LDL受容体の細胞外ドメインの構造は,エンドソームのpHで
Gabby Rudenko1, Lisa Henry, Keith Henderson
1Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard Y4-206, Dallas, TX 75390, USA.
まとめ
低密度リポタンパク質受容体は,エンドソーム内のコレステロールを放出します. 提案されたメカニズムは,ベータプロペラドメインが代替基板として作用し,コレステロールホメオスタシスのためのカルシウム依存性リポタンパク質の放出を促進することを含む.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- 細胞生物学 細胞生物学
背景:
- 低密度リポタンパク質受容体 (LDLR) は,コレステロールの恒常性にとって極めて重要です.
- LDLRは,酸性エンドソームにおけるリポプロテインエンドサイトーシスとリガンド放出を媒介する.
- リガンド放出の構造的基礎を理解することは,コレステロール代謝の鍵です.
研究 の 目的:
- エンドソーム内のLDLRからリポプロテインが放出される構造的メカニズムを解明する.
- 低pHでのLDLR構造の役割を調査する.
主な方法:
- pH 5.3 でのX線結晶学
- LDLRのリガンド結合とEGF前駆体ホモロジードメインの構造分析.
主要な成果:
- pH5.3では,LDLRリガンド結合ドメイン (モジュールR2-R7) がEGF前駆体ホモロジードメイン (モジュールA,B,ベータプロペラ,C) の上に弧する.
- リポプロテイン結合に不可欠なR4およびR5モジュールは,カルシウム結合ループを通じてβプロペラと相互作用します.
- 結晶構造は,エンドソームのpHで特定のドメイン相互作用を明らかにします.
結論:
- ベータプロペラドメインを含むリポタンパク質の放出のための新しいメカニズムが提案されています.
- ベータプロペラルは,リガンド結合ドメインの代替基板としてカルシウムに依存した方法で作用します.
- この相互作用は,脂質タンパク質の放出を促進し,コレステロールの恒常性を助けます.
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