GAP結合/"エフェクタ"ドメインの変異によるRasHの腫瘍性形態の優先抑制
C L Farnsworth1, M S Marshall, J B Gibbs
1Department of Biochemistry, Tufts University Health Sciences Campus, Boston, Massachusetts 02111.
Cell
|February 8, 1991
まとめ
RasHタンパク質の突然変異は,正常なRash機能を保ちながら,腫瘍的形態を選択的に減少させます. これは,Rasタンパク質のエフェクタドメインを阻害することによって,Ras駆動がんに対する標的治療戦略を示唆しています.
科学分野:
- 分子生物学は分子生物学である.
- 腫瘍学 腫瘍学
- バイオケミストリー バイオケミストリー
背景:
- Rasタンパク質は,細胞の信号伝達経路の重要な調節体です.
- Ras遺伝子の変異は,ヒトのがん,特に腫瘍性Rasの一般的な原動力である.
- 正常なRas機能を維持しながら,腫瘍性Rasをターゲットにすることは,重要な治療上の課題です.
研究 の 目的:
- 特定のRash変異 (D33H/P34S,D38N) が正常なRashタンパク質と腫瘍性Rashタンパク質の両方の変換活動に及ぼす影響を調査する.
- これらの突然変異がRasタンパク質に与える影響を明らかにするために,GTPase活性化タンパク質 (GAP) とRasタンパク質の相互作用,および下流信号伝達.
- これらの突然変異の潜在能力を,標的がん治療の開発の基礎として探求する.
主な方法:
- RasH構造にD33H/P34SおよびD38N変異を導入するためのサイト指向型変異.
- 細胞培養におけるワイルド型および変異RASHタンパク質の変換活性を測定するためのアッセイ.
- 酵母アデニリルサイクラゼ刺激アッセイは,下流結合効率を評価する.
- GTPase活性化タンパク質 (GAP) の結合親和性を評価するための共免疫プレシピテーションアッセイ.
主要な成果:
- D33H/P34S変異は,腫瘍性RasH (G12VとQ61L) の変換活性をそれぞれ400倍と20倍に大幅に低下させた.
- この変異は,正常なRasHの変換活動や,Ras経路の機能を回復する能力に影響しませんでした.
- 変異は下流結合を減少させたが,正常なRasHにおけるGAP結合の減少によって部分的に相殺され,GTP結合Ras.が上昇した.
- 腫瘍性Rashでは,突然変異が結合を減少させ,GAP結合が減少しても,GAP刺激によるGTPアゼ活性が欠如しているため,補償はできませんでした.
結論:
- 特定のRasH変異は,正常なRas機能を損なうことなく,腫瘍性Ras変容活性を選択的に低下させることができます.
- これらの変異は,Rasのダウンストリームシグナル伝達とGAPの相互作用に影響を与え,Rasの調節に関する洞察を提供します.
- Rasタンパク質のGAP結合/エフェクタドメインをターゲットにすることは,ヒト腫瘍における腫瘍性Rasの優先無活性化のための有望な戦略です.
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