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Updated: May 9, 2026

10:13
Measuring G-protein-coupled Receptor Signaling via Radio-labeled GTP Binding
Published on: June 9, 2017
ヒトのB級グルカゴンGタンパク質結合受容体の構造
Fai Yiu Siu1, Min He, Chris de Graaf
1Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Nature
|July 19, 2013
まとめ
グルカゴン受容体 (GCGR) 構造が決定され,グルカゴンを結合するためのユニークな特徴が明らかになりました. これは,グルコースホメオスタシスの調節と潜在的な治療目標についての洞察を提供します.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- 分子内分泌学 分子内分泌学
背景:
- グルカゴン受容体 (GCGR) は,肝臓におけるグルコースの放出に対するグルカゴンの作用を媒介することによって,グルコースホメオスタシスにとって極めて重要です.
- GCGRの分子機構を理解することは,糖尿病などの代謝障害の管理に不可欠です.
研究 の 目的:
- ヒトのGCGR.GR.へのグルカゴンの結合の構造的基礎を解明する.
- GCGRのネイティブリガンドであるグルカゴンによる分子認識と活性化メカニズムを理解する.
主な方法:
- ヒトのGCGR7の結晶構造の決定,3.4 Å解像度で7つのトランスメブランヘリコドメイン.
- 受容体-リガンドの相互作用を調査するための広範なサイト固有の突然変異.
- GCGR.GRに結合したグルカゴンのハイブリッドモデルの開発.
主要な成果:
- 結晶構造は,典型的なクラスAのGPCRと異なる,GCGRトランスメブランドメインのユニークな特徴を明らかにします.
- 第"回トランスメブランヘリクスの顕著な"茎"領域は,膜の上部に広がり,細胞外領域を位置づけています.
- グルカゴン結合部位は,細胞外ドメインと茎によって形成され,ペプチドの捕獲とトランスメブランドメインとの相互作用を容易にします.
結論:
- 決定された構造と結合モデルは,GCGRがグルカゴンを認識し結合する方法について,前例のない洞察を提供します.
- GCGRのユニークな構造要素は,グルコースホメオスタシスにおけるその機能の鍵です.
- この構造情報は,代謝疾患のGCGRを標的とした新しい治療法の開発を導くことができます.
関連する概念動画
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...
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...
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...
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.
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...

