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Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry
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Vpr protein of human immunodeficiency virus type 1 binds to 14-3-3 proteins and facilitates complex formation with

Tomoshige Kino1, Alexander Gragerov, Antonio Valentin

  • 1Human Retrovirus Section, Center for Cancer Research, National Cancer Institute-Frederick, Bldg. 535, Rm. 210, Frederick, MD 21702-1201, USA.

Journal of Virology
|February 15, 2005
PubMed

Insights

The HIV protein Vpr interacts with 14-3-3 proteins, which are crucial for cell cycle arrest. Vpr facilitates the association of 14-3-3 and Cdc25C, promoting G2/M phase arrest independently of Cdc25C phosphorylation.

Area of Science:

  • Cellular biology
  • Virology
  • Molecular mechanisms of viral pathogenesis

Background:

  • The human immunodeficiency virus (HIV) protein Vpr plays a role in viral replication and pathogenesis.
  • Vpr is known to induce cell cycle arrest at the G2/M phase.
  • 14-3-3 proteins are a family of regulatory molecules involved in numerous cellular processes, including cell cycle control.

Purpose of the Study:

  • To identify cellular interactors of HIV Vpr using a yeast two-hybrid screen.
  • To elucidate the mechanism by which Vpr induces cell cycle arrest.
  • To investigate the role of 14-3-3 proteins in Vpr-mediated cell cycle arrest.

Main Methods:

  • Yeast two-hybrid screening to identify Vpr-interacting proteins.
  • Site-directed mutagenesis to generate Vpr mutants.
  • Cell cycle analysis in human cells.
  • Co-immunoprecipitation assays to detect protein complexes.

Main Results:

  • Vpr directly interacts with 14-3-3 proteins, and this interaction is dependent on a specific Vpr residue (R80).
  • Vpr-mediated cell cycle arrest is dependent on the presence of 14-3-3 proteins.
  • Vpr facilitates the association between 14-3-3 proteins and Cdc25C phosphatase, leading to G2/M arrest.
  • Vpr promotes the Vpr/14-3-3/Cdc25C complex formation independently of Cdc25C phosphorylation at serine 216.

Conclusions:

  • HIV Vpr utilizes cellular 14-3-3 proteins to induce G2/M cell cycle arrest.
  • Vpr's interaction with 14-3-3 proteins is critical for its cell cycle-arresting function.
  • Vpr promotes the formation of a ternary complex involving Vpr, 14-3-3, and Cdc25C, irrespective of Cdc25C phosphorylation status.

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