@phdthesis{Blachutzik2012,
  author    = {Blachutzik, J{\"o}rg O.},
  title     = {Visualisierung von Plasmamembran-Dom{\"a}nen in Arabidopsis thaliana},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71925},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2012},
  abstract  = {Unter Verwendung fluoreszenzmarkierter Remorine der taxonomischen Gruppe 1b wurden Nanodom{\"a}nen in Arabidopsis Plasmamembranen (PM) unter Verwendung hoch aufl{\"o}sender Laser Scanning-Systeme sichtbar gemacht. In diesen kompartimentierten Membranbereichen lagerten sich Sterol-abh{\"a}ngige Remorine aus verschiedenen Pflanzen-familien zusammen und zeigten dort Kolokalisation. Dies wurde statistisch belegt durch hohe Pearson und Spearman Korrelationskoeffizienten. Remorine konnten schließlich als pflanzliche Markerproteine f{\"u}r kompartimentierte Membranbereiche etabliert werden. Die Nanodom{\"a}nen zeigten zu keinem Zeitpunkt laterale Bewegungen in der PM und scheinen sowohl von zytoskelett{\"a}ren Strukturen als auch von Komponenten der Zellwand stabilisiert zu werden. M{\"o}glicherweise spielen transmembrane Tetraspanine sowie GPI-verankerte SKU5-Proteine eine Rolle bei der stabilen Verankerung. F{\"u}r zwei native Arabidopsis Remorine wurden posttranslationale Modifikationsstellen aufgedeckt, die der Anheftung dieser hydrophilen Proteine an die PM dienen. Weiterhin scheinen gleichartige Remorine miteinander zu interagieren. Beispielsweise waren im Zytosol lokalisierte Remorin-Mutanten bei einer gleichzeitigen Expression der entsprechenden Voll{\"a}ngenproteine erneut an der PM zu finden. F{\"u}r die Remorine wurde postuliert, dass sie mit anderen Proteinen interagieren und dabei makromolekulare Strukturen ausbilden. Den Remorinen k{\"o}nnte daher eine Aufgabe bei der molekularen Organisation pflanzlicher Membrandom{\"a}nen zukommen, indem sie ein filamentartiges Netzwerk innerhalb distinkter Dom{\"a}nen ausbilden, das m{\"o}glicherweise zur Stabilit{\"a}t und Aufrechterhaltung dieser spezialisierten Bereiche beitr{\"a}gt. Unter Einbeziehung der STED-Mikroskopie wurde eine empirische Gr{\"o}ßenverteilung von 97±4nm Durchmesser f{\"u}r PM-st{\"a}ndige Dom{\"a}nen in Arabidopsis ermittelt. Hinsichtlich der physiologischen Relevanz konnte gezeigt werden, dass die Dom{\"a}nen eine Rolle bei der ABA-vermittelten, kalziumabh{\"a}ngigen Regulation des Anionenkanals SLAH3 einnehmen. SLAH3 wird durch kalziumabh{\"a}ngige Kinasen aus der CDPK-Familie aktiviert, im Speziellen durch CPK21 und CPK23. Beide Kinasen werden durch die ABA-sensitiven Phosphatasen ABI1 und ABI2 reguliert. Die spezifisch stattfindenden Interaktionen zwischen SLAH3 und CPK21, sowie zwischen CPK21 und ABI1 waren auf Nanodom{\"a}nen beschr{\"a}nkt und wurden durch die Methodik der bimolekularen Fluoreszenzkomplementation erstmals in planta nachgewiesen, mit Remorinen der taxonomischen Gruppe 1b als etablierte Markerproteine f{\"u}r Membrandom{\"a}nen.},
  subject      = {Plasmamembran},
  language  = {de}
}
@article{AvotaBodemChithelenetal.2021,
  author    = {Avota, Elita and Bodem, Jochen and Chithelen, Janice and Mandasari, Putri and Beyersdorf, Niklas and Schneider-Schaulies, J{\"u}rgen},
  title     = {The Manifold Roles of Sphingolipids in Viral Infections},
  series = {Frontiers in Physiology},
  volume    = {12},
  journal   = {Frontiers in Physiology},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2021.715527},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246975},
  year      = {2021},
  abstract  = {Sphingolipids are essential components of eukaryotic cells. In this review, we want to exemplarily illustrate what is known about the interactions of sphingolipids with various viruses at different steps of their replication cycles. This includes structural interactions during entry at the plasma membrane or endosomal membranes, early interactions leading to sphingolipid-mediated signal transduction, interactions with internal membranes and lipids during replication, and interactions during virus assembly and budding. Targeted interventions in sphingolipid metabolism - as far as they can be tolerated by cells and organisms - may open novel possibilities to support antiviral therapies. Human immunodeficiency virus type 1 (HIV-1) infections have intensively been studied, but for other viral infections, such as influenza A virus (IAV), measles virus (MV), hepatitis C virus (HCV), dengue virus, Ebola virus, and severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), investigations are still in their beginnings. As many inhibitors of sphingolipid metabolism are already in clinical use against other diseases, repurposing studies for applications in some viral infections appear to be a promising approach.},
