1] CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France [2] INSERM U1054, 34090 Montpellier, France [3] Universités Montpellier I et II, 34090 Montpellier, France.
Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany.
Nat Commun. 2014 Oct 17;5:5206. doi: 10.1038/ncomms6206.
Efficient cell-to-cell communication relies on the accurate signalling of cell surface receptors. Understanding the molecular bases of their activation requires the characterization of the dynamic equilibrium between active and resting states. Here, we monitor, using single-molecule Förster resonance energy transfer, the kinetics of the reorientation of the extracellular ligand-binding domain of the metabotropic glutamate receptor (mGluR), a class C G-protein-coupled receptor. We demonstrate that most receptors oscillate between a resting- and an active-conformation on a sub-millisecond timescale. Interestingly, we demonstrate that differences in agonist efficacies stem from differing abilities to shift the conformational equilibrium towards the fully active state, rather than from the stabilization of alternative static conformations, which further highlights the dynamic nature of mGluRs and revises our understanding of receptor activation and allosteric modulation.
有效的细胞间通讯依赖于细胞表面受体的信号传递的准确性。要了解其激活的分子基础，就需要对活性和静止状态之间的动态平衡进行描述。在这里，我们利用单分子Förster 共振能量转移，来监测代谢型谷氨酸受体（mGluR）的胞外配体结合域的重定向的动力学，mGluR 是一种 C 类 G 蛋白偶联受体。我们证明，在亚毫秒的时间尺度上，大多数受体在静止和激活构象之间振荡。有趣的是，我们证明，激动剂效力的差异源自于将构象平衡向完全激活状态转移的能力的不同，而不是来自于替代静态构象的稳定，这进一步突出了 mGluR 的动态性质，并修正了我们对受体激活和变构调节的理解。
