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  • The EMBO Journal (2006) 25, 5339 - 5348
  • doi:10.1038/sj.emboj.7601394

Published online: 26 October 2006

Negative regulation of condensin I by CK2-mediated phosphorylation

Ai Takemoto1,2,7, Keiji Kimura1,3,4,7, Junn Yanagisawa3, Shigeyuki Yokoyama2,5 and Fumio Hanaoka1,4,6

  1. Cellular Physiology Laboratory, Discovery Research Institute, RIKEN, Wako, Saitama, Japan
  2. Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
  3. Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba Science City, Ibaraki, Japan
  4. Solution Oriented Research for Science and Technology (SORST) from the Japan Science and Technology Agency, Wako, Saitama, Japan
  5. RIKEN Genomic Sciences Center, Suehiro-cho, Tsurumi, Yokohama, Japan
  6. Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
  7. These authors contributed equally to this work

Correspondence to:

Keiji Kimura, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8572, Japan. Tel.: +81 29 853 6632; Fax: +81 29 853 4605; E-mail: kekimura@sakura.cc.tsukuba.ac.jp

Fumio Hanaoka, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamada-Oka, Suita, Osaka 565-0871, Japan. Tel.: +81 6 6879 7975; Fax: +81 6 6877 9382. E-mail: fhanaoka@fbs.osaka-u.ac.jp

Received 19 May 2006; Accepted 27 September 2006

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.

  • Keywords:

    • chromosome condensation,
    • CK2,
    • condensing,
    • interphase,
    • phosphorylation