シナプトタグミンIとIVは,C(2) AドメインにおけるCa(2+) 結合とは独立してトランスミッター放出を促進する
Iain M Robinson1, Ravi Ranjan, Thomas L Schwarz
1Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK. i.robinson@gen.cam.ac.uk
Nature
|July 12, 2002
まとめ
シナプトタグミンIのC2Aドメインは,カルシウム依存神経伝達物質の放出に不可欠ではありません. 関連するタンパク質であるシナプトタグミンIVは,実際にシナプス伝達を促進し,その提案された抑制作用に挑戦します.
科学分野:
- 神経科学は神経科学である.
- 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:
- カルシウムイオン (Ca2+) は,膀融合を促進することによって,神経末端における神経伝達物質の放出を誘発する.
- シナプトタグミンIはCa2+を感知する主な候補であり,そのC2AドメインはCa2+の結合と,フォスフォリピドとシンタキシンとの相互作用に関与しています.
- シナプトタグミンIに関する以前の遺伝学的研究は,Ca2+センシングトリガーとしての結合の役割に関して不確実な結果をもたらしました.
研究 の 目的:
- シナプトタグミンI C2AドメインのCa2+結合部位がCa2+依存のシナプス伝送に必要かどうかを調査する.
- シナプトタグミンIVのシナプス伝達における機能,特に阻害剤または促進剤として作用するかどうかを決定する.
主な方法:
- シナプトタグミンI C2AドメインのCa2+結合部位に重要なアスパルテートを変異させる.
- 内生シナプトタグミンIが欠けているドロソフィラの変異したシナプトタグミンIの発現.
- 改変されたドロソフィラにおけるシナプス伝播のCa2+依存性特性を評価する.
主要な成果:
- シナプトタグミンI C2AドメインのCa2+結合部位の破壊は,Ca2+依存のシナプス伝送を変化させなかった.
- シナプトタグミンIVは,タンパク質が欠けているドロソフィラのシナプトタグミンIを効果的に置き換えた.
- シナプトタグミンIVは,シナプス伝播を阻害するのではなく促進することが判明しました.
結論:
- シナプトタグミンのC2Aドメインは,Ca2+依存のシナプス伝達には必要ありません.
- シナプトタグミンIVは,シナプス伝達を促進する役割を果たし,以前は阻害物質であるという仮説とは対照的です.
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