Title: Homeostasis of branched-chain amino acids is critical for the activity of TOR signaling in Arabidopsis

Journal Article · · eLife
ORCiD logo [1];  [2];  [3]; ORCiD logo [3];  [4];  [3];  [5]; ORCiD logo [6]; ORCiD logo [7]
  1. MSU-DOE Plant Research Lab, Michigan State University, East Lansing, United States, Department of Plant Biology, Michigan State University, East Lansing, United States
  2. Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, United States
  3. Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, United States
  4. MSU-DOE Plant Research Lab, Michigan State University, East Lansing, United States
  5. Department of Plant Biology, Michigan State University, East Lansing, United States
  6. Department of Plant Biology, Michigan State University, East Lansing, United States, Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, United States
  7. MSU-DOE Plant Research Lab, Michigan State University, East Lansing, United States, Department of Plant Biology, Michigan State University, East Lansing, United States, Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, United States
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The target of rapamycin (TOR) kinase is an evolutionarily conserved hub of nutrient sensing and metabolic signaling. In plants, a functional connection of TOR activation with glucose availability was demonstrated, while it is yet unclear whether branched-chain amino acids (BCAAs) are a primary input of TOR signaling as they are in yeast and mammalian cells. Here, we report on the characterization of an Arabidopsis mutant over-accumulating BCAAs. Through chemical interventions targeting TOR and by examining mutants of BCAA biosynthesis and TOR signaling, we found that BCAA over-accumulation leads to up-regulation of TOR activity, which causes reorganization of the actin cytoskeleton and actin-associated endomembranes. Finally, we show that activation of TOR is concomitant with alteration of cell expansion, proliferation and specialized metabolism, leading to pleiotropic effects on plant growth and development. These results demonstrate that BCAAs contribute to plant TOR activation and reveal previously uncharted downstream subcellular processes of TOR signaling.

Research Organization:
Michigan State Univ., East Lansing, MI (United States); Michigan State Univ., East Lansing, MI (United States). MSU-DOE Plant Research Laboratory; Univ. of Wisconsin, Madison, WI (United States)
Sponsoring Organization:
National Institute of Food and Agriculture; National Science Foundation (NSF); USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
FG02-91ER20021; SC0018409
OSTI ID:
1577388
Journal Information:
eLife, Journal Name: eLife Vol. 8; ISSN 2050-084X
Publisher:
eLife Sciences Publications, Ltd.Copyright Statement
Country of Publication:
United States
Language:
English

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