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Development and Application of Rapamycin-regulated Tyrosine Phosphatases
Published on: September 6, 2024
Rapamycin activates Tap42-associated phosphatases by abrogating their association with Tor complex 1
Gonghong Yan1, Xiaoyun Shen, Yu Jiang
1Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
The EMBO Journal
|July 29, 2006
Summary
Rapamycin treatment rapidly releases Tap42-phosphatase complexes from TORC1 on membranes, revealing a novel Tor signaling mechanism. This dissociation, not kinase inhibition, explains rapamycin
Area of Science:
- Molecular Biology
- Cell Signaling
- Yeast Genetics
Background:
- Tap42-phosphatase complexes are key targets in the rapamycin-sensitive Tor signaling pathway in Saccharomyces cerevisiae.
- Rapamycin's rapid activation of these phosphatases is crucial for Tor-mediated transcriptional regulation, but the underlying mechanism remains unclear.
Purpose of the Study:
- To elucidate the mechanism behind the rapid activation of Tap42-associated phosphatases by rapamycin.
- To investigate the role of Tor complex 1 (TORC1) in regulating Tap42-phosphatase complex localization and activity.
Main Methods:
- Investigated the localization of Tap42-phosphatase complexes in Saccharomyces cerevisiae.
- Utilized rapamycin treatment and nutrient deprivation as experimental conditions.
- Analyzed the association and dissociation dynamics between Tap42-phosphatase complexes and TORC1.
Main Results:
- Tap42-phosphatase complexes primarily associate with TORC1 on membrane structures.
- Rapamycin treatment causes rapid release of these complexes from membranes into the cytosol.
- Complex disassembly occurs slowly post-release, likely due to Tap42 dephosphorylation; nutrient deprivation also triggers release.
Conclusions:
- The association of Tap42-phosphatase complexes with TORC1 is a critical regulatory point for Tor signaling influenced by nutrient availability.
- Rapamycin's action involves disrupting the interaction between Tor and its downstream targets, rather than direct kinase inhibition.
- This study provides a new model for understanding rapamycin's effects on cellular signaling pathways.
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