Isoform specific phosphorylation of protein phosphatase 2C expressed in COS7 cells

Takayasu Kobayashi, Kazuyuki Kusuda, Motoko Ohnishi, Hong Wang, Shoko Ikeda, Masahito Hanada, Yuchio Yanagawa, Shinri Tamura

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7 Citations (Scopus)


Of the six distinct isoforms of mouse protein phosphatase 2C (PP2C) (α, β-1, β-2, β-3, β-4 and β-5), PP2Cα was specifically phosphorylated on the serine residue(s) when expressed in COS7 cells. Analysis of phosphorylation sites using site-directed mutagenesis demonstrated that Ser- 375 and/or Ser377 were phosphorylated in vivo. These serine residues were the sites of phosphorylation by casein kinase II in vitro. Phosphorylation of PP2Cα was enhanced two-fold by the addition of okadaic acid to the culture medium, but addition of cyclosporin A had no such effect. These results suggest that the expressed PP2Cα is phosphorylated by a casein kinase II- like protein kinase and dephosphorylated by PP1 and/or PP2A in COS7 cells.

Original languageEnglish
Pages (from-to)222-226
Number of pages5
JournalFEBS Letters
Issue number3
Publication statusPublished - 1998 Jul 3


  • Okadaic acid
  • Phosphorylation
  • Protein phosphatase 2C
  • Site-directed mutagenesis


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