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Regulation of cell cycle transcription factor Swi5 by karyopherin Msn5

Francisco José Taberner1, Inma Quilis, Josep Sendra

  • 1Deparament de Bioquimica i Biologia Molecular, Universitat de Valencia, Valencia, Spain.

Biochimica Et Biophysica Acta
|March 1, 2012
PubMed

Insights

The budding yeast karyopherin Msn5 regulates the nuclear export of Swi5, a transcription factor crucial for mitotic exit. Msn5 inactivation leads to toxic nuclear accumulation of Swi5, impacting cell growth.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • The budding yeast karyopherin Msn5 is implicated in regulating mitotic exit.
  • Msn5's role in the localization and function of the transcription factor Swi5 is not fully understood.

Purpose of the Study:

  • To investigate the molecular mechanisms by which Msn5 influences Swi5 localization and function during the cell cycle.
  • To determine the physiological consequences of Msn5 inactivation on Swi5 levels and activity.

Main Methods:

  • Yeast genetics and molecular biology techniques were employed.
  • Analysis of protein localization, interaction, synthesis, and degradation was performed.
  • Transcriptional activity assays were conducted.

Main Results:

  • Msn5 is essential for the nuclear export of Swi5, a key transcription factor for mitotic exit.
  • Msn5 inactivation leads to reduced Swi5 protein levels via a post-transcriptional defect in synthesis, not degradation.
  • Despite altered localization and levels, Swi5-dependent transcription remains functional, but high nuclear Swi5 is toxic without Msn5.

Conclusions:

  • Msn5's nuclear export function is critical for preventing toxic accumulation of Swi5 in the nucleus.
  • Msn5 plays a vital role in maintaining cellular homeostasis by regulating Swi5 levels and localization during mitosis.

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