Express yourself: how PP2A-B55Pab1 helps TORC1 talk to TORC2

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Visualization and Quantification of Endogenous Intra-Organelle Protein Interactions at ER-Mitochondria Contact Sites by Proximity Ligation Assays
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Visualization and Quantification of Endogenous Intra-Organelle Protein Interactions at ER-Mitochondria Contact Sites by Proximity Ligation Assays

Published on: October 20, 2023

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Ruth Martín1, Sandra Lopez-Aviles2

  • 1Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo, Gaustadalleen 21, 0349, Oslo, Norway.

Current Genetics
|June 24, 2017
PubMed

Insights

Nitrogen availability controls cell fate via TOR signaling. PP2A-B55Pab1 phosphatase mediates crosstalk between TORC1 and TORC2, crucial for fission yeast differentiation.

Area of Science:

  • Cellular biology
  • Molecular signaling
  • Biochemistry

Background:

  • TOR complexes (TORC1 and TORC2) are central regulators of cell growth, proliferation, and fate in response to nutrient availability.
  • PP2A-B55Pab1, a phosphatase, has emerged as a key regulator in fission yeast, influencing cell cycle and sexual differentiation.
  • Nitrogen availability is a critical environmental cue that impacts cellular processes.

Purpose of the Study:

  • To review the current understanding of the interplay between TOR complexes and PP2A-B55Pab1 in response to nitrogen availability.
  • To highlight the role of PP2A-B55Pab1 as a mediator of crosstalk between TORC1 and TORC2.
  • To identify future research directions regarding phosphatase activity in TOR signaling.

Main Methods:

  • Literature review of studies on TOR signaling and PP2A-B55Pab1 in fission yeast.
  • Analysis of the regulatory mechanisms connecting nitrogen sensing to cell fate decisions.
  • Discussion of experimental evidence for crosstalk between TOR signaling modules.

Main Results:

  • PP2A-B55Pab1 acts as a crucial mediator, integrating signals from both TORC1 and TORC2.
  • This phosphatase activity is essential for enabling the differentiation program in response to nitrogen availability.
  • The crosstalk mediated by PP2A-B55Pab1 is vital for coordinating cell cycle progression and sexual differentiation.

Conclusions:

  • The phosphatase PP2A-B55Pab1 plays a pivotal role in integrating TORC1 and TORC2 signaling pathways.
  • Understanding this phosphatase-mediated crosstalk is key to comprehending how cells adapt to nitrogen availability.
  • Further investigation into phosphatase activity within TOR signaling networks is warranted to fully elucidate cellular responses.
Keywords:
DifferentiationGad8Nitrogen signalingPP2A-B55TORC1TORC2

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