197,572 research outputs found
Protein kinase A (PKA) is central for forward transport of two pore domain potassium channels K2P3.1 and K2P9.1
No full textAcid sensitive two-pore domain potassium channels (K2P3.1 and K2P9.1) play key roles in both physiological and pathophysiological mechanisms, the most fundamental of which is control of resting membrane potential of cells in which they are expressed. These background leak channels are constitutively active once expressed at the plasma membrane and hence tight control of their targeting and surface expression is fundamental to the regulation of K+ flux and cell excitability. The chaperone protein, 14-3-3, binds to a critical phosphorylated serine in the channel C-termini of K2P3.1 and K2P9.1 (S393 and S373, respectively) and overcomes retention in the endoplasmic reticulum by ?COP. We sought to identify the kinase responsible for phosphorylation of the terminal serine in human and rat variants of K2P3.1 and K2P9.1. Adopting a bioinformatic approach, three candidate protein kinases were identified: cAMP-dependent protein kinase (PKA), ribosomal S6 kinase (RSK) and protein kinase C (PKC). In vitro phosphorylation assays were utilised to determine the ability of the candidate kinases to phosphorylate the channel C-termini. Electrophysiological measurements of human K2P3.1 transiently expressed in HEK293 cells and cell surface assays of GFP-tagged K2P3.1 and K2P9.1 enabled the functional implications of phosphorylation by specific kinases to be determined. All our findings support the conclusion that PKA is responsible for the phosphorylation of the terminal serine in both K2P3.1 and K2P9.1. <br/
A viologen phosphorus dendritic molecule as a carrier of ATP and Mant-ATP: Spectrofluorimetric and NMR studies
No full textInternational audienceIn this work, the interactions between a viologen phosphorus dendrimer of generation 0 (VPD) and ATP or 2'-/3'-O-(N'-methylanthraniloyl)-ATP (Mant-ATP) were investigated by NMR and fluorescence spectroscopy methods. ATP and Mant-ATP were used as model molecules of purine and pyrimidine nucleoside analogues (NAs), which are antimetabolites commonly used in anticancer therapy. Complexes of VPD with NAs may help to overcome severe limitations of NAs associated with their low solubility, stability or resistance to cancer cells. The aim of the presented study was to evaluate the stoichiometry and the mechanism of formation of complexes between dendrimers and nucleotides: ATP and Mant-ATP. Moreover, we examined the efficiency of complex formation in relation to temperature, the type of solvent, NaCl concentration, pH and environment polarity. It was observed that viologen phosphorus dendrimers form complexes with ATP and Mant-ATP with high efficiency. Obtained complexes are stabilized by electrostatic and aromatic aromatic interactions as driving forces
The pathway of cross-presentation is influenced by the particle size of phagocytosed antigen
No full textCross-presentation is the presentation by MHC class I of antigenic peptides from exogenous proteins that have been internalised and processed by professional antigen presenting cells, eg. dendritic cells (DC). We have investigated the influence of particle size and antigen load on cross-presentation following antigen delivery on microspheres (MS). Cross-presentation from small particles (0.8 ?m) is sensitive to proteasome inhibition and the blockade of ER-resident MHC class I complex export, whereas cross-presentation from larger particles (aggregated clumps of 0.8 ?m MS) is resistant to these antagonists. This observation may have been overlooked previously, due to the heterogeneity of particle size and MS uptake in unsorted DC populations. Whilst larger particles carry more antigen, we show that antigen load does not influence the cross-presentation pathway utilised. Whereas early endosome autoantigen 1 (EEA1) could be observed in all phagosomes, we observed endoplasmic reticulum SNARE of 24 kDa (ERS24) and cathepsin S in association with 3.0 ?m and aggregated 0.8 ?m MS, but not individual 0.8 ?m MS. A potential mechanism underlying our observations may be the activation of ?-catenin by disruption of E-cadherin-mediated adhesion. Activated ?-catenin was detected in the cytoplasm of cells after phagocytosis of MS (highest levels for the largest particles). We propose that particle size can direct the use of different pathways for the cross-presentation of an identical antigen. Furthermore, these pathways have differing yields of MHC class I-peptide complexes, which is an important variable in designing vaccination strategies for maximal antigen expression and CD8(+) T cell priming
