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 脆性X智力低下蛋白。FMRP是RNA结合蛋白 发现于一种叫做信使核糖核蛋白的大的RNA-蛋白质复合物中 （mRNP）颗粒。FMRP主要位于细胞质中，但穿梭于 从细胞核中释放出来所有这些功能-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， 通过磷酸化来调节。在大鼠脑的制备中， 有证据表明，刺激组1代谢型谷氨酸受体 （mGluRs）增加啮齿动物FMRP（Fmrp）的表达。我们认为mGluR 激活激酶的刺激导致Fmrp磷酸化， 含有mRNP以调节其功能。我们将描述的作用， 通过使用转染的细胞系， 纯化的重组Fmrp和神经元培养物，具体目的如下： 1.研究酪氨酸磷酸化对细胞内 定位、RNA结合和蛋白质-蛋白质相互作用。 2.鉴定使Fmrp磷酸化的丝氨酸/苏氨酸激酶并表征 这种磷酸化在细胞内定位、RNA结合 以及Fmrp的蛋白-蛋白相互作用。 3.表征m-GluR-刺激对含有M-GluR的mRNP的影响。 FmrI mRNA。了解磷酸化如何影响Fmrp功能， 特别是对大脑中受体刺激的反应， 了解FMRP的正常功能，以及它的缺乏如何导致 智力迟钝。

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.