@phdthesis{Elsner2022,
  author    = {Elsner, Clara Dorothea},
  title     = {Ultrastructural analysis of biogenesis and release of endothelial extracellular vesicles},
  doi       = {10.25972/OPUS-28852},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-288526},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {Extracellular vesicle (EV)-mediated intercellular communication through exosomes, microvesicles (MVs) and apoptotic bodies has been shown to be implicated in various physiological as well as pathological processes such as the development and progression of atherosclerosis. While the cellular machinery controlling EV formation and composition has been studied extensively, little is known about the underlying morphological processes. This study focuses on a detailed ultrastructural analysis of the different steps of EV formation and release in Myocardial Endothelial (MyEnd) and Aortic Endothelial (AoEnd) cells cultured under serum starvation and inflammatory stimulation with TNF-α. Detailed morphological analyses were conducted applying and comparing different high- resolution light and electron microscopic methods. In this study, we could depict all steps of MV biogenesis named in literature. However, during the study of exosome biogenesis, we discovered a yet undescribed process: Instead of a direct fusion with the plasma membrane, multivesicular bodies were incorporated into a new distinct cellular compartment bound by fenestrated endothelium first. This may present a novel step in exosome biogenesis and warrants further study. Regarding the conditions of cell cultivation, we observed that the commonly used serum starvation causes MyEnd cells, but not AoEnd cells, to enter apoptosis after 48 hours. When preparing functional EV studies, we therefore recommend assessing the morphological condition of the serum-starved cells at different cultivation points first. When evaluating MV production, a statistical analysis showed that the more time AoEnd cells spent in cultivation under serum starvation, the higher the percentage of MV producing cells. However, additional TNF-α stimulation induced a significantly higher MV production than serum starvation alone. Lastly, our results show that TNF-α stimulation of AoEnd cells in vitro leads to the upregulation of CD44, an adhesion molecule critical in the early stages of atherosclerosis. CD44 was then depicted on the surface of generated MVs and exosomes. We conclude that under inflammatory conditions, EVs can mediate the transfer of CD44 from endothelial cells to target cells. This could be a novel mechanism by which MVs contribute to the development and progression of atherosclerotic disease and should be clarified by further studies.},
  subject      = {Vesikel},
  language  = {en}
}
@phdthesis{Kwok2020,
  author    = {Kwok, Chee Keong},
  title     = {Scaling up production of reprogrammed cells for biomedical applications},
  doi       = {10.25972/OPUS-19186},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-191865},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {Induced pluripotent stem cells (iPSCs) have been recognised as a virtually unlimited source of stem cells that can be generated in a patient-specific manner. Due to these cells' potential to give rise to all differentiated cell types of the human body, they have been widely used to derive differentiated cells for drug screening and disease modelling purposes. iPSCs also garner much interest as they can potentially serve as a source for cell replacement therapy. Towards the realisation of these biomedical applications, this thesis aims to address challenges that are associated with scale-up, safety and biofabrication. Firstly, the manufacture of a high number of human iPSCs (hiPSCs) will require standardised procedures for scale-up and the development of a flexible bioprocessing method, since standard adherent hiPSC culture exhibits limited scalability and is labour-intensive. While the quantity of cells that are required for cell therapy depends largely on the tissue and defect that these replacing cells are meant to correct, an estimate of 1 × 10^9 has been suggested to be sufficient for several indications, including myocardial infarction and islet replacement for diabetes. Here, the development of an integrated, microcarrier-free workflow to transition standard adherent hiPSC culture (6-well plates) to scalable stirred suspension culture in bioreactors (1 L working volume, 2.4 L maximum working volume) is presented. The two-phase bioprocess lasts 14 days and generates hiPSC aggregates measuring 198 ± 58 μm in diameter on the harvesting day, yielding close to 2 × 10^9 cells. hiPSCs can be maintained in stirred suspension for at least 7 weeks with weekly passaging, while exhibiting pluripotency-associated