Related Experiment Video

Updated: May 8, 2026

Inherent Dynamics Visualizer, an Interactive Application for Evaluating and Visualizing Outputs from a Gene Regulatory Network Inference Pipeline
10:44

Inherent Dynamics Visualizer, an Interactive Application for Evaluating and Visualizing Outputs from a Gene Regulatory Network Inference Pipeline

Published on: December 7, 2021

TORC1 signaling is governed by two negative regulators in fission yeast

Ning Ma1, Qingbin Liu, Lili Zhang

  • 1Division of Molecular Pharmacology and Pharmacogenomics, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.

Genetics
|August 13, 2013
PubMed

Insights

Researchers identified Npr2 as a negative regulator of the target of rapamycin (TOR) pathway in yeast. Unlike Tsc2, Npr2 appears to be involved in nutrient sensing feedback loops, impacting cell growth and metabolism.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • The target of rapamycin (TOR) pathway is a crucial regulator of cell growth, metabolism, and nutrient sensing.
  • TOR complex 1 (TORC1) signaling is tightly controlled, and its dysregulation is implicated in various cellular processes.
  • Identifying negative regulators of TORC1 is essential for understanding cellular homeostasis.

Purpose of the Study:

  • To conduct a genome-wide screen in Schizosaccharomyces pombe to identify novel negative regulators of TORC1 signaling.
  • To characterize the function of identified regulators by comparing their phenotypes to known regulators like Tsc2.
  • To elucidate the specific roles of Npr2 and Tsc2 in TORC1 pathway regulation and nutrient sensing.

Main Methods:

  • Genome-wide screening of Schizosaccharomyces pombe mutants.
  • Phenotypic analysis including amino acid uptake, Cat1 permease localization, rapamycin sensitivity, and Isp5 transcription.
  • Comparative analysis of mutant phenotypes (e.g., Δnpr2 vs. Δtsc2).

Main Results:

  • A genome-wide screen identified Npr2 as a negative regulator of TORC1 signaling in S. pombe.
  • Δnpr2 mutants exhibited phenotypes similar to Δtsc2 mutants, including amino acid uptake defects and Cat1 permease mislocalization.
  • Distinct phenotypes were observed between Δnpr2 and Δtsc2 mutants regarding rapamycin supersensitivity and Isp5 transcription, suggesting differential roles.
  • Tor2 was shown to regulate amino acid homeostasis at both transcriptional and post-transcriptional levels.
  • Npr2, but not Tsc2, appears to be involved in the feedback loop of a nutrient-sensing pathway.

Conclusions:

  • Both Npr2 and Tsc2 function as negative regulators of TORC1 signaling in S. pombe.
  • Npr2 plays a role in regulating amino acid homeostasis and may participate in nutrient-sensing feedback mechanisms.
  • Tsc2 and Npr2 exhibit both overlapping and distinct functions in TORC1 pathway regulation.
  • These findings contribute to a deeper understanding of the complex regulatory network governing cell growth and metabolism.
Keywords:
Npr2TORC1Tor2Tsc2nutrient response

More Related Videos

Dissection of Drosophila Ovaries04:55

Dissection of Drosophila Ovaries

Published on: October 19, 2006

Spatiotemporal Analysis of Cytokinetic Events in Fission Yeast11:19

Spatiotemporal Analysis of Cytokinetic Events in Fission Yeast

Published on: February 20, 2017

Related Concept Videos

Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
Canonical Wnt Signaling Pathway02:54

Canonical Wnt Signaling Pathway

The gene encoding the main signaling molecules of the Wnt signaling pathways (the Wnt proteins) was discovered almost four decades ago by Nüsslein-Volhard and Wieschaus. They identified and originally named the gene "wingless" (wg) after a phenotype discovered during their landmark genetic screen in Drosophila for body pattern defects. At around the same time, another researcher named Harold Varmus found that a murine tumor virus activates the mammalian wg homolog, Int-1, which results in tumor...
Canonical Wnt Signaling Pathway02:54

Canonical Wnt Signaling Pathway

The gene encoding the main signaling molecules of the Wnt signaling pathways (the Wnt proteins) was discovered almost four decades ago by Nüsslein-Volhard and Wieschaus. They identified and originally named the gene "wingless" (wg) after a phenotype discovered during their landmark genetic screen in Drosophila for body pattern defects. At around the same time, another researcher named Harold Varmus found that a murine tumor virus activates the mammalian wg homolog, Int-1, which results in tumor...