Effects of mTORC1 inhibition on proteasome activity and levels

BMB Rep. 2022 Apr;55(4):161-165. doi: 10.5483/BMBRep.2022.55.4.032.

Abstract

The mechanistic target of rapamycin (mTOR) regulates numerous extracellular and intracellular signals involved in the maintenance of cellular homeostasis and cell growth. mTOR also functions as an endogenous inhibitor of autophagy. Under nutrient-rich conditions, mTOR complex 1 (mTORC1) phosphorylates the ULK1 complex, preventing its activation and subsequent autophagosome formation, while inhibition of mTORC1 using either rapamycin or nutrient deprivation induces autophagy. Autophagy and proteasomal proteolysis provide amino acids necessary for protein translation. Although the connection between mTORC1 and autophagy is well characterized, the association of mTORC1 inhibition with proteasome biogenesis and activity has not been fully elucidated yet. Proteasomes are long-lived cellular organelles. Their spatiotemporal rather than homeostatic regulation could be another adaptive cellular mechanism to respond to starvation. Here, we reviewed several published reports and the latest research from our group to examine the connection between mTORC1 and proteasome. We have also investigated and described the effect of mTORC1 inhibition on proteasome activity using purified proteasomes. Since mTORC1 inhibitors are currently evaluated as treatments for several human diseases, a better understanding of the link between mTORC1 activity and proteasome function is of utmost importance. [BMB Reports 2022; 55(4): 161-165].

Publication types

  • News

MeSH terms

  • Autophagy
  • Autophagy-Related Protein-1 Homolog / metabolism
  • Humans
  • Mechanistic Target of Rapamycin Complex 1 / metabolism
  • Proteasome Endopeptidase Complex* / metabolism
  • Sirolimus / pharmacology
  • TOR Serine-Threonine Kinases* / metabolism

Substances

  • Autophagy-Related Protein-1 Homolog
  • Mechanistic Target of Rapamycin Complex 1
  • TOR Serine-Threonine Kinases
  • Proteasome Endopeptidase Complex
  • Sirolimus