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

项目概要 细胞依赖脂肪酸来产生细胞膜和储存能量。在细胞内， 脂肪酸通过一系列代谢酶融入膜和储存甘油脂中。的 许多代谢性疾病都强调了这一过程对人类健康和疾病的重要性 其特点是脂质蓄积功能失调。尽管从脂肪合成甘油脂很重要 酸细胞稳态和人类疾病，但人们对酸的变构机制知之甚少。 调节和控制这个过程。 Birsoy 实验室最近利用 CRISPR 基因筛选和无偏脂质组学鉴定出钙调神经磷酸酶 B 同源蛋白 1 (CHP1) 作为内质网 (ER) 甘油脂合成的新型调节剂。在这个 最近发表的研究表明，CHP1 的丢失严重削弱了脂肪酸的掺入和储存 在哺乳动物细胞和无脊椎动物模型生物中。从机制上讲，我们的实验室证明 CHP1 控制 通过激活 ER GPAT、GPAT4（甘油脂的初始限速酶）合成甘油脂 ER 内合成。 CHP1 激活 GPAT4 的机制是直接的，因为发现 CHP1 和GPAT4形成复合物。这项工作确定 CHP1 是甘油脂合成的少数调节蛋白之一 迄今为止所描述的。我们相信其他此类控制脂质代谢的调节机制可能存在。 该提案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因子。在目标 1 中，我们寻求了解准确的 CHP1 结合并激活 GPAT4 的机制。这将提供对翻译后的深入了解 脂质代谢的调节并指导未来与 CHP1 类似的其他机制的研究。在目标 2 中，我们将 利用我们最近生成的新型小鼠模型来研究 ER GPAT 在体内稳态和 NASH 等疾病。在目标 3 中，我们寻求确定调节 ER 驻留 GPAT4 的其他机制 通过公正的基因筛查和蛋白质组学方法。从基础生物化学到小鼠 建模，该应用程序将解决细胞代谢中突出的基本问题并理解 这种生物学在困扰人类的复杂疾病的背景下。本论文提出的创新性研究 申请除了个性化的培养计划外，还将提供严格的博士后培训，为您做好准备 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.