Serine/Threonine phosphatase activity of calcineurin is inhibited by sodium orthovanadate and dithiothreitol reverses the inhibitory effect

Motohiro Morioka, Kohji Fukunaga, Takayuki Kawano, Shu Hasegawa, Kohjiro Korematsu, Yutaka Kai, Jun ichiro Hamada, Eishichi Miyamoto, Yukitaka Ushio

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Orthovanadate is known to be an inhibitor of protein tyrosine phosphatases. However, we found that it inhibited calcineurin which has the activity of a serine/threonine protein phosphatase, using casein phosphorylated by cyclic AMP-dependent protein kinase as a substrate. Orthovanadate inhibits the Mn2+-activated activity of purified calcineurin to 20%; this is not the case without Mn2+. Furthermore, 10 mM dithiothreitol (DTT) reversed the inhibitory effects of orthovanadate. Orthovanadate showed the same inhibitory effect for calcineurin activity in homogenates as for the purified enzyme; the inhibitory effect was reversed by DTT. These results indicate that orthovanadate inhibits not only protein tyrosine phosphatases as reported, but also serine/threonine phosphatase activity of calcineurin.

Original languageEnglish
Pages (from-to)342-345
Number of pages4
JournalBiochemical and biophysical research communications
Volume253
Issue number2
DOIs
Publication statusPublished - 1998 Dec 18
Externally publishedYes

Keywords

  • Calcineurin
  • Sodium orthovanadate

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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