1,721,041 research outputs found
Routing of normal and mutant brush-border sucrase-isomaltase and lactase-phlorizin hydrolase
No full textItem does not contain fulltextKUN, 14 januari 1998Promotor : Ginsel, L.A. Co-promotor : Fransen, J.A.M.119 p
A study of the coupling between morphodynamics and energy metabolism in macrophages
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130268.pdf (Publisher’s version ) (Open Access)Radboud Universiteit Nijmegen, 10 oktober 2014Promotor : Wieringa, B. Co-promotor : Fransen, J.A.M
DMPK isoforms in muscle and brain cells. Localization and function.
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85871.pdf (Publisher’s version ) (Open Access)Radboud Universiteit Nijmegen, 01 april 2011Promotor : Wieringa, B. Co-promotores : Wansink, D.G., Fransen, J.A.M.157 p
Protein Tyrosine Phospatase PTPRR isoforms in cellular signaling and trafficking.
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27024.pdf (Publisher’s version ) (Open Access)Previous work has revealed the existence of two Protein Tyrosine Phosphatases in mouse, PTPBR7 and PTP-SL, that were in part identical, suggesting that they originated from the same gene, termed Ptprr (1,5,6). In this thesis, I report on the characterization of the various PTPRR isoforms in neuronal cells and demonstrate that the single copy mouse gene Ptprr gives rise to four mRNAs that encode PTPBR7, PTP-SL and two PTPPBS protein variants through the use of distinct promoters, alternative splicing and differential translation initiation starts. In addition, the receptor-type PTPBR7 protein isoform was found to undergo N-terminal proteolytic cleavage at a furin-like convertase consensus site, adding an additional, fifth, member for which the name PTPBR7-65 was coined. Localization studies that focused on the different PTPRR isoforms revealed that PTPBR7 and PTP-SL are both present and co-localize in late endocytic compartments and in the Golgi area. PTPBR7 shows an additional localization at the plasma membrane (1,7), and interestingly on early endosomes as well. The 42 and 37 kDa PTPPBS proteins are genuine cytosolic proteins. Live-imaging studies revealed that PTPBR7 and PTP-SL vesicles are highly motile in both anterograde and retrograde directions. PTP-SL is involved in the ERK-MAP kinase signaling pathway, but interestingly, we also found it to interact with the 4-adaptin subunit of the AP-4 adaptor complex, an important component of the vesicular transport machinery. Taken together, studies described in this thesis point to a possible role for PTP-SL, and other PTPRR family members, in vesicle trafficking between the Golgi-apparatus and endocytic compartments and localized signaling.RU Radboud Universiteit Nijmegen, 24 november 2005Promotor : Wieringa, B. Co-promotores : Fransen, J.A.M., Hendriks, W.J.A.J.176 p
Rab proteins specify motorized vesicle transport.
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71292.pdf (Publisher’s version ) (Open Access)Small GTPases of the Rab-family are key regulators of intracellular membrane traffic. These proteins constantly cycle between an 'active' GTP-bound and 'inactive' GDP-bound state. In their GTP-bound conformation Rab proteins can engage in complex formation with so called effector proteins. It is at this level that the control of membrane transport is exerted. To date more than 60 Rab-family members, including isoforms, are recognized. To this family also belongs the Golgi-localized Rab6. In the past three different isoforms of this protein were identified: Rab6A, Rab6A'(generated by alternative splicing of a homologues but distinct exon within the Rab6 gene), and a brain specific isoform, Rab6B. Rab6A' is the isoform regulating the entire retrograde pathway from late endosomes to ER, whereas Rab6A seems dispensable for this route. The role of Rab6B is still ill-defined and therefore the main focus of this study. Studies using GFP-Rab6B in neuronal cells revealed the bi-directional movement of Rab6B positive structures in neurites of these cells, possibly belonging to the post-Golgi compartment. This latter finding was corroborated with a tsVSVG-assay, which localized Rab6B on vesicles moving from the Golgi towards the plasma membrane. Furthermore we also found co-localization of Rab6B with vesicles containing internalized GPI-anchored proteins. A regulatory role for Rab6B in the internalization of these proteins can therefore be anticipated. To learn more about the molecular environment of Rab6B we searched for novel Rab6B interacting proteins. Of the newly identified Rab6B interactors two were analyzed in more detail, namely Bicaudal-D1 and DYNLRB1. Whereas Bicaudal-D1 provides an indirect binding of Rab6B to the dynein/dynactin motor protein complex, DYNLRB1 assures direct binding. Dynein/dynactin is the main microtubule based motor protein complex responsible for long range retrograde transport. Based on our findings we expect an important role for Rab6B in regulating this process which, especially in neurons, is important in cell survival and viability.RU Radboud Universiteit Nijmegen, 29 mei 2008Promotor : Wieringa, B. Co-promotor : Fransen, J.A.M.151 p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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