InsP3受容体と貯蔵されたHtrp3チャンネルとの機能的相互作用
K Kiselyov1, X Xu, G Mozhayeva
1Department of Physiology, University of Texas Southwestern Medical Center at Dallas, 75235, USA.
Nature
|December 16, 1998
まとめ
貯蔵されたカルシウムチャネル (SOC) は,カルシウム (Ca2+) 貯蔵庫の枯渇によって活性化されます. この研究は,InsP3受容体がHtrp3 SOCと直接相互作用し,Ca2+の流入を調節し,細胞シグナル伝達におけるカップリング仮説を支持することを示しています.
科学分野:
- 細胞生物学 細胞生物学
- 分子シグナリング
- イオンチャンネル生理学 イオンチャンネル生理学
背景:
- カルシウムイオン (Ca2+) は,刺激時に貯蔵物から放出される重要な細胞内伝達物質である.
- 貯蔵庫の枯渇は,貯蔵庫が操作するチャネル (SOC) 経由でCa2+の流入を誘発し,Ca2+の放出によって電流が活性化される (I ((crac)).
- Ca2+貯蔵庫の枯渇とSOC/I(crac) アクティベーションを結びつけるメカニズムについては,依然として議論されており,メッセンジャー分子または直接受容体結合を提案するモデルがあります.
研究 の 目的:
- 貯蔵されたチャネルHtrp3とイノシトール1,4,5-トリフォスファート (InsP3) 受容体間の機能的相互作用を調査する.
- InsP3受容体がCa2+貯蔵庫の枯渇に反応してSOCとI ((crac) の活動を直接調節するかどうかを決定する.
- カルシウムシグナル伝達の結合仮説を支持する証拠を提供すること.
主な方法:
- HEK293細胞における哺乳類のHtrp3チャネルの安定的な発現.
- SOCとI ((crac) の電気生理学的記録は,完ぺきなおよび切断された膜パッチに記録されています.
- InsP3による刺激と,Ca2+貯蔵庫の枯渇と受容体洗浄後のチャネル活動の評価.
主要な成果:
- Htrp3チャネルは,InsP3受容体と密接な機能的相互作用を示した.
- Htrp3チャネルの活性化は,無傷の細胞におけるCa2+の動員と,切断されたパッチにおけるInsP3の直接的適用で観察されました.
- 洗浄時に失われるInsP3誘発のHtrp3活性化は,InsP3結合のInsP3受容体を加えることで回復しました.
結論:
- この発見は,カルシウムシグナル伝達における結合仮説の有力な証拠を提供する.
- InsP3受容体は,InsP3によって活性化されると,蓄積されたカルシウムチャンネル (SOC) と直接相互作用し,それを調節します.
- この直接的な相互作用のメカニズムは,細胞内貯蔵庫の枯渇後のCa2+の流入を制御するために重要である.
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