Leucine Signals to mTORC1 via Its Metabolite Acetyl-Coenzyme A

Cell Metab. 2019 Jan 8;29(1):192-201.e7. doi: 10.1016/j.cmet.2018.08.013. Epub 2018 Sep 6.

Abstract

The mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) is a master regulator of cell growth and metabolism. Leucine (Leu) activates mTORC1 and many have tried to identify the mechanisms whereby cells sense Leu in this context. Here we describe that the Leu metabolite acetyl-coenzyme A (AcCoA) positively regulates mTORC1 activity by EP300-mediated acetylation of the mTORC1 regulator, Raptor, at K1097. Leu metabolism and consequent mTORC1 activity are regulated by intermediary enzymes. As AcCoA is a Leu metabolite, this process directly correlates with Leu abundance, and does not require Leu sensing via intermediary proteins, as has been described previously. Importantly, we describe that this pathway regulates mTORC1 in a cell-type-specific manner. Finally, we observed decreased acetylated Raptor, and inhibited mTORC1 and EP300 activity in fasted mice tissues. These results provide a direct mechanism for mTORC1 regulation by Leu metabolism.

Keywords: Raptor; acetyl-CoA; amino acid sensing; autophagy; leucine; mTOR; starvation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyl Coenzyme A / metabolism*
  • Animals
  • Cell Line
  • E1A-Associated p300 Protein / metabolism*
  • Female
  • Humans
  • Leucine / physiology*
  • Male
  • Mechanistic Target of Rapamycin Complex 1 / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Regulatory-Associated Protein of mTOR / metabolism*

Substances

  • Regulatory-Associated Protein of mTOR
  • Acetyl Coenzyme A
  • E1A-Associated p300 Protein
  • EP300 protein, human
  • Ep300 protein, mouse
  • Mechanistic Target of Rapamycin Complex 1
  • Leucine