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Charakterisierung der endosomalen Qb-SNAREs Vti1a und Vti1b / Characterization of the endosomal Qb-SNAREs Vti1a and Vti1bKreykenbohm, Vera 03 November 2004 (has links)
No description available.
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Real time course of transmitter release of SSVs and LDCVs; SNARE function analysed in synaptobrevin2 and cellubrevin knock out mice / Real time course of transmitter release of SSVs and LDCVs; SNARE function analysed in synaptobrevin2 and cellubrevin knock out mice / Analyse des wahren Zeitverlaufs der Neurotransmitterfreisetzung aus SSVs und LDCVs; Analyse der SNARE-Funktion in Synaptobrevin2- und Cellubrevin-defizienten Mäusen / Analyse des wahren Zeitverlaufs der Neurotransmitterfreisetzung aus SSVs und LDCVs; Analyse der SNARE-Funktion in Synaptobrevin2- und Cellubrevin-defizienten MäusenZhao, Ying 06 November 2003 (has links)
No description available.
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Charakterisierung von SNARE-Proteinen in der Hefe Saccharomyces cerevisiae / Characterization of SNARE proteins in the yeast Saccharomyces cerevisiaeDilcher, Meik 30 January 2003 (has links)
No description available.
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Fluoreszenzmikroskopische Studien an Plasmamembranen zur Untersuchung der molekularen Mechanismen der neuronalen Exocytose / Fluorescence Microscopy Studies of Plasma Membranes to Analyse the Molecular Machinery of Neuronal ExocytosisZilly, Felipe Emilio 06 July 2006 (has links)
No description available.
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Comparative studies on regulation of SNARE complex formation by the SM protein Sly1p / Vergleichende Studien zur Regulation der SNARE Komplex Bildung durch das SM protein Sly1pDemircioglu, Fatma Esra 01 November 2011 (has links)
No description available.
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Functions of Vti1a and Vti1b in the Development of the Mouse Nervous System: Evidence from Double Knockout Mice / Functions of Vti1a and Vti1b in the Development of the Mouse Nervous System: Evidence from Double Knockout MiceKunwar, Ajaya Jang 29 April 2008 (has links)
No description available.
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Fluoreszenzmikroskopische Studien an Plasmamembranen zur Untersuchung der molekularen Mechanismen der neuronalen Exocytose / Fluorescence Microscopy Studies of Plasma Membranes to Analyse the Molecular Machinery of Neuronal ExocytosisZilly, Felipe Emilio 06 July 2006 (has links)
No description available.
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Mechanisms of exosome biogenesis and secretion / Mécanismes de biogénèse et sécrétion des exosomesColombo, Marina 22 November 2012 (has links)
Les exosomes sont des vésicules membranaires de 30 à 100 nm de diamètre, formées dans les endosomes multivésiculaires et sécrétées par la plupart des cellules. Les propriétés biophysiques et biochimiques des exosomes ainsi que les mécanismes permettant leur biogénèse et sécrétion ont fait l’objet de nombreuses études. Cependant, ces derniers sont encore méconnus, limitant l'analyse des fonctions des exosomes in vivo. Au moins deux mécanismes ont été proposés pour la biogénèse des exosomes : un mécanisme nécessiterait l’action de protéines impliquées dans le tri endosomal, les ESCRT (« endosomalsorting complex required for transport »). Un autre mécanisme serait indépendant de leur fonction. La sécrétion des exosomes, une fois générés dans les endosomes, requiert la petite GTPase, Rab27a, comme montré dans un modèle cellulaire humain. Mes travaux de thèse ont porté sur l’étude des mécanismes moléculaires impliqués dans la biogénèse et la sécrétion des exosomes. Une première étude visant à analyser la fonction de Rab27a dans des cellules murines, m’a permis de mettre en évidence l’existence de différentes populations d’exosomes, dont la sécrétion dépend ou non de Rab27a. Une deuxième étude a eu pour objectif d’analyser l’implication des ESCRT dans la biogénèse des exosomes dans des cellules HeLa CIITA. Le criblage d’une librairie d’ARN d’interférence dirigés contre les différentes protéines ESCRT, a permis l’identification de 7 molécules potentiellement impliquées dans cette voie : HRS, STAM1, TSG101, leur inactivation induisant la diminution de la sécrétion des exosomes. L’inactivation de CHMP4C, VPS4B,VTA1 et ALIX, au contraire, l’augmente. L’inhibition de l’expression de ces candidats suivie de l’analyse des exosomes sécrétés a démontré l’hétérogénéité des vésicules sécrétées, et une modification de leur taille et de leur composition protéique par rapport aux cellules contrôle. Plus particulièrement, l’inactivation d’ALIX induit une augmentation de lasécrétion d‘exosomes de plus grande taille, et l’enrichissement sélectif en molécules de CMH de classe II. En accord, j’ai montré que les cellules inactivées pour ALIX, aussi bien des cellules HeLa que des cellules dendritiques humaines ont une plus forte expression de CMH de classe II à la surface et dans des compartiments intracellulaires. Ces résultats suggèrent l’implication de certains membres de la