markers TRA-1-60, TRA-1-81, SSEA-4, OCT4, and SOX2. These cells retain their ability to differentiate into cells of all the three germ layers in vitro, exemplified by cells positive for AFP, SMA, or TUBB3. Additionally, they maintain a stable karyotype and continue to respond to specification cues, demonstrated by directed differentiation into beating cardiomyocyte-like cells. Therefore, the aim of manufacturing high hiPSC quantities was met using a state-of-the-art scalable suspension bioreactor platform. Secondly, multipotent stem cells such as induced neural stem cells (iNSCs) may represent a safer source of renewable cells compared to pluripotent stem cells. However, pre-conditioning of stem cells prior to transplantation is a delicate issue to ensure not only proper function in the host but also safety. Here, iNSCs which are normally maintained in the presence of factors such as hLIF, CHIR99021, and SB431542 were cultured in basal medium for distinct periods of time. This wash-out procedure results in lower proliferation while maintaining key neural stem cell marker PAX6, suggesting a transient pre-differentiated state. Such pre-treatment may aid transplantation studies to suppress tumourigenesis through transplanted cells, an approach that is being evaluated using a mouse model of experimental focal demyelination and autoimmune encephalomyelitis. Thirdly, biomedical applications of stem cells can benefit from recent advancements in biofabrication, where cells can be arranged in customisable topographical layouts. Employing a 3DDiscovery bioprinter, a bioink consisting of hiPSCs in gelatin-alginate was extruded into disc-shaped moulds or printed in a cross-hatch infill pattern and cross-linked with calcium ions. In both discs and printed patterns, hiPSCs recovered from these bioprints showed viability of around 70\% even after 4 days of culture when loaded into gelatin-alginate solution in aggregate form. They maintained pluripotency-associated markers TRA-1-60 and SSEA-4 and continued to proliferate after re-plating. As further proof-of-principle, printed hiPSC 3D constructs were subjected to targeted neuronal differentiation, developing typical neurite outgrowth and resulting in a widespread network of cells throughout and within the topology of the printed matrix. Staining against TUBB3 confirmed neuronal identity of the differentiated cellular progeny. In conclusion, these data demonstrate that hiPSCs not only survive the 3D-printing process but were able to differentiate along the printed topology in cellular networks.},
  subject      = {scale-up},
  language  = {en}
}
@phdthesis{Srinivasan2013,
  author    = {Srinivasan, Aruna},
  title     = {RS1 protein dependent and independent short and long term regulation of sodium dependent glucose transporter -1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85665},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2013},
  abstract  = {The Na+-D-glucose cotransporter in small intestine is regulated in response to food composition. Short term regulation of SGLT1 occurs post-transcriptionally in response to changes in luminal glucose. Adaptation to dietary carbohydrate involves long term regulation at the transcriptional level. The intracellular protein RS1 (gene RSC1A1) is involved in transcriptional and post-transcriptional regulation of SGLT1. RS1 contains an N-terminal domain with many putative phosphorylation sites. By Expressing SGLT1 in oocytes of Xenopus laevis it was previously demonstrated that the post-transcriptional down-regulation of SGLT1 by RS1 was dependent on the intracellular glucose concentration and activated by protein kinase C (PKC). The role of RS1 for short term regulation of SGLT1 in mouse small intestine in response to glucose and PKC was investigated comparing effects in RS1-/- mice and wildtype mice. Effects on SGLT1 activity were determined by measuring phlorizin inhibited uptake of α-methylglucoside (AMG). The involvement of RS1 in glucose dependent short term regulation could not be elucidated for technical reasons. However, evidence for RS1 independent short-term downregulation of SGLT1 after stimulation of PKC could be provided. It was shown that this downregulation includes decrease in the amount and/or in turnover of SGLT1 in the brush-border membrane as well as an increase of substrate affinity for AMG transport. Trying to elucidate the role of RS1 in long term regulation of SGLT1 in small intestine in response to glucose and fat content of the diet, wildtype and RS1-/- mice were kept for 2 months on a normo-caloric standard diet with high glucose and low fat content (ND), on a hyper-caloric glucose-galactose reduced diet with high fat content (GGRD) or on a hyper-caloric diet with a high fat and high glucose content (HFHGD). Thereafter the animals were starved overnight and SGLT1 mediated AMG uptake was measured. Independent of diet AMG uptake in ileum was smaller compared to duodenum and jejunum. In jejunum of wildtype and RS1-/- mice kept on the fat rich diets (GGRD and HFHGH) transport activity of SGLT1 was lower compared to mice kept on ND with low fat content. This result suggests an RS1 independent downregulation due to fat content of diet. Different to RS1-/- mice, the duodenum of wildtype mice showed transport activity of SGLT1 smaller in mice kept on glucose galactose reduced diet (GGRD) compared to the glucose galactose rich diets (ND and HFHGG). These data indicate that RS1 is involved in glucose dependent long term regulation in duodenum.},
  subject      = {Glucosetransportproteine},
  language  = {en}
}
@phdthesis{Heupel2010,
  author    = {Heupel, Wolfgang-Moritz Felix},
  title     = {Role and modulation of cadherins in pathologic processes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-52716},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2010},
  abstract  = {Ca2+ dependent cell adhesion molecules (cadherins) are central for a variety of cell and tissue functions such as morphogenesis, epithelial and endothelial barrier formation, synaptic function and cellular signaling. Of paramount importance for cadherin function is their specific extracellular adhesive trans-interaction. Cadherins are embedded in a cellular environment of intracellular and extracellular regulators that modify cadherin binding in response to various physiological and pathological stimuli. Most experimental approaches used for studying cadherin interaction however lack a physiological proof of principle mostly by not investigating cadherins in their physiological environment. In the present cumulative dissertation, experimental approaches were applied to characterize and modulate vascular endothelial (VE)-cadherin and desmocadherin functions in the (patho-)physiological contexts of endothelial permeability regulation and disturbance of epidermal barrier function, which is typical to the blistering skin disease pemphigus, respectively. Whereas VE-cadherin is a key regulator of the endothelial barrier that separates the blood compartment from the interstitial space of tissues, desmosomal cadherins are crucial for maintenance of epidermal integrity and separation of the external environment from the body's internal milieu. Cadherin functions were both investigated in cell-free and cell-based conditions: by using biophysical single molecule techniques like atomic force microscopy (AFM), cadherin function could be investigated in conditions, where contributions of intracellular signaling were excluded. These experiments were, however, compared and combined with cell-based experiments in which cadherins of epidermal or endothelial cell cultures were probed by laser force microscopy (laser tweezers), fluorescence recovery after photobleaching (FRAP) and other techniques. The autoimmune blistering skin diseases pemphigus foliaceus (PF) and pemphigus vulgaris (PV) are caused by autoantibodies directed against the extracellular domains of the desmosomal cadherins desmoglein (Dsg) 1 and 3, which are important for epidermal adhesion. The mechanism of autoantibody-induced cell dissociation (acantholysis) in pemphigus, however, is still not fully understood. For the first time, it is shown by AFM force spectroscopy that pemphigus autoantibodies directly inhibit Dsg3 adhesion by steric hindrance but do not inhibit adhesion of Dsg1. However, the full pathogenicity of the autoantibodies depended on cellular signaling processes, since autoantibodies targeting Dsg1 also resulted in loss of cadherin-mediated adhesion in cell-based experiments. However, two other signaling pathways that have been reported to be involved in pemphigus pathogenesis, i.e. epidermal growth factor receptor (EGFR) and c-Src activation, were not found to be important in this context. Furthermore, peptide-based modulators of cadherin functions were generated for Dsg1/3 and VE-cadherin. By comparing Dsg1, Dsg3 and VE-cadherin sequences to published X-ray structures of cadherin trans-interactions, specific amino acid sequences of the binding pockets of these cadherins were identified. Peptide versions of these motifs were synthesized and the antagonistic functions of these "single peptides" were validated by AFM force spectroscopy as well as by cell-based assays. By linking two single peptides in tandem, stabilization of cadherin bonds because of by cross-bridge formation between trans-interacting cadherins was demonstrated. Protective effects of tandem peptides were shown by partly preventing pemphigus autoantibody-induced acantholysis, or in the case of VE-cadherin, by stabilizing endothelial barrier properties against barrier disrupting agents like the Ca2+ ionophore A23187 and an inhibitory VE-cadherin antibody. Most importantly, VE-cadherin tandem peptides abolished microvascular hyperpermeability induced by the physiologic inflammatory agent tumor necrosis factor-α in the rat mesentery in vivo. Both classes of tandem peptides therefore can be considered as a starting point for the generation of potential therapeutic agents that might prevent cell dissociation in pemphigus and breakdown of the endothelial barrier under inflammatory conditions.},
