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Cytomegaloviral protein kinase pUL97 interacts with the nuclear mRNA export factor pUL69 to modulate its intranuclear

Marco Thomas1, Sabine Rechter1, Jens Milbradt1

  • 1Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.

The Journal of General Virology
|February 17, 2009
PubMed

Insights

Human cytomegalovirus (HCMV) protein pUL97 directly interacts with and phosphorylates nuclear export factor pUL69. This interaction and phosphorylation by pUL97 regulates pUL69

Area of Science:

  • Virology
  • Molecular Biology
  • Cellular Biology

Background:

  • Human cytomegalovirus (HCMV) encodes key regulatory proteins like pUL97 (kinase) and pUL69 (mRNA export).
  • Previous studies indicated kinase inhibitors cause pUL69 aggregation within infected cells.

Purpose of the Study:

  • To investigate the interaction between HCMV pUL97 and pUL69.
  • To determine if pUL97 phosphorylates pUL69 and how this affects pUL69's function.

Main Methods:

  • Coimmunoprecipitation assays to demonstrate protein-protein interaction.
  • Deletion mapping to identify interaction domains.
  • In vitro kinase assays to confirm phosphorylation.
  • Analysis of nuclear RNA export efficiency.

Main Results:

  • pUL97 and pUL69 interact directly, with specific domains identified for binding.
  • pUL97 phosphorylates pUL69 in vitro.
  • Catalytically inactive pUL97 or interaction-deficient pUL69 did not result in phosphorylation.
  • pUL69-mediated nuclear RNA export efficiency correlated with active pUL97 kinase.

Conclusions:

  • A specific interaction between pUL97 and pUL69 occurs.
  • pUL97-mediated phosphorylation of pUL69 is crucial.
  • This phosphorylation event influences the regulatory functions of pUL69, particularly nuclear RNA export.

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