Dephosphorylation of the inhibitory phosphorylation site S287 in Xenopus Cdc25C by protein phosphatase-2A is inhibited by 14-3-3 binding

James R.A. Hutchins, Dina Dikovskaya, Paul R. Clarke

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Cdc25C phosphatase induces mitosis by dephosphorylating and activating Cdc2/cyclin B protein kinase. Phosphorylation of Xenopus Cdc25C at serine 287 creates a binding site for a 14-3-3 protein and restrains activation during interphase. Here, we show that dephosphorylation of S287 is catalysed by protein phosphatase-2A in Xenopus egg extracts. 14-3-3 protein binding to Cdc25C inhibits dephosphorylation of S287, providing a mechanism to maintain phosphorylation of that site during interphase. The rate of dephosphorylation of S287 is not increased in mitotic extracts, indicating that the phosphorylation status of the site is likely to be controlled through modulation of kinases or 14-3-3 binding activity.

Original languageEnglish
Pages (from-to)267-271
Number of pages5
JournalFEBS Letters
Issue number1-3
Publication statusPublished - 25 Sep 2002



  • 14-3-3 protein
  • Cdc25
  • Cell cycle checkpoint
  • Chk1
  • Protein phosphatase

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