Genetically encoded intrabody sensors illuminate structural and functional diversity in GPCR-ß-arrestin complexes
Genetically encoded intrabody sensors illuminate structural and functional diversity in GPCR-ß-arrestin complexes
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基因编码的体内传感器阐明了 GPCR-à-arrestin 复合物的结构和功能多样性
DOI：
10.1101/651463
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Baidya M
中科院分区：
文献类型：
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作者：
Baidya M
受体阻滞素(β-arrestins，βARRs)在激动剂刺激下的相互作用是G蛋白偶联受体(GPCRs)导致受体脱敏、内吞和信号转导的标志。尽管β受体的整体功能作用通常被认为在不同的受体之间是保守的，但新出现的数据现在清楚地揭示了β受体的受体特异性功能贡献。然而，潜在的机制仍然主要是推测的，并且是我们目前对GPCR信号和调控范例理解中的一个关键缺失环节。在这里，我们开发了合成的基于体内的构象传感器，帮助我们可视化GPCRARR1复合体在细胞环境中的组装和运输，以时空分辨率为一系列广泛的受体。令人惊讶的是，这些构象传感器揭示了GPCRARR复合体中前所未有的多样性水平，这种多样性超出了当前基于亲和力分类和基于磷酸化代码的相互作用模式的框架。更重要的是，这种由磷酸化位点的空间特征引起的构象多样性直接表现为不同的功能结果，包括β受体在不同受体的信号转导中的相反贡献。综上所述，这些发现发现，尽管总体上有相似的相互作用和贩运模式，但不同GPCRs的βARR复合体存在关键的结构和功能差异，这些GPCRs定义和微调受体特异性的下游反应。
Interaction of β-arrestins (βarrs) upon agonist-stimulation is a hallmark of G protein-coupled receptors (GPCRs) resulting in receptor desensitization, endocytosis and signaling. Although overall functional roles of βarrs are typically believed to be conserved across different receptors, emerging data now clearly unveils receptor-specific functional contribution of βarrs. The underlying mechanism however remains mostly speculative and represents a key missing link in our current understanding of GPCR signaling and regulatory paradigms. Here, we develop synthetic intrabody-based conformational sensors that help us visualize the assembly and trafficking of GPCR-βarr1 complexes in cellular context for a broad set of receptors with spatio-temporal resolution. Surprisingly, these conformational sensors reveal a previously unappreciated level of diversity in GPCR-βarr complexes that extends beyond the current framework of affinity-based classification and phosphorylation-code-based interaction patterns. More importantly, this conformational diversity arising from spatial signature of phosphorylation sites manifests directly in the form of distinct functional outcomes, including even opposite contribution of βarrs in signal-transduction for different receptors. Taken together, these findings uncover that despite an overall similar interaction and trafficking patterns; critical structural and functional differences exist in βarr complexes for different GPCRs that define and fine-tune receptor-specific downstream responses.