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Naf1alpha is phosphorylated in mitotic phase and required to protect cells against apoptosis

Shengliang Zhang1, Marthandan Mahalingam, Nobuo Tsuchida

  • 1Department of Molecular Cellular Oncology, Graduate School, Tokyo Medical & Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.

Biochemical and Biophysical Research Communications
|January 3, 2008
PubMed

Insights

Naf1alpha, an HIV Nef-associated factor, is phosphorylated during mitosis and protects cells from apoptosis. Overexpression prevents cell death, while knockdown increases sensitivity to apoptosis.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Virology

Background:

  • Naf1alpha is a ubiquitously expressed HIV Nef-associated factor.
  • Previous research indicated Naf1alpha phosphorylation via the MEK/ERK2 pathway upon EGF stimulation.

Purpose of the Study:

  • To investigate additional phosphorylation events of Naf1alpha during the cell cycle.
  • To elucidate the role of Naf1alpha in apoptosis regulation.

Main Methods:

  • Cell synchronization in M phase using anti-mitosis reagents.
  • Overexpression and knockdown of Naf1alpha using Saos-2 cells.
  • Assessment of apoptosis induction by trichostatin A (TSA).

Main Results:

  • Naf1alpha undergoes phosphorylation during M phase, which diminishes upon exit to G1 phase.
  • Overexpression of Naf1alpha suppressed TSA-induced apoptosis in Saos-2 cells.
  • Naf1alpha knockdown sensitized Saos-2 cells to TSA-induced apoptosis.

Conclusions:

  • Naf1alpha phosphorylation is cell cycle-dependent, occurring during M phase.
  • Naf1alpha plays a significant role in protecting cells from apoptosis.
  • These findings highlight Naf1alpha's physiological importance in preventing apoptosis induction.

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