Elucidation of a dynamic interplay between a beta-2 adrenergic receptor, its agonist, and stimulatory G protein.-猫眼课题宝

DOI：

10.1073/pnas.2215916120

发表时间：

2023-03-07

期刊：

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

影响因子：

11.1

通讯作者：

中科院分区：

综合性期刊1区

文献类型：

作者：

Han, Yanxiao;Dawson, John R. D.;DeMarco, Kevin R.;Rouen, Kyle C.;Bekker, Slava;Yarov-Yarovoy, Vladimir;Clancy, Colleen E.;Xiang, Yang K.;Vorobyov, Igor

关键词：

G protein-coupled receptor G protein norepinephrine sympathetic nervous system molecular dynamics

来源链接：

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10013855/

G蛋白偶联受体（GPCR）和G蛋白一起工作以将来自各种激素和神经递质分子的信号传递穿过细胞膜，并且它们的激活和随后的解离启动下游信号传导事件的级联，从而导致细胞行为的调节。在这里，我们研究了一个原型GPCR，β-2肾上腺素能受体在其活性状态下，与神经递质去甲肾上腺素和刺激G蛋白的相互作用，使用多微秒长的原子计算机模拟，以了解如何在这个系统中的能量和结构变化可以启动细胞信号。我们的研究结果为我们提供了内在的分子机制，这可能会控制G蛋白从GPCR中解离，并强调了蛋白质结构域和配体动力学在这一关键的生物学过程中的重要性。G蛋白偶联受体（GPCR）代表了跨膜信号转导的最大的膜受体群。配体诱导的GPCR活化触发G蛋白活化，随后是各种信号级联。了解配体结合GPCR和GPCR G蛋白的结构和能量决定因素对于设计靶向这些蛋白质的特定构象以精确控制其信号传导特性的药理学治疗至关重要。在这项研究中，我们集中在一个原型的GPCR，β 2肾上腺素能受体（β 2 AR），其内源性激动剂，去甲肾上腺素（NE）和刺激性G蛋白（Gs）的相互作用。利用分子动力学（MD）模拟，我们证明了阳离子NE，NE（+），通过Gs蛋白募集与β 2 AR结合的稳定性，与实验观察一致。我们还捕捉到配体从β 2 AR上部分解离以及在NE（+）-β 2 AR-Gs三元复合物中Gs在闭合和开放构象之间的构象相互转换，而它仍然与受体结合。NE（+）结合位姿的变化改变了Gs α亚基（Gsα）的构象转变。结果表明，Gsα α1和α5螺旋结构域间的运动和堆积对Gsα和β 2 AR之间的距离增加具有重要意义，这可能表明Gsα的部分解离。当Gsα主要处于开放状态时，Gsα和β 2 AR之间的距离开始增加，并可由β 2 AR的胞内环3（ICL 3）与Gsα相互作用触发，引起α5螺旋的构象变化。我们的研究结果有助于解释配体和GPCR介导的G蛋白激活调节的分子机制。

G protein-coupled receptors (GPCRs) and G proteins work together to transmit signals from various hormone and neurotransmitter molecules across cell membranes, and their activation and subsequent dissociation initiate a cascade of downstream signaling events resulting in modulation of cellular behavior. Here, we studied the interactions of a prototypical GPCR, beta-2 adrenergic receptor in its active state, with neurotransmitter norepinephrine and stimulatory G protein using multi-microsecond–long atomistic computer simulations to understand how energetic and structural changes in this system could initiate cellular signaling. Our results provided us with intrinsic molecular mechanisms, which may control G protein dissociation from GPCRs, and highlighted the importance of protein domain and ligand dynamics in this crucial biological process. G protein-coupled receptors (GPCRs) represent the largest group of membrane receptors for transmembrane signal transduction. Ligand-induced activation of GPCRs triggers G protein activation followed by various signaling cascades. Understanding the structural and energetic determinants of ligand binding to GPCRs and GPCRs to G proteins is crucial to the design of pharmacological treatments targeting specific conformations of these proteins to precisely control their signaling properties. In this study, we focused on interactions of a prototypical GPCR, beta-2 adrenergic receptor (β2AR), with its endogenous agonist, norepinephrine (NE), and the stimulatory G protein (Gs). Using molecular dynamics (MD) simulations, we demonstrated the stabilization of cationic NE, NE(+), binding to β2AR by Gs protein recruitment, in line with experimental observations. We also captured the partial dissociation of the ligand from β2AR and the conformational interconversions of Gs between closed and open conformations in the NE(+)–β2AR–Gs ternary complex while it is still bound to the receptor. The variation of NE(+) binding poses was found to alter Gs α subunit (Gsα) conformational transitions. Our simulations showed that the interdomain movement and the stacking of Gsα α1 and α5 helices are significant for increasing the distance between the Gsα and β2AR, which may indicate a partial dissociation of Gsα The distance increase commences when Gsα is predominantly in an open state and can be triggered by the intracellular loop 3 (ICL3) of β2AR interacting with Gsα, causing conformational changes of the α5 helix. Our results help explain molecular mechanisms of ligand and GPCR-mediated modulation of G protein activation.