Cytomegaloviral protein kinase pUL97 interacts with the nuclear mRNA export factor pUL69 to modulate its intranuclear localization and activity.
Human cytomegalovirus encodes a number of phosphorylation-regulated proteins, including the autophosphorylating protein kinase pUL97 and the nuclear mRNA export factor pUL69. Recently, it was reported that the kinase inhibitor roscovitine induces an intranuclear aggregation of pUL69 in infected fibroblasts. Here, we demonstrate that pUL97-specific kinase inhibitors induce a similar pUL69 aggregation. Furthermore, a direct pUL69-pUL97 interaction was demonstrated by coimmunoprecipitation analyses. Deletion mapping identified the domains required for interaction in both proteins (1-140/478-532 in pUL69 and 231-336 in pUL97). Further analysis of the immunoprecipitates by in vitro kinase assays demonstrated the phosphorylation of pUL69 by pUL97. However, catalytically inactive mutants of pUL97 and interaction-negative fragments of pUL69 were phosphorylation-negative. Moreover, an analysis of the pUL69-mediated nuclear RNA export indicated a correlation of the export efficiency with the presence of active pUL97 kinase. These data suggest a specific pUL69-pUL97 interaction and pUL97-mediated phosphorylation which influences the regulatory activities of pUL69.
Thomas
Marco
M
Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
Rechter
Sabine
S
Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
Milbradt
Jens
J
Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
Auerochs
Sabrina
S
Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
Müller
Regina
R
Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
Stamminger
Thomas
T
Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
Marschall
Manfred
M
Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.
D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D003587:Cytomegalovirus / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts; D017353:Gene Deletion; D015967:Gene Expression Regulation, Viral; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
D010750:Phosphoproteins; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D015534:Trans-Activators; C446019:pUL69 protein, Human herpesvirus 5; D017853:Phosphotransferases (Alcohol Group Acceptor); C075365:ganciclovir kinase