Role of phosphorylation on FMRP function

描述(由申请人提供)： 脆性X智力低下是由于缺乏表达 脆性X智力低下蛋白。FMRP是一种RNA结合蛋白 发现于一种称为信使核糖核蛋白的大型RNA-蛋白质复合体中 (MRNP)粒子。FMRP主要位于细胞质中，但穿梭于 走出了原子核。所有这些功能--核转位，RNA 结合和蛋白质-蛋白质相互作用-已经在其他系统中显示出 通过磷酸化来调节。在从老鼠脑中提取的制剂中，有 有证据表明，刺激第1组代谢性谷氨酸受体 (MGluRs)增加啮齿动物FMRP(FMRP)的表达。我们建议mGluR 刺激激活了激酶，导致了FMRP的磷酸化 含有-mRNP以调节其功能。我们将描述其角色 通过使用转基因细胞系对FMRP功能进行磷酸化， 纯化的重组FMRP和神经元培养具有以下特定目的： 1.检测酪氨酸磷酸化在细胞内的作用 FMRP的定位、RNA结合和蛋白质-蛋白质相互作用。 2.鉴定可磷酸化FMRP的丝氨酸/苏氨酸激酶 这种磷酸化在细胞内定位、RNA结合中的作用 以及FMRP的蛋白质-蛋白质相互作用。 3.表征m-Glur刺激对含有 FMRI基因的表达。了解磷酸化如何影响FMRP功能， 尤其是对大脑中的受体刺激的反应，会给 深入了解FMRP的正常功能，以及它的缺失如何导致 精神发育迟滞。

DESCRIPTION (provided by applicant): Fragile X mental retardation is caused by the absence of expression of the Fragile X Mental Retardation Protein, FMRP. FMRP is an RNA binding protein found in a large, RNA-protein complex called a messenger ribonucleoprotein (mRNP) particle. FMRP is located primarily in the cytoplasm but shuttles into and out of the nucleus. All of these functions - nuclear translocation, RNA binding, and protein-protein interactions - have been shown in other systems to be modulated by phosphorylation. In preparations from rat brain, there is evidence that stimulation of the group 1 metabotropic glutamate receptors (mGluRs) increases expression of rodent FMRP (Fmrp). We propose that mGluR stimulation, which activates kinases, results in the phosphorylation the Fmrp containing-mRNP to modulate its function. We will characterize the role of phosphorylation on Fmrp function through the use of transfected cell lines, purified recombinant Fmrp and neuronal cultures in the following specific aims: 1. Examine the role of tyrosine phosphorylation on the intracellular localization, RNA binding, and protein-protein interactions of Fmrp. 2. Identify serine/threonine kinases that phosphorylate Fmrp and characterize the role of this phosphorylation on the intracellular localization, RNA binding and protein-protein interactions of Fmrp. 3. Characterize the effect of m-GluR-stimulation on the mRNP containing the FmrI mRNA. Understanding how phosphorylation affects Fmrp function, particularly in response to receptor stimulation in the brain, will give insight into the normal function of Fmrp, as well as how its absence leads to mental retardation.