Department of Materials Science and Engineering, Johns Hopkins University, 3400 Charles Street, Baltimore, Maryland.
Department of Chemistry, Center for Biophysics and Quantitative Biology, School of Chemical Sciences, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.
Biophys J. 2023 Oct 17;122(20):4113-4120. doi: 10.1016/j.bpj.2023.09.011. Epub 2023 Sep 21.
The activity of many membrane receptors is controlled through their lateral association into dimers or higher-order oligomers. Although Förster resonance energy transfer (FRET) measurements have been used extensively to characterize the stability of receptor dimers, the utility of FRET in studies of larger oligomers has been limited. Here we introduce an effective equilibrium dissociation constant that can be extracted from FRET measurements for EphA2, a receptor tyrosine kinase (RTK) known to form active oligomers of heterogeneous distributions in response to its ligand ephrinA1-Fc. The newly introduced effective equilibrium dissociation constant has a well-defined physical meaning and biological significance. It denotes the receptor concentration for which half of the receptors are monomeric and inactive, and the other half are associated into oligomers and are active, irrespective of the exact oligomer size. This work introduces a new dimension to the utility of FRET in studies of membrane receptor association and signaling in the plasma membrane.
许多膜受体的活性是通过它们的侧向缔合形成二聚体或更高阶的寡聚体来控制的。虽然Förster 共振能量转移（FRET）测量已被广泛用于表征受体二聚体的稳定性，但 FRET 在更大寡聚体研究中的应用受到限制。在这里，我们引入了一个有效的平衡解离常数，可以从 EphA2 的 FRET 测量中提取出来，EphA2 是一种受体酪氨酸激酶（RTK），已知在其配体 EphrinA1-Fc 的作用下形成异质分布的活性寡聚体。新引入的有效平衡解离常数具有明确的物理意义和生物学意义。它表示受体浓度，在此浓度下，一半的受体是单体和非活性的，另一半则缔合形成寡聚体并具有活性，而与确切的寡聚体大小无关。这项工作为 FRET 在质膜中膜受体缔合和信号转导研究中的应用带来了新的维度。
