ABI1 of Arabidopsis is a protein serine/threonine phosphatase highly regulated by the proton and magnesium ion concentration

FEBS Lett. 1998 Mar 6;424(1-2):100-4. doi: 10.1016/s0014-5793(98)00149-5.


The plant hormone abscisic acid (ABA) mediates various responses such as stomatal closure, maintenance of seed dormancy, and inhibition of plant growth. All three responses are regulated by the ABI1 gene product. The ABI1 protein (ABI1p) has been characterized as a protein serine/threonine phosphatase of type 2C that is highly affected in its activity by changes in the proton and magnesium ion concentrations. In the ABA-insensitive mutant abi1 of Arabidopsis thaliana a single amino acid exchange in the primary structure results in both a dominant insensitive phenotype and a strongly reduced protein phosphatase activity in vitro by possibly impairing metal ion coordination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology
  • Arabidopsis Proteins*
  • Dose-Response Relationship, Drug
  • Hydrogen-Ion Concentration
  • Magnesium / pharmacology
  • Phosphoprotein Phosphatases / drug effects*
  • Phosphoprotein Phosphatases / isolation & purification*
  • Phosphoprotein Phosphatases / metabolism
  • Plant Proteins / isolation & purification*
  • Plant Proteins / metabolism
  • Protons
  • Serine / metabolism
  • Threonine / metabolism


  • Arabidopsis Proteins
  • Plant Proteins
  • Protons
  • Threonine
  • Serine
  • ABI1 protein, Arabidopsis
  • Phosphoprotein Phosphatases
  • Magnesium