Two proton pump interactors identified from a direct phosphorylation screening of a rice cDNA library by using a recombinant BRI1 receptor kinase

Shuichi Hirabayashi, Yasuhiko Matsushita, Michio Sato, Rie Oh-I, Masahiro Kasahara, Hiroshi Abe, Hiroshi Nyunoya

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A direct phosphorylation screening of a rice cDNA library resulted in isolation of 35 BIP clones encoding brassinosteroid receptor kinase (BRI1)-interacting proteins. Among the candidate substrates for BRI1, two clones were found to encode similar proton pump interactor proteins homologous to Arabidopsis PPI1, which was reported to interact with a regulatory region of plasma membrane H+-ATPase. The rice proton pump interactors BIP103 and BIP131 contained 627 and 621 amino acids, respectively, with carboxyl-terminal hydrophobic region characteristic of tail-anchored proteins. Northern blotting analysis indicated that mRNAs for both interactors increased significantly after brassinolide treatment of lamina joint cells, which are especially sensitive to exogenous brassinosteroids.

Original languageEnglish
Pages (from-to)35-45
Number of pages11
JournalPlant Biotechnology
Issue number1
Publication statusPublished - 2004 Mar



  • BRI1
  • Brassinosteroid
  • H-ATPase
  • Lamina joint
  • Phosphorylation screening
  • Protein interaction
  • Proton pump interactor
  • Receptor kinase
  • Rice

ASJC Scopus subject areas

  • Biotechnology
  • Agronomy and Crop Science
  • Plant Science

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