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Golgi manganese transport is required for rapamycin signaling in Saccharomyces cerevisiae

Gina Devasahayam1, Daniel J Burke, Thomas W Sturgill

  • 1Department of Pharmacology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908, USA.

Genetics
|July 3, 2007
PubMed

Insights

Manganese (Mn2+) in the Golgi inhibits TORC1 signaling, impacting rapamycin sensitivity in yeast. Loss of the Pmr1 ATPase restores sensitivity, suggesting Mn2+ transport is key to regulating this pathway.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The Pmr1 Golgi Ca2+/Mn2+ ATPase regulates target of rapamycin complex 1 (TORC1) signaling.
  • TORC1 is a critical pathway in yeast, sensitive to rapamycin.
  • Pmr1 deletion confers rapamycin resistance, while TOR1 deletion causes hypersensitivity.

Purpose of the Study:

  • Investigate the genetic interactions between pmr1 and tor1.
  • Elucidate the roles of Ca2+ and Mn2+ transport in TORC1 signaling and rapamycin response.
  • Determine the specific compartment and transport mechanisms involved.

Main Methods:

  • Genetic interaction analysis of pmr1 and tor1 mutants.
  • Utilized separation-of-function Pmr1 mutants (D53A and Q783A).
  • Assessed rapamycin sensitivity and growth on MnCl2-containing media.

Main Results:

  • Deletion of TOR1 restored wild-type phenotypes to pmr1 strains, including MnCl2 growth and rapamycin sensitivity.
  • Mn2+ partially suppressed rapamycin resistance, indicating manganese regulation of Tor1 and Tor2.
  • Mn2+ transport into the Golgi lumen by Pmr1 is required for rapamycin sensitivity; specific Pmr1 mutants showed altered sensitivity.

Conclusions:

  • Manganese (Mn2+) in the Golgi lumen inhibits TORC1 signaling.
  • Pmr1-mediated Mn2+ transport is essential for maintaining rapamycin sensitivity.
  • The findings highlight the intricate relationship between metal ion homeostasis and nutrient signaling pathways.

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