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邻近蛋白质组学揭示肾上腺素CaV1.2通道的激活机制
2020-01-29 16:28

美国哥伦比亚大学Steven O. Marx、哈佛医学院Marian Kalocsay等研究人员合作利用邻近蛋白质组学揭示肾上腺素CaV1.2通道的激活机制。这一研究成果2020年1月22日在线发表在国际学术期刊《自然》上。

研究人员揭示了β-肾上腺素能激动剂刺激电压门控钙通道的机制。研究人员在小鼠心脏中表达与抗坏血酸过氧化物酶5偶连的α1C或β2B亚基,并使用多重定量蛋白质组学来跟踪CaV1.2附近的数百种蛋白质。研究人员观察到钙通道抑制因子Rad(一种单体G蛋白),在CaV1.2微环境中富集,但在β-肾上腺素刺激过程中被耗尽。蛋白激酶A对Rad上特定丝氨酸残基的磷酸化作用降低了其对β亚基的亲和力,并减轻了CaV1.2的组成型抑制作用,这被视为通道开放可能性的增加。Rad或其同源物Rem在HEK293T细胞中的表达也可通过蛋白激酶A刺激CaV1.3和CaV2.2,从而揭示了进化保守的机制,即可在电压门控钙通道上赋予肾上腺素调节能力。
 
据介绍,在战斗或逃跑反应期间心脏收缩力的增加是由通过CaV1.2电压门控钙通道的β-肾上腺素能增加来实现的。然而,这种增加在表达突变型CaV1.2α1C和β亚基的转基因小鼠心脏中仍然存在,由于这些突变不能被蛋白激酶A(一种β肾上腺素信号传导的重要下游介质)磷酸化,从而表明这种增加还需要非通道因子。
 
附:英文原文

Title: Mechanism of adrenergic Ca V 1.2 stimulation revealed by proximity proteomics

Author: Guoxia Liu, Arianne Papa, Alexander N. Katchman, Sergey I. Zakharov, Daniel Roybal, Jessica A. Hennessey, Jared Kushner, Lin Yang, Bi-Xing Chen, Alexander Kushnir, Katerina Dangas, Steven P. Gygi, Geoffrey S. Pitt, Henry M. Colecraft, Manu Ben-Johny, Marian Kalocsay, Steven O. Marx

Issue&Volume: 2020-01-22

Abstract: Increased cardiac contractility during the fight-or-flight response is caused by β-adrenergic augmentation of CaV1.2 voltage-gated calcium channels1,2,3,4. However, this augmentation persists in transgenic murine hearts expressing mutant CaV1.2 α1C and β subunits that can no longer be phosphorylated by protein kinase A—an essential downstream mediator of β-adrenergic signalling—suggesting that non-channel factors are also required. Here we identify the mechanism by which β-adrenergic agonists stimulate voltage-gated calcium channels. We express α1C or β2B subunits conjugated to ascorbate peroxidase5 in mouse hearts, and use multiplexed quantitative proteomics6,7 to track hundreds of proteins in the proximity of CaV1.2. We observe that the calcium-channel inhibitor Rad8,9, a monomeric G protein, is enriched in the CaV1.2 microenvironment but is depleted during β-adrenergic stimulation. Phosphorylation by protein kinase A of specific serine residues on Rad decreases its affinity for β subunits and relieves constitutive inhibition of CaV1.2, observed as an increase in channel open probability. Expression of Rad or its homologue Rem in HEK293T cells also imparts stimulation of CaV1.3 and CaV2.2 by protein kinase A, revealing an evolutionarily conserved mechanism that confers adrenergic modulation upon voltage-gated calcium channels.

DOI: 10.1038/s41586-020-1947-z

Source: https://www.nature.com/articles/s41586-020-1947-z

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
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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