内皮素受体B型(ETB)表现出与包括Gs在内的各种异源三聚体G蛋白亚型的混杂偶联,Gi/o,Gq/11和G12/13。最近的荧光和结构研究提出了有关这些G蛋白亚型的偶联效率和决定因素的问题。在这里,通过采用综合方法,结合氢/氘交换质谱和基于NanoLuc二进制技术的细胞系统,我们研究了Gs的构象变化,Gi,和由ETB激活触发的Gq。ETB与Gi和Gq耦合,但不与Gs耦合。我们强调了特定区域的关键作用,在ETB-Gi1或ETB-Gq偶联中包括Gα的C末端和ETB的胞内环2(ICL2)。虽然Gα的C末端对于ETB-Gi1和ETB-Gq偶联是必需的,ETBICL2影响Gq耦合但不影响Gi1耦合。我们的结果表明,ETB与Gs的耦合效率不同,Gi1和Gq,伴随着ETB诱导的激活后G蛋白的明显构象变化。
The endothelin receptor type B (ETB) exhibits promiscuous coupling with various heterotrimeric G protein subtypes including Gs, Gi/o, Gq/11, and G12/13. Recent fluorescence and structural studies have raised questions regarding the coupling efficiencies and determinants of these G protein subtypes. Herein, by utilizing an integrative approach, combining hydrogen/deuterium exchange mass spectrometry and NanoLuc Binary Technology-based cellular systems, we investigated conformational changes of Gs, Gi, and Gq triggered by ETB activation. ETB coupled to Gi and Gq but not with Gs. We underscored the critical roles of specific regions, including the C terminus of Gα and intracellular loop 2 (ICL2) of ETB in ETB-Gi1 or ETB-Gq coupling. Although The C terminus of Gα is essential for ETB-Gi1 and ETB-Gq coupling, ETB ICL2 influences Gq-coupling but not Gi1-coupling. Our results suggest a differential coupling efficiency of ETB with Gs, Gi1, and Gq, accompanied by distinct conformational changes in G proteins upon ETB-induced activation.