  subject      = {Cadherine},
  language  = {en}
}
@phdthesis{Gorbunov2008,
  author    = {Gorbunov, Dmitry},
  title     = {Rat organic cation transporter 1 (rOCT1): investigation of conformational changes and ligand binding},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32645},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2008},
  abstract  = {Polyspecific organic cation transporters (OCTs) of the SLC22 family mediate downhill transport of organic cations and play an essential role in excretion and distribution of endogenous organic cations and for the uptake, elimination and distribution of cationic drugs and toxins. Although physiological and pharmacological significance of OCTs is widely accepted, many questions concerning structure and transport mechanism still remain open. To investigate conformational changes of the rat OCT1 during transport cycle, voltage-clamp fluorometry was performed with a cysteine-deprived mutant in which phenylalanine 483 in transmembrane helix (TMH) 11 close to the extracellular surface was replaced by cysteine and covalently labeled with tetramethylrhodamine-6-maleimide. Potential-dependent fluorescence changes were observed that were sensitive to the presence of substrates choline, tetraethylammonium (TEA), 1-methyl-4-phenylpyridinium (MPP), and of the contransported inhibitor tetrabutylammonium (TBuA). The data suggest that the transporter undergoes conformational changes in voltage- and substrate-dependent manner which are compatible with alternating access mechanism. Using potential-dependent fluorescence changes as readout, one high-affinity binding site per substrate and two highaffinity binding sites for TBuA were identified in addition to the previously described single interaction sites. Coexisting high-affinity cation binding sites in organic cation transporters may collect xenobiotics and drugs; however, translocation of organic cations across the membrane may only be induced when a low-affinity cation binding site is loaded. Whereas high-affinity binding of TBuA has no effect on cation uptake by wildtype rat OCT1, replacement by cysteine or serine of amino acids W147, F483, and F486 located in a modeled contact region between TMH2 and TMH11 outside the binding pocket leads to inhibition of MPP or TEA uptake. Thus, mutations of amino acids in transport relevant key positions, which can be distinct from the cation binding region, may transform noninhibitory highaffinity binding sites of high-affinity inhibition sites and thereby cause adverse drug reactions in patients.},
  subject      = {Kationentransporter 1 der Ratte},
  language  = {en}
}
@phdthesis{Chintalapati2013,
  author    = {Chintalapati, Chakravarthi},
  title     = {Ornithine decarboxylase is the receptor of regulatory protein RS1 (RSC1A1) mediating RS1 dependent shortterm regulation of glucose transporter SGLT1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85622},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2013},
  abstract  = {RS1 is the intron less singel copy gene involved in regulation of plasme membrane transporters. Ornithine decarboxylase is identified as the receptor of RS1 specific for the release of vesicles containing SGLT1 specifically at the trans-golgi network. RS1 decreases the activity of ODC there by inhibiting the release of vesicles containing specifically SGLT1.},
  subject      = {Ornithindecarboxylase},
  language  = {en}
}
@phdthesis{Filatova2009,
  author    = {Filatova, Alina},
  title     = {Mechanism and Control of Nuclear-Cytoplasmic Translocation of the Transporter Regulator RS1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-38512},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2009},
