Biochemical and Structural Analysis of the Nucleoporin Nup214 and its Involvement in mRNA Export

In order to gain a deeper understanding of the role of nups in leukemogenesis, and to make sense of the architecture and regulation of the mRNA export machinery at the NPC, I set out to biochemically and structurally characterize Nup214. In this thesis, I present the crystal structure of the human Nup214 N-terminal domain at 1.65 Å resolution. The structure reveals a sevenbladed !-propeller fold followed by a 30-residue C-terminal extended peptide segment (CTE). The CTE folds back onto the !-propeller and binds to its bottom face. Conserved surface patches on the Nup214 NTD reveal putative proteininteraction sites, one of which is crucial for the interaction with Ddx19. Using a comprehensive mutational and biochemical analysis, the interaction between the Nup214 NTD and Ddx19 is dissected. The structure of the Nup214 NTD•Ddx19 in its ADP-bound state at 2.5 Å resolution reveals the molecular basis for the interaction between the two proteins. A conserved residue of Ddx19 is shown to be crucial for complex formation in vitro and in vivo. Strikingly, the interaction surfaces exhibit strongly opposing surface potentials, with the helicase surface being positively and the Nup214 surface being negatively charged. Ddx19 is shown to bind RNA only in its ATP-bound state, and the binding of RNA and the Nup214 NTD is mutually exclusive. Finally, I speculate that Nup214 is the ATP-exchange factor for Ddx19, and propose the Ddx19 ATPase cycle as the terminal step in mRNA export

Die Potentiale von Augmented und Virtual Reality in den Gesundheitswissenschaften

Poster im Rahmen der Community Health Konferenz 2020 der Hochschule für Gesundheit Bochu

Terminologische Untersuchung Deutsch-Englisch zu Autismusspektrumstörungen mit besonderem Schwerpunkt auf dem Asperger-Syndrom

Die vorliegende Arbeit stellt einen Versuch dar, die Terminologie im Bereich der Autismusspektrumstörungen, fokussiert auf das Asperger-Syndrom, nach den Grundsätzen der übersetzungsorientierten Terminologiearbeit und unter besonderer Berücksichtigung des deutschen und angloamerikanischen Sprachraumes zu erfassen und zu beschreiben. Mit der Beantwortung der Forschungsfrage „Wie sieht der IST-Zustand der Fachterminologie im Bereich Autismus nach der Aufnahme des Asperger-Syndroms in die internationale Diagnoseklassifikation der WHO 1992 und dem Aufkommen des Web 2.0 aus?“ soll ÜbersetzerInnen und DolmetscherInnen die Möglichkeit geboten werden, sich an Hand eines theoretischen Teils einen Überblick über die Thematik zu verschaffen und sich rasch mit der Terminologie dieses Fachgebietes vertraut machen zu können. \ud Nach einem historischen Überblick über die Entstehung des Fachgebietes wie auch des Begriffes wird gezeigt, dass mehrere Störungen auf dem autistischen Spektrum existieren (frühkindlicher Autismus, atypischer Autismus und Asperger-Syndrom), die in ihren verschieden starken Ausprägungen Betroffene von „behindert“ bis hin zu „fast normal“ wirken lassen. Autismus wird unter Berücksichtigung der internationalen Klassifikationssysteme ICD-10 und DSM-IV von anderen Störungen abgegrenzt, worauf Häufigkeit (Prävalenz) sowie Entstehungsgeschichte (Ätiologie und Pathogenese), aber auch zweifelhafte Erklärungsmodelle bezüglich der Ursachen der Störungen und Scharlatanerie bei propagierten Heilungsmethoden beleuchtet werden. Als meistverbreitete Ausprägung von Autismus wird detaillierter auf das Asperger-Syndrom eingegangen, wobei auch empfehlenswerte Therapieansätze wie Psychotherapie, Pharmakotherapie und diverse Therapieprogramme aufgezeigt werden. Den Abschluss bildet ein Ausschnitt aus der Welt des Internets, das von Betroffenen, Eltern oder Freunden bzw. Partnern als Möglichkeit zur Selbsthilfe, manchmal jedoch auch zu reiner Selbstdarstellung genutzt wird

