PreprintCited by 1,384PI3K/AKT/mTOR signaling in cancerCancer, Hypoxia, and MetabolismMetabolism, Diabetes, and Cancer

Regulation of mTOR function in response to hypoxia by REDD1 and the TSC1/TSC2 tumor suppressor complex

Open access
Brugarolas, James, Lei, Kui, Hurley, Rebecca L., Manning, Brendan D., Reiling, Jan H., Hafen, Ernst, Witters, Lee A., Ellisen, Leif W. +1 more·2004·Genes & Development

Abstract

Mammalian target of rapamycin (mTOR) is a central regulator of protein synthesis whose activity is modulated by a variety of signals. Energy depletion and hypoxia result in mTOR inhibition. While energy depletion inhibits mTOR through a process involving the activation of AMP-activated protein kinase (AMPK) by LKB1 and subsequent phosphorylation of TSC2, the mechanism of mTOR inhibition by hypoxia is not known. Here we show that mTOR inhibition by hypoxia requires the TSC1/TSC2 tumor suppressor complex and the hypoxia-inducible gene REDD1/RTP801 . Disruption of the TSC1/TSC2 complex through loss of TSC1 or TSC2 blocks the effects of hypoxia on mTOR, as measured by changes in the mTOR targets S6K and 4E-BP1, and results in abnormal accumulation of Hypoxia-inducible factor (HIF). In contrast to energy depletion, mTOR inhibition by hypoxia does not require AMPK or LKB1. Down-regulation of mTOR activity by hypoxia requires de novo mRNA synthesis and correlates with increased expression of the hypoxia-inducible REDD1 gene. Disruption of REDD1 abrogates the hypoxia-induced inhibition of mTOR, and REDD1 overexpression is sufficient to down-regulate S6K phosphorylation in a TSC1/TSC2-dependent manner. Inhibition of mTOR function by hypoxia is likely to be important for tumor suppression as TSC2-deficient cells maintain abnormally high levels of cell proliferation under hypoxia.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1101/gad.1256804

Cites

56 of 56 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Redd1 is a new stress-induced protein and a negative regulator of mTOR through the TSC1/TSC2 complex.

    “Redd1 is a new stress-induced protein and is known as a negative regulator of mTOR through TSC1/TSC2 complex [106–115].”

    From PKR, the double stranded RNA‐dependent protein kinase as a critical target in Alzheimer's disease (2009) · cites this paper as [108]

    The Discussion (page not supplied) describes Redd1 as stress-induced and reports that its suppression of mTOR signaling requires Tsc2. It presents signaling through the Tsc1/Tsc2 complex as the simplest model, however, and says a parallel pathway cannot be excluded; the claim states that mechanism more definitively than the paper does. (LLM, conf=0.85)

    Experimental — accuracy not yet measured
  • Under hypoxia, energy expenditure is decreased, leading to inhibition of high-energy-consuming events such as protein translation, leading to inhibition of mTOR and S6K.

    “Under hypoxia, energy expenditure is decreased, leading to the inhibition of high–energy-consuming events such as protein translation, leading to the inhibition of mTOR and S6K (27).”

    From Hypoxia decreases insulin signaling pathways in adipocytes. (2009) · cites this paper as [27]

  • TSC1/2 is responsive to hypoxia through the actions of REDD.

    “TSC1/2 is also responsive to hypoxia through the actions of REDD (70).”

    From Placental Origins of Chronic Disease (2016) · cites this paper as [70]

  • Hypoxia-dependent regulation through REDD1 disrupts cytosolic 14-3-3-bound TSC2 and enables subsequent TSC2 localization to the lysosome where it can inhibit Rheb.

    “Another example of this localization dependency includes hypoxia-dependent regulation through REDD1 (Brugarolas et al., 2004), which disrupts cytosolic 14-3-3-bound TSC2 and enables subsequent TSC2 localization to the lysosome where it can inhibit Rheb (DeYoung et al., 2008).”

    From Signal integration in the (m)TORC1 growth pathway (2018) · cites this paper as Brugarolas et al., 2004

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

1 retracted

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Brugarolas, J., Lei, K., Hurley, R. L., Manning, B. D., Reiling, J. H., Hafen, E., Witters, L. A., Ellisen, L. W., & Kaelin, W. G.
Affiliations
  • Brigham and Women's Hospital (US)
  • Dartmouth College (US)
Venue
Genes & Development
Published
2004-11-15
Volume
18
Issue
23
Pages
2893-2904
ISSN
  • 0890-9369 (ISSN-L)
  • 1549-5477
OpenAlex
W2115820946
Cited by
1,384
References
56
Citations by year
2026: 49 · 2025: 43 · 2024: 46 · 2023: 68 · 2022: 71 · 2021: 94 · 2020: 74 · 2019: 66 · 2018: 57 · 2017: 68 · 2016: 65 · 2015: 55 · 2014: 83 · 2013: 77 · 2012: 80
Type
posted content
Language
en
Open access
Locations
  • Genes & Development (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • Zurich Open Repository and Archive (University of Zurich) (acceptedVersion, other-oa)
  • Zurich Open Repository and Archive (University of Zurich) (submittedVersion, other-oa)
  • Zurich Open Repository and Archive (University of Zurich)
Funders
  • U.S. Department of Defense
  • Howard Hughes Medical Institute
  • Barr Foundation
  • National Institutes of Health
  • National Cancer Institute (R01CA122589)
  • National Institute of Diabetes and Digestive and Kidney Diseases (DK-35712, R01DK035712)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › PI3K/AKT/mTOR signaling in cancer
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cancer Research › Cancer, Hypoxia, and Metabolism
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
Keywords
mTOR, hypoxia, REDD1, RTP801, TSC1/TSC2 complex, tumor suppressor, hypoxia-inducible factor, S6K phosphorylation, 4E-BP1, AMPK, LKB1, mRNA synthesis, tumor suppression, cell proliferation
MeSH terms
Tuberous Sclerosis Complex 1 Protein, Tuberous Sclerosis Complex 2 Protein, Animals, Hypoxia, Cell Division, Mice, Inbred C57BL, Phosphorylation, Protein Kinases, Repressor Proteins, Transcription Factors, Down-Regulation, 3T3 Cells, Ribosomal Protein S6 Kinases, Tumor Suppressor Proteins, RNA, Small Interfering, Mice, TOR Serine-Threonine Kinases

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review