Different kinases phosphorylate nucleophosmin/B23 at different sites during G2and M phases of the cell cycle

Pei S. Jiang, Jei H. Chang, Yat Ming Yung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

31 Citations (Scopus)


The recombinant GST-nucleophosmin/B23 and the truncated mutants were tested for phosphorylation in cell-free extracts of G2and M phases or by purified kinases. Our results indicated that a threonine residue at amino acids (a.a.) 185-240 was phosphorylated by cdc2 kinase during the entry of mitosis while the serine phosphorylation site at the middle acidic portion of the molecule (a.a. 83-152) was phosphorylated by casein kinase II during G2phase. Our results also showed that there was possibly another serine phosphorylation at site other than the middle portion of nucleophosmin/B23 (a.a. 83-152) during the entry of cells into mitosis. The demonstration of the characteristic changes in phosphorylation of nucleophosmin/B23 during the cell cycle implicates important role of nucleophosmin/B23 in the control of the fate of nucleoli and cell growth.
Original languageEnglish
Pages (from-to)151-160
Number of pages10
JournalCancer Letters
Issue number1-2
Publication statusPublished - 29 May 2000
Externally publishedYes


  • Cell cycle
  • Nucleophosmin/B23
  • Phosphorylation

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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