Recently it has been shown that the proinflammatory NF-B pathway promotes efficient influenza virus propagation. Based on these findings, it was suggested that NF-B blockade may be a promising approach for antiviral intervention. The classical virus-induced activation of the NF-B pathway requires proteasomal degradation of the inhibitor of NF-B, IB. Therefore, we hypothesized that inhibition of proteasomal IB degradation should impair influenza A virus (IAV) replication. We chose the specific proteasome inhibitor PS-341, which is a clinically approved anticancer drug also known as
Influenza viruses have to overcome the type I interferon induced antiviral response to successfully propagate in target cells. A major antiviral factor induced by interferons is the protein kinase R (PKR) that is further activated by dsRNA and phosphorylates the eukaryotic initiation factor 2 (eIF2α). This results in inhibition of protein translation thereby limiting viral replication. Here we describe a novel mechanism by which influenza A viruses escape the antiviral action of PKR. We demonstrate that the mitogen-activated protein kinase-activated protein kinases (MAPKAPKs) MK2 and MK3 are activated on virus infection and, in their active form, directly interact with the repressor of the inhibitor of PKR p88(rIPK). This leads to recruitment of a tetrameric protein complex consisting of p88(rIPK), the inhibitor of PKR p58(IPK) and PKR itself, and finally results in inhibition of the kinase. The importance of MKs for influenza virus propagation was further underscored by demonstrating reduced viral progeny in cells genetically deficient in MK2 or MK3 genes as well as in highly proliferating tumor cells, in which expression of MKs was diminished by specific small interfering RNA. Accordingly, knockdown of MKs resulted in enhanced phosphorylation of PKR and its substrate eIF2α.
bApoptosis induction is an important host defense mechanism to control viral infection, which is antagonized by viral proteins. Murine cytomegalovirus m41.1 encodes a viral inhibitor of BAK oligomerization (vIBO) that blocks the mitochondrial apoptosis mediator BAK. However, its importance for viral fitness in vivo has not been investigated. Here, we show that an m41.1-deficient virus attains reduced titers in salivary glands of wild-type but not Bak1 ؊/؊ mice, indicating a requirement of BAK inhibition for optimal dissemination in vivo.
ZusammenfassungZentrales Anliegen der Arbeit war es, die schulinspektionsbezogene Handlungskoordination der Akteure Schulleitung, Qualitätsanalyse, Schulaufsicht und staatlicher Schulentwicklungsberatung bei der Qualitätsanalyse an Grundschulen in Nordrhein-Westfalen empirisch zu untersuchen. Die Studie wurde dabei von drei Forschungsfragen geleitet, die sich a) auf die Ausgestaltung des Zusammenwirkens bei der Qualitätsanalyse, b) die subjektiven Vorstellungen der Akteure, die diesem Handeln zugrunde liegen, und c) auf Vorschläge für eine Weiterentwicklung des Verfahrens bezogen. Zentrale Ergebnisse werden nun zusammengefasst und anschließend unter Rückgriff auf die in Kapitel 8 herausgearbeiteten Interpretationlinien und die diskutierten weiterführenden Überlegungen problematisiert.
ZusammenfassungIn diesem Kapitel werden zentrale Aspekte Neuer Schulsystemsteuerung und ihre Folgen für Schule und Schulaufsicht in Deutschland erläutert. Hieran anknüpfend wird die Educational Governance als Forschungsperspektive expliziert. Anschließend rückt dann die Schulinspektion in den Fokus der Betrachtung, indem die Programmatik und Anlage beschrieben wird und eine aktuelle Bestandsaufnahme zu den Inspektionsverfahren der deutschen Bundesländer erfolgt.
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