Innovative Technologien für die Pflege – Der Einsatz von VR & 3D-Druck am Pflegebett

Poster im Rahmen der Clusterkonferenz Pflege 2020

Crystal Structure of the N-Terminal Domain of Nup358/RanBP2

Key steps in mRNA export are the nuclear assembly of messenger ribonucleoprotein particles (mRNPs), the translocation of mRNPs through the nuclear pore complex (NPC), and the mRNP remodeling events at the cytoplasmic side of the NPC. Nup358/RanBP2 is a constituent of the cytoplasmic filaments of the NPC specific to higher eukaryotes and provides a multitude of binding sites for the nucleocytoplasmic transport machinery. Here, we present the crystal structure of the Nup358 N-terminal domain (NTD) at 0.95 Å resolution. The structure reveals an α-helical domain that harbors three central tetratricopeptide repeats (TPRs), flanked on each side by an additional solvating amphipathic α helix. Overall, the NTD adopts an unusual extended conformation that lacks the characteristic peptide-binding groove observed in canonical TPR domains. Strikingly, the vast majority of the NTD surface exhibits an evolutionarily conserved, positive electrostatic potential, and we demonstrate that the NTD possesses the capability to bind single-stranded RNA in solution. Together, these data suggest that the NTD contributes to mRNP remodeling events at the cytoplasmic face of the NPC

Human Bocavirus NS1 and NS1-70 Proteins Inhibit TNF-α-Mediated Activation of NF-κB by targeting p65.

Human bocavirus (HBoV), a parvovirus, is a single-stranded DNA etiologic agent causing lower respiratory tract infections in young children worldwide. Nuclear factor kappa B (NF-κB) transcription factors play crucial roles in clearance of invading viruses through activation of many physiological processes. Previous investigation showed that HBoV infection could significantly upregulate the level of TNF-α which is a strong NF-κB stimulator. Here we investigated whether HBoV proteins modulate TNF-α-mediated activation of the NF-κB signaling pathway. We showed that HBoV NS1 and NS1-70 proteins blocked NF-κB activation in response to TNF-α. Overexpression of TNF receptor-associated factor 2 (TRAF2)-, IκB kinase alpha (IKKα)-, IκB kinase beta (IKKβ)-, constitutively active mutant of IKKβ (IKKβ SS/EE)-, or p65-induced NF-κB activation was inhibited by NS1 and NS1-70. Furthermore, NS1 and NS1-70 didn't interfere with TNF-α-mediated IκBα phosphorylation and degradation, nor p65 nuclear translocation. Coimmunoprecipitation assays confirmed the interaction of both NS1 and NS1-70 with p65. Of note, NS1 but not NS1-70 inhibited TNF-α-mediated p65 phosphorylation at ser536. Our findings together indicate that HBoV NS1 and NS1-70 inhibit NF-κB activation. This is the first time that HBoV has been shown to inhibit NF-κB activation, revealing a potential immune-evasion mechanism that is likely important for HBoV pathogenesis

The role of NF-kB triggered inflammation in cerebral ischemia

Cerebral ischemia is a devastating disease that affects many people worldwide every year. The neurodegenerative damage as a consequence of oxygen and energy deprivation, to date, has no known effective treatment. The ischemic insult is followed by an inflammatory response that involves a complex interaction between inflammatory cells and molecules which play a role in the progression towards cell death. However, there is presently a matter of controversy over whether inflammation could either be involved in brain damage or be a necessary part of brain repair. The inflammatory response is triggered by inflammasomes, key multiprotein complexes that promote secretion of pro-inflammatory cytokines. An early event in post-ischemic brain tissue is the release of certain molecules and reactive oxygen species (ROS) from injured neurons which induce the expression of the nuclear factor-kappaB (NF-kB), a transcription factor involved in the activation of the inflammasome. There are conflicting observations related to the role of NF-kB. While some observe that NF-kB plays a damaging role, others suggest it to be neuroprotective in the context of cerebral ischemia, indicating the need for additional investigation. Here we discuss the dual role of the major inflammatory signaling pathways and provide a review of the latest research aiming to clarify the relationship between NF- kB mediated inflammation and neuronal death in cerebral ischemia