  language  = {en}
}
@article{MuranyiMalkuschMuelleretal.2013,
  author    = {Muranyi, Walter and Malkusch, Sebastian and M{\"u}ller, Barbara and Heilemann, Mike and Kr{\"a}usslich, Hans-Georg},
  title     = {Super-Resolution Microscopy Reveals Specific Recruitment of HIV-1 Envelope Proteins to Viral Assembly Sites Dependent on the Envelope C-Terminal Tail},
  series = {PLoS Pathogens},
  volume    = {9},
  journal   = {PLoS Pathogens},
  number    = {2},
  doi       = {10.1371/journal.ppat.1003198},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131235},
  pages     = {e1003198},
  year      = {2013},
  abstract  = {The inner structural Gag proteins and the envelope (Env) glycoproteins of human immunodeficiency virus (HIV-1) traffic independently to the plasma membrane, where they assemble the nascent virion. HIV-1 carries a relatively low number of glycoproteins in its membrane, and the mechanism of Env recruitment and virus incorporation is incompletely understood. We employed dual-color super-resolution microscopy visualizing Gag assembly sites and HIV-1 Env proteins in virus-producing and in Env expressing cells. Distinctive HIV-1 Gag assembly sites were readily detected and were associated with Env clusters that always extended beyond the actual Gag assembly site and often showed enrichment at the periphery and surrounding the assembly site. Formation of these Env clusters depended on the presence of other HIV-1 proteins and on the long cytoplasmic tail (CT) of Env. CT deletion, a matrix mutation affecting Env incorporation or Env expression in the absence of other HIV-1 proteins led to much smaller Env clusters, which were not enriched at viral assembly sites. These results show that Env is recruited to HIV-1 assembly sites in a CT-dependent manner, while Env\((\Delta CT)\) appears to be randomly incorporated. The observed Env accumulation surrounding Gag assemblies, with a lower density on the actual bud, could facilitate viral spread in vivo. Keeping Env molecules on the nascent virus low may be important for escape from the humoral immune response, while cell-cell contacts mediated by surrounding Env molecules could promote HIV-1 transmission through the virological synapse.},
  language  = {en}
}
@article{BoertleinSchumacherKleuseretal.2019,
  author    = {B{\"o}rtlein, Charlene and Schumacher, Fabian and Kleuser, Burkhard and D{\"o}lken, Lars and Avota, Elita},
  title     = {Role of neutral sphingomyelinase-2 (NSM 2) in the control of T cell plasma membrane lipid composition and cholesterol homeostasis},
  series = {Frontiers in Cell and Developmental Biology},
  volume    = {7},
  journal   = {Frontiers in Cell and Developmental Biology},
  number    = {226},
  issn      = {2296-634X},
  doi       = {10.3389/fcell.2019.00226},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-190596},
  year      = {2019},
  abstract  = {The activity of neutral sphingomyelinase-2 (NSM2) to catalyze the conversion of sphingomyelin (SM) to ceramide and phosphocholine at the cytosolic leaflet of plasma membrane (PM) is important in T cell receptor (TCR) signaling. We recently identified PKCζ as a major NSM2 downstream effector which regulates microtubular polarization. It remained, however, unclear to what extent NSM2 activity affected overall composition of PM lipids and downstream effector lipids in antigen stimulated T cells. Here, we provide a detailed lipidomics analyses on PM fractions isolated from TCR stimulated wild type and NSM2 deficient (ΔNSM) Jurkat T cells. This revealed that in addition to that of sphingolipids, NSM2 depletion also affected concentrations of many other lipids. In particular, NSM2 ablation resulted in increase of lyso-phosphatidylcholine (LPC) and lyso-phosphatidylethanolamine (LPE) which both govern PM biophysical properties. Crucially, TCR dependent upregulation of the important T cell signaling lipid diacylglycerol (DAG), which is fundamental for activation of conventional and novel PKCs, was abolished in ΔNSM cells. Moreover, NSM2 activity was found to play an important role in PM cholesterol transport to the endoplasmic reticulum (ER) and production of cholesteryl esters (CE) there. Most importantly, CE accumulation was essential to sustain human T cell proliferation. Accordingly, inhibition of CE generating enzymes, the cholesterol acetyltransferases ACAT1/SOAT1 and ACAT2/SOAT2, impaired TCR driven expansion of both CD4\(^+\) and CD8\(^+\) T cells. In summary, our study reveals an important role of NSM2 in regulating T cell functions by its multiple effects on PM lipids and cholesterol homeostasis.},
