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TIP41 interacts with TAP42 and negatively regulates the TOR signaling pathway
1Division of Biochemistry, Biozentrum, University of Basel, CH-4056, Basel, Switzerland.
Molecular Cell
|December 14, 2001
Summary
TIP41 protein regulates the TOR pathway in yeast by inhibiting TAP42, which controls the SIT4 phosphatase. TIP41
Area of Science:
- Molecular Biology
- Yeast Genetics
- Signal Transduction
Background:
- The rapamycin-sensitive TOR kinases regulate the SIT4 phosphatase via TAP42 interaction.
- Understanding the regulation of SIT4 phosphatase is crucial for cellular signaling.
- The TOR pathway plays a key role in cell growth and metabolism.
Purpose of the Study:
- To identify and characterize novel regulators of the SIT4 phosphatase.
- To elucidate the role of TIP41 in the TOR signaling pathway.
- To investigate the interaction between TIP41, TAP42, and SIT4.
Main Methods:
- Gene deletion studies in Saccharomyces cerevisiae.
- Analysis of protein-protein interactions.
- Assays for phosphatase activity and protein localization.
Main Results:
- TIP41 deletion confers rapamycin resistance and suppresses tap42 mutations.
- TIP41 binds to TAP42, inhibiting SIT4 phosphatase activity.
- Rapamycin treatment enhances TIP41 binding to TAP42 via SIT4-dependent dephosphorylation of TIP41.
Conclusions:
- TIP41 acts as a negative regulator of the TOR pathway by inhibiting TAP42.
- TIP41 is part of a feedback loop amplifying SIT4 phosphatase activity under TOR inactivation.
- TIP41 is essential for regulating SIT4-dependent events, including NPR1 dephosphorylation and GLN3 nuclear translocation.
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