Phosphorylation of the Arabidopsis AtrbohF NADPH oxidase by OST1 protein kinase

FEBS Lett. 2009 Sep 17;583(18):2982-6. doi: 10.1016/j.febslet.2009.08.033. Epub 2009 Aug 29.


The plant hormone abscisic acid (ABA) triggers production of reactive oxygen species (ROS) in guard cells via the AtrbohD and AtrbohF NADPH oxidases, leading to stomatal closure. The ABA-activated SnRK2 protein kinase open stomata 1 (OST1) (SRK2E/SnRK2.6) acts upstream of ROS in guard cell ABA signaling. Here, we report that OST1 phosphorylates Ser13 and Ser174 on AtrbohF. In addition, substitution of Ser174 to Ala results in a approximately 40% reduction in the phosphorylation of AtrbohF by OST1. We also show that OST1 physically interacts with AtrbohF. These results provide biochemical evidence suggesting that OST1 regulates AtrbohF activity.

Publication types

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

MeSH terms

  • Abscisic Acid / pharmacology
  • Arabidopsis Proteins / metabolism*
  • NADPH Oxidases / metabolism*
  • Phosphorylation
  • Protein Binding
  • Protein Kinases / metabolism*
  • Reactive Oxygen Species / metabolism
  • Serine / metabolism


  • Arabidopsis Proteins
  • Reactive Oxygen Species
  • Serine
  • Abscisic Acid
  • NADPH Oxidases
  • Protein Kinases
  • OST1 protein, Arabidopsis