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核の位置情報信号を特異的に結合するサイトソリックタンパク質は,核輸入の受容体である
1Department of Cell, Molecular and Structural Biology, Northwestern University Medical School, Chicago, Illinois 60611.
Cell
|September 6, 1991
まとめ
研究者らは,核位置配列 (NLS) を結合する2つの牛の赤血球タンパク質を特定しました. これらのNLS結合タンパク質は,NEM感受性受容体として作用し,細胞のないシステムでの核輸入を促進します.
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.
- タンパク質生化学 タンパク質生化学
背景:
- 核インポートは,遺伝子発現と細胞機能を調節する重要な細胞プロセスです.
- 核位置配列 (NLS) は,タンパク質を核に導きます.
- 細胞系因子は核輸入を媒介することが知られているが,その特定の役割は完全に解明されていない.
研究 の 目的:
- 核インポートに関与するタンパク質を特定し,特徴づけること.
- 核タンパク質の輸送を媒介するNLS結合タンパク質の役割を調査する.
- 核輸入因子のN-エチルマレイミド (NEM) に対する感受性を決定する.
主な方法:
- 牛の赤血球から54kgと56kgのポリペプチドを浄化する.
- 穿透性細胞システムを用いたin vitro核輸入アッセイ.
- 精製されたタンパク質によるNLS結合活性と輸入刺激の評価.
- 精製されたタンパク質と細胞溶融因子のNEM感受性の分析.
主要な成果:
- SV40大T抗原NLSを特異的に結合する2つの主要なポリペプチド (54および56kd) を精製した.
- 精製されたNLS結合タンパク質は,NLSを含む光タンパク質の核インポートを細胞のないシステムで2〜3倍に強化しました.
- 輸入刺激は飽和性であり,サイトゾールに依存し,NEM感受性受容体によって媒介された.
- NEM処理は,NLS結合に影響を与えることなく,浄化されたタンパク質のインポート刺激能力を無効化しました.
結論:
- 精製された54KDと56KDの牛の赤血球タンパク質は,核輸入のためのNEM感受性受容体として機能する.
- これらのNLS結合タンパク質は,タンパク質の核への輸送を媒介するために不可欠です.
- 効率的なin vitro核インポートには,NEM感受性およびNEM感受性のない追加の細胞系因子も必要である.
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