1,720,965 research outputs found
Protein kinase C-mediated phosphorylation of the BGT1 epithelial gamma-aminobutyric acid transporter regulates its association with LIN7 PDZ proteins - A post-translational mechanism regulating transporter surface density
No full textThe Na/Cl-dependent BGT1 transporter has osmoprotective functions by importing the small osmolyte betaine into the cytosol of renal medullary epithelial cells. We have demonstrated previously that the surface localization of the transporter in Madin-Darby canine kidney cells depends on its association with the LIN7 PDZ protein through a PDZ target sequence in the last 5 residues of the transporter (-KETHL). Here we describe a protein kinase C (PKC)-mediated mechanism regulating the association between BGT1 and LIN7. Reduced transport activity paralleled by the intracellular relocalization of the transporter was observed in response to the PKC activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment. This activation caused clathrin-dependent internalization of the transporter and its targeting to a recycling compartment that contains the truncated transporter lacking the LIN7 binding motif (BGTDelta5) but not the LIN7 partner of BGT1. The decreased association between BGT1 and LIN7 was demonstrated further by coimmunoprecipitation studies and in vitro binding to recombinant LIN7 fusion protein. The TPA treatment induced phosphorylation of surface BGT1 on serine and threonine residues. However, a greater increase in phosphothreonines than phosphoserines was measured in the wild type transporter, whereas the opposite was true in the BGTSer mutant in which a serine replaced the threonine 612 in the LIN7 association motif (-KESHL). No similar increase in relative phosphoserines or phosphothreonines was found in the BGTDelta5 transporter. Moreover, phosphorylation of threonine 612 in a BGT COOH-terminal peptide impaired its association with recombinant LIN7. Taken together, these data demonstrate that the post-translational regulation of BGT1 surface density is a result of transporter phosphorylation and that threonine 612 is an essential residue in this PKC-mediated regulation
Mammalian LIN-7 PDZ proteins associate with beta-catenin at the cell junctions of epithelia and neurons
No full textThe heterotrimeric PDZ complex containing LIN-2, LIN-7 and LIN-10 is known to be involved in the organization of epithelial and neuronal junctions in Caenorhabditis elegans and mammals. We report here that mammalian LIN-7 PDZ proteins form a complex with cadherin and β-catenin in epithelia and neurons. The association of LIN-7 with cadherin and β-catenin is Ca2+ dependent and is mediated by the direct binding of LIN-7 to the C-terminal PDZ target sequence of β-catenin, as demonstrated by means of co-immunoprecipitation experiments and in vitro binding assays with the recombinant glutathione S-transferase:LIN-7A. The presence of β-catenin at the junction is required in order to relocate LIN-7 from the cytosol to cadherin-mediated adhesions, thus indicating that LIN-7 junctional recruitment is β-catenin dependent and that one functional role of the binding is to localize LIN-7. Moreover, when LIN-7 is present at the β-catenin-containing junctions, it determines the accumulation of binding partners, thus suggesting the mechanism by which β-catenin mediates the organization of the junctional domai
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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