14-3-3 proteins associate with the regulatory phosphorylation site of spinach leaf nitrate reductase in an isoform-specific manner and reduce dephosphorylation of Ser-543 by endogenous protein phosphatases

FEBS Lett. 1996 Nov 25;398(1):26-30. doi: 10.1016/s0014-5793(96)01188-x.


Three lines of evidence indicate that the 14-3-3 proteins that inactivate the phosphorylated form of spinach leaf NADH:nitrate reductase (NR) bind to the enzyme at the regulatory phosphorylation site (Ser-543). First, a phosphorylated synthetic peptide based on the regulatory site can prevent and also reverse the inactivation of phospho-NR caused by 14-3-3 proteins. Second, sequence-specific and phosphorylation-dependent binding of the aforementioned synthetic peptide to the 14-3-3 proteins was demonstrated in vitro. Third, 14-3-3 proteins were required for the ATP-dependent phosphorylation of NR (as assessed by activity measurements) in the presence of NR-kinase and leaf protein phosphatases. Lastly, we demonstrate specificity of recombinant Arabidopsis 14-3-3 isoforms in the interaction with phospho-NR: omega> chi> upsilon>>> phi, psi.

Publication types

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

MeSH terms

  • 14-3-3 Proteins
  • Amino Acid Sequence
  • Arabidopsis / enzymology
  • Binding Sites
  • Enzyme Activation
  • Isoenzymes
  • Molecular Sequence Data
  • Nitrate Reductase
  • Nitrate Reductases / metabolism*
  • Peptide Fragments / chemical synthesis
  • Peptide Fragments / metabolism
  • Phosphoprotein Phosphatases / metabolism*
  • Phosphorylation
  • Plant Leaves / metabolism*
  • Plant Proteins / metabolism*
  • Proteins / metabolism*
  • Serine / metabolism
  • Spinacia oleracea / metabolism*
  • Tyrosine 3-Monooxygenase*


  • 14-3-3 Proteins
  • Isoenzymes
  • Peptide Fragments
  • Plant Proteins
  • Proteins
  • Serine
  • Tyrosine 3-Monooxygenase
  • Nitrate Reductases
  • Nitrate Reductase
  • Phosphoprotein Phosphatases