CPK12: A Ca2+-dependent protein kinase balancer in abscisic acid signaling

Plant Signal Behav. 2011 Nov;6(11):1687-90. doi: 10.4161/psb.6.11.17954. Epub 2011 Nov 1.

Abstract

Ca2+ is believed to be a critical second messenger in ABA signal transduction. Ca2+-dependent protein kinases (CDPKs) are the best characterized Ca2+ sensors in plants. Recently, we identified an Arabidopsis CDPK member CPK12 as a negative regulator of ABA signaling in seed germination and post-germination growth, which reveals that different members of the CDPK family may constitute a regulation loop by functioning positively and negatively in ABA signal transduction. We observed that both RNA interference and overexpression of CPK12 gene resulted in ABA-hypersensitive phenotypes in seed germination and post-germination growth, suggesting a high complexity of the CPK12-mediated ABA signaling pathway. CPK12 stimulates a negative ABA-signaling regulator (ABI2) and phosphorylates two positive ABA-signaling regulators (ABF1 and ABF4), which may partly explain the ABA hypersensitivity induced by both downregulation and upregulation of CPK12 expression. Our data indicate that CPK12 appears to function as a balancer in ABA signal transduction in Arabidopsis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / metabolism*
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Calcium-Calmodulin-Dependent Protein Kinases / genetics
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
  • Gene Expression Regulation, Plant
  • Germination
  • Signal Transduction

Substances

  • Arabidopsis Proteins
  • Abscisic Acid
  • CPK12 protein, Arabidopsis
  • Calcium-Calmodulin-Dependent Protein Kinases