  abstract  = {Das RS1 Protein (Gen RSC1A1) beteiligt sich an der Regulation des Na+-D-Glukose-kotransporters SGLT1 und einiger anderer Transporter. In subkonfluenten LLC-PK1 Zellen hemmt RS1 die Freisetzung von SGLT1 aus dem trans-Golgi-Netzwerk und die Transkription von SGLT1. W{\"a}hrend es sich in konfluenten Zellen haupts{\"a}chlich im Zytoplasma befindet, ist RS1 in subkonfluenten Zellen im Kern und im Zytoplasma lokalisiert. In der vorliegenden Arbeit wurden Mechanismus und Regulation der konfluenzabh{\"a}ngigen Kernlokalisation von RS1 untersucht. Dabel konnte gezeigt werden, dass die von Konfluenz abh{\"a}ngige Kernlokalisation von RS1 durch den Zellzyklus reguliert wird. In RS1 aus Sus scrofa (pRS1) wurde eine Sequenz identifiziert („nuclear shuttling signal", NS), die f{\"u}r die konfluenzabh{\"a}ngige Verteilung von RS1 verantwortlich ist und sowohl das Signal f{\"u}r die Kernlokalisation (NLS) als auch das Signal f{\"u}r den Export aus dem Kern (NES) beinhaltet. Die NLS und NES Signale von RS1 vermitteln die Translokation des Proteins in den Kern und aus dem Kern mit Hilfe von Importin \&\#946;1 bzw. CRM1, wobei die Verteilung von RS1 zwischen Kern und Zytoplasma durch die Aktivit{\"a}t des Exportsystems bestimmt wird. Es wurde gezeigt, dass die benachbarte Proteinkinase C (PKC) Phosphorylierungsstelle an Serin 370 von pRS1 die NS-gesteuerte Kernlokalisierung kontrolliert und f{\"u}r die vom Zellzyklus abh{\"a}ngige Kernlokalisation notwendig ist. Aufgrund der Ergebnisse der ortsgerichteten Mutagenese, PKC-Aktivierungsexperimenten und Massenspektrometrie-Analyse des Phosphorylierungsmusters von RS1 wurde ein Modell vorgeschlagen, das die Regulation der Kernlokalisation des RS1 Proteins in LLC-PK1 Zellen beschreibt. Dem Modell zufolge wird RS1 in subkonfluenten Zellen stark in den Kern bef{\"o}rdert, w{\"a}hrend der Export von RS1 aus dem Kern nicht stattfindet. Das f{\"u}hrt zur Anreicherung von RS1 im Kern. Nach Konfluenz wird Serin 370 durch PKC phosphoryliert, was die Steigerung des RS1-Exports aus dem Kern beg{\"u}nstigt und die {\"u}berwiegend zytoplasmatische Lokalisation des Proteins in konfluenten Zellen hervorruft. Die konfluenzabh{\"a}ngige Regulation der Lokalisation von RS1 kann die Expression von SGLT1 w{\"a}hrend der Regeneration von Enterozyten im D{\"u}nndarm und der Regeneration von Zellen der Nierentubuli nach hypox{\"a}mischem Stress kontrollieren. Außerdem deutet die Analyse der Genexpression in embryonalen Fibroblasten der RS-/- M{\"a}use deutet darauf hin, dass die transkriptionale Regulation durch RS1 im Zellzyklus und bei der Zellteilung eine wichtige Rolle spielen kann. Da die Lokalisation von RS1 zellzyklusabh{\"a}ngig ist, kann RS1 f{\"u}r die Regulation der Transporter in spezifischen Phasen des Zellzyklus wichtig sein.},
  subject      = {RS1},
  language  = {en}
}
@phdthesis{Shatskaya2006,
  author    = {Shatskaya, Natalia},
  title     = {Identification of amino acids within the substrate binding region of organic cation transporters (OCTZs) that are involved in binding of corticosterone},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-20430},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2006},
  abstract  = {The polyspecific organic cation transporters (OCT) are involved in the elimination and distribution of drugs, environmental toxins, and endogenous organic cations including monoamine neurotransmitters. Steroid hormones inhibit organic cation transport by the three OCT subtypes with different affinities showing distinct species difference; for example, the IC50 values for corticosterone inhibition of cation uptake by transporters rOCT1 and rOCT2 are ~150\&\#956;M and ~4 \&\#956;M, respectively. By introducing domains and amino acids from rOCT2 into rOCT1, we identified three amino acids in the presumed 10th TMD of rOCT2 which are responsible for the higher affinity of corticosterone in comparison to rOCT1. This is the first study which revealed the components of the binding site for corticosterone in OCTs. The evidence is presented that these amino acids (alanine 443, leucine 447, and glutamine 448 in rOCT1 and isoleucine 443, tyrosine 447, and glutamate 448 in rOCT2) are probably located within the substrate binding region of OCTs since the affinity of transported cations was increased together with the affinity of corticosterone. In the double mutant rOCT1(L447Y/Q448E) the IC50 value for the inhibition of [3H]MPP (0.1 \&\#956;M) uptake by corticosterone (24 ± 4 \&\#956;M) was significantly higher compared to the IC50 value for inhibition of [14C]TEA (10 \&\#956;M) uptake (5.3 ± 1.7 \&\#956;M), indicating an allosteric interaction between transported substrate and corticosterone. The data suggest that more than one compound can bind simultaneously to the substrate binding region. These results confirm previous suggestion that binding of substrates and inhibitors to OCTs involves interaction with a comparatively large surface that may include multiple binding domains rather than with a structurally restricted single binding site.},
  subject      = {Kation},
  language  = {en}
}
@phdthesis{Rehman2018,
  author    = {Rehman, Saba},
