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This Article Full Text (Papers in Press[PDF]) All Versions of this Article: vir.0.013532-0v1 90/12/2829    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Labiuk, S. L Articles by van Drunen Littel-van den Hurk, S. PubMed PubMed Citation Articles by Labiuk, S. L Articles by van Drunen Littel-van den Hurk, S. Agricola Articles by Labiuk, S. L Articles by van Drunen Littel-van den Hurk, S.

The major tegument protein VP8 of bovine herpesvirus-1 is subject to phosphorylation by viral US3 and cellular CK2 protein kinases

¹ University of Saskatchewan;
² University of Alberta

³ E-mail: sylvia.vandenhurk{at}usask.ca

The UL47 gene product, VP8, is one of the major tegument proteins of bovine herpesvirus-1 (BHV-1) and subject to phosphorylation. Analysis of protein bands co-immunoprecipitated with VP8 from BHV-1-infected cells by mass spectroscopy suggested that VP8 interacts with two protein kinases: cellular CK2 and viral US3. CK2 is a highly conserved cellular protein, expressed ubiquitously and known to phosphorylate numerous proteins. The US3 gene product is one of the viral kinases produced by BHV-1 during infection. Interactions of CK2 and US3 with VP8 were confirmed outside the context of infection when FLAG-VP8 was expressed alone or co-expressed with US3-HA in Cos-7 cells. Furthermore, VP8 and US3 co-localized in the nucleus during viral infection. To explore the significance of these interactions, an in vitro kinase assay was performed, which demonstrated that VP8 is heavily phosphorylated by CK2. In the presence of the highly specific CK2 kinase inhibitor 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole (DMAT), phosphorylation of VP8 was significantly reduced. Phosphorylation of VP8 was also inhibited by the presence of kenpaullone, another less specific CK2 inhibitor, but not by protein kinase CK1 or protein kinase C inhibitors. When VP8 and US3 were both included in the kinase assay in the presence of DMAT, phosphorylation of VP8 was again observed. Autophosphorylation of US3 was also detected and not inhibited by DMAT. Based on these results we propose that VP8 interacts with cellular CK2 and viral US3 in BHV-1-infected cells, and is in turn subject to kinase activities associated with both of these proteins.

Received 25 May 2009; accepted 16 August 2009.