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The role of phosphatases in TOR signaling in yeast

K Düvel1, J R Broach

  • 1Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.

Current Topics in Microbiology and Immunology
|October 17, 2003
PubMed

Insights

The TOR pathway regulates yeast cell growth and proliferation. Researchers identified protein phosphatases (PP2A) and Tap42 as key components, revealing complex signaling mechanisms.

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The Target of Rapamycin (TOR) pathway is crucial for cell growth and proliferation in eukaryotes.
  • TOR signaling involves a cascade of proteins, including type 2A protein phosphatases (PP2A).
  • PP2A and the related phosphatase Sit4 play significant roles in yeast.

Purpose of the Study:

  • To elucidate the roles of PP2A and Sit4 phosphatases in yeast.
  • To investigate the function of complexes formed between phosphatases and Tap42, a TOR target.
  • To understand how Tap42 mediates TOR functions, particularly in transcriptional regulation.

Main Methods:

  • Focus on the roles of PP2A and Sit4 in yeast.
  • Analysis of complexes between catalytic subunits of PP2A/Sit4 and Tap42.
  • Examination of Tap42's role in mediating TOR functions.

Main Results:

  • Tap42 is a direct target of Tor protein kinases in yeast.
  • Tap42 appears to mediate many TOR functions, especially transcriptional modulation.
  • The precise mechanism of Tap42 (inhibition vs. activation of phosphatases) remains unclear.
  • TOR also influences some processes independently of Tap42.

Conclusions:

  • TOR proteins utilize multiple pathways to regulate yeast transcriptional and physiological processes.
  • Tap42 is a key mediator of TOR signaling, but its exact function is still under investigation.
  • Understanding the TOR-Tap42 interaction is critical for deciphering cellular growth regulation.

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