SnRK1-triggered switch of bZIP63 dimerization mediates the low-energy response in plants

Elife. 2015 Aug 11;4:e05828. doi: 10.7554/eLife.05828.

Abstract

Metabolic adjustment to changing environmental conditions, particularly balancing of growth and defense responses, is crucial for all organisms to survive. The evolutionary conserved AMPK/Snf1/SnRK1 kinases are well-known metabolic master regulators in the low-energy response in animals, yeast and plants. They act at two different levels: by modulating the activity of key metabolic enzymes, and by massive transcriptional reprogramming. While the first part is well established, the latter function is only partially understood in animals and not at all in plants. Here we identified the Arabidopsis transcription factor bZIP63 as key regulator of the starvation response and direct target of the SnRK1 kinase. Phosphorylation of bZIP63 by SnRK1 changed its dimerization preference, thereby affecting target gene expression and ultimately primary metabolism. A bzip63 knock-out mutant exhibited starvation-related phenotypes, which could be functionally complemented by wild type bZIP63, but not by a version harboring point mutations in the identified SnRK1 target sites.

Keywords: SnRK1 kinase; arabidopsis; bZIP transcription factor; cell biology; metabolic reprogramming; plant biology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / metabolism*
  • Basic-Leucine Zipper Transcription Factors / deficiency
  • Basic-Leucine Zipper Transcription Factors / metabolism*
  • Gene Expression Regulation, Plant*
  • Gene Knockout Techniques
  • Genetic Complementation Test
  • Phosphorylation
  • Protein Multimerization*
  • Protein Processing, Post-Translational
  • Protein-Serine-Threonine Kinases / metabolism*

Substances

  • Arabidopsis Proteins
  • Basic-Leucine Zipper Transcription Factors
  • bZIP63 protein, Arabidopsis
  • Protein-Serine-Threonine Kinases
  • SnRK1 protein, Arabidopsis

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.