Customer Relationship Management : strategische Ausrichtung statt IT-getriebenem Aktivismus

Der Begriff Customer Relationship Management (CRM) ist heute in aller Munde. Wie immer, wenn ein solches „buzzword“ auftaucht, besteht viel Unklarheit darüber, was es eigentlich bedeutet und inwieweit es etwas wirklich Neues darstellt. Insbesondere IT-Unternehmen suggerieren häufig, daß ein erfolgreiches Kundenbeziehungsmanagement im wesentlichen eine Frage der richtigen Hard- und Software sei. Das Resultat ist häufig ein IT-getriebener Aktivismus, der die hochgesteckten Erwartungen natürlich nicht erfüllen kann. Für eine erfolgreiches CRM sind insbesondere drei Aspekte von besonderer Bedeutung: 1. Eine systematische Aufnahme und Auswertung kundenbezogener Informationen 2. Die Entwicklung eines klaren CRM-Konzeptes sowie 3. Die Schaffung entsprechender Implementierungsvoraussetzungen im Unternehmen. Auf diese Aspekte geht das vorliegende Papier ein. Es soll Managern einen systematischen Zugang zur strategisch konzeptionellen Facette des Customer Relationship Management geben. Ein saubere Ausarbeitung dieser strategisch-konzeptionellen Aspekte ist unerläßliche Voraussetzung dafür, daß in einem zweiten Schritt entsprechende IT-Konzepte wirkungsvoll eingesetzt werden können

A Proteomic Survey of Host and Virus Reveals Differential Dynamics

We studied the dynamics of the proteome of influenza virus A/PR/8/34 (H1N1) infected Madin-Darby canine kidney cells up to 12 hours post infection by mass spectrometry based quantitative proteomics using the approach of stable isotope labeling by amino acids in cell culture (SILAC). We identified 1311 cell proteins and, apart from the proton channel M2, all major virus proteins. Based on their abundance two groups of virus proteins could be distinguished being in line with the function of the proteins in genesis and formation of new virions. Further, the data indicate a correlation between the amount of proteins synthesized and their previously determined copy number inside the viral particle. We employed bioinformatic approaches such as functional clustering, gene ontology, and pathway (KEGG) enrichment tests to uncover co- regulated cellular protein sets, assigned the individual subsets to their biological function, and determined their interrelation within the progression of viral infection. For the first time we are able to describe dynamic changes of the cellular and, of note, the viral proteome in a time dependent manner simultaneously. Through cluster analysis, time dependent patterns of protein abundances revealed highly dynamic up- and/or down-regulation processes. Taken together our study provides strong evidence that virus infection has a major impact on the cell status at the protein level

Characterization of Hantavirus N Protein Intracellular Dynamics and Localization

Hantaviruses are enveloped viruses that possess a tri-segmented, negative-sense RNA genome. The viral S-segment encodes the multifunctional nucleocapsid protein (N), which is involved in genome packaging, intracellular protein transport, immunoregulation, and several other crucial processes during hantavirus infection. In this study, we generated fluorescently tagged N protein constructs derived from Puumalavirus (PUUV), the dominant hantavirus species in Central, Northern, and Eastern Europe. We comprehensively characterized this protein in the rodent cell line CHO-K1, monitoring the dynamics of N protein complex formation and investigating co-localization with host proteins as well as the viral glycoproteins Gc and Gn. We observed formation of large, fibrillar PUUV N protein aggregates, rapidly coalescing from early punctate and spike-like assemblies. Moreover, we found significant spatial correlation of N with vimentin, actin, and P-bodies but not with microtubules. N constructs also co-localized with Gn and Gc albeit not as strongly as the glycoproteins associated with each other. Finally, we assessed oligomerization of N constructs, observing efficient and concentration-dependent multimerization, with complexes comprising more than 10 individual proteins

