Research Abstract


Greatwall kinase and cyclin B-Cdk1 are both critical constituents of M-phase-promoting factor

2012年9月11日 Nature Communications 3 : 1059 doi: 10.1038/ncomms2062


原 昌稔1,†, 阿部 優介1,†, 田中 利明2, 山元 孝佳1,†, 奥村 英一1 & 岸本 健雄1

  1. 東京工業大学 大学院生命理工学研究科 生命情報専攻
  2. 東京工業大学 大学院生命理工学研究科 生体システム専攻
    †現所属: マサチューセッツ工科大学 ホワイトヘッド研究所(米国)(原);
    公益財団法人 がん研究会 がん研究所実験病理部(阿部);
    東京大学大学院 理学系研究科 生物科学専攻(山元)
Maturation/M-phase-promoting factor is the universal inducer of M-phase in eukaryotic cells. It is currently accepted that M-phase-promoting factor is identical to the kinase cyclin BCdk1. Here we show that cyclin BCdk1 and M-phase-promoting factor are not in fact synonymous. Instead, M-phase-promoting factor contains at least two essential components: cyclin BCdk1 and another kinase, Greatwall kinase. In the absence of Greatwall kinase, the M-phase-promoting factor is undetectable in oocyte cytoplasm even though cyclin BCdk1 is fully active, whereas M-phase-promoting factor activity is restored when Greatwall kinase is added back. Although the excess amount of cyclin BCdk1 alone, but not Greatwall kinase alone, can induce nuclear envelope breakdown, spindle assembly is abortive. Addition of Greatwall kinase greatly reduces the amount of cyclin BCdk1 required for nuclear envelope breakdown, resulting in formation of the spindle with aligned chromosomes. M-phase-promoting factor is thus a system consisting of one kinase (cyclin BCdk1) that directs mitotic entry and a second kinase (Greatwall kinase) that suppresses the protein phosphatase 2A-B55 which opposes cyclin BCdk1.