ARSK1 activates TORC1 signaling to adjust growth to phosphate availability in Arabidopsis

Curr Biol. 2023 May 8;33(9):1778-1786.e5. doi: 10.1016/j.cub.2023.03.005. Epub 2023 Mar 23.

Abstract

Nutrient sensing and signaling are essential for adjusting growth and development to available resources. Deprivation of the essential mineral phosphorus (P) inhibits root growth.1 The molecular processes that sense P limitation to trigger early root growth inhibition are not known yet. Target of rapamycin (TOR) kinase is a central regulatory hub in eukaryotes to adapt growth to internal and external nutritional cues.2,3 How nutritional signals are transduced to TOR to control plant growth remains unclear. Here, we identify Arabidopsis-root-specific kinase 1 (ARSK1), which attenuates initial root growth inhibition in response to P limitation. We demonstrate that ARSK1 phosphorylates and stabilizes the regulatory-associated protein of TOR 1B (RAPTOR1B), a component of the TOR complex 1, to adjust root growth to P availability. These findings uncover signaling components acting upstream of TOR to balance growth to P availability.

Keywords: ARSK1; Arabidopsis; RAPTOR1B; TOR; TORC1 signaling; early signaling; phosphorus deficiency; phosphorylation; root growth.

Publication types

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

MeSH terms

  • Arabidopsis Proteins* / genetics
  • Arabidopsis Proteins* / metabolism
  • Arabidopsis* / metabolism
  • Mechanistic Target of Rapamycin Complex 1 / genetics
  • Mechanistic Target of Rapamycin Complex 1 / metabolism
  • Phosphates / metabolism
  • Signal Transduction / physiology
  • Sirolimus / pharmacology

Substances

  • Arabidopsis Proteins
  • Phosphates
  • Sirolimus
  • Mechanistic Target of Rapamycin Complex 1