Relevance of Host Cell Surface Glycan Structure for Cell Specificity of Influenza A Viruses

first_page settings Order Article Reprints Open AccessHypothesis Relevance of Host Cell Surface Glycan Structure for Cell Specificity of Influenza A Viruses by Markus Kastner 1,†,‡, Andreas Karner 1,†,§ [ORCID] , Rong Zhu 1,† [ORCID] , Qiang Huang 2 [ORCID] , Andreas Geissner 3,4,‖, Anne Sadewasser 5,¶, Markus Lesch 6, Xenia Wörmann 6, Alexander Karlas 6,**, Peter H. Seeberger 3,4 [ORCID] , Thorsten Wolff 5 [ORCID] , Peter Hinterdorfer 1 [ORCID] , Andreas Herrmann 7 and Christian Sieben 8,9,* [ORCID] 1 Institute for Biophysics, Johannes Kepler University Linz, 4020 Linz, Austria 2 State Key Laboratory of Genetic Engineering, Shanghai Engineering Research Center of Industrial Microorganisms, MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai 200438, China 3 Department for Biomolecular Systems, Max Planck Institute for Colloids and Interfaces, 14476 Potsdam, Germany 4 Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany 5 Division of Influenza and other Respiratory Viruses, Robert Koch-Institute, 13353 Berlin, Germany 6 Molecular Biology Department, Max Planck Institute for Infection Biology, 10117 Berlin, Germany 7 Institut für Chemie und Biochemie, Freie Universität Berlin, Altensteinstraße 23a, 14195 Berlin, Germany 8 Nanoscale Infection Biology Group, Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany 9 Institute for Genetics, Technische Universität Braunschweig, 38106 Braunschweig, Germany * Author to whom correspondence should be addressed. † These authors contributed equally to this work. ‡ Current address: Materials Characterization Lab (MCL), Materials Research Institute (MRI), Pennsylvania State University, University Park, PA 16802, USA. § Current address: University of Applied Sciences Upper Austria, School of Medical Engineering and Applied Social Sciences, Garnisonstr. 21, 4020 Linz, Austria. ‖ Current address: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada. ¶ Current address: Secarna Pharmaceuticals GmbH & Co. KG, Am Klopferspitz 19, 82152 Planegg, Germany. ** Current address: Viral Vectors and Gene Therapeutics, ProBioGen AG, 13086 Berlin, Germany. Viruses 2023, 15(7), 1507; https://doi.org/10.3390/v15071507 Received: 9 May 2023 / Revised: 21 June 2023 / Accepted: 28 June 2023 / Published: 5 July 2023 (This article belongs to the Special Issue Physical Virology - Viruses at Multiple Levels of Complexity) Download Browse Figures Review Reports Versions Notes Abstract Influenza A viruses (IAVs) initiate infection via binding of the viral hemagglutinin (HA) to sialylated glycans on host cells. HA’s receptor specificity towards individual glycans is well studied and clearly critical for virus infection, but the contribution of the highly heterogeneous and complex glycocalyx to virus–cell adhesion remains elusive. Here, we use two complementary methods, glycan arrays and single-virus force spectroscopy (SVFS), to compare influenza virus receptor specificity with virus binding to live cells. Unexpectedly, we found that HA’s receptor binding preference does not necessarily reflect virus–cell specificity. We propose SVFS as a tool to elucidate the cell binding preference of IAVs, thereby including the complex environment of sialylated receptors within the plasma membrane of living cells

Heterogeneity of AMPA receptor trafficking and molecular interactions revealed by superresolution analysis of live cell imaging

Simultaneous tracking of many thousands of individual particles in live cells is possible now with the advent of high-density superresolution imaging methods. We present an approach to extract local biophysical properties of cell-particle interaction from such newly acquired large collection of data. Because classical methods do not keep the spatial localization of individual trajectories, it is not possible to access localized biophysical parameters. In contrast, by combining the high-density superresolution imaging data with the present analysis, we determine the local properties of protein dynamics. We specifically focus on AMPA receptor (AMPAR) trafficking and estimate the strength of their molecular interaction at the subdiffraction level in hippocampal dendrites. These interactions correspond to attracting potential wells of large size, showing that the high density of AMPARs is generated by physical interactions with an ensemble of cooperative membrane surface binding sites, rather than molecular crowding or aggregation, which is the case for the membrane viral glycoprotein VSVG. We further show that AMPARs can either be pushed in or out of dendritic spines. Finally, we characterize the recurrent step of influenza trajectories. To conclude, the present analysis allows the identification of the molecular organization responsible for the heterogeneities of random trajectories in cells

