1,720,972 research outputs found
The E2 ubiquitin conjugating enzyme UBC3B interacts with the F-box protein betaTrCP following its CK2-dependent phosphorylation
No full textCK2-dependent phosphorylation of the E2 ubiquitin conjugating enzyme UBC3B induces its interaction with beta-TrCP and enhances -beta-catenin degradation
No full textProtein kinase CK2 is a ubiquitous and pleiotropic Ser/Thr protein kinase involved in cell growth and transformation. Here we report the identification by yeast interaction trap of a CK2 interacting protein, UBC3B, which is highly homologous to the E2 ubiquitin conjugating enzyme UBC3/CDC34. UBC3B complements the yeast cdc34-2 cell cycle arrest mutant in S. cerevisiae and transfers ubiquitin to a target substrate in vitro. UBC3B is specifically phosphorylated by CK2 in vitro and in vivo. We mapped by deletions and site directed mutagenesis the phosphorylation site to a serine residue within the C-terminal domain in position 233 of UBC3B and in the corresponding serine residue of UBC3. Following CK2-dependent phosphorylation both UBC3B and UBC3 bind to the F-box protein beta-TrCP, the substrate recognition subunit of an SCF (Skp1, Cul1, F-box) ubiquitin ligase. Furthermore, we observed that co-transfection of CK2alpha' together with UBC3B, but not with UBC3DeltaC, enhances the degradation of beta-catenin. Taken together these data suggest that CK2-dependent phosphorylation of UBC3 and UBC3B functions by regulating beta-TrCP substrate recognition
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
Protein kinase CK2a' is induced by serum as a delayed early gene and cooperates with Ha-ras in fibroblast transformation
No full textProtein kinase CK2 is an ubiquitous and pleiotropic Ser/Thr protein kinase composed of two catalytic (α and/or α′) and two noncatalytic (β) subunits forming a heterotetrameric holoenzyme involved in cell growth and differentiation. Here we report the identification, cloning, and oncogenic activity of the murine CK2α′ subunit. Serum treatment of quiescent mouse fibroblasts induces CK2α′ mRNA expression, which peaks at 4 h. The kinetics ofCK2α′ expression correlate with increased kinase activity toward a specific CK2 holoenzyme peptide substrate. The ectopic expression of CK2α′ (or CK2α) cooperates with Ha-ras in foci formation of rat primary embryo fibroblasts. Moreover, we observed that BALB/c 3T3 fibroblasts transformed with Ha-ras and CK2α′ show a faster growth rate than cells transformed with Ha-rasalone. In these cells the higher growth rate correlates with an increase in calmodulin phosphorylation, a protein substrate specifically affected by isolated CK2 catalytic subunits but not by CK2 holoenzyme, suggesting that unbalanced expression of a CK2 catalytic subunit synergizes with Ha-ras in cell transformation
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
Protein kinase CK2 alpha' is induced by serum as delayed early gene and cooperates with Ha-Ras in fibroblast transformation.
No full textBiochemistry and Molecular Biology, 7,36
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