Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden.
MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, United Kingdom.
Nat Commun. 2019 Feb 8;10(1):667. doi: 10.1038/s41467-019-08630-2.
Class F receptors are considered valuable therapeutic targets due to their role in human disease, but structural changes accompanying receptor activation remain unexplored. Employing population and cancer genomics data, structural analyses, molecular dynamics simulations, resonance energy transfer-based approaches and mutagenesis, we identify a conserved basic amino acid in TM6 in Class F receptors that acts as a molecular switch to mediate receptor activation. Across all tested Class F receptors (FZD SMO), mutation of the molecular switch confers an increased potency of agonists by stabilizing an active conformation as assessed by engineered mini G proteins as conformational sensors. Disruption of the switch abrogates the functional interaction between FZDs and the phosphoprotein Dishevelled, supporting conformational selection as a prerequisite for functional selectivity. Our studies reveal the molecular basis of a common activation mechanism conserved in all Class F receptors, which facilitates assay development and future discovery of Class F receptor-targeting drugs.
F 类受体被认为是有价值的治疗靶点，因为它们在人类疾病中发挥作用，但伴随受体激活的结构变化仍未被探索。我们利用群体和癌症基因组学数据、结构分析、分子动力学模拟、基于共振能量转移的方法和突变，在 F 类受体中鉴定出 TM6 中的一个保守碱性氨基酸，它作为分子开关介导受体激活。在所有测试的 F 类受体（FZD SMO）中，分子开关的突变通过稳定活性构象赋予激动剂更高的效力，这可以通过作为构象传感器的工程化 mini G 蛋白来评估。开关的破坏消除了 FZDs 与磷酸蛋白 Dishevelled 之间的功能相互作用，支持构象选择是功能选择性的前提。我们的研究揭示了所有 F 类受体中保守的常见激活机制的分子基础，这有助于检测方法的开发和未来 F 类受体靶向药物的发现。
