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哺乳類のTPC1チャネルの電圧とフォスフォリピドの活性化に関する構造的洞察
Ji She1,2, Jiangtao Guo3, Qingfeng Chen1,2,4
1Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9040, USA.
Nature
|March 22, 2018
まとめ
マウスTPC1 (MmTPC1) の構造的な洞察は,この電圧依存ナトリウムチャネルがどのように開くかを明らかにします. フォスファチチドリノシトール3,5-二酸化物 (PtdIns(3,5) P2) の結合と膜脱極化は,MmmTPC1ゲートとイオン選択性を調節する.
科学分野:
- 構造生物学
- イオンチャネル生物物理学
- 細胞生理学
背景:
- 臓器二孔チャネル (TPC) は,内解体機能に不可欠な電圧ゲートイオンチャネルである.
- 哺乳類のTPC1とTPC2は,臓器生理を調節するエンドリソーム膜に局所されている.
- TPCはホモダイマーであり,各サブユニットは6つのトランスメブラン (6-TM) ドメインを含んでいる.
研究 の 目的:
- 哺乳類のTPC1の機能と調節の基礎となる構造的メカニズムを解明する.
- TPCチャネルのイオン選択性とゲートメカニズムに関する洞察を提供すること.
- 電圧と脂質結合体の活性化との相互作用を理解する.
主な方法:
- マウスTPC1 (MmTPC1) の構造を決定する電子冷凍顕微鏡 (冷凍EM)
- 構造的な発見を検証し,チャネルゲーティングを理解するための機能分析.
- アポ閉鎖状態とリガンド結合状態の構造的比較.
主要な成果:
- 閉ざされたアポ状態とPtdIns ((3,5) P2-bound開いた状態でMmmTPC1の高解像度の冷凍-EM構造を決定した.
- Na+の選択性に関与する コインスロット型のイオン経路を特定した.
- 第2の6TMドメインのみが電圧依存性を有することを明らかにした.
- PtdIns ((3,5) P2が最初の6-TMドメインに結合すると,脱極化時にチャンネルが活性化します.
結論:
- MmTPC1の構造は,哺乳類のTPCチャネル選択性とゲートに関する包括的な洞察を提供します.
- この研究は,電圧依存における電圧感知領域の役割を強調しています.
- PtdIns ((3,5) P2媒介の活性化と電圧と脂質調節の相互作用を示しています.
- 6-TM電圧ゲートチャネルにおける脂質結合と調節の新鮮な側面を明らかにした.
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