Regulation of mRNA Partitioning to the Endoplasmic Reticulum

描述（由申请人提供）：在当代模型中，真核细胞分离合成不同类别的蛋白质；分泌/整体膜蛋白由内质网（ER）和细胞质溶胶中的可溶性蛋白组成。然而，最近关于细胞质和内质网区室之间mRNA分配的研究发现，内质网在可溶性和分泌/膜蛋白的合成中都起着重要作用。除了描述内质网在整体蛋白质合成中的新功能外，这些发现还发现了我们对真核细胞如何在两个区室之间分配mrna并反过来调节这两大类蛋白质合成的理解中的一个重大空白。为了解决这一空白，我们的研究重点是1)了解真核细胞如何在细胞质溶胶和内质网（ER）之间分配mrna； 2)确定真核细胞在稳态和细胞应激过程中如何调节细胞质溶胶和内质网区室的蛋白质合成活性。这项研究有望为健康和疾病中蛋白质合成的调控机制提供重要的见解。此外，这项研究将为我们理解真核生物生命所必需的mRNA定位和蛋白质合成途径做出重大贡献。提出了三个具体目标：i)确定SRP途径在mRNA向内质网分配中的体内作用；ii)确定将非规范mRNA分配给内质网的mRNA定位信号；iii)确定内质网室在胞质蛋白合成中的全局作用。为了解决这些特定的目标，我们将使用哺乳动物组织培养细胞模型，并将强调已建立的细胞分离生化技术，报告mRNA原位定位的细胞生物学分析以及赋予ER定位的mRNA结构/功能元件的分子生物学分析。许多突出的人类疾病，包括肥胖、糖尿病和中风，会激活细胞应激反应，从而深刻地改变细胞合成蛋白质的类型和数量，从而影响细胞的生存能力。通过了解细胞如何决定在健康和疾病中制造哪种蛋白质以及制造多少蛋白质，我们将了解细胞对病理性压力作出反应的基本机制。通过了解这些机制，我们希望确定治疗干预的新靶点。

DESCRIPTION (provided by applicant): In contemporary models, eukaryotic cells segregate the synthesis of different classes of proteins; secretory/integral membrane proteins are made on the endoplasmic reticulum (ER) and soluble proteins in the cytosol. Recent studies of mRNA partitioning between the cytosol and ER compartments have, however, identified a prominent role for the ER in the synthesis of both soluble and secretory/membane proteins alike. In addition to describing new functions for the ER in global protein synthesis, these findings identify a significant gap in our understanding of how eukaryotic cells partition mRNAs between the two compartments and in turn regulate the synthesis of these two broad classes of proteins. To address this gap, we are focusing our research efforts to 1) understand how eukaryotic cells partition mRNAs between the cytosol and the endoplasmic reticulum (ER) and 2) determine how eukaryotic cells regulate the protein synthesis activity of the cytosol and ER compartments during homeostasis and cell stress. This research is expected to provide significant insights into the regulatory mechanisms governing protein synthesis in health and disease. In addition, this research will serve as a significant contribution to our understanding of the mRNA localization and protein synthesis pathways that are essential to eukaryotic life. Three specific aims are proposed: i) Define the in vivo role of the SRP pathway in mRNA partitioning to the ER; ii) Identify the mRNA localization signals that confer non-canonical mRNA partitioning to the ER and iii) Define the global role of the ER compartment in cytosolic protein syntehsis. To address these specific aims, we will use mammalian tissue culture cell models and will emphasize established biochemical techniques of cell fractionation, cell biological analysis of reporter mRNA localization in situ and molecular biological analysis of the structure/function elements of mRNAs that confer ER localization. Many prominent human diseases, including obesity, diabetes and stroke activate cell stress responses that profoundly alter the types and amounts of proteins cells synthesize and consequently, cell viability. By understanding how cells decide which and how much of each protein to make, in health and disease, we will understand the basic mechanisms used by cells to respond to pathological stress. By understanding these mechanisms, we hope to identify new targets for therapeutic intervention.