シュゴシンはタンパク質フォスファタゼ2Aと連携してコヘシンを保護します
Tomoya S Kitajima1, Takeshi Sakuno, Kei-ichiro Ishiguro
1Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan.
Nature
|March 17, 2006
まとめ
シュゴシンは,ミトーシスとマイオシスにおける染色体分離に不可欠な保存されたメカニズムであるデフォスフォリレーションを通じて,セントロメリックコヘシンを保護する. この研究では,タンパク質フォスファタゼ2A (PP2A) が,この保護過程の鍵であると特定されています.
科学分野:
- 細胞生物学 細胞生物学
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
背景:
- 姉妹染色体凝結は,細胞分裂中の正確な染色体分離に不可欠です.
- セントロメリックコヘシンはシュゴシンによって保護されていますが,そのメカニズムは不明です.
研究 の 目的:
- センターメリック・コヘシンにおけるシュゴシンに依存した保護のメカニズムを解明する.
- セントロメリック・コヘシン (centromeric cohesion) の保護に関与する分子プレーヤーを特定する.
主な方法:
- シュゴシンと相互作用するタンパク質を特定するための共免疫プレシピテーション.
- 免疫光顕微鏡で,タンパク質の局所を決定する.
- 精製されたタンパク質を用いたインビトロフォスファターゼアッセイ.
- 核分裂酵母における機能的分析.
主要な成果:
- タンパク質フォスファタゼ2A (PP2A) の特定の亜型がヒトのシュゴシンと関連していることが判明しました.
- PP2Aはセントロメアでシュゴシンとコロカライズし,コヘシン保護に不可欠です.
- シュゴシン-PP2A複合体は,コヘシンを in vitro で脱酸化し,そのリン酸化を逆転させます.
- このメカニズムはヒトミトーシスと分裂酵母ミオシスの両方で保存されます.
結論:
- シュゴシン (Shugoshin) は,PP2Aを募集して活性化させ,コヘシン (cohesin) の脱リン酸化につながり,センターメリックコヘシン (centromeric cohesin) を保護する.
- この保存されたメカニズムは,ミトーシスとミオシスの両方で適切な染色体分離を保証します.
- この発見は,真核細胞の細胞分裂における基本的なプロセスを明らかにしています.
関連する概念動画
02:20Cohesins
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
02:17Separation of Sister Chromatids
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...
00:50Anaphase Promoting Complex
The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
02:20Cohesins
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
02:17Separation of Sister Chromatids
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...
00:50Anaphase Promoting Complex
The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...