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腫瘍死滅因子シグナル伝達における中性および酸性スフィンゴミエリナーゼの機能的二分法
K Wiegmann1, S Schütze, T Machleidt
1Institut für Medizinische Mikrobiologie und Hygiene, Technische Universität München, Federal Republic of Germany.
Cell
|September 23, 1994
まとめ
腫瘍死滅因子 (TNF) は,2種類のスフィンゴミエライナーゼ (SMases) を独立して活性化します. これらの酵素はセラミドを生成し,NF-カッパB活性化やタンパク質キナーゼシグナル伝達などの異なるシグナル伝達経路を制御します.
科学分野:
- 細胞生物学 細胞生物学
- 分子シグナリング
- バイオケミストリー バイオケミストリー
背景:
- セラミドは,成長因子受容体シグナル伝達経路における重要な第2のメッセンジャーとして作用します.
- スフィンゴミエリナーゼ (SMases) は,セラミド生成を司る酵素である.
- 腫瘍死滅因子 (TNF) 受容体のシグナル伝達には,複雑な下流イベントが含まれています.
研究 の 目的:
- TNF受容体シグナル伝達における中性 (N-) SMaseと酸性 (A-) SMaseの異なる役割を調査する.
- 異なるSMaseタイプから生成されるセラミドによって調節される特定のシグナル伝達経路を解明する.
- N-SMaseとA-SMase媒介経路の間でクロストークが存在するかどうかを判断する.
主な方法:
- TNF受容体55 (TNF-R55) の活性化により,SMase活性が刺激される.
- 膜関連N-SMaseとエンドソーマルA-SMaseによるセラミド産生を区別する.
- タンパク質キナーゼ活性化,フォスフォリパゼA2,NF-カッパB活性化を含む下流信号伝達イベントの評価.
主要な成果:
- TNF受容体結合は,異なる受容体ドメインを通じて,N-SMaseとA-SMaseの両方を迅速に活性化します.
- N-SMaseの活性化により,プロリン誘導タンパク質キナーゼ (proline-directed protein kinase) とフォスフォリファーゼA2.2を誘発するセラミド生成が生じます.
- A-SMaseの活性化により,特にNF-kappa B.を活性化するセラミド生成が生じる.
- N-SMaseとA-SMaseのシグナル伝達経路の間のクロストークは観察されなかった.
結論:
- N-SMaseとA-SMaseは,TNF受容体シグナル伝達によって独立して活性化されます.
- セラミドのダウンストリーム効果は,その生産場所 (トポロジー) に依存しています.
- この2つのSMase経路は,TNF受容体信号伝導の異なる側面を制御し,重複しない.
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