A protein kinase target of a PDK1 signalling pathway is involved in root hair growth in Arabidopsis

Richard G. Anthony, Rossana Henriques, Anne Helfer, Tamás Mészáros, Gabino Rios, Christa Testerink, Teun Munnik, Maria Deák, Csaba Koncz, László Bögre*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

229 Citations (Scopus)


Here we report on a lipid-signalling pathway in plants that is downstream of phosphatidic acid and involves the Arabidopsis protein kinase, AGC2-1, regulated by the 3′-phosphoinositide-dependent kinase-1 (AtPDK1). AGC2-1 specifically interacts with AtPDK1 through a conserved C-terminal hydrophobic motif that leads to its phosphorylation and activation, whereas inhibition of AtPDK1 expression by RNA interference abolishes AGC2-1 activity. Phosphatidic acid specifically binds to AtPDK1 and stimulates AGC2-1 in an AtPDK1-dependent manner. AtPDK1 is ubiquitously expressed in all plant tissues, whereas expression of AGC2-1 is abundant in fast-growing organs and dividing cells, and activated during re-entry of cells into the cell cycle after sugar starvation-induced G1-phase arrest. Plant hormones, auxin and cytokinin, synergistically activate the AtPDK1-regulated AGC2-1 kinase, indicative of a role in growth and cell division. Cellular localisation of GFP-AGC2-1 fusion protein is highly dynamic in root hairs and at some stages confined to root hair tips and to nuclei. The agc2-1 knockout mutation results in a reduction of root hair length, suggesting a role for AGC2-1 in root hair growth and development.

Original languageEnglish
Pages (from-to)572-581
Number of pages10
JournalEMBO Journal
Issue number3
Publication statusPublished - 11 Feb 2004
Externally publishedYes


  • AGC kinase
  • Growth signalling
  • Lipid signalling
  • PDK1
  • Phosphatidic acid
  • Root hair elongation


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