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视紫红质与G蛋白偶联受体激酶1复合物的结构获解析
2021-07-18 14:36

美国普渡大学John J. G. Tesmer研究组取得一项新突破。他们的最新研究解析了视紫红质与G蛋白偶联受体(GPCR)激酶(GRK)1复合物的结构。2021年7月14日出版的《自然》杂志在线发表了这项成果。

在本研究中,研究人员解析了一系列光活化视紫红质 (Rho*)与视紫红质激酶 (GRK1) 结合的冷冻电镜单粒子重建结构,其中GRK1的N末端形成了一个螺旋,结合在Rho*开放的细胞质裂隙中。该螺旋还与GRK1激酶结构域相结合,并将其稳定在活跃的构象状态。GPCR中许多保守碱性残基和GRK中保守酸性残基之间的静电相互作用进一步稳定了该复合物。研究人员并没有观察到GRK1 G蛋白信号同源结构域或视紫红质C末端调节因子的密度图。质谱分析交联证实了这些结果,并揭示了与受体结合GRK1的动态转变,这些转变有利于催化受体尾部多个位点的磷酸化。

研究确定了一些GRK1残基,其突变增强了激酶活性以及与 Rho* 的交联能力,并发现了参与酸性磷脂激活的残基。基于这些数据,研究人员提出了一个小家族蛋白激酶如何识别并被数百种不同GPCR激活的通用模型。

据介绍,G蛋白偶联受体激酶对活化的GPCR进行选择性磷酸化,从而开启其脱敏基序。尽管尚不清楚GRK如何识别这些受体,但GRK N末端保守区域对于该过程至关重要。

附:英文原文

Title: Structures of rhodopsin in complex with G-protein-coupled receptor kinase 1

Author: Qiuyan Chen, Manolo Plasencia, Zhuang Li, Somnath Mukherjee, Dhabaleswar Patra, Chun-Liang Chen, Thomas Klose, Xin-Qiu Yao, Anthony A. Kossiakoff, Leifu Chang, Philip C. Andrews, John J. G. Tesmer

Issue&Volume: 2021-07-14

Abstract: G-protein-coupled receptor (GPCR) kinases (GRKs) selectively phosphorylate activated GPCRs, thereby priming them for desensitization1. Although it is unclear how GRKs recognize these receptors2,3,4, a conserved region at the GRK N terminus is essential for this process5,6,7,8. Here we report a series of cryo-electron microscopy single-particle reconstructions of light-activated rhodopsin (Rho*) bound to rhodopsin kinase (GRK1), wherein the N terminus of GRK1 forms a helix that docks into the open cytoplasmic cleft of Rho*. The helix also packs against the GRK1 kinase domain and stabilizes it in an active configuration. The complex is further stabilized by electrostatic interactions between basic residues that are conserved in most GPCRs and acidic residues that are conserved in GRKs. We did not observe any density for the regulator of G-protein signalling homology domain of GRK1 or the C terminus of rhodopsin. Crosslinking with mass spectrometry analysis confirmed these results and revealed dynamic behaviour in receptor-bound GRK1 that would allow the phosphorylation of multiple sites in the receptor tail. We have identified GRK1 residues whose mutation augments kinase activity and crosslinking with Rho*, as well as residues that are involved in activation by acidic phospholipids. From these data, we present a general model for how a small family of protein kinases can recognize and be activated by hundreds of different GPCRs.

DOI: 10.1038/s41586-021-03721-x

Source: https://www.nature.com/articles/s41586-021-03721-x

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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