New insight into the phosphorylation-regulated intranuclear localization of human cytomegalovirus pUL69 mediated by cyclin-dependent kinases (CDKs) and viral CDK orthologue pUL97

• Published in: Journal of general virology Vol. 97; no. 1; pp. 144 - 151
• Main Authors: Graf, Laura, Feichtinger, Sabine, Naing, Zin, Hutterer, Corina, Milbradt, Jens, Webel, Rike, Wagner, Sabrina, Scott, Gillian M, Hamilton, Stuart T, Rawlinson, William D, Stamminger, Thomas, Thomas, Marco, Marschall, Manfred
• Format: Journal Article
• Language: English
• Published: England 01-01-2016
• Subjects: Cyclin-Dependent Kinase 9 - metabolism; Cytomegalovirus - physiology; Herpesviridae; Host-Pathogen Interactions; Humans; Phosphorylation; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Protein Processing, Post-Translational; Protein Transport; Trans-Activators - metabolism
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/jgv.0.000337

Cyclin-dependent kinases (CDKs) are multifaceted regulators involved in the replication of human cytomegalovirus. Recently, we demonstrated an interaction of CDK9-cyclin T1 as well as viral CDK orthologue pUL97 with the viral regulator pUL69, thereby leading to pUL69-activating phosphorylation. Here, we demonstrate that colocalization and direct pUL69-cyclin T1 interaction is independent of viral strains and host cell types. In vitro phosphorylation of pUL69 by CDK9 or pUL97 did not occur in a single site-specific manner, but at multiple sites. The previously described fine-speckled nuclear aggregation of pUL69 was assigned to the late phase of viral replication. CDK inhibitors, including a novel inhibitor of the CDK-activating kinase CDK7, massively intensified this fine-speckled accumulation. Interestingly, we also observed spontaneous pUL69 accumulation in the absence of inhibitors at a lower frequency. These findings provide new insight into pUL69 kinase interregulation and emphasize the importance of pUL69 phosphorylation for correct intranuclear localization.