  language  = {en}
}
@article{AgarwalYangRiceetal.2014,
  author    = {Agarwal, Shailesh R. and Yang, Pei-Chi and Rice, Monica and Singer, Cherie A. and Nikolaev, Viacheslav O. and Lohse, Martin J. and Clancy, Colleen E. and Harvey, Robert D.},
  title     = {Role of Membrane Microdomains in Compartmentation of cAMP Signaling},
  series = {PLOS ONE},
  volume    = {9},
  journal   = {PLOS ONE},
  number    = {4},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0095835},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116673},
  pages     = {e95835},
  year      = {2014},
  abstract  = {Spatially restricting cAMP production to discrete subcellular locations permits selective regulation of specific functional responses. But exactly where and how cAMP signaling is confined is not fully understood. Different receptors and adenylyl cyclase isoforms responsible for cAMP production are not uniformly distributed between lipid raft and non-lipid raft domains of the plasma membrane. We sought to determine the role that these membrane domains play in organizing cAMP responses in HEK293 cells. The freely diffusible FRET-based biosensor Epac2-camps was used to measure global cAMP responses, while versions of the probe targeted to lipid raft (Epac2-MyrPalm) and non-raft (Epac2-CAAX) domains were used to monitor local cAMP production near the plasma membrane. Disruption of lipid rafts by cholesterol depletion selectively altered cAMP responses produced by raft-associated receptors. The results indicate that receptors associated with lipid raft as well as non-lipid raft domains can contribute to global cAMP responses. In addition, basal cAMP activity was found to be significantly higher in non-raft domains. This was supported by the fact that pharmacologic inhibition of adenylyl cyclase activity reduced basal cAMP activity detected by Epac2-CAAX but not Epac2-MyrPalm or Epac2-camps. Responses detected by Epac2-CAAX were also more sensitive to direct stimulation of adenylyl cyclase activity, but less sensitive to inhibition of phosphodiesterase activity. Quantitative modeling was used to demonstrate that differences in adenylyl cyclase and phosphodiesterase activities are necessary but not sufficient to explain compartmentation of cAMP associated with different microdomains of the plasma membrane.},
  language  = {en}
}
@phdthesis{Kuehlkamp2001,
  author    = {K{\"u}hlkamp, Thomas},
  title     = {Der plasmamembran assoziierte Transportregulator RS1 bindet Ubiquitin und gelangt in den Zellkern},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-1179507},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2001},
  abstract  = {Die vorliegende Arbeit liefert wichtige Erkenntnisse {\"u}ber die subzellul{\"a}re Verteilung und die Funktion des RS1-Proteins vom Schwein (pRS1), einem Regulator von Plasmamembran-transportern. Das gr{\"u}n fluoreszierende Protein (GFP) wurde mit pRS1 fusioniert und in LLC-PK1 Zellen exprimiert. Das GFP-pRS1 Fusionsprodukt (96 kD) konnte an der Plasmamembran, im Zytosol und im Zellkern entdeckt werden. Bei GFP-Fusion mit trunkierten pRS1-Proteinen zeigte sich, dass der C-Terminus die Kernlokalisierung beeinflusst. Dagegen wurde die Kernlokalisierung durch eine Trunkierung des N-Terminus nicht gest{\"o}rt. Im C-Terminus des pRS1 konnte von AS 579 bis 616 eine Ubiquitin associated domain (UBA) identifiziert werden, die auch in den anderen bisher bekannten RS1-Proteinen aus Mensch, Kaninchen und Maus konserviert vorliegt. Eine Ubiquitin-Affinit{\"a}tschromatographie zeigte, dass das pRS1-Protein Ubiquitin auf nicht kovalente Weise bindet. Nach der Trunkierung der UBA-Dom{\"a}ne war keine Wechselwirkung des pRS1-Proteins mit Ubiquitin mehr feststellbar. Ein konserviertes Di-Leucin-Endozytose-Motiv (pRS1 AS 366/67) deutet eine Funktion des pRS1-Proteins bei der Internalisierung von Plasmamembranproteinen an. Deshalb wurde das Endozytoseverhalten von pRS1 {\"u}berexprimierenden LLC-PK1 Zellen untersucht, wobei sich zeigte, dass diese Zellen eine deutlich h{\"o}here Aufnahme des Endozytosefarbstoffes RH 414 aufwiesen als Zellen, die pRS1 nicht {\"u}berexprimierten. Die in dieser Arbeit gesammelten Daten zum RS1-Protein wurden zusammen mit fr{\"u}her erhobenen Ergebnissen zum RS1-Protein im Rahmen eines Modells zusammengefasst. In diesem hypothetischen Modell wird angenommen, dass RS1 ein Adapterprotein ist, welches die ubiquitinabh{\"a}ngige Endozytose von Plasmamembrantransportern vermittelt und als Signalmolek{\"u}l in den Zellkern gelangen kann, wo es an der Transcriptionsrepression des SGLT1 beteiligt ist.},
  subject      = {Ubiquitin},
  language  = {de}
}