受体活性调节蛋白(RAMPs)是与特定G蛋白偶联受体(GPCRs)形成复合物并调节其功能的辅助分子。已经确定RAMP与GPCRs的胰高血糖素受体家族相互作用,但是对其潜在机制知之甚少。在这项研究中,我们使用生物发光共振能量转移(BRET)方法来全面研究这种相互作用。结合cAMP积累,Gαq激活和β-arrestin1/2募集测定,我们不仅验证了以前报道的GPCR-RAMP对,而且还确定了GPCR-RAMP相互作用的新模式。虽然RAMP1能够修饰胰高血糖素受体(GCGR)和胰高血糖素样肽-1受体(GLP-1R)引起的三个信号事件,RAMP2主要影响GCGR招募β-arrestin1/2,GLP-1R和胰高血糖素样肽-2受体,除了涵盖这三种途径的生长激素释放激素受体外,RAMP3对所有家庭成员都显示出广泛的负面影响。我们的结果表明,RAMP以受体特异性方式调节胰高血糖素受体家族成员之间的G蛋白依赖性和非依赖性信号转导。映射这种相互作用提供了对RAMP在配体识别和受体激活中的作用的新见解。
Receptor activity-modulating proteins (RAMPs) are accessory molecules that form complexes with specific G protein-coupled receptors (GPCRs) and modulate their functions. It is established that RAMP interacts with the glucagon receptor family of GPCRs but the underlying mechanism is poorly understood. In this study, we used a bioluminescence resonance energy transfer (BRET) approach to comprehensively investigate such interactions. In conjunction with cAMP accumulation, Gα q activation and β-arrestin1/2 recruitment assays, we not only verified the GPCR-RAMP pairs previously reported, but also identified new patterns of GPCR-RAMP interaction. While RAMP1 was able to modify the three signaling events elicited by both glucagon receptor (GCGR) and glucagon-like peptide-1 receptor (GLP-1R), and RAMP2 mainly affected β-arrestin1/2 recruitment by GCGR, GLP-1R and glucagon-like peptide-2 receptor, RAMP3 showed a widespread negative impact on all the family members except for growth hormone-releasing hormone receptor covering the three pathways. Our results suggest that RAMP modulates both G protein dependent and independent signal transduction among the glucagon receptor family members in a receptor-specific manner. Mapping such interactions provides new insights into the role of RAMP in ligand recognition and receptor activation.