Impact of Ca2+ on structure of soybean CDPKβ and accessibility of the Tyr-24 autophosphorylation site

Man Ho Oh, Xia Wu, Steven C. Huber

Research output: Contribution to journalArticlepeer-review

Abstract

Several plant CDPKs were recently shown to be dual specificity kinases rather than Ser/Thr kinases as traditionally classified by sequence analysis. In the present study we confirm the autophosphorylation of recombinant soybean His6-GmCDPKβ at the Tyr-24 site using sequence-and modification-specific antibodies. Homology modeling of soybean CDPKβ based on recent structures determined for several apicomplexan CDPKs suggested that phosphotyrosine-24 may be inaccessible to phosphatases. However, we report that dephosphorylation of CDPKβ by the protein tyrosine phosphatase 1B, PTP1B, was not restricted in the presence of calcium. Thus, despite conformational changes likely associated with calcium binding to the CDPKs, phosphotyrosine sites remain fully accessible to dephosphorylation suggesting the possibility of conformational breathing and flexing.

Original languageEnglish (US)
Article numbere27671
JournalPlant Signaling and Behavior
Volume8
Issue number12
DOIs
StatePublished - 2013

Keywords

  • Calcium signaling
  • Conformational change
  • Homology modeling
  • Modification-specific antibodies
  • Protein tyrosine phosphatase 1b (PTP1B)
  • Tyrosine autophosphorylation

ASJC Scopus subject areas

  • Plant Science

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