Beyond a Fluorescent Probe: Inhibition of Cell Division Protein FtsZ by mant-GTP Elucidated by NMR and Biochemical Approaches
No full text© 2015 American Chemical Society. FtsZ is the organizer of cell division in most bacteria and a target in the quest for new antibiotics. FtsZ is a tubulin-like GTPase, in which the active site is completed at the interface with the next subunit in an assembled FtsZ filament. Fluorescent mant-GTP has been extensively used for competitive binding studies of nucleotide analogs and synthetic GTP-replacing inhibitors possessing antibacterial activity. However, its mode of binding and whether the mant tag interferes with FtsZ assembly function were unknown. Mant-GTP exists in equilibrium as a mixture of C2′- and C3′-substituted isomers. We have unraveled the molecular recognition process of mant-GTP by FtsZ monomers. Both isomers bind in the anti glycosidic bond conformation: 2′-mant-GTP in two ribose puckering conformations and 3′-mant-GTP in the preferred C2′ endo conformation. In each case, the mant tag strongly interacts with FtsZ at an extension of the GTP binding site, which is also supported by molecular dynamics simulations. Importantly, mant-GTP binding induces archaeal FtsZ polymerization into inactive curved filaments that cannot hydrolyze the nucleotide, rather than straight GTP-hydrolyzing assemblies, and also inhibits normal assembly of FtsZ from the Gram-negative bacterium Escherichia coli but is hydrolyzed by FtsZ from Gram-positive Bacillus subtilis. Thus, the specific interactions provided by the fluorescent mant tag indicate a new way to search for synthetic FtsZ inhibitors that selectively suppress the cell division of bacterial pathogens.BFU2011-23416 and BFU2014-51823-R (J.M.A), CTQ2012-32065 (J.J.B.), CM 2010/BMD-2353 (J.J.B. and J.M.A.), FCT SFRH/BPD/65462/2009 and UID/Multi/04378/2013 (F.M.) and a FPI fellowship (L.B.R.A).Peer Reviewe
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Bulan\u131k Mant\u131\u11f\u131n Ak\u131ll\u131 Etmenlere B\ufct\ufcnle\u15ftirilmesi : Bir SFS czerinde Deneyler
No full textAbstract: Siber-fiziksel Sistemler (SFS), anl\u131k d\u131\u15f de\u11fi\u15fikliklerin oldu\u11fu fiziksel d\ufcnya ile etkile\u15fime giren karma\u15f\u131k yap\u131daki sistemlerdir. Literat\ufcrde, yaz\u131l\u131m etmenleri bu karma\u15f\u131k yap\u131daki sistemlerin programlanmas\u131 i\ue7in bir se\ue7enek olarak kabul edilir ve sahip olduklar\u131 \uf6zellikleri geli\u15ftirmek i\ue7in bulan\u131k mant\u131k ile birlikte kullan\u131labilir. Etmen odakl\u131 yakla\u15f\u131mlar, \uf6zellikle Kan\u131-\u130stek-Hedef (K\u130H) mimarisi, \ue7e\u15fitli uygulamalarda kullan\u131lmaktad\u131r. Siber-fiziksel Sistemler alan\u131nda \uf6zerklik, \uf6nalma ve insan benzeri ak\u131l y\ufcr\ufctme, bir sistemin zekas\u131n\u131 geli\u15ftirmek i\ue7in gereken temel unsurlard\u131r. K\u130H etmenleri taraf\u131ndan bu \uf6zellikler, sistemlerin karma\u15f\u131k oldu\u11fu SFS de uygulanabilir ve bulan\u131k mant\u131k ile kapasiteleri geni\u15fletilebilir. Bu \ue7al\u131\u15fma, SFS'deki kusurlu olabilecek hesaplamalar\u131 azaltmak amac\u131yla bulan\u131k mant\u131\u11f\u131 baz alarak K\u130H mimarisine ba\u11fl\u131 ak\u131ll\u131 etmenleri uygular.
6nerilen bulan\u131k K\u130H yakla\u15f\u131m\u131n\u131 de\u11ferlendirmek i\ue7in bir M\u130B fan sistemi kullan\u131lm\u131\u15ft\u131r. \u130lk olarak, s\u131cakl\u131k duyargas\u131n\u131n herhangi bir \uf6rnekleme g\ufcr\ufclt\ufcs\ufc olmadan ideal oldu\u11fu varsay\u131larak sistem test edilmi\u15ftir. Normal K\u130H ve bulan\u131k mant\u131k tabanl\u131 K\u130H ayr\u131 ayr\u131 uygulanarak sonu\ue7lar test edilmi\u15ftir. Daha sonra -+ be\u15f hata oran\u131 dikkate al\u131narak veri \uf6rnekleme s\ufcreci test edilmi\u15ftir. Hem ideal hem de g\ufcr\ufclt\ufcl\ufc veriler i\ue7in bulan\u131k K\u130H yakla\u15f\u131m\u131n\u131n \uf6nemli bir geli\u15fme g\uf6sterdi\u11fi sonucuna var\u131lm\u131\u15ft\u131r. Ayr\u131ca, somut bir vaka \ue7al\u131\u15fmas\u131 da kullanarak Jason K\u130H i\ue7in ak\u131l y\ufcr\ufctme d\uf6ng\ufcs\ufc k\u131s\u131tlamalar\u131 denenmi\u15ftir
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