We recently reported a physical interaction between the angiotensin II (AngII) receptor (AT1R) and thrombin receptor (PAR1) in HEK293 cells using bioluminescence resonance energy transfer (BRET) technology. This was characterized by thrombin trans-activating AT1R and the synergistic responses of the AT1R–PAR1 complex. Here, we investigated the other face of the coin by examining the effect of AT1R on PAR1 activity using BRET. AngII/AT1R did not promote PAR1 activation in the absence of thrombin. However, the combination of thrombin and AngII resulted in their synergistic/allosteric action. Moreover, AngII/AT1R potentiated the maximal thrombin responses, suggesting specific conformational changes within the AT1R–PAR1 complex. Overall, our data confirm the functional AT1R–PAR1 interplay and further support the implication of both AT1R and PAR1 protomers in their synergistic interaction as previously reported.

中文翻译：

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生物发光共振能量转移揭示凝血酶和血管紧张素 II 受体的协同激活

我们最近使用生物发光共振能量转移 (BRET) 技术报道了 HEK293 细胞中血管紧张素 II (AngII) 受体 (AT1R) 和凝血酶受体 (PAR1) 之间的物理相互作用。这以凝血酶反式激活 AT1R 和 AT1R-PAR1 复合物的协同反应为特征。在这里，我们通过使用 BRET 检查 AT1R 对 PAR1 活动的影响来研究硬币的另一面。在没有凝血酶的情况下，AngII/AT1R 不会促进 PAR1 的激活。然而，凝血酶和 AngII 的组合导致它们的协同/变构作用。此外，AngII/AT1R 增强了最大的凝血酶反应，表明 AT1R-PAR1 复合物中的特定构象变化。总体，