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カルシウムボウルとRCKドメインが欠けているBK(Ca) カリウムチャネルのカルシウム活性化

Rebecca Piskorowski¹, Richard W Aldrich

¹Department of Molecular and Cellular Physiology, and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305-5345, USA.

|December 6, 2002

まとめ

大導電性カルシウム活性化カリウム (BK(Ca)) チャンネルは,カルシウムシグナル伝達と細胞興奮性を結びつける. この研究では,C端領域がBK (BK) ・Ca (Ca) 経路カルシウム活性化に欠かせないことが明らかになり,以前の仮説に異議を唱えた.

科学分野:

分子生物学は分子生物学である.
神経科学は神経科学である.
バイオフィジックス生物物理学

背景:

大導電性カルシウム活性化カリウム (BK(Ca)) チャンネルは,神経伝達物質の放出や滑らかな筋肉のリラックスなどの生理学的プロセスに不可欠です.
これらのチャネルは,細胞内カルシウムシグナル伝達経路と細胞膜の興奮性を結びつける.
BK(Ca) 経路の活性化は,膜電圧と細胞内カルシウム濃度の両方に依存しています.

研究の目的:

細胞内C末端領域がBK (BK) 経路のカルシウム依存活性化における役割を調査する.
"カルシウムボウル"とRCKドメインを含むC端末が,生理学的条件下でBK(Ca) チャンネル機能のために必要かどうかを判断する.

主な方法:

BK(Ca) チャンネル活動に関する電気生理学的記録.
細胞内C端末領域全体に欠けているBK(Ca) チャンネル変種を利用する.

主要な成果:

細胞内C末端なしで設計されたBCK (Ca) チャンネルは,カルシウムに対して正常な感受性を示した.
これらの発見は,カルシウムで活性化されたBCK (Ca) 経路の開口にはC端が不要であることを示しています.
C末端内の"カルシウムボウル"とRCKドメインは,カルシウムゲーティングに不可欠ではありません.

結論:

BK(Ca) 経路の細胞内C端は,カルシウム媒介による活性化には欠かせない.
これは,カルシウム結合部位がC末端部位にのみ存在するという長年にわたる仮説に異議を唱える.
代替メカニズムや地域が,BCK (((Ca)) 経路カルシウム感受性に関与している可能性があります.

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