ヘテロトリメリックGタンパク質のアルファサブユニットの活性化のための構造的決定因子
D G Lambright1, J P Noel, H E Hamm
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510.
Nature
|June 23, 1994
まとめ
GTP結合時のトランスデューシンアルファ-GDPの構造の変化は,結晶構造分析によって明らかにされました. これらのシフトは,他のGTPasesとは異なり,Gタンパク質のシグナル伝達とエフェクター活性化に不可欠です.
科学分野:
- 構造生物学 構造生物学とは
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
背景:
- ヘテロトリメリックGタンパク質は,重要な信号トランスデューサである.
- Gタンパク質のアルファサブユニットは,グアニンヌクレオチド (GDP/GTP) に結合し,信号伝達経路を調節する.
- Gタンパク質の活性化メカニズムを理解することは,細胞シグナル伝達研究にとって不可欠です.
研究 の 目的:
- 活性化時にトランスデューシンアルファサブユニットの構造変化を明らかにする.
- 非アクティブのGDP制約状態とアクティブのGTP制約状態を比較する.
- GTP結合がGタンパク質エフェクター相互作用にどのように影響するかを理解する.
主な方法:
- X線結晶学を使用して,トランスデューシンα.GDP.の1.8A結晶構造を決定しました.
- GDP関連構造と,GTP-gamma S.による活性化複合体の以前に決定された構造の比較.
主要な成果:
- 結晶構造は,GTP結合時にトランスデューシンアルファサブユニットにおける明確な構成変化を明らかにします.
- GTPのターミナルフォスファートによって引き起こされた構造の変化は,エフェクタ結合領域に広がります.
- これらの活性化によって引き起こされる変化は,他のGTPaseスーパーファミリーのメンバーで観察されたものとは異なります.
結論:
- GTP結合は,トランスデューシンアルファサブユニットにおける特定の構造的再配置を誘導する.
- これらの再編成は,アクティベーションシグナルを下流エフェクターに伝送するのに非常に重要です.
- この発見は,異異トリメリックGタンパク質のユニークな活性化メカニズムについての洞察を提供します.
関連する概念動画
G-protein Coupled Receptors
G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
G-protein Coupled Receptors
G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
G Protein-coupled Receptors
G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
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...
G Protein-coupled Receptors
G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
Transducer Mechanism: G Protein–Coupled Receptors
G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs.
GPCRs are also called heptahelical, 7TM, or...
GPCRs are also called heptahelical, 7TM, or...


