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Functional disruption of the moloney murine leukemia virus preintegration complex by vaccinia-related kinases

Yasutsugu Suzuki1, Kanako Ogawa, Yoshio Koyanagi

  • 1Laboratory for Host Factors, Center for Emerging Virus Research, Kyoto University, Kyoto 606-8507, Japan. ysuzuki@virus.kyoto-u.ac.jp

The Journal of Biological Chemistry
|June 1, 2010
PubMed

Insights

Cellular kinases, including vaccinia-related kinases (VRK), can inactivate retroviral preintegration complexes (PICs) by phosphorylating barrier-to-autointegration factor (BAF). This phosphorylation disrupts BAF

Area of Science:

  • Molecular Biology
  • Virology
  • Biochemistry

Background:

  • Retroviral integration is mediated by the preintegration complex (PIC).
  • Barrier-to-autointegration factor (BAF) is crucial for PIC function, protecting viral DNA and promoting intermolecular integration.
  • BAF's activity is regulated by phosphorylation by vaccinia-related kinases (VRKs).

Purpose of the Study:

  • To investigate the role of VRK-mediated BAF phosphorylation in regulating Moloney murine leukemia virus (MMLV) preintegration complex (PIC) activity.
  • To determine if VRK1 and VRK2 can abolish PIC function through BAF phosphorylation.
  • To explore the effect of nucleotides like ATP on PIC function and BAF dissociation.

Main Methods:

  • In vitro assays using MMLV PICs.
  • Phosphorylation of BAF by VRK1 and VRK2.
  • Analysis of BAF's DNA binding activity and dissociation from PICs.
  • Assessment of intermolecular and autointegration activities of PICs.
  • Experiments with VRK1 knockdown cells and ATP treatment.

Main Results:

  • VRK1 abolished MMLV PIC intermolecular integration activity in vitro.
  • VRK1-mediated phosphorylation led to BAF dissociation from PICs and enhanced autointegration.
  • VRK1 and VRK2 hyperphosphorylated BAF, abrogating its function in PICs.
  • ATP treatment inhibited PIC intermolecular integration by causing BAF dissociation.
  • ATP-induced disruption was not observed in PICs from VRK1 knockdown cells.

Conclusions:

  • Cellular kinases, particularly VRK1 and VRK2, can inactivate retroviral integration complexes.
  • VRK-mediated BAF phosphorylation is a mechanism to regulate PIC activity by dissociating BAF.
  • These findings suggest a cellular control mechanism for retroviral integration through BAF phosphorylation.

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