópiz-Yurell
Minería y Geología , 2000,
Abstract: Se presentan los resultados de la investigación cinética por reducción termoprogramada de óxidos de níquel no estequiométricos obtenidos a partir de la termosíntesis del carbonato básico de níquel industrial purificado, y se establecen en ellos condiciones de formación de óxido de níquel (III) mediante calentamiento lento y con una gran superficie de contacto con el aire que circunda la muestra. Se comprueba que el contenido de níquel (III) disminuye en las muestras al aumentar la temperatura de termosíntesis, mientras que el de níquel (II) aumenta. Se determinan las etapas de reducción de estos óxidos y los parámetros cinéticos de las transformaciones que tienen lugar y se establece que las mismas ocurren por el modelo cinético G1, que representa un crecimiento bidimensional a partir de los núcleos del metal producto de la reducción
Localization of Nucleoporin Tpr to the Nuclear Pore Complex Is Essential for Tpr Mediated Regulation of the Export of Unspliced RNA  [PDF]
Kalpana Rajanala, Vinay Kumar Nandicoori
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0029921
Abstract: Nucleoporin Tpr is a component of the nuclear pore complex (NPC) that localizes exclusively to intranuclear filaments. Tpr functions as a scaffolding element in the nuclear phase of the NPC and plays a role in mitotic spindle checkpoint signalling. Export of intron-containing mRNA in Mason Pfizer Monkey Virus is regulated by direct interaction of cellular proteins with the cis-acting Constitutive Transport Element (CTE). In mammalian cells, the transport of Gag/Pol-CTE reporter construct is not very efficient, suggesting a regulatory mechanism to retain this unspliced RNA. Here we report that the knockdown of Tpr in mammalian cells leads to a drastic enhancement in the levels of Gag proteins (p24) in the cytoplasm, which is rescued by siRNA resistant Tpr. Tpr's role in the retention of unspliced RNA is independent of the functions of Sam68 and Tap/Nxf1 proteins, which are reported to promote CTE dependent export. Further, we investigated the possible role for nucleoporins that are known to function in nucleocytoplasmic transport in modulating unspliced RNA export. Results show that depletion of Nup153, a nucleoporin required for NPC anchoring of Tpr, plays a role in regulating the export, while depletion of other FG repeat-containing nucleoporins did not alter the unspliced RNA export. Results suggest that Tpr and Nup153 both regulate the export of unspliced RNA and they are most likely functioning through the same pathway. Importantly, we find that localization of Tpr to the NPC is necessary for Tpr mediated regulation of unspliced RNA export. Collectively, the data indicates that perinuclear localization of Tpr at the nucleopore complex is crucial for regulating intron containing mRNA export by directly or indirectly participating in the processing and degradation of aberrant mRNA transcripts.
Perfis dos utilizadores da internet em Portugal  [cached]
Nuno de Almeida Alves
Análise Social , 2008,
Abstract: Este artigo identifica um conjunto diversificado de perfis de utilizadores da internet que se revelam pertinentes para o conhecimento acerca do uso social das tecnologias da informa o. Estes perfis espelham fórmulas particulares de articula o entre os posicionamentos sociais dos indivíduos e os respectivos usos que fazem da internet. This article identifies a broad range of internet user profiles, which are relevant for an understanding of the social use of information technology. These profiles reflect particular forms of linkage between individuals' social positions and how they use the internet.
The Interaction of CRM1 and the Nuclear Pore Protein Tpr  [PDF]
Charles L. Zhao, Seyed Hanif Mahboobi, Ruhollah Moussavi-Baygi, Mohammad R. K. Mofrad
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093709
Abstract: While much has been devoted to the study of transport mechanisms through the nuclear pore complex (NPC), the specifics of interactions and binding between export transport receptors and the NPC periphery have remained elusive. Recent work has demonstrated a binding interaction between the exportin CRM1 and the unstructured carboxylic tail of Tpr, on the nuclear basket. Strong evidence suggests that this interaction is vital to the functions of CRM1. Using molecular dynamics simulations and a newly refined method for determining binding regions, we have identified nine candidate binding sites on CRM1 for C-Tpr. These include two adjacent to RanGTP – from which one is blocked in the absence of RanGTP – and three next to the binding region of the cargo Snurportin. We report two additional interaction sites between C-Tpr and Snurportin, suggesting a possible role for Tpr import into the nucleus. Using bioinformatics tools we have conducted conservation analysis and functional residue prediction investigations to identify which parts of the obtained binding sites are inherently more important and should be highlighted. Also, a novel measure based on the ratio of available solvent accessible surface (RASAS) is proposed for monitoring the ligand/receptor binding process.
