School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 16419, Republic of Korea.
Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.
Commun Biol. 2024 Mar 23;7(1):362. doi: 10.1038/s42003-024-06056-1.
Muscarinic acetylcholine receptor M3 (M3) and its downstream effector Gq/11 are critical drug development targets due to their involvement in physiopathological processes. Although the structure of the M3-miniGq complex was recently published, the lack of information on the intracellular loop 3 (ICL3) of M3 and extensive modification of Gαq impedes the elucidation of the molecular mechanism of M3-Gq coupling under more physiological condition. Here, we describe the molecular mechanism underlying the dynamic interactions between full-length wild-type M3 and Gq using hydrogen-deuterium exchange mass spectrometry and NanoLuc Binary Technology-based cell systems. We propose a detailed analysis of M3-Gq coupling through examination of previously well-defined binding interfaces and neglected regions. Our findings suggest potential binding interfaces between M3 and Gq in pre-assembled and functionally active complexes. Furthermore, M3 ICL3 negatively affected M3-Gq coupling, and the Gαq AHD underwent unique conformational changes during M3-Gq coupling.
毒蕈碱型乙酰胆碱受体 M3（M3）及其下游效应物 Gq/11 因其参与生理病理过程而成为药物开发的关键靶点。尽管 M3-miniGq 复合物的结构最近已经公布，但由于缺乏 M3 的细胞内环 3（ICL3）的信息以及 Gαq 的广泛修饰，阻碍了在更生理条件下阐明 M3-Gq 偶联的分子机制。在这里，我们使用氘氢交换质谱和 NanoLuc Binary Technology 基于细胞系统描述全长野生型 M3 和 Gq 之间动态相互作用的分子机制。我们通过检查先前定义明确的结合界面和被忽视的区域，提出了对 M3-Gq 偶联的详细分析。我们的研究结果表明，在预组装和功能活性复合物中，M3 和 Gq 之间存在潜在的结合界面。此外，M3 ICL3 负向影响 M3-Gq 偶联，并且在 M3-Gq 偶联过程中，Gαq AHD 经历了独特的构象变化。
