Luo Fang, Qin GeGe, Wang Lina, Fang Xiaohong
CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Research Center for Molecular Science, Institute of Chemistry, Chinese Academy of Science, Beijing, China.
Department of Chemistry, University of the Chinese Academy of Sciences, Beijing, China.
Front Chem. 2022 Jan 19;9:779940. doi: 10.3389/fchem.2021.779940. eCollection 2021.
The GABAB receptor is a typical G protein-coupled receptor, and its functional impairment is related to a variety of diseases. While the premise of GABAB receptor activation is the formation of heterodimers, the receptor also forms a tetramer on the cell membrane. Thus, it is important to study the effect of the GABAB receptor aggregation state on its activation and signaling. In this study, we have applied single-molecule photobleaching step counting and single-molecule tracking methods to investigate the formation and change of GABAB dimers and tetramers. A single-molecule stoichiometry assay of the wild-type and mutant receptors revealed the key sites on the interface of ligand-binding domains of the receptor for its dimerization. Moreover, we found that the receptor showed different aggregation behaviors at different conditions. Our results offered new evidence for a better understanding of the molecular basis for GABAB receptor aggregation and activation.
GABAB受体是一种典型的G蛋白偶联受体，其功能受损与多种疾病相关。虽然GABAB受体激活的前提是异二聚体的形成，但该受体在细胞膜上也会形成四聚体。因此，研究GABAB受体聚集状态对其激活和信号传导的影响很重要。在本研究中，我们应用单分子光漂白步计数和单分子追踪方法来研究GABAB二聚体和四聚体的形成与变化。对野生型和突变型受体的单分子化学计量分析揭示了受体配体结合域界面上其二聚化的关键位点。此外，我们发现该受体在不同条件下表现出不同的聚集行为。我们的结果为更好地理解GABAB受体聚集和激活的分子基础提供了新证据。
