PKL01, an Ndr kinase homologue in plant, shows tyrosine kinase activity

Syouichi Katayama, Yasunori Sugiyama, Naoya Hatano, Toru Terachi, Noriyuki Sueyoshi, Isamu Kameshita

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Protein phosphorylation by protein tyrosine (Tyr) kinases plays important roles in a variety of signalling pathways in cell growth, differentiation and oncogenesis in animals. Despite the absence of classical Tyr kinases in plants, a similar ratio of phosphotyrosine residues in phosphorylated proteins was found in Arabidopsis thaliana as in human. However, protein kinases responsible for tyrosine phosphorylation in plants except some dedicated dual-specificity kinases still remain unclear. In this study, we found that PKL01, a nuclear Dbf2-related (Ndr) kinase homologue in Lotus japonicus, was autophosphorylated at a tyrosine residue when it was expressed in Escherichia coli, but kinase-dead mutant of PKL01 was not. Tyrosine phophorylation site in PKL01 was identified as Tyr-56 by LC-MS/MS analysis. Recombinant PKL01, which had been dephosphorylated by an alkaline phosphatase, could be phosphorylated again at the Tyr residue when it was incubated with ATP. Furthermore, other Ndr kinases in plants and PKL01 phosphorylated on Tyr residues in the exogenous substrates such as poly(Glu, Tyr)4:1 and casein. Therefore, the Ndr kinases in plants, which had been assumed as protein serine (Ser)/threonine (Thr) kinases, turned out to be dual-specificity kinases responsible for phosphorylation of Tyr residues and Ser/Thr residues in plant proteins.

Original languageEnglish
Pages (from-to)347-353
Number of pages7
JournalJournal of biochemistry
Issue number4
Publication statusPublished - Oct 2012
Externally publishedYes


  • Lotus japonicus
  • Ndr kinase
  • autophosphorylation
  • dual-specificity kinase
  • protein tyrosine kinase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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