Silencing Nuclear Pore Protein Tpr Elicits a Senescent-Like Phenotype in Cancer Cells  [PDF]
Brigitte David-Watine
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0022423
Abstract: Background Tpr is a large coiled-coil protein located in the nuclear basket of the nuclear pore complex for which many different functions were proposed from yeast to human. Methodology/Principal Findings Here we show that depletion of Tpr by RNA interference triggers G0–G1 arrest and ultimately induces a senescent-like phenotype dependent on the presence of p53. We also found that Tpr depletion impairs the NES [nuclear export sequence]-dependent nuclear export of proteins and causes partial co-depletion of Nup153. In addition Tpr depletion impacts on level and function of the SUMO-protease SENP2 thus affecting SUMOylation regulation at the nuclear pore and overall SUMOylation in the cell. Conclusions Our data for the first time provide evidence that a nuclear pore component plays a role in controlling cellular senescence. Our findings also point to new roles for Tpr in the regulation of SUMO-1 conjugation at the nuclear pore and directly confirm Tpr involvement in the nuclear export of NES-proteins.
Designed hybrid TPR peptide targeting Hsp90 as a novel anticancer agent
Tomohisa Horibe, Masayuki Kohno, Mari Haramoto, Koji Ohara, Koji Kawakami
Journal of Translational Medicine , 2011, DOI: 10.1186/1479-5876-9-8
Abstract: We focused on the interaction of Hsp90 with its cofactor protein p60/Hop, and engineered a cell-permeable peptidomimetic, termed "hybrid Antp-TPR peptide", modeled on the binding interface between the molecular chaperone Hsp90 and the TPR2A domain of Hop.It was demonstrated that this designed hybrid Antp-TPR peptide inhibited the interaction of Hsp90 with the TPR2A domain, inducing cell death of breast, pancreatic, renal, lung, prostate, and gastric cancer cell lines in vitro. In contrast, Antp-TPR peptide did not affect the viability of normal cells. Moreover, analysis in vivo revealed that Antp-TPR peptide displayed a significant antitumor activity in a xenograft model of human pancreatic cancer in mice.These results indicate that Antp-TPR peptide would provide a potent and selective anticancer therapy to cancer patients.Heat-shock protein 90 (Hsp90) is a molecular chaperone [1] that participates in the quality control of protein folding. The mechanism of action of Hsp90 includes sequential ATPase cycles and the stepwise recruitment of cochaperones, including Hsp70, CDC37, p60/Hsp-organizing protein (Hop), and p23 [2,3]. In particular, Hsp90 and Hsp70 interact with numerous cofactors containing so-called tetratricopeptide repeat (TPR) domains. TPR domains are composed of loosely conserved 34-amino acid sequence motifs that are repeated between one and 16 times per domain. Originally identified in components of the anaphase-promoting complex [4,5], TPR domains are now known to mediate specific protein interactions in numerous cellular contexts [6-8]. Moreover, apart from serving mere anchoring functions, TPR domains of the chaperone cofactors Hip and p60/Hop also are able to regulate the ATPase activities of Hsp70 and Hsp90, respectively [9,10]. Each 34-amino acid motif forms a pair of antiparallel α-helices. These motifs are arranged in a tandem array into a superhelical structure that encloses a central groove. The TPR-domain-containing cofactors of the Hsp70/Hsp
Molecular mechanism of cytotoxicity induced by Hsp90-targeted Antp-TPR hybrid peptide in glioblastoma cells  [cached]
Horibe Tomohisa,Torisawa Aya,Kohno Masayuki,Kawakami Koji
Molecular Cancer , 2012, DOI: 10.1186/1476-4598-11-59
