Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
CSIR-Central Drug Research Institute, Lucknow 226031, India.
Nat Nanotechnol. 2017 Dec;12(12):1190-1198. doi: 10.1038/nnano.2017.188. Epub 2017 Oct 2.
Beta-arrestins (βarrs) critically mediate desensitization, endocytosis and signalling of G protein-coupled receptors (GPCRs), and they scaffold a large number of interaction partners. However, allosteric modulation of their scaffolding abilities and direct targeting of their interaction interfaces to modulate GPCR functions selectively have not been fully explored yet. Here we identified a series of synthetic antibody fragments (Fabs) against different conformations of βarrs from phage display libraries. Several of these Fabs allosterically and selectively modulated the interaction of βarrs with clathrin and ERK MAP kinase. Interestingly, one of these Fabs selectively disrupted βarr-clathrin interaction, and when expressed as an intrabody, it robustly inhibited agonist-induced endocytosis of a broad set of GPCRs without affecting ERK MAP kinase activation. Our data therefore demonstrate the feasibility of selectively targeting βarr interactions using intrabodies and provide a novel framework for fine-tuning GPCR functions with potential therapeutic implications.
β-arrestins（βarrs）在 G 蛋白偶联受体（GPCRs）的脱敏、内吞和信号转导中起着关键作用，并且它们作为支架与大量的相互作用伙伴结合。然而，βarrs 支架能力的变构调节以及其相互作用界面的直接靶向以选择性地调节 GPCR 功能尚未得到充分探索。在这里，我们从噬菌体展示文库中鉴定出了一系列针对βarrs 不同构象的合成抗体片段（Fabs）。这些 Fab 中的几种可以变构并选择性地调节βarrs 与网格蛋白和 ERK MAP 激酶的相互作用。有趣的是，其中一种 Fab 可以选择性地破坏βarr-网格蛋白相互作用，当作为内体表达时，它可以强烈抑制广泛的一组 GPCR 激动剂诱导的内吞作用，而不影响 ERK MAP 激酶的激活。因此，我们的数据证明了使用内体选择性靶向βarr 相互作用的可行性，并为精细调节 GPCR 功能提供了一个新的框架，具有潜在的治疗意义。
