The chromosomal association of condensin II is regulated by a noncatalytic function of PP2A

• DOI: 10.1038/nsmb.1708
• Publication Date: 2009-11-18T16:28:06Z
• Authors: Ai Takemoto; Kazuhiro Maeshima; Tsuyoshi Ikehara; Kazumitsu Yamaguchi; Akiko Murayama; Shihoko Imamura; Naoko Imamoto; Shigeyuki Yokoyama; Tatsuya Hirano; Yoshinori Watanabe; Fumio Hanaoka; Junn Yanagisawa; Keiji Kimura
• Keywords: Adenosine Triphosphatases; 0303 health sciences; Xenopus; Kinesins; Polyenes; Alkenes; Models, Biological; Chromosomes; Cell Line; DNA-Binding Proteins; 03 medical and health sciences; Pyrones; Multiprotein Complexes; Okadaic Acid; Animals; Humans; Protein Phosphatase 2; Enzyme Inhibitors; Cells, Cultured

Mitotic chromosomal assembly in vertebrates is regulated by condensin I and condensin II, which work cooperatively but have different chromosomal localization profiles and make distinct mechanistic contributions to this process. We show here that protein phosphatase 2A (PP2A), which interacts with condensin II but not condensin I, plays an essential role in targeting condensin II to chromosomes. Unexpectedly, our data indicate that PP2A acts as a recruiter protein rather than a catalytic enzyme to target condensin II to chromosomes. This recruiting activity of PP2A was inhibited by okadaic acid, but not by fostriecin, even though both molecules strongly inhibited the catalytic activity of PP2A. Additionally, we found that the chromokinesin KIF4a is also targeted to chromosomes via the noncatalytic activity of PP2A. Thus, our studies reveal a previously unknown contribution of PP2A to chromosome assembly.