The N-terminus of the yeast G protein-coupled receptor Ste2p plays critical roles in surface expression, signaling, and negative regulation.
The N-terminus of the yeast G protein-coupled receptor Ste2p plays critical roles in surface expression, signaling, and negative regulation.
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DOI：
10.1016/j.bbamem.2015.12.017
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发表时间：
2016-04
期刊：
影响因子：
--
通讯作者：
Becker JM
中科院分区：
文献类型：
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作者：
Uddin MS;Hauser M;Naider F;Becker JM
G蛋白偶联受体（GPCR）在迄今为止检测的所有真核细胞中均被发现，其中它们作为膜结合蛋白发挥功能，所述膜结合蛋白结合大量细胞外配体以启动控制细胞生理学的细胞内信号转导系统。GPCR具有七个七螺旋跨膜结构域，其通过细胞外和细胞内环与细胞外N-末端和细胞内C-末端连接。N-末端是大多数GPCR中研究最少的结构域。酵母Ste 2 p蛋白是十三个氨基酸组成的肽类信息素α-因子的受体，已被广泛用作研究GPCR结构和功能的模型。在这项研究中，我们构建了一些删除的Ste 2 p N-末端，并发现了一个意想不到的功能，作为一个负调控域。我们研究了N-末端在表达、信号传导功能和配体结合特性中的作用，发现残基11-30在细胞表面上的受体表达中起关键作用。研究还表明，N-末端的残基2-10参与信号传导的负调控，如通过观察这些残基的缺失增强交配和基因诱导所示。此外，我们的结果表明残基21-30对于最佳信号传导是必需的。总体而言，我们建议，N-末端的Ste 2 p在控制受体功能中起着多种调节作用。
G protein-coupled receptors (GPCRs) are found in all eukaryotic cells examined to date where they function as membrane-bound proteins that bind a multitude of extracellular ligands to initiate intracellular signal transduction systems controlling cellular physiology. GPCRs have seven heptahelical membrane spanning domains connected by extracellular and intracellular loops with an extracellular N-terminus and an intracellular C-terminus. The N-terminus has been the least studied domain of most GPCRs. The yeast Ste2p protein, the receptor for the thirteen amino acid peptide pheromone α-factor, has been used extensively as a model to study GPCR structure and function. In this study we constructed a number of deletions of the Ste2p N-terminus and uncovered an unexpected function as a negative regulatory domain. We examined the role of the N-terminus in expression, signaling function and ligand-binding properties and found that the residues 11-30 play a critical role in receptor expression on the cell surface. The studies also indicated that residues 2-10 of the N-terminus are involved in negative regulation of signaling as shown by the observation that deletion of these residues enhanced mating and gene induction. Furthermore, our results indicated that the residues 21-30 are essential for optimal signaling. Overall, we propose that the N-terminus of Ste2p plays multiple regulatory roles in controlling receptor function.