  title     = {Identification of accessible and closed substrate binding sites in the outward open cleft of rat Organic Cation Transporter 1 (rOCT1)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169992},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2018},
  abstract  = {The present study was conducted on the rOCT1, a member of SLC22 family. Structurally, it consists of 12 membrane spanning α-helices with both N- and C-termini intracellular. Studies done so far, through tracer uptake and inhibition, reconstitution of rOCT1 in nanodiscs and proteoliposomes and voltage-clamp fluorometry, have identified the main amino acids in the cleft of rOCT1 that interact in a critical manner with the substrates/inhibitors either directly or indirectly. Homology modeling studies have also supported these observations. In the present study we aimed at measuring the binding of substrates MPP+ and TEA+ to rOCT1 at 0oC in order to establish the amino acids in the cleft region that interact with the substrate when the transporter is frozen in the outward-open conformation. Previously identified crucial amino acids (Asp475, Phe160, Leu447, Arg440, Trp218 and Tyr222) were selected for the study. rOCT1 wild-type and its mutants were stably expressed in HEK293 cells and these cells were used for the binding measurements with the radioactive substrate (MPP+ or TEA+) at 0°C in Mg-Ca-PBS buffer as described in "Materials and Methods" section in detail. rOCT1 wild-type revealed for MPP+-binding a KD which was not significantly different from the corresponding Km value. Also, after addition of 10 nM non-radioactive MPP+, an initial increase of about 20\% in bound MPP+ was observed. The results indicate that the Km for transport is dependent on the binding of MPP+ to the outward-open conformation and hints at the possibility of allosteric interaction between the binding sites. Mutations at position Trp218, Phe160 and Asp475 resulted in a change in the KD value. Trp218 mutations also showed an allosteric increase similar to the rOCT1 wild-type. This study suggests that these amino acids are located at a critical position in the outward-open conformation for MPP+ transport. TEA+-binding could not be observed in rOCT1 wild-type, indicating that the binding site is perhaps inaccessible for TEA+ in frozen outward-open state. The mutants D475E, F160A, L447F, R440K and Y222F showed a very low affinity binding with a very high KD value as compared to the corresponding Km values indicating that the transporter might have different affinities for extra-cellular binding alone and for the complete transport process especially if temperature is the limiting factor. Substrate inhibition studies done using both MPP+ and TEA+ have confirmed the existence of overlapping binding sites for these two ligands. This study has confirmed the direct interaction of Trp218, Phe160, Asp475 with MPP+ and Phe160, Asp475, Leu447, Arg440 and Tyr222 with TEA+ in the outward-open conformation.},
  subject      = {Kation},
  language  = {en}
}
@phdthesis{Leyerer2005,
  author    = {Leyerer, Marina},
  title     = {Identification and characterization of Nuclear Localization Signal of pRS1 protein},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-25573},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2005},
  abstract  = {RS1, ein Genprodukt von RSC1A1, ist entscheidend an der zelldichteabh{\"a}ngigen transkriptionellen Herunterregulation von SGLT1 in LLC-PK1 Zellen und an der post-transkriptionellen Herunterregulation von SGLT1 im D{\"u}nndarm beteiligt. RS1 hemmt die Freigabe von SGLT1 enthaltenden Vesikeln aus dem trans-Golgi Netzwerk und wandert in den Zellkern wo es die Transkription von SGLT1 inhibiert. In der vorliegenden Arbeit identifizierten wir eine neuartige 21 Aminos{\"a}uren lange nicht-konventionelle Kernlokalisierungssequenz (RS1 NLS) in RS1 vom Schwein (pRS1), die f{\"u}r die Kernlokalisierung von pRS1 n{\"o}tig und ausreichend ist. RS1 NLS ist von zwei Konsensussequenzen f{\"u}r Phosphorylierung umrahmt, welche f{\"u}r die konfluenzabh{\"a}ngige Regulierung von RS1 NLS verantwortlich sind: Eine Stelle f{\"u}r Casein Kinase 2 (CK2) in der Position 348 und eine Stelle f{\"u}r Protein Kinase C (PKC) in der Position 370. Es wurde eine konfluenz-abh{\"a}ngige Kernlokalisierung mit den Aminos{\"a}uren 342-374 (R-NLS-Reg) beobachtet. Die Mutationsanalyse deutete darauf hin, dass Kernlokalisierung durch die Phosphorylierung von Serin 370 (PKC) geblockt wird, und dass die Phosphorylierung von Serin 348 (CK2) die Phosphorylierung von Serin 370 verhindert. Da w{\"a}hrend der Konfluenz CK2 herunterreguliert und PKC hochreguliert wird, deuten unsere Daten darauf hin, dass die Kernlokalisierung die zelldichteabh{\"a}ngigen Ver{\"a}nderungen in der transkriptionellen und posttranskriptionellen Hemmung von SGLT1 Expression koordiniert.},
  subject      = {Regulierung},
  language  = {en}
}