外細胞融合は,Rab3aペプチドによって活性化されます

A F Oberhauser¹, J R Monck, W E Balch

¹Department of Physiology and Biophysics, Mayo Clinic, Rochester, Minnesota 55905.

Nature

|November 19, 1992

まとめ

GTP結合タンパク質は,膜融合を調節する. 特定のRab3aペプチドはエクソサイトス脱粒化を誘発し,Rab3タンパク質の活性化がこのプロセスをマスト細胞で駆動することを示唆しています.

科学分野:

細胞生物学細胞生物学
分子生物学は分子生物学である.
メンブラン取引メンブラン取引

背景:

ラブ族の小さなGTP結合タンパク質は,細胞内膜融合に関与しています.
エキゾサイトーシスには,細胞機能に不可欠なプロセスである膜融合が含まれています.

研究の目的:

マスト細胞におけるエクソサイトーシスの調節におけるGTP結合タンパク質の役割を調査する.
エキゾサイト融合現象を直接測定し,重要な規制メカニズムを特定する.

主な方法:

パッチクランプ技術を活用して,外細胞融合イベントを直接測定しました.
GTP-gamma SとGTPでマスト細胞の細胞内 perfusion を使用しました.
Rab3aエフェクタドメインに対応する合成オリゴペプチドをテストした.

主要な成果:

GTP-ガンマSは,マスト細胞の完全なエクソサイト性脱粒化を誘導した.
GTPが抑制されたGTP-ガンマS誘発の脱粒化は,持続的なGTP結合タンパク質の活性化が融合に十分であることを示しています.
Rab3aエフェクタドメインペプチドはGTP-gamma S効果を模倣し,選択的にMg2+とATPに依存するデグラヌレーションを誘導した.
GDP-βSはペプチド反応を加速させ,結合部位の競争を示唆した.

結論:

Rab GTP結合タンパク質の持続的な活性化は,エクソサイト膜融合を引き起こすのに十分である.
Rab3aタンパク質は,マスト細胞における細胞外融合を調節する上で重要な役割を果たしているようです.
この発見は,エクソサイトーシスの調節のための特定の分子機構を明らかにしています.

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