Phosphorylation barcode-dependent signal bias of the dopamine D1 receptor
Phosphorylation barcode-dependent signal bias of the dopamine D1 receptor
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DOI：
10.1101/2020.03.03.971846
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发表时间：
2020-03
期刊：
影响因子：
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通讯作者：
A. Kaya;Nicole A. Perry;V. Gurevich;T. M. Iverson
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作者：
A. Kaya;Nicole A. Perry;V. Gurevich;T. M. Iverson
受体磷酸化在GPCR调控中的功能重要性已被证明。在过去的十年中，磷酸条形码的概念被开发来解释GPCR下游的抑制蛋白依赖性信号网络的多维性质。在这里，我们使用多巴胺-1受体（D1 R），探讨受体磷酸化对G蛋白依赖性和arrestin依赖性ERK和Src激活的影响。我们的研究表明，D1 R细胞内环-3磷酸化影响G蛋白和arrestins。差异D1 R磷酸化可将信号传导导向ERK或Src活化。这意味着磷酸化诱导受体和/或结合arrestin的不同构象，以启动或选择不同的细胞信号通路。激动剂激活的G蛋白偶联受体（GPCR）必须从数百个潜在的下游信号级联和效应器中正确选择。为了实现这一点，GPCR首先结合到中间信号蛋白，如G蛋白或抑制蛋白。这些中间体启动信号级联，促进不同效应物的活性，包括几种蛋白激酶。G蛋白与抑制蛋白在启动和指导信号传导中的相对作用引起了激烈的争论，目前仍不清楚如何选择正确的最终信号传导途径，因为蛋白质伴侣已经准备就绪。在这里，我们开始去卷积的过程中，从多巴胺D1受体（D1 R）的信号偏差，探索因素，促进ERK 1/2或Src的激活，导致细胞生长和增殖的激酶。我们发现ERK 1/2的激活同时涉及arrestin和Gαs，而Src的激活仅依赖于arrestin。有趣的是，我们发现磷酸化模式影响arrestin和Gαs偶联，这表明细胞调节G蛋白信号的另一种方式。D1 R胞内环3中的磷酸化位点对于指导G蛋白与抑制蛋白的结合以及在ERK 1/2和Src的激活之间进行选择特别重要。总的来说，这些研究将功能结果与信号偏差的物理基础相关联，并提供了关于GPCR信号如何定向的基本信息。
Significance The functional importance of receptor phosphorylation in GPCR regulation has been demonstrated. Over the past decade, the phospho-barcode concept was developed to explain the multidimensional nature of the arrestin-dependent signaling network downstream of GPCRs. Here, we used the dopamine-1 receptor (D1R) to explore the effect of receptor phosphorylation on G protein-dependent and arrestin-dependent ERK and Src activation. Our studies suggest that D1R intracellular loop-3 phosphorylation affects both G proteins and arrestins. Differential D1R phosphorylation can direct signaling toward ERK or Src activation. This implies that phosphorylation induces different conformations of receptor and/or bound arrestin to initiate or select different cellular signaling pathways. Agonist-activated G protein-coupled receptors (GPCRs) must correctly select from hundreds of potential downstream signaling cascades and effectors. To accomplish this, GPCRs first bind to an intermediary signaling protein, such as G protein or arrestin. These intermediaries initiate signaling cascades that promote the activity of different effectors, including several protein kinases. The relative roles of G proteins versus arrestins in initiating and directing signaling is hotly debated, and it remains unclear how the correct final signaling pathway is chosen given the ready availability of protein partners. Here, we begin to deconvolute the process of signal bias from the dopamine D1 receptor (D1R) by exploring factors that promote the activation of ERK1/2 or Src, the kinases that lead to cell growth and proliferation. We found that ERK1/2 activation involves both arrestin and Gαs, while Src activation depends solely on arrestin. Interestingly, we found that the phosphorylation pattern influences both arrestin and Gαs coupling, suggesting an additional way the cells regulate G protein signaling. The phosphorylation sites in the D1R intracellular loop 3 are particularly important for directing the binding of G protein versus arrestin and for selecting between the activation of ERK1/2 and Src. Collectively, these studies correlate functional outcomes with a physical basis for signaling bias and provide fundamental information on how GPCR signaling is directed.