来自N端PAC1R替代拼接的修改联体选择性的结构基础
Jessica J Lu1,2, Giuseppe Deganutti3, Miaomiao Li1,2
1Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
概括
pituitary adenyl cyclase-activating polypeptide 1 receptor (PAC1R) 的短变体 (PAC1sR) 由于其细胞外域 (ECD) 的结构差异与零变体 (PAC1nR) 相比,显示出增强的VIP活性. 这种拼接会影响连接体结合和G蛋白信号传递.
科学领域:
- 分子药理学分子药理学
- 结构生物学是结构生物学.
- G蛋白结合受体研究研究
背景情况:
- pituitary adenyl cyclase-activating polypeptide 1受体 (PAC1R) 是一个由PACAP和VIP激活的B1类GPCR.
- 交替拼接生成具有不同功能特性的PAC1R短 (PAC1sR) 和零 (PAC1nR) 变体.
- 了解ECD拼接如何影响PAC1R功能和连接体选择性至关重要.
研究的目的:
- 从药理上描述和从结构上阐明PAC1sR和PAC1nR之间的功能差异.
- 调查PACSR增强VIP活动的机制基础.
- 了解 ECD 拼接对 PAC1R 配体参与和下游信号的影响.
主要方法:
- 综合功能测试以评估PAC1sR和PAC1nR激活的信号结果.
- 低温电子显微镜 (Cryo-EM) 用于确定与VIP结合的PAC1sR和PAC1nR的结构.
- 分子动力学 (MD) 模拟来分析连接体-受体和受体-G蛋白相互作用.
主要成果:
- 与PAC1nR相比,VIP,但不是PACAP,在各种功能终点中在PAC1sR表现出全球增强的活动.
- 冷-EM结构显示,PAC1nR在PAC1sR中缺少暂时的零循环参与,影响VIP结合.
- MD模拟预测了差异性的Gs蛋白相互作用,表明PAC1sR.在VIP亲和力上具有更大的全osteric影响.
结论:
- PAC1R ECD拼接显著改变了VIP活动和信号配置文件.
- 结构上的差异,特别是PAC1nR中的零循环相互作用,是PAC1sR和PAC1nR之间的功能分歧的基础.
- 这项研究提供了关于PAC1R连接体选择性和信号的结构性见解,由替代拼接驱动.
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