nature

当前位置: Nature » 蛋白&蛋白质组学 » 正文

美国学者获得活动中的G-蛋白偶联受体的结构图像

标签:GPCR 光线 激素
摘要 : 杜克大学医学院、密歇根大学和斯坦福大学合作,获得了活动中的G-蛋白偶联受体(GPCR)的结构图像。这一项研究为完全了解我们的机体响应包括光线、激素和各种化学物质在内的一系列广泛刺激的机制至关重要。相关文章发表于2014年6月22日的《Nature》杂志上。

GPCRs是最大的人类疾病药物靶标家族,其涉及心血管疾病、神经系统疾病和各种类型的癌症。蛋白质β-arrestin对于调控这些蛋白至关重要,作者们显现了β-arrestin蛋白与参与人类“攻击或逃避”(fight-or-flight)反应的受体形成的复合物的图像。

 

Structural model of the [bgr]2V2R-[bgr]-arrestin-1-Fab30 complex.

 

“Arrestin的主要作用是给GPCR信号戴上帽子。阐明这一复合物的结构对于了解这些受体丧失反应,从而阻止异常信号的机制具有极其重要的意义,”密歇根大学生命科学学院的Georgios Skiniotis教授说。

“由于这一蛋白质复合物不稳定且高度动态,实验要求分离大量的蛋白质,对这一信号装置进行高分辨率显像是一个挑战,”共同主要作者Arun K. Shukla。Shukla与杜克大学医学院医学教授Robert J. Lefkowitz合作,现在印度理工大学生物科学和生物工程系建立了一个独立的实验室。

在获得可直接进行结构显像的材料后,作者们利用电子显微镜揭示出了这一信号装置中单个的分子彼此之间的组织构建方式。

将数以千计的单幅图像组合到一起生成了更好地有关这一分子结构的图像。他们通过交联分析和质谱法检测进一步阐明了这一图像。

作者的下一个目标是利用X-射线晶体学获得了有关这一装置的更多细节。然后在实验中利用这些原子细节来设计出一些新型药物,更好的了解GPCR生物学的一些基本概念。

Shukla说:“这还只是开始,还有漫长的路要走。我们还必须显像其他GPCRs的相似复合物,从而全面地了解这一受体家族。”

原文摘要:

Visualization of arrestin recruitment by a G-protein-coupled receptor

Arun K. Shukla, Gerwin H. Westfield, Kunhong Xiao, Rosana I. Reis, Li-Yin Huang, Prachi Tripathi-Shukla, Jiang Qian, Sheng Li, Adi Blanc, Austin N. Oleskie, Anne M. Dosey, Min Su,Cui-Rong Liang, Ling-Ling Gu, Jin-Ming Shan, Xin Chen, Rachel Hanna, Minjung Choi, Xiao Jie Yao, Bjoern U. Klink, Alem W. Kahsai, Sachdev S. Sidhu, Shohei Koide, Pawel A. Penczek, Anthony A. Kossiakoff et al.

G-protein-coupled receptors (GPCRs) are critically regulated by β-arrestins, which not only desensitize G-protein signalling but also initiate a G-protein-independent wave of signalling. A recent surge of structural data on a number of GPCRs, including the β2 adrenergic receptor (β2AR)–G-protein complex, has provided novel insights into the structural basis of receptor activation. However, complementary information has been lacking on the recruitment of β-arrestins to activated GPCRs, primarily owing to challenges in obtaining stable receptor–β-arrestin complexes for structural studies. Here we devised a strategy for forming and purifying a functional human β2AR–β-arrestin-1 complex that allowed us to visualize its architecture by single-particle negative-stain electron microscopy and to characterize the interactions between β2AR and β-arrestin 1 using hydrogen–deuterium exchange mass spectrometry (HDX-MS) and chemical crosslinking. Electron microscopy two-dimensional averages and three-dimensional reconstructions reveal bimodal binding of β-arrestin 1 to the β2AR, involving two separate sets of interactions, one with the phosphorylated carboxy terminus of the receptor and the other with its seven-transmembrane core. Areas of reduced HDX together with identification of crosslinked residues suggest engagement of the finger loop of β-arrestin 1 with the seven-transmembrane core of the receptor. In contrast, focal areas of raised HDX levels indicate regions of increased dynamics in both the N and C domains of β-arrestin 1 when coupled to the β2AR. A molecular model of the β2AR–β-arrestin signalling complex was made by docking activated β-arrestin 1 and β2AR crystal structures into the electron microscopy map densities with constraints provided by HDX-MS and crosslinking, allowing us to obtain valuable insights into the overall architecture of a receptor–arrestin complex. The dynamic and structural information presented here provides a framework for better understanding the basis of GPCR regulation by arrestins.

对应Nature杂志: 2014年8月14日Nature杂志精选

浏览次数:113

热门文章TOP

RSS订阅 - 填写您的邮件地址,订阅我们的精彩内容: - 网站地图
网站联系电话:020-87540820 备案号:粤ICP备11050685号-8 增值电信业务经营许可证:粤B2-20120479
©2011-2015 生物帮 All rights reserved.