Cytokinin fluoroprobe reveals multiple sites of cytokinin perception at plasma membrane and endoplasmic reticulum

Nat Commun. 2020 Aug 27;11(1):4285. doi: 10.1038/s41467-020-17949-0.


Plant hormone cytokinins are perceived by a subfamily of sensor histidine kinases (HKs), which via a two-component phosphorelay cascade activate transcriptional responses in the nucleus. Subcellular localization of the receptors proposed the endoplasmic reticulum (ER) membrane as a principal cytokinin perception site, while study of cytokinin transport pointed to the plasma membrane (PM)-mediated cytokinin signalling. Here, by detailed monitoring of subcellular localizations of the fluorescently labelled natural cytokinin probe and the receptor ARABIDOPSIS HISTIDINE KINASE 4 (CRE1/AHK4) fused to GFP reporter, we show that pools of the ER-located cytokinin receptors can enter the secretory pathway and reach the PM in cells of the root apical meristem, and the cell plate of dividing meristematic cells. Brefeldin A (BFA) experiments revealed vesicular recycling of the receptor and its accumulation in BFA compartments. We provide a revised view on cytokinin signalling and the possibility of multiple sites of perception at PM and ER.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / cytology
  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Brefeldin A / pharmacology
  • Cell Membrane / metabolism*
  • Cytokinins / chemistry
  • Cytokinins / metabolism*
  • Endoplasmic Reticulum / metabolism*
  • Fluorescent Dyes / chemistry*
  • Fluorescent Dyes / metabolism
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Meristem / cytology
  • Meristem / metabolism
  • Plants, Genetically Modified
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction / drug effects


  • Arabidopsis Proteins
  • Cytokinins
  • Fluorescent Dyes
  • Receptors, Cell Surface
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Brefeldin A
  • Protein Kinases
  • WOL protein, Arabidopsis