Regulation of GnRH receptor signaling by lipid rafts

性状（由申请方提供）：促性腺激素释放激素（GnRH）通过与垂体促性腺激素表面的同源受体结合并刺激促黄体激素和促卵泡激素的合成和分泌来发挥其生物学作用。在分子水平上，GnRH受体的参与启动了一系列复杂的信号传导事件，包括促分裂原活化蛋白激酶（MAPK）途径的激活;这种激活是诱导促性腺激素功能所必需的几个基因所必需的。因此，了解GnRH诱导的MAPK信号转导的调节在生殖内分泌学中具有重要意义。调节信号传导途径的一种机制涉及信号分子通过与称为脂筏的专门质膜结构域结合而进行的亚细胞区室化。脂筏是富含胆固醇和鞘脂的膜结构域，具有独特的生物物理特性，已被证明可作为多蛋白信号复合物组装的平台。在这里，我们提供了初步的证据表明，GnRH受体以及关键的MAPK信号分子与脂筏在鼠α T3 -1促性腺细胞系。该建议概述了一组实验，旨在测试的假设，脂筏调节促性腺激素释放激素诱导的MAPK信号，促进可定义的MAPK信号模块的区室化组装。我们将使用各种生物化学，分子和细胞生物学技术来研究脂筏在α T3 -1细胞以及初级分化的小鼠促性腺激素细胞中GnRH诱导的MAPK信号传导中的作用。

DESCRIPTION (provided by applicant): Gonadotropin-releasing hormone (GnRH) exerts its biological effects by binding to its cognate receptor on the surface of pituitary gonadotropes and stimulating the synthesis and secretion of luteinizing hormone and follicle-stimulating hormone. At the molecular level, engagement of the GnRH receptor initiates a complex series of signaling events including activation of the mitogen-activated protein kinase (MAPK) pathways; this activation is required for the induction of several genes essential for gonadotrope function. Understanding the regulation of GnRH-induced MAPK signaling is thus of great importance in reproductive endocrinology. One mechanism by which signaling pathways are regulated involves subcellular compartmentalization of signaling molecules through their association with specialized plasma membrane domains called lipid rafts. Lipid rafts are cholesterol and sphingolipid rich membrane domains with distinct biophysical properties that have been shown to function as platforms for the assembly of multi-protein signaling complexes. Here we provide preliminary evidence that the GnRH receptor as well as key MAPK signaling molecules are associated with lipid rafts in the murine alphaT3-1 gonadotrope cell line. This proposal outlines a set of experiments designed to test the hypothesis that lipid rafts regulate GnRH-induced MAPK signaling in gonadotropes by facilitating the compartmentalized assembly of definable MAPK signaling modules. We will use a variety of biochemical, molecular, and cell-biological techniques to study the role of lipid rafts in GnRH-induced MAPK signaling both in alphaT3-1 cells, as well as in primary differentiated mouse gonadotropes.