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Co-immunoprecipitation Assay Using Endogenous Nuclear Proteins from Cells Cultured Under Hypoxic Conditions
09:17

Co-immunoprecipitation Assay Using Endogenous Nuclear Proteins from Cells Cultured Under Hypoxic Conditions

Published on: August 2, 2018

mTORC1 signaling under hypoxic conditions is controlled by ATM-dependent phosphorylation of HIF-1α

Hakan Cam1, John B Easton, Anthony High

  • 1Center for Childhood Cancer, Nationwide Children's Hospital, Columbus, OH 43205, USA.

Molecular Cell
|November 25, 2010
PubMed

Insights

Hypoxia suppresses mTORC1 signaling via ATM-dependent phosphorylation of HIF-1α. This pathway links hypoxic stress to mTORC1 regulation and may play a role in pediatric solid tumor development.

Area of Science:

  • Cellular biology
  • Molecular signaling
  • Oncology

Background:

  • The mechanistic target of rapamycin complex-1 (mTORC1) is a key regulator of cell growth and metabolism.
  • Hypoxia (low oxygen) suppresses mTORC1 signaling, but the precise mechanisms remain unclear.
  • Understanding how hypoxia impacts mTORC1 is crucial for comprehending cellular stress responses.

Purpose of the Study:

  • To elucidate the signaling pathway through which hypoxia suppresses mTORC1.
  • To investigate the direct link between hypoxia-induced stress and mTORC1 regulation.
  • To explore the role of this pathway in pediatric solid tumor development.

Main Methods:

  • Investigated the effect of hypoxia on mTORC1 signaling.
  • Utilized biochemical assays to detect protein phosphorylation.
  • Examined the role of ataxia telangiectasia mutated (ATM) and hypoxia-inducible factor 1-alpha (HIF-1α) in hypoxia-induced mTORC1 suppression.
  • Analyzed pediatric solid tumor xenografts for pathway deregulation.

Main Results:

  • Hypoxia induces ATM-dependent phosphorylation of HIF-1α at serine 696.
  • This phosphorylation event mediates the downregulation of mTORC1 signaling under hypoxic conditions.
  • Deregulation of ATM/HIF-1α/mTORC1 pathways was observed in pediatric solid tumor xenografts.

Conclusions:

  • ATM-dependent HIF-1α phosphorylation is a key mechanism by which hypoxia suppresses mTORC1.
  • This finding establishes a direct link between hypoxic stress and mTORC1 regulation.
  • Dysregulation of this pathway in tumors suggests its importance in pediatric solid tumor development and highlights hypoxic regulation of mTORC1 as a potential therapeutic target.

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