Trehalose 6-Phosphate Positively Regulates Fatty Acid Synthesis by Stabilizing WRINKLED1
WRINKLED1 (WRI1), the transcriptional activator of fatty acid synthesis, was recently identified as a target of KIN10, a catalytic α-subunit of the SUCROSE-NON-FERMENTING-1-RELATED PROTEIN KINASE-1 (SnRK1). For this work, we tested the hypothesis that trehalose 6-phosphate (T6P), a signal of cellular sucrose status, can regulate FA synthesis by inhibiting SnRK1. Incubation of Brassica napus suspension cells in medium containing T6P, or overexpression of the Escherichia coli T6P synthase, OtsA, in tobacco, significantly increased T6P levels, WRI1 levels and FA synthesis rates. T6P directly bound to purified recombinant KIN10 with an equilibrium dissociation constant (Kd) of 32 ± 6 μM using microscale thermophoresis. GEMINIVIRUS REP-INTERACTING KINASE1 (GRIK1) bound to KIN10 (Kd 19 ± 3 μM) and activated it by phosphorylation. In the presence of T6P the GRIK1-KIN10 association was weakened by more than threefold (Kd 67.7 ± 9.8 μM) which reduced both the phosphorylation of KIN10 and its activity. T6P-dependent inhibition of SnRK1 activity is reduced in extracts of individual Arabidopsis grik1 and grik2 mutants relative to wild type, while SnRK1 activity in grik1grik2 extracts is enhanced by T6P. These results indicate the T6P sensitivity of SnRK1 in vivo is GRIK1/GRIK2-dependent. A mechanistic model is proposed that links sugar signaling and FA homeostasis.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 1472222
- Alternate ID(s):
- OSTI ID: 1467850
- Report Number(s):
- BNL-209015-2018-JAAM; /plantcell/30/10/2616.atom
- Journal Information:
- Plant Cell, Journal Name: Plant Cell Vol. 30 Journal Issue: 10; ISSN 1040-4651
- Publisher:
- Oxford University PressCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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