Structural basis of NINJ1-mediated plasma membrane rupture in cell death

Eukaryotic cells can undergo different forms of programmed cell death, many of which culminate in plasma membrane rupture as the defining terminal event; 1-7; . Plasma membrane rupture was long thought to be driven by osmotic pressure, but it has recently been shown to be in many cases an active process, mediated by the protein ninjurin-1; 8; (NINJ1). Here we resolve the structure of NINJ1 and the mechanism by which it ruptures membranes. Super-resolution microscopy reveals that NINJ1 clusters into structurally diverse assemblies in the membranes of dying cells, in particular large, filamentous assemblies with branched morphology. A cryo-electron microscopy structure of NINJ1 filaments shows a tightly packed fence-like array of transmembrane α-helices. Filament directionality and stability is defined by two amphipathic α-helices that interlink adjacent filament subunits. The NINJ1 filament features a hydrophilic side and a hydrophobic side, and molecular dynamics simulations show that it can stably cap membrane edges. The function of the resulting supramolecular arrangement was validated by site-directed mutagenesis. Our data thus suggest that, during lytic cell death, the extracellular α-helices of NINJ1 insert into the plasma membrane to polymerize NINJ1 monomers into amphipathic filaments that rupture the plasma membrane. The membrane protein NINJ1 is therefore an interactive component of the eukaryotic cell membrane that functions as an in-built breaking point in response to activation of cell death

Rare mutations in SQSTM1 modify susceptibility to frontotemporal lobar degeneration

Mutations in the gene coding for Sequestosome 1 (SQSTM1) have been genetically associated with amyotrophic lateral sclerosis (ALS) and Paget disease of bone. In the present study, we analyzed the SQSTM1 coding sequence for mutations in an extended cohort of 1,808 patients with frontotemporal lobar degeneration (FTLD), ascertained within the European Early-Onset Dementia consortium. As control dataset, we sequenced 1,625 European control individuals and analyzed whole-exome sequence data of 2,274 German individuals (total n = 3,899). Association of rare SQSTM1 mutations was calculated in a meta-analysis of 4,332 FTLD and 10,240 control alleles. We identified 25 coding variants in FTLD patients of which 10 have not been described. Fifteen mutations were absent in the control individuals (carrier frequency < 0.00026) whilst the others were rare in both patients and control individuals. When pooling all variants with a minor allele frequency < 0.01, an overall frequency of 3.2 % was calculated in patients. Rare variant association analysis between patients and controls showed no difference over the whole protein, but suggested that rare mutations clustering in the UBA domain of SQSTM1 may influence disease susceptibility by doubling the risk for FTLD (RR = 2.18 [95 % CI 1.24-3.85]; corrected p value = 0.042). Detailed histopathology demonstrated that mutations in SQSTM1 associate with widespread neuronal and glial phospho-TDP-43 pathology. With this study, we provide further evidence for a putative role of rare mutations in SQSTM1 in the genetic etiology of FTLD and showed that, comparable to other FTLD/ALS genes, SQSTM1 mutations are associated with TDP-43 pathology

Investigating the role of filamin C in Belgian patients with frontotemporal dementia linked to GRN deficiency in FTLD-TDP brains

TAR DNA-binding protein 43 (TDP-43) inclusions are pathological hallmarks of patients with frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Loss of TDP-43 in zebrafish engenders a severe muscle and vascular phenotype with a concomitant elevation of filamin C (FLNC) levels, an observation confirmed in the frontal cortex of FTLD-TDP patients. Here, we aimed to further assess the contribution of FLNC to frontotemporal dementia (FTD) etiology. We conducted a mutational screening of FLNC in a cohort of 529 unrelated Belgian FTD and FTD-ALS patients, and a control cohort of 920 unrelated and age-matched individuals. Additionally we performed an in-depth characterization of FLNC expression levels in FTD patients and a murine FTD model. In total 68 missense variants were identified of which 19 (MAF C) loss-of-function mutation. Increased FLNC levels were, to a lesser extent, also identified in a FLNC p.V831I variant carrier and in FTD patients with the p.R159H mutation in valosin-containing protein (VCP). The GRN-associated increase of FLNC was confirmed in the frontal cortex of aged Grn knockout mice starting at 16-18 months of age. Combined quantitative proteomic and bioinformatic analyses of the frontal cortex of FTD patients possessing elevated FLNC levels, identified multiple altered protein factors involved in accelerated aging, neurodegeneration and synaptogenesis. Our findings further support the involvement of aberrant FLNC expression levels in FTD pathogenesis. Identification of increased FLNC levels in aged Grn mice and impaired pathways related to aging and neurodegeneration, implies a potential role for FLNC in mediating or accelerating the aging process

