Negative regulation of condensin I by CK2-mediated phosphorylation

EMBO J. 2006 Nov 15;25(22):5339-48. doi: 10.1038/sj.emboj.7601394. Epub 2006 Oct 26.


Condensin I, which plays an essential role in mitotic chromosome assembly and segregation in vivo, constrains positive supercoils into DNA in the presence of adenosine triphosphate in vitro. Condensin I is constitutively present in a phosphorylated form throughout the HeLa cell cycle, but the sites at which it is phosphorylated in interphase cells differ from those recognized by Cdc2 during mitosis. Immunodepletion, in vitro phosphorylation, and immunoblot analysis using a phospho-specific antibody suggested that the CK2 kinase is likely to be responsible for phosphorylation of condensin I during interphase. In contrast to the slight stimulatory effect of Cdc2-induced phosphorylation of condensin I on supercoiling, phosphorylation by CK2 reduced the supercoiling activity of condensin I. CK2-mediated phosphorylation of condensin I is spatially and temporally regulated in a manner different to that of Cdc2-mediated phosphorylation: CK2-dependent phosphorylation increases during interphase and decreases on chromosomes during mitosis. These findings are the first to demonstrate a negative regulatory mode for condensin I, a process that may influence chromatin structure during interphase and mitosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / physiology*
  • Animals
  • CDC2 Protein Kinase / genetics
  • CDC2 Protein Kinase / physiology
  • Casein Kinase II / genetics
  • Casein Kinase II / physiology*
  • Chromatin / genetics
  • Chromatin / physiology
  • DNA, Superhelical / physiology
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • HeLa Cells
  • Humans
  • In Vitro Techniques
  • Interphase
  • Mitosis
  • Multiprotein Complexes / genetics
  • Multiprotein Complexes / physiology*
  • Oocytes / metabolism
  • Phosphorylation
  • Xenopus


  • Chromatin
  • DNA, Superhelical
  • DNA-Binding Proteins
  • Multiprotein Complexes
  • condensin complexes
  • Casein Kinase II
  • CDC2 Protein Kinase
  • Adenosine Triphosphatases