Distinct profiles of functional discrimination among G proteins determine the actions of G protein-coupled receptors.
Distinct profiles of functional discrimination among G proteins determine the actions of G protein-coupled receptors.
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DOI：
10.1126/scisignal.aab4068
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发表时间：
2015-12-01
影响因子：
7.3
通讯作者：
Martemyanov KA
中科院分区：
文献类型：
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作者：
Masuho I;Ostrovskaya O;Kramer GM;Jones CD;Xie K;Martemyanov KA
G蛋白偶联受体家族的成员在许多生理功能中发挥着关键作用，并已被广泛用于治疗疾病。单个GPCRs通过激活异源三聚体G蛋白对细胞生理和信号转导产生不同和不同的影响。哺乳动物基因组编码16个不同的G蛋白α亚基，每个亚基都有不同的特性。在这里，我们开发了一种单一平台的光学策略来直接监测活细胞中G蛋白的激活，并使用它来描述一系列不同G蛋白中单个GPCR的活动，同时量化它们的信号和激活率的大小。我们报告说，GPCRs以不同的效率和动力学与多个G蛋白结合，产生定义单个受体的指纹图谱。我们发现，不同类别的GPCR配体，包括完全和部分激动剂、变构调节剂和拮抗剂，都明显地影响这些指纹，从而在功能上偏向GPCR信号。最后，我们发现细胞内信号调节剂进一步改变了GPCRs的G蛋白偶联轮廓，这表明它们的差异表达可能以细胞特有的方式改变信号结果。。这些观察表明，GPCRs对细胞生理学影响的多样性可能是由它们对具有不同信号幅度和激活动力学的多个G蛋白的不同参与决定的，这些特性可以被药理学利用。
Members of the G protein coupled receptor (GPCR) family play key roles in many physiological functions and have been extensively exploited pharmacologically to treat diseases. Individual GPCRs exert diverse and distinct effects on cellular physiology and transduce signals by activating heterotrimeric G proteins. Mammalian genomes encode 16 different G protein alpha subunits, and each one of them has distinct properties. Here, we developed a single-platform, optical strategy for the direct monitoring of G protein activation in live cells, and using it we profiled the activities of individual GPCRs across a range of different G proteins, simultaneously quantifying both magnitude of their signaling and activation rates. We report that GPCRs engage multiple G proteins with varying efficacy and kinetics, generating fingerprint-like profiles that define individual receptors. We found that different classes of GPCR ligands, including full and partial agonists, allosteric modulators, and antagonists distinctly affected these fingerprints to functionally bias GPCR signaling. Finally, we showed that intracellular signaling modulators further altered the G protein–coupling profiles of GPCRs, which suggests that their differential expression may alter signaling outcomes in a cell-specific manner. . These observations suggest that the diversity of the effects of GPCRs on cellular physiology may be determined by their differential engagement of multiple G proteins with varying signal magnitudes and activation kinetics, properties that may be exploited pharmacologically.