Host cell invasion by influenza A virus

Influenzaviren müssen in die Wirtszelle aufgenommen werden, um dort ihr Genom freizusetzen und ihre Replikation mit Hilfe des Reproduktionsapparats der Zelle einzuleiten. Der komplexe Replikationszyklus der Influenza A Viren ist noch nicht vollständig verstanden. Er beginnt mit der Bindung des viralen Hämagglutinins (HA) an Sialinsäure (SA) auf der Zelloberfläche der Wirtszelle. In dieser Arbeit wurde die Virusbindung an Zellen mit unterschiedlicher Rezeptorkomposition verglichen. Dabei konnte gezeigt werden, dass für die zelluläre Spezifität die Präsentation des Rezeptors innerhalb der Plasmamembran der Zelle eine größere Rolle spielt als die Struktur des Rezeptorglykans selbst. Des Weiteren deuten die Beobachtung sehr kleiner Kräfte und ein stufenweises Öffnen von Bindungen auf eine multivalente Interaktion hin. Multivalenz wird oft in biologischen Bindungsprozessen beobachtet und kann Bindungskräfte enorm verstärken. Basierend auf diesen Ergebnissen wurden inhibitorische Nanopartikel entwickelt, die die natürliche Zelloberfläche als hochaffine Bindungsalternative imitieren. Verschiedenartige Nanopartikel wurden evaluiert und konnten die Virusaktivität um mehr als 80 % hemmen. Nach der Bindung wird das Virus durch Endozytose in die Zelle aufgenommen. Durch spezifische Virusmarkierung und gleichzeitiger Expression von zellulären Markerproteinen wurde der Transport einzelner Viren in lebenden Zellen verfolgt. Dabei konnte gezeigt werden, dass das Virus sowohl durch frühe, als auch durch späte Endosomen wandern muss, um sein Genom erfolgreich in das Zytoplasma zu entlassen. Außerdem verzögert das Virus die endosomale Ansäuerung um eine optimale Aufenthaltsdauer im Endosom und die lokalisierte Fusion in der Nähe des Zellkerns zu gewährleisten. Pharmakologisches Eingreifen in diese Prozesse konnte zudem weitere kritische Faktoren identifizieren, die die Effizienz der Virusinfektion stark beeinflussen.Influenza virus must enter a host cell to deliver its genome, use the cells reproductive machinery and eventually initiate its replication. The replication cycle of influenza A virus is very complex and still not fully understood. It generally starts with binding of the viral protein hemagglutinin (HA) to its cellular receptor sialic acid (SA). In this work, virus-cell attachment forces were investigated at the single molecule level using intact virus binding to living cells, a set-up that closely mimics the in vivo situation. Cells of different surface SA composition were compared. It could be shown that the unique presentation of the ligand within the cells plasma membrane, rather than the structure of the receptor-glycan itself, strongly affects cellular specificity. The low binding forces as well as the observation of stepwise unbinding events suggest a multivalent interaction type. Based on this finding, inhibitory nanoparticles mimicking the cell surface were constructed. Different particles were evaluated and shown to efficiently inhibit virus infection by ≥ 80 %. Since many molecular details of multivalent interactions remain poorly understood parameters such as ligand spacing and presentation were varied and revealed that the density of ligands as well as the interacting surface plays critical roles for virus inhibition. Upon attachment, the virus enters the cell by endocytosis. Virus trafficking was followed at the single-virus level in living cells. The kinetics of virus transport were visualized using fluorescent marker proteins in combination with specific virus labeling. It was found that the virus needs to progress through early and late endosomal compartments in order to efficiently uncoat and release its genome. Further, the virus delays the endosomal acidification to ensure optimal residence time and fusion in the region close to the host cell nucleus. Drug treatment furthermore unraveled critical factors influencing viral infection efficiency