title: Cellular Casein Kinase 2 and Protein Phosphatase 2A Modulate Replication Site Assembly of Bluetongue Virus.
abstract: A number of cytoplasmic replicating viruses produce cytoplasmic inclusion bodies or protein aggregates; however, a hallmark of viruses of the Reoviridae family is that they utilize these sites for purposes of replication and capsid assembly, functioning as viral assembly factories. Here we have used bluetongue virus (BTV) as a model system for this broad family of important viruses to understand the mechanisms regulating inclusion body assembly. Newly synthesized viral proteins interact with sequestered viral RNA molecules prior to capsid assembly and double-stranded RNA synthesis within viral inclusion bodies (VIBs). VIBs are predominantly comprised of a BTV-encoded non-structural protein 2 (NS2). Previous in vitro studies indicated that casein kinase 2 (CK2) mediated the phosphorylation of NS2, which regulated the propensity of NS2 to form larger aggregates. Using targeted pharmacological reagents, specific mutation in the viral genome by reverse genetics and confocal microscopy, here we demonstrate that CK2 activity is important for BTV replication. Furthermore, we show that a novel host cell factor, protein phosphatase 2A, is involved in NS2 dephosphorylation and that, together with CK2, it regulates VIB morphology and virus replication. Thus, these two host enzymes influence the dynamic nature of VIB assembly/disassembly, and these concerted activities may be relevant to the assembly and the release of these cores from VIBs.
authors.affiliation: From the Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom.
authors.forename: Bjorn-Patrick
authors.initials: BP
authors.lastname: Mohl
authors.affiliation: From the Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom polly.roy@lshtm.ac.uk.
authors.forename: Polly
authors.initials: P
authors.lastname: Roy
mesh_terms: D001820:Bluetongue virus / Q000502:physiology*; D047390:Casein Kinase II / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004789:Enzyme Activation; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D019065:Virus Assembly; D014779:Virus Replication
chemical_list: D047390:Casein Kinase II; D054648:Protein Phosphatase 2
keywords: CK2; VIBs; bluetongue virus; phosphorylation; protein phosphatase 2 (PP2A); viral protein; viral replication; virus assembly; virus inclusion bodies