Translation regulation by molecular switch RNA-binding protein LARP1

这项研究计划的目标是揭示RNA结合蛋白的分子机制 (RBP)调控基因表达的决定性阶段，翻译。为了维持体内平衡， 途径通过RBP传递有关其环境的信息来指导细胞的翻译输出; RBP最终抑制或刺激相关mRNA的翻译，这取决于细胞是否 需要它所编码的蛋白质产物在分子水平上，信号通过RBP构象传递。 从细微到大规模的变化。这种变化改变RBP表面化学和形状， 增强或减弱它们与RNA和其他蛋白质的相互作用。这些移动的分子 相互作用将RNA分流到适当的途径：翻译，储存或衰变。一些限制性商业惯例可以指导 将RNA靶向相反的端点，从而充当分子开关。令人惊讶的是，指导原则 令人惊讶的是，细胞的这些基本决定没有得到充分的研究。 RBP与其靶RNA的特异性和非特异性相互作用在几个水平上是可调的。 首先，大多数RBP具有多个RNA结合结构域（RBD），它们的相对方向保持不变 通过接头区域，并且可以基于RNA和蛋白质结合伴侣而改变。第二，大多数限制性商业惯例 来自描述细胞环境的信号通路的输入，并作为响应，启动基因 表达变化;不同的途径最终导致不同的翻译后修饰（PTM）， 通过相同的RBP导致不同的翻译结果。第三，RNA接受共转录和转录后转录， 向其RBP伙伴发出各种信息的修饰;这些标记可以由此诱导RBP 构象变化，改变相互作用物和翻译结果。这些信号之间的相互作用 输入和翻译输出并不很清楚。我们建议使用RBP La相关蛋白1 （LARP 1）作为用于理解细胞如何整合来自多RBD RBP，PTM， 和转录后mRNA修饰以指导特定转录物的翻译。 我们将使用生物化学，生物物理学和结构生物学来解决这些基本问题， 翻译调节我们将研究三个LARP 1 RBD-两个由400个氨基酸分开， 一级结构-通过空间传递它们的结合状态，以调节相关的翻译。 成绩单我们还将研究翻译后修饰如何影响RNA和蛋白质结合 LARP 1的活性，以管理不同类别的mRNA的翻译。由于LARP 1识别co-和 转录后RNA修饰，我们还将利用这个系统来了解RBP如何响应 RNA靶点的信息来调整结构-功能关系。我们的工作将推动LARP 1生物学 向前发展，也产生概念上的进步，适用于许多，如果不是全部，翻译监管机构限制性商业惯例。

The goal of this research program is to uncover the molecular mechanisms underlying RNA-binding protein (RBP) regulation of the decisive stage of gene expression, translation. To maintain homeostasis, signaling pathways direct the cell’s translational output by relaying information about its environment through RBPs; RBPs ultimately repress or stimulate the translation of associated mRNAs depending on whether the cell needs the protein product it encodes. At the molecular level, signals are transduced by RBP conformational changes, ranging from subtle to large-scale. Such changes alter RBP surface chemistry and shape, in turn strengthening or weakening their interactions with RNA and other proteins. These shifting molecular interactions shunt RNAs down the appropriate pathway: translation, storage, or decay. Some RBPs can guide target RNAs to opposing endpoints, thereby acting as molecular switches. Surprisingly, the principles guiding such fundamental decisions by the cell are surprisingly understudied. The specific and nonspecific interactions that RBPs have with their target RNAs are tunable on several levels. First, most RBPs have multiple RNA-binding domains (RBDs), the relative orientations of which are maintained by linker regions and can change based on RNA and protein binding partners. Second, most RBPs receive input from signaling pathways that describe the cellular environment and, in response, actuate gene expression changes; different pathways culminate in different post-translational modifications (PTMs) that can lead to divergent translational outcomes via the same RBP. Third, RNAs receive co- and post-transcriptional modifications that signal various messages to their RBP partners; these marks can thereby induce RBP conformational change, altering interactors and translational outcome. The interplay among these signaling inputs and translational output is not well understood. We propose to use the RBP La-related protein 1 (LARP1) as a model system for understanding how cells integrate information from multi-RBD RBPs, PTMs, and post-transcriptional mRNA modifications to direct the translation of specific transcripts. We will use biochemistry, biophysics, and structural biology to address these fundamental questions of translation regulation. We will examine how the three LARP1 RBDs—two separated by 400 amino acids in primary structure—communicate their binding statuses through space to regulate the translation of associated transcripts. We will also investigate how post-translational modifications affect the RNA- and protein-binding activities of LARP1 to manage the translation of distinct classes of mRNAs. Since LARP1 recognizes co- and post-transcriptional RNA modifications, we will also utilize this system to understand how RBPs respond to information from RNA targets to adjust structure-function relationships. Our work will propel LARP1 biology forward and also yield conceptual advances that are applicable to many, if not all, translation regulator RBPs.