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Updated: Jul 16, 2026

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RhoC GTPase Activation Assay
Published on: August 22, 2010
GTPase活性化タンパク質Rap1GAPは,アスパラジンの触媒を使用しています
Oliver Daumke1, Michael Weyand, Partha P Chakrabarti
1Max-Planck-Institut für Molekulare Physiologie, Otto-Hahnstr. 11, 44227 Dortmund, Germany.
Nature
|May 14, 2004
まとめ
Rap1GAPは,Rap1シグナル伝達の調節体であり,GTPの水解を刺激するためにアルギニンではなくアスパラジンの触媒を使用しています. このユニークなメカニズムは,他のGTPase活性化タンパク質と異なっており,結核性硬化症に影響を及ぼしています.
科学分野:
- 分子生物学は分子生物学である.
- 細胞シグナル伝達 細胞信号伝達
- 構造生物学 構造生物学とは
背景:
- Rap1は,RasのようなGTPaseで,細胞結合とシグナル伝達経路を調節しています.
- Rap1の活動は,GTP酵素活性化タンパク質 (GAPs) によって制御され,GTPの水解を強化する.
- 他のRas型タンパク質とは異なり,Rap1にはGTP水解のための触媒性グルタミンが欠け,そのGAPは構造的に異なる.
研究 の 目的:
- Rap1の特定の活性化剤であるRap1GAPの触媒メカニズムを解明する.
- Rap1GAPのユニークなGTPase活性化機能の構造的基礎を決定する.
主な方法:
- ラップ1GAP触媒ドメインの構造を決定するX線結晶学.
- 特定のアミノ酸の役割を調査するために,サイト指向型変異性.
- 光定位と停止フローの運動測定法で,酵素活性を測定する.
主要な成果:
- Rap1GAP触媒ドメインの結晶構造は2.9 Å解像度で決定されました.
- Rap1GAPは,GTPの水解を促進するために,他のGAPに含まれる触媒アルギニンではなく,触媒アスパラジン残基を使用しています.
- 変異分析と運動測定は,Rap1GAPの機能におけるこのアスパラジンの重要な役割を確認しました.
結論:
- Rap1GAPは,アスパラジン残基を含む新しい触媒機構を使用して,Rap1 GTPaseを活性化します.
- この独特なメカニズムは,GAPの機能の多様性を強調し,結核性硬化症のような疾患を理解する上で潜在的な意味を持つ.
関連する概念動画
GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
Rab Cascades
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
Activation and Inactivation of G Proteins
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...

