細胞内アゴニストによるクラスB1のGPCR活性化
Kazuhiro Kobayashi1, Kouki Kawakami2, Tsukasa Kusakizako1
1Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
Nature
|June 7, 2023
まとめ
研究者らは,Gタンパク質結合受容体 (GPCR) に新しい細胞内結合ポケットを発見した. この発見はバイアスアゴニストが 選択的にシグナル伝達経路を活性化し 新しい薬の開発の道を開くことを明らかにしています
科学分野:
- 構造生物学
- 薬理学について
- 生物化学
背景:
- Gタンパク質結合受容体 (GPCRs) は通常,オーステリックポケットにリガンドを結合させ,構造変化を引き起こし,Gタンパク質とβ-アレスティンを活性化させます.
- 信号からの有害な影響は,選択的なトランスデューサーの活性化を理解する必要があります.
- 細胞内バイアスアゴニストは,受容体の細胞内空間に結合し,経路特異のシグナル伝達に最近興味を示しています.
研究 の 目的:
- 細胞内バイアスアゴニズムの構造的基礎を解明する.
- GPCRsの細胞内空間にアゴニスト結合の証拠を提供するために.
- 選択的Gタンパク質対β-アレスティンの活性化のメカニズムを理解する.
主な方法:
- 複合体の構造を決定するために,冷凍電子顕微鏡 (cryo-EM) が使用された.
- 複合体は,ヒト副甲状腺ホルモン1型受容体 (PTH1R),Gs,およびアゴニストPCO371で構成されていました.
- 構造分析は,PCO371の結合モードと受容体構成への影響に焦点を当てた.
主要な成果:
- 構造は,アゴニストPCO371が細胞内ポケットのPTH1Rに結合し,Gsと直接相互作用することを明らかにした.
- この結合は,細胞外アロステリック信号の伝播なしに活性コンファメーションを誘導し,トランスメブランヘリックス6を安定させます.
- PCO371は,保存された細胞内ポケットに結合することによって,15のクラスB1GPCRのうち7を活性化します.
結論:
- GPCRにおける新しい保存された細胞内アゴニスト結合ポケットが特定されました.
- この研究は,受容体-トランスデューサインターフェースを標的とした細胞内バイアスの構造的証拠を提供します.
- このメカニズムはベータアレスティン結合よりもGタンパク質結合を優遇し,選択的な薬剤開発の洞察を提供します.
関連する概念動画
GPCRs Regulate Adenylyl Cylase Activity
7.3K
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of...
7.3K
Activation and Inactivation of G Proteins
11.1K
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...
11.1K
G Protein-coupled Receptors
16.6K
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...
16.6K
G-Protein Gated Ion Channels
5.6K
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory...
Sensory...
5.6K
G-protein Coupled Receptors
131.6K
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.
131.6K
Transducer Mechanism: G Protein–Coupled Receptors
4.0K
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,...
GPCRs are also called heptahelical,...
4.0K


