Understanding the regulation of ER GPATs to control glycerolipid synthesis in disease

项目摘要 细胞依赖于脂肪酸来产生膜和储存能量。在细胞内， 脂肪酸通过一系列代谢酶结合到膜上并储存甘油脂。的 这一过程对人类健康和疾病的重要性突出表现在许多代谢性疾病 其特征是功能失调的脂质积累。尽管从脂肪合成甘油脂质的重要性 酸的细胞内稳态和人类疾病，相对较少的了解变构机制， 规范和控制这个过程。 使用CRISPR基因筛选和无偏见的脂质组学，Birsoy实验室最近发现了钙调神经磷酸酶B 同源蛋白1（CHP 1）作为内质网（ER）甘油脂合成的新调节剂。在这 最近发表的研究，我们的实验室表明，损失了CHP 1严重钝化脂肪酸的掺入和储存 在哺乳动物细胞和无脊椎动物模式生物中。从机制上讲，我们的实验室证明， 通过激活ER GPAT，GPAT 4，甘油脂质的初始限速酶， 在ER中合成。CHP 1激活GPAT 4的机制是直接的，因为发现CHP 1 和GPAT 4形成复合物。这项工作确定CHP 1是为数不多的甘油脂合成调控蛋白之一 描述到目前为止。我们相信可能存在其他这样的调节机制来控制脂质代谢。 这项提议旨在更深入地了解我们在前期工作中发现的新生物学， 发现ER GPAT活性和功能的其他调节剂。在目标1中，我们试图理解精确的 CHP1结合并激活GPAT4的机制。这将提供深入了解翻译后 调节脂质代谢，并指导未来类似于CHP 1的其他机制的研究。在目标2中，我们 利用我们最近产生的一种新的小鼠模型来研究ER GPAT在体内稳态和 疾病如NASH。在目标3中，我们试图确定调节ER驻留GPAT 4的其他机制。 通过无偏见的基因筛选和蛋白质组学方法。将基础生物化学跨越到小鼠 建模，这个应用程序将解决突出的基本问题，在细胞代谢和理解 这种生物学在折磨人类的复杂疾病的背景下。本文提出的创新研究 申请除了个性化的培训计划，将提供严格的博士后培训，将准备 让我成为一名独立调查员

PROJECT SUMMARY Cells are dependent on fatty acids for the generation of membranes and the storage of energy. Within the cell, fatty acids incorporate into membrane and storage glycerolipids through a series of metabolic enzymes. The importance of this process to human health and disease is highlighted by the fact that many metabolic diseases are characterized by dysfunctional lipid accumulation. Despite the importance of glycerolipid synthesis from fatty acids cellular homeostasis and human disease, relatively little is known about the allosteric mechanisms that regulate and control this process. Using CRISPR genetic screens and unbiased lipidomics, the Birsoy lab recently identified calcineurin B homologous protein 1 (CHP1) as a novel regulator of endoplasmic reticulum (ER) glycerolipid synthesis. In this recently published study, our lab showed that loss off CHP1 severely blunted fatty acid incorporation and storage in mammalian cells and invertebrate model organisms. Mechanistically, our lab demonstrated that CHP1 controls glycerolipid synthesis by activating the ER GPAT, GPAT4, the initial rate limiting enzyme for glycerolipid synthesis within the ER. The mechanism by which CHP1 activates GPAT4 is direct, as it was found that CHP1 and GPAT4 form a complex. This work identified CHP1 as one of few regulatory proteins of glycerolipid synthesis described to date. We believe other such regulatory mechanisms control lipid metabolism likely exist. This proposal seeks to more deeply understand the novel biology discovered in our preliminary work and discover additional regulators of ER GPAT activity and function. In Aim 1, we seek to understand the precise mechanism by which CHP1 binds and activates GPAT4. This will provide insight into the posttranslational regulation of lipid metabolism and guide future study of other mechanisms analogous to CHP1. In Aim 2, we will utilize a novel mouse model we recently generated to study ER GPAT function in vivo in both homeostasis and disease such as NASH. In Aim 3, we seek to identify additional mechanisms regulating ER resident GPAT4 through unbiased genetic screening and proteomic approaches. Spanning basic biochemistry to mouse modeling, this application will address outstanding fundamental questions in cellular metabolism and understand this biology in the context of complex diseases afflicting humankind. The innovative studies proposed in this application in addition to the personalized training plan, will provide rigorous postdoctoral training that will prepare me to become an independent investigator.