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

Markus Bachmann, Joan L. Huber, Gurdeep S. Athwal, Ke Wu, Robert J. Ferl, Steven C. Huber

Research output: Contribution to journalArticle


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 Arabinopsis 14-3-3 isoforms in the interaction with phospho-NR: ω > χ > υ >>> φ, Ψ.

Original languageEnglish (US)
Pages (from-to)26-30
Number of pages5
JournalFEBS Letters
Issue number1
StatePublished - Nov 25 1996



  • 14-3-3 protein
  • Binding site
  • Inhibitor protein
  • Isoform specificity
  • Nitrate reductase
  • Protein phosphatase
  • Regulatory phosphorylation site

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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