Regulation of mRNA Partitioning to the Endoplasmic Reticulum

描述(申请人提供)：在现代模型中，真核细胞分离合成不同类别的蛋白质；分泌/整合膜蛋白质在内质网(ER)上产生，可溶蛋白质在胞浆中产生。然而，最近对胞浆和内质网之间的mRNA分配的研究发现，内质网在合成可溶性和分泌/膜蛋白方面都具有显著的作用。除了描述内质网在全球蛋白质合成中的新功能外，这些发现还发现了我们在理解真核细胞如何在两个隔室之间分配mRNAs并进而调节这两大类蛋白质的合成方面的一个重大差距。为了解决这一差距，我们的研究重点是：1)了解真核细胞如何在胞浆和内质网(ER)之间划分mRNAs；2)确定真核细胞如何在稳态和细胞应激期间调节胞浆和内质网的蛋白质合成活性。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。我们提出了三个具体的目标：1)明确SRP通路在内质网信使核糖核酸分配中的作用；2)确定给予内质网非规范信使核糖核酸分配的信使定位信号；3)确定内质网在胞浆蛋白合成中的整体作用。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、报告基因原位定位的细胞生物学分析以及提供内质网定位的mRNAs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，都会激活细胞应激反应，从而深刻改变细胞合成的蛋白质的类型和数量，从而影响细胞的活力。通过了解细胞如何在健康和疾病中决定每种蛋白质的哪些和多少，我们将了解细胞用来应对病理性应激的基本机制。通过了解这些机制，我们希望为治疗干预找到新的靶点。

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.