Structures of the Signal Recognition Particle Receptor from the Archaeon Pyrococcus furiosus: Implications for the Targeting Step at the Membrane

In all organisms, a ribonucleoprotein called the signal recognition particle (SRP) and its receptor (SR) target nascent proteins from the ribosome to the translocon for secretion or membrane insertion. We present the first X-ray structures of an archeal FtsY, the receptor from the hyper-thermophile Pyrococcus furiosus (Pfu), in its free and GDP•magnesium-bound forms. The highly charged N-terminal domain of Pfu-FtsY is distinguished by a long N-terminal helix. The basic charges on the surface of this helix are likely to regulate interactions at the membrane. A peripheral GDP bound near a regulatory motif could indicate a site of interaction between the receptor and ribosomal or SRP RNAs. Small angle X-ray scattering and analytical ultracentrifugation indicate that the crystal structure of Pfu-FtsY correlates well with the average conformation in solution. Based on previous structures of two sub-complexes, we propose a model of the core of archeal and eukaryotic SRP•SR targeting complexes

MOS11: A New Component in the mRNA Export Pathway

Nucleocytoplasmic trafficking is emerging as an important aspect of plant immunity. The three related pathways affecting plant immunity include Nuclear Localization Signal (NLS)–mediated nuclear protein import, Nuclear Export Signal (NES)–dependent nuclear protein export, and mRNA export relying on MOS3, a nucleoporin belonging to the Nup107–160 complex. Here we report the characterization, identification, and detailed analysis of Arabidopsis modifier of snc1, 11 (mos11). Mutations in MOS11 can partially suppress the dwarfism and enhanced disease resistance phenotypes of snc1, which carries a gain-of-function mutation in a TIR-NB-LRR type Resistance gene. MOS11 encodes a conserved eukaryotic protein with homology to the human RNA binding protein CIP29. Further functional analysis shows that MOS11 localizes to the nucleus and that the mos11 mutants accumulate more poly(A) mRNAs in the nucleus, likely resulting from reduced mRNA export activity. Epistasis analysis between mos3-1 and mos11-1 revealed that MOS11 probably functions in the same mRNA export pathway as MOS3, in a partially overlapping fashion, before the mRNA molecules pass through the nuclear pores. Taken together, MOS11 is identified as a new protein contributing to the transfer of mature mRNA from the nucleus to the cytosol

Structure and Morphology of Silver Nanoparticles on the (111) Surface of Cerium Oxide

The structure of Ag nanoparticles of different size, supported on the cerium oxide (111) surface, was investigated by X-ray absorption fine structure at the Ag K-edge. The results of the data analysis in the near and extended energy range are interpreted with the help of the results obtained by X-ray photoelectron spectroscopy and scanning tunneling microscopy measurements and allow to obtain a detailed atomic scale description of the model system investigated. The Ag nanoparticles have an average size of a few tens of angstroms, which increases with increasing deposited Ag amount. The nanoparticles show a slight tendency to nucleate at the step edges between different cerium oxide layers and they have a face centered cubic structure with an Ag-Ag interatomic distance contracted by 3-4% with respect to the bulk value. The interatomic distance contraction is mainly ascribed to dimensionality induced effects, while epitaxial effects have a minor role. The presence of Ag-O bonds at the interface between the nanoparticles and the supporting oxide is also detected. The Ag-O interatomic distance decreases with decreasing nanoparticle size