TR2 nuclear receptor in vitamin A signaling

这个项目的长期目标是了解维生素A信号是如何被孤核蛋白调节的。 受体属于TR 2和TR 4家族。以前的研究主要集中在 TR 2包括i）直接募集辅阻遏物如组蛋白脱乙酰酶（HDAC），受体相互作用 蛋白140（RIP 140）和SMRT（活性机制），和ii）与RA受体（RAR）竞争， 维甲酸X受体（RXR）的DNA结合（被动机制）。 基于最近的研究，该更新建议关注新的配体非依赖性信号通路 能够改变TR 2和TR 4的性质和活性，从而调节RAR| 32、cyclin D1和apoE 基因.将检验三个假设：i）TR 2和TR 4的生物学活性可由蛋白质调节， 修饰（生化因子）及其与辅调节因子（动力学因子）的相互作用，ii） 生理相关的受体活性通过它们与，或募集， 特异性共调节子结合到靶基因的调节区上（动态因子），和iii）配体- 独立激活的受体复合物可以促进靶基因的染色质重塑以激活 转录。目的我将通过研究配体的机制来解决第一和第二个假设- 通过蛋白质修饰引起的受体活性的独立调节（使用蛋白质组学 方法），影响：i）受体的生化性质，ii）受体的一般性质，iii）受体- 共调节因子相互作用动力学和iv）TR 2和TR 4共调节因子复合物对靶基因的动力学。目的 II将通过操纵TR 2和TR 4在生理相关的细胞培养中解决第三个假设， 并测定其修饰对靶基因的影响。待检查的生物效应 包括共调节复合物的形成和染色质构象的改变（重塑），或 靶基因启动子（RAR）上的组蛋白修饰|32、细胞周期蛋白Dl和apoE）及其生物学 在P19细胞周期进程中的活性以及靶基因的转录效率。结果从两个在 体外（aim 1）和体内（aim 2）系统将被整合，以构建一个全面的概述， 这些孤儿受体调节维生素A信号通路的机制， 特别是关于由受体的蛋白质修饰产生的信号。

The long-term goal of this project is to understandhow vitamin A signaling is modulated by orphannuclear receptors belonged to the TR2 and TR4 family. Previous studiesfocused on the repressive mechanisms of TR2 that include i) directly recruitingco-repressors like histone deacetylases (HDACs), receptor interacting protein 140 (RIP140) and SMRT (an active mechanism), and ii) competing with RA receptors (RARs) and retinoid X receptor (RXR) for DNA binding (a passive mechanism).By extending from these conclusions and based upon recent studies, this renewal proposal focuses on novel ligand-independent signaling pathways that can modify the property and activity of TR2 and TR4 for the regulation of RAR|32, cyclin D1 and apoE genes. Three hypotheses will be tested: i) the biological activity of TR2 and TR4 can be modulated by protein modification (biochemical factors) and their interaction with coregulators (kinetic factors), ii) the physiologically relevant receptor activity is manifested through their interaction with, or recruitment of, specific coregulators onto the regulatory region of the target gene (dynamic factors), and iii)the ligand- independently activated receptor complex can contribute to chromatin remodeling of target gene to activate transcription. Aim I will address the first and second hypotheses by examining the mechanisms of ligand- independent modulation of receptor activity elicited through protein modifications (using a proteomic approach) that affect: i) the biochemical nature of receptors, ii) the general property of receptors, iii) receptor- coregulator interaction kinetics and iv) dynamics of TR2 and TR4 coregularory complex on target genes. Aim II will address the third hypothesis in physiologically relevant cell cultures by manipulatingTR2 and TR4, and determiningthe effects of their modification on target genes. The biological effects to be examined include the formation of coregulatory complexes and alteration in chromatin conformation (remodeling) or histone modification on the target gene promoters (RAR|32, cyclin Dl and apoE) and theirbiological activities in P19 cell cycle progression as well as transcription efficiency of target genes. Results from both in vitro (aim 1) and in vivo (aim 2) systems will be integrated to construct a comprehensive overview of the mechanisms underlyingthe modulation of vitamin A signalingpathways by these orphan receptors, specifically with respect to signals generated from protein modifications of receptors.