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NATURE:β休止生物传感器揭示了一个快速、受体依赖性激活/失活循环

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发表于 2016-3-27 13:25:14 | 显示全部楼层 |阅读模式
ABSTRACT:
(β-)Arrestins are important regulators of G-protein-coupled receptors (GPCRs)1, 2, 3. They bind to active, phosphorylated GPCRs and thereby shut off ‘classical’ signalling to G proteins3, 4, trigger internalization of GPCRs via interaction with the clathrin machinery5, 6, 7 and mediate signalling via ‘non-classical’ pathways1, 2. In addition to two visual arrestins that bind to rod and cone photoreceptors (termed arrestin1 and arrestin4), there are only two (non-visual) β-arrestin proteins (β-arrestin1 and β-arrestin2, also termed arrestin2 and arrestin3), which regulate hundreds of different (non-visual) GPCRs. Binding of these proteins to GPCRs usually requires the active form of the receptors plus their phosphorylation by G-protein-coupled receptor kinases (GRKs)1, 3, 4. The binding of receptors or their carboxy terminus as well as certain truncations induce active conformations of (β-)arrestins that have recently been solved by X-ray crystallography8, 9, 10. Here we investigate both the interaction of β-arrestin with GPCRs, and the β-arrestin conformational changes in real time and in living human cells, using a series of fluorescence resonance energy transfer (FRET)-based β-arrestin2 biosensors. We observe receptor-specific patterns of conformational changes in β-arrestin2 that occur rapidly after the receptor–β-arrestin2 interaction. After agonist removal, these changes persist for longer than the direct receptor interaction. Our data indicate a rapid, receptor-type-specific, two-step binding and activation process between GPCRs and β-arrestins. They further indicate that β-arrestins remain active after dissociation from receptors, allowing them to remain at the cell surface and presumably signal independently. Thus, GPCRs trigger a rapid, receptor-specific activation/deactivation cycle of β-arrestins, which permits their active signalling.

(β-)arrestins在G蛋白偶联受体(GPCRs)的重要调节剂1,2,3。他们的结合活性,磷酸化的受体,从而关闭'经典'的信号到G 蛋白3,4,触发内化GPCR通过互动的网格设备5、6、7和介导的信号通过“非经典”通路1,2。除了两可视arrestins结合杆和视锥感光细胞(称为β-Arrestin1和arrestin4),只有两个(非可视)β-抑制蛋白(β-β-Arrestin1和β-arrestin2的,也被称为arrestin2和arrestin3),从而调节数百种不同的(非可视)G蛋白偶联受体。这些蛋白质GPCR结合通常需要加上的受体通过G-蛋白偶联受体激酶磷酸化的活性形式(GRK)1,3,4。受体或其羧基末端以及某些截断诱导活性构象的结合(β-)最近被X射线晶体8,9解决了抑制,10。在这里,我们研究的相互作用β休止与G蛋白偶联受体,和β-实时抑制蛋白的构象变化和人类细胞,使用一系列的荧光共振能量转移(FRET)为基础的β-arrestin2的生物传感器。我们观察到,在β迅速发生–β-arrestin2的受体相互作用后的构象变化的受体特异性模式arrestin2。激动剂清除后,这些变化持续时间比直接受体的相互作用。我们的数据表明,一个快速、受体的特定类型,两步结合和激活过程之间的G蛋白偶联受体和β-捕获。他们进一步表明,β- arrestins保持活跃,从受体解离后,使他们能够保持在细胞表面,想必信号独立。因此,G蛋白偶联受体触发快速,受体的特异性激活/失活循环β-抑制,允许他们的信号传导。

原文链接(请戳):http://www.nature.com/nature/jou ... ll/nature17198.html

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