The calcium-dependent protein kinase HvCDPK1 mediates the gibberellic acid response of the barley aleurone through regulation of vacuolar function

Plant J. 2004 Jul;39(2):206-18. doi: 10.1111/j.1365-313X.2004.02121.x.


In the aleurone cells of the cereal grain, gibberellic acid (GA) induces the secretion of hydrolases that mobilize endosperm reserves to fuel early seedling growth. GA is known to trigger a range of cellular responses, including increases in cytoplasmic calcium, vacuolar reserve mobilization, gene transcription, and the synthesis and secretion of hydrolases. To further define elements of the Ca2+-dependent GA response machinery, we have cloned a Ca2+-dependent protein kinase (HvCDPK1) from these cells. Although expression of an inactivated (D140N) version of this kinase did not affect GA-induced gene expression or changes in cytosolic Ca2+, it did inhibit secretion, cell vacuolation, and vacuolar acidification, all responses linked to the GA response. Additionally, recombinant wild-type HvCDPK1 activated the V-type H(+)-ATPase present in isolated aleurone vacuoles. These results suggest HvCDPK1 may mediate Ca2+-dependent events of the GA response, such as control of vacuolar function, that lie downstream of transcriptional regulation.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Calcium / metabolism
  • Cloning, Molecular
  • Cytosol / metabolism
  • Escherichia coli / genetics
  • Gene Expression Regulation, Plant
  • Gibberellins / pharmacology*
  • Hordeum / cytology
  • Hordeum / genetics*
  • Hydrogen-Ion Concentration
  • Protein Kinases / genetics*
  • Protein Kinases / metabolism
  • Recombinant Proteins / metabolism
  • Seeds / cytology
  • Seeds / genetics
  • Signal Transduction
  • Transcription, Genetic
  • Vacuoles / metabolism


  • Gibberellins
  • Recombinant Proteins
  • gibberellic acid
  • Protein Kinases
  • calcium-dependent protein kinase
  • Adenosine Triphosphatases
  • Calcium