マクロサイクルペプチドによるヘトロトリメルGαシグナリングのステート選択的調節
Shizhong A Dai1, Qi Hu1, Rong Gao2
1Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
Cell
|September 28, 2022
まとめ
研究者らは,Gαsタンパク質を標的とする新しい循環性ペプチド,GN13とGD20を発見した. これらの阻害剤は選択的にGαsの活性を調節し,GTPase関連の疾患に対する新たな治療手段を提供している.
科学分野:
- 生物化学
- 薬理学について
- 分子生物学
背景:
- Gタンパク質結合受容体 (GPCR) 信号伝達経路は,細胞の調節において極めて重要です.
- 刺激性Gタンパク質アルファサブユニット (Gαs) は,循環型AMP (cAMP) 産生の主なレギュラーである.
- Gαsを含むGTPaseは,高親和性核酸結合により,歴史的に挑戦的な薬物標的である.
研究 の 目的:
- Gαsタンパク質を標的とする新しい阻害剤を特定する.
- GTPaseの活性調節剤としてのサイクルペプチドの可能性を調査する.
- Gαsの状態依存性阻害剤を開発する.
主な方法:
- サイクリックペプチドの大きな化学図書館のスクリーニング
- マクロサイクルペプチドGN13とGD20の識別と特徴付け
- コクリスタログラフィーは,阻害剤の結合モードを決定する.
- 細胞シグナリングアッセイにおける阻害剤の活性評価
主要な成果:
- 2つのマクロサイクリックペプチド,GN13とGD20は,Gαs阻害体として特定されました.
- GD20はGαsの非活性状態を標的とする.
- これらのペプチドは,Gαsと特定のヌクレオチド結合状態に対して高い選択性を示す.
- 同結晶構造は,スイッチII/α3ポケット内の明確な結合相互作用を明らかにした.
- 細胞に浸透する類型は,細胞内のGαs/Gβγ信号伝達を調節した.
結論:
- Gαsを標的とするサイクルペプチド阻害剤の発見は,重要な進歩を表しています.
- これらの発見は,状態依存のGTPase阻害剤の開発のための新しい可能性を開きます.
- この研究は,GPCR経路を標的とした将来の治療戦略の基盤を提供します.
関連する概念動画
Activation and Inactivation of G Proteins
7.5K
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...
7.5K
GPCRs Regulate Adenylyl Cylase Activity
5.8K
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...
5.8K
Amplifying Signals via Enzymatic Cascade
8.7K
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
8.7K
G-Protein Gated Ion Channels
4.8K
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...
4.8K
Calmodulin-dependent Signaling
5.2K
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
5.2K
GPCR Desensitization
6.3K
G protein-coupled receptor (GPCR) signaling plays a crucial role in cell functioning. GPCR desensitization is an equally essential process. It allows cells to respond to changing environments and regain sensitivity to new stimuli while preventing unnecessary stimulation when no longer needed. Prolonged exposure to stimuli leads to GPCR desensitization. It involves blocking the receptors from binding and activating additional G proteins. This inhibits activation of downstream effectors, thereby...
6.3K


