Covalent targeting of the vacuolar H +-ATPase activates autophagy via mTORC1 inhibition

Nat Chem Biol. 2019 Aug;15(8):776-785. doi: 10.1038/s41589-019-0308-4. Epub 2019 Jul 8.

Abstract

Autophagy is a lysosomal degradation pathway that eliminates aggregated proteins and damaged organelles to maintain cellular homeostasis. A major route for activating autophagy involves inhibition of the mTORC1 kinase, but current mTORC1-targeting compounds do not allow complete and selective mTORC1 blockade. Here, we have coupled screening of a covalent ligand library with activity-based protein profiling to discover EN6, a small-molecule in vivo activator of autophagy that covalently targets cysteine 277 in the ATP6V1A subunit of the lysosomal v-ATPase, which activates mTORC1 via the Rag guanosine triphosphatases. EN6-mediated ATP6V1A modification decouples the v-ATPase from the Rags, leading to inhibition of mTORC1 signaling, increased lysosomal acidification and activation of autophagy. Consistently, EN6 clears TDP-43 aggregates, a causative agent in frontotemporal dementia, in a lysosome-dependent manner. Our results provide insight into how the v-ATPase regulates mTORC1, and reveal a unique approach for enhancing cellular clearance based on covalent inhibition of lysosomal mTORC1 signaling.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / drug effects*
  • Autophagy / physiology
  • Cell Line
  • Gene Expression Regulation / drug effects
  • Gene Knockdown Techniques
  • Humans
  • Mechanistic Target of Rapamycin Complex 1 / antagonists & inhibitors*
  • Mice
  • Molecular Structure
  • Proto-Oncogene Proteins c-akt
  • Vacuolar Proton-Translocating ATPases / metabolism*

Substances

  • Mechanistic Target of Rapamycin Complex 1
  • Proto-Oncogene Proteins c-akt
  • Vacuolar Proton-Translocating ATPases