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04:36
Assay for Adhesion and Agar Invasion in S. cerevisiae
Published on: November 8, 2006
Efficient Tor signaling requires a functional class C Vps protein complex in Saccharomyces cerevisiae
Sara A Zurita-Martinez1, Rekha Puria, Xuewen Pan
1Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
Genetics
|June 15, 2007
Summary
Tor1 kinase is crucial for nutrient response and cell growth in yeast. It works with the Class C Vps complex to maintain amino acid levels, essential for survival under stress.
Area of Science:
- Cell Biology
- Molecular Biology
- Yeast Genetics
Background:
- Tor kinases regulate nutrient responses and cell growth.
- Saccharomyces cerevisiae has two Tor proteins, Tor1 and Tor2, with overlapping functions.
- The specific roles of Tor1 in relation to other cellular processes are not fully understood.
Purpose of the Study:
- To identify genes that interact with TOR1 to affect cell fitness or viability.
- To elucidate the role of Tor1 in cellular processes beyond known rapamycin-sensitive functions.
- To investigate the relationship between Tor1 and vacuolar function, specifically the Class C Vps complex.
Main Methods:
- Conducted a global genetic fitness/lethal interaction screen for TOR1.
- Identified mutations in vacuolar function genes, including EGO/Gse and PAS complexes.
- Analyzed synthetic lethal interactions between tor1 and Class C Vps complex mutants.
Main Results:
- Mutations in vacuolar function genes (EGO/Gse, PAS) reduced fitness with tor1.
- tor1 is synthetically lethal with mutations in Class C Vps complex components.
- Class C Vps mutants exhibit impaired recovery from rapamycin-induced growth arrest, poor survival during nitrogen starvation, and low amino acid levels.
- Glutamate or glutamine addition restored viability to a tor1 pep3 mutant.
Conclusions:
- Tor1 is more critical than Tor2 for rapamycin-sensitive signaling under amino acid limitation.
- The Class C Vps complex is essential for intracellular amino acid homeostasis, which is required for efficient Tor signaling.
- Tor1's function is linked to amino acid homeostasis via the Class C Vps complex, independent of its known role in protein sorting.
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