famille ESCRT dans la voie de biogenèse et sécrétion des exosomes, ainsi qu’un rôle potentiel d’Alix dans le trafic des molécules CMH de classe II, et dans la modulation de la composition protéique des exosomes. / Exosomes are small membrane vesicles with sizes ranging from 30 to 100 nm in diameter, which are formed in multivesicular endosomes and secreted by most cell types. Numerous studies have focused on the biophysical and biochemical properties of exosomes, as well as the mechanisms of biogenesis and secretion of these vesicles. However, these aspects are not fully understood, which limits the analysis of the functions of exosomes in vivo. At least two mechanisms have been proposed for the biogenesis of exosomes : one would rely on the function of proteins involved in endosomal sorting, the ESCRT family (for “endosomal sorting complex required for transport”). Another mechanism would be independent of their activity. Once exosomes are formed in endosomes, their secretion requires the small GTPase RAB27A, as shown in a human cell line. The objective of my PhD project was to gain insights into the molecular mechanisms that drive exosome biogenesis and secretion. A first study performed to analyze the function of Rab27a in murine cells allowed me to show the existence of different populations of exosomes, dependent or not on Rab27a for their secretion. A second study was aimed at analyzing the involvement of ESCRT proteins in exosome biogenesis in HeLa-CIITA cells. Seven molecules potentially involved in this process were identified on the basis of the screening of an RNA interference library directed against the different ESCRT proteins: the inactivation of HRS, STAM1 and TSG101 induced a decrease in exosome secretion, whereas the down regulation of CHMP4C, VPS4B, VTA1 and ALIX increased it. Gene expression of the different candidate proteins was inhibited and exosomes secreted by these cells were analyzed: we showed the heterogeneity of the secreted vesicles, as well as an alteration of their size and protein composition, as compared to control cells. In particular, the inactivation of ALIX induced an increase in the secretion of larger vesicles, and the selective enrichment of these vesicles in MHC class II molecules. Accordingly, I showed that both HeLa-CIITA and human primary dendritic cells inactivated for ALIX possess a higher expression of MHC class II molecules at the cell surface and in intracellular compartments. These results suggest that some members of the ESCRT family are involved in the exosome biogenesis and secretion pathway, and propose a potential role of ALIX in the trafficking of MHC class II molecules and in the modulation of the protein composition of exosomes.
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Interaction of hERG Channels and Syntaxin 1AMihic, Anton 14 July 2009 (has links)
The human ether-à-go-go related gene (hERG) encodes the pore-forming voltage-gated K+ channel that is essential for cardiac repolarization. Dr. Tsushima’s laboratory has previously characterized the endogenous expression of SNARE proteins in the mammalian heart, and the interaction of the SNARE protein syntaxin 1A (STX1A) with several cardiac ion channels. Here, we utilize a multi-disciplinary approach to describe the inhibitory effect of STX1A on hERG channel function. STX1A impairs hERG channel maturation and trafficking to the plasma membrane and induces a hyperpolarizing shift in the voltage-sensitivity of steady-state inactivation. We identify the residues involved in this protein-protein interaction through the use of hERG truncation mutations. We also describe the pharmacological and temperature-mediated rescue of hERG channel trafficking in the presence of STX1A. The regulation of cardiac ion channels by SNARE proteins represents a novel biological mechanism that may have universally intrinsic implications for normal and diseased heart function.
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Interaction of hERG Channels and Syntaxin 1AMihic, Anton 14 July 2009 (has links)
The human ether-à-go-go related gene (hERG) encodes the pore-forming voltage-gated K+ channel that is essential for cardiac repolarization. Dr. Tsushima’s laboratory has previously characterized the endogenous expression of SNARE proteins in the mammalian heart, and the interaction of the SNARE protein syntaxin 1A (STX1A) with several cardiac ion channels. Here, we utilize a multi-disciplinary approach to describe the inhibitory effect of STX1A on hERG channel function. STX1A impairs hERG channel maturation and trafficking to the plasma membrane and induces a hyperpolarizing shift in the voltage-sensitivity of steady-state inactivation. We identify the residues involved in this protein-protein interaction through the use of hERG truncation mutations. We also describe the pharmacological and temperature-mediated rescue of hERG channel trafficking in the presence of STX1A. The regulation of cardiac ion channels by SNARE proteins represents a novel biological mechanism that may have universally intrinsic implications for normal and diseased heart function.
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