Abstract: Background Heat-shock protein 90 (Hsp90) is vital to cell survival under conditions of stress, and binds client proteins to assist in protein stabilization, translocation of polypeptides across cell membranes, and recovery of proteins from aggregates. Therefore, Hsp90 has emerged as an important target for the treatment of cancer. We previously reported that novel Antp-TPR hybrid peptide, which can inhibit the interaction of Hsp90 with the TPR2A domain of Hop, induces selective cytotoxic activity to discriminate between normal and cancer cells both in vitro and in vivo. Results In this study, we investigated the functional cancer-cell killing mechanism of Antp-TPR hybrid peptide in glioblastoma (GB) cell lines. It was demonstrated that Antp-TPR peptide induced effective cytotoxic activity in GB cells through the loss of Hsp90 client proteins such as p53, Akt, CDK4, and cRaf. Antp-TPR also did not induce the up-regulation of Hsp70 and Hsp90 proteins, although a small-molecule inhibitor of Hsp90, 17-AAG, induced the up-regulation of these proteins. It was also found that Antp-TPR peptide increased the endoplasmic reticulum unfolded protein response, and the cytotoxic activity of this hybrid peptide to GB cells in the endoplasmic reticulum stress condition. Conclusion These results show that targeting of Hsp90 by Antp-TPR could be an attractive approach to selective cancer-cell killing because no other Hsp90-targeted compounds show selective cytotoxic activity. Antp-TPR might provide potent and selective therapeutic options for the treatment of cancer.
Ligand Recognition by the TPR Domain of the Import Factor Toc64 from Arabidopsis thaliana  [PDF]
Rashmi Panigrahi, Abdussalam Adina-Zada, James Whelan, Alice Vrielink
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0083461
Abstract: The specific targeting of protein to organelles is achieved by targeting signals being recognised by their cognate receptors. Cytosolic chaperones, bound to precursor proteins, are recognized by specific receptors of the import machinery enabling transport into the specific organelle. The aim of this study was to gain greater insight into the mode of recognition of the C-termini of Hsp70 and Hsp90 chaperones by the Tetratricopeptide Repeat (TPR) domain of the chloroplast import receptor Toc64 from Arabidopsis thaliana (At). The monomeric TPR domain binds with 1:1 stoichiometry in similar micromolar affinity to both Hsp70 and Hsp90 as determined by isothermal titration calorimetry (ITC). Mutations of the terminal EEVD motif caused a profound decrease in affinity. Additionally, this study considered the contributions of residues upstream as alanine scanning experiments of these residues showed reduced binding affinity. Molecular dynamics simulations of the TPR domain helices upon peptide binding predicted that two helices within the TPR domain move backwards, exposing the cradle surface for interaction with the peptide. Our findings from ITC and molecular dynamics studies suggest that AtToc64_TPR does not discriminate between C-termini peptides of Hsp70 and Hsp90.
Escoamento de ar através de embalagens de polapa de frutas em caixas comerciais: efeito sobre os perfis de velocidade em túneis de congelamento  [cached]
Resende Jaime Vilela de,Neves Filho Lincoln de Camargo,Silveira Jr. Vivaldo
Ciência e Tecnologia de Alimentos , 2002,
Abstract: As varia es nas velocidades do ar causadas pela resistência ao escoamento em fun o da quantidade de embalagens de polpa de frutas (100g), acondicionadas em caixas comerciais durante o processo de congelamento, foram avaliadas e as vaz es estimadas, com base em um método de tratamento dos dados experimentais. As velocidades foram medidas antes da passagem do ar pelo empilhamento de caixas na camara. As medi es foram analisadas utilizando-se uma rotina de regress o n o linear e as vaz es determinadas pelo método de integra o numérica dos perfis das velocidades ajustadas. O método apresentou estima o 10% superior à encontrada pelo método tradicional. Mantendo as condi es operacionais do ventilador constantes, a vaz o para arranjos de sete camadas resultou ser 62% inferior à de três camadas e, 50,9% inferior à de cinco camadas. Estes valores foram proporcionais à redu o do espa o livre para escoamento do ar.
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