Proteome-wide cellular thermal shift assay reveals unexpected cross-talk between brassinosteroid and auxin signaling

Proc Natl Acad Sci U S A. 2022 Mar 15;119(11):e2118220119. doi: 10.1073/pnas.2118220119. Epub 2022 Mar 7.


SignificanceChemical genetics, which investigates biological processes using small molecules, is gaining interest in plant research. However, a major challenge is to uncover the mode of action of the small molecules. Here, we applied the cellular thermal shift assay coupled with mass spectrometry (CETSA MS) to intact Arabidopsis cells and showed that bikinin, the plant-specific glycogen synthase kinase 3 (GSK3) inhibitor, changed the thermal stability of some of its direct targets and putative GSK3-interacting proteins. In combination with phosphoproteomics, we also revealed that GSK3s phosphorylated the auxin carrier PIN-FORMED1 and regulated its polarity that is required for the vascular patterning in the leaf.

Keywords: auxin; brassinosteroids; cellular thermal shift assay; chemical genetics.

MeSH terms

  • Aminopyridines / metabolism
  • Arabidopsis
  • Arabidopsis Proteins / metabolism
  • Brassinosteroids / metabolism*
  • Indoleacetic Acids / metabolism*
  • Phosphoproteins / metabolism
  • Protein Binding
  • Protein Stability
  • Proteome*
  • Proteomics / methods
  • Signal Transduction*
  • Succinates / metabolism


  • Aminopyridines
  • Arabidopsis Proteins
  • Brassinosteroids
  • Indoleacetic Acids
  • Phosphoproteins
  • Proteome
  • Succinates
  • bikinin