Analysis of Lipolytic Trafficking in Adipocytes.

项目摘要/摘要 细胞中性脂代谢紊乱促进肥胖、糖尿病、脂肪肝的进展 疾病和癌症。该项目的长期科学目标是了解分子机制。 控制脂质储存和动员，以确定新的治疗干预点。 ABHD5调节细胞脂代谢，包括限速甘油三酯脂肪酶PNPLA2/ATGL 在关键的代谢组织中。然而，ABHD5，一种缺乏酶活性的蛋白质， 激活PNPLA2(和其他PNPLA)仍然是一个重要的谜团。 我们推测，生物膜的重塑是ABHD5的一般机制 调节酶对膜分隔的中性脂质底物的访问。从机制上讲，我们假设 配体结合稳定靶向并改变膜的ABHD5分子和大分子构象 生物物理性质(张力和曲率)允许脂肪酶进入特定的底物隔离 在脂滴(LDs)内。我们将使用ABHD5和信息性的新型化学探针来验证这一假设 活脂肪细胞中的基因突变(目标1)。我们将直接评估ABHD5对生物物理的影响 使用高分辨率和高通量阵列的模型LD系统中膜的特性 方法(目标2)。这些目标旨在高度互补，并提供强大的交叉- 实验平台间的验证。 此外，我们提供的数据表明，ABHD5针对的是特定的亚细胞部位 LDS是在补充脂肪酸后形成的。此外，ABHD5与PLIN5的相互作用，由 ABHD5配体油酰辅酶A促进LD的形成。目标3将剖析由 ABHD5/PLIN5复合体，并与AIM 2合作，评估这种相互作用对生物物理的影响 模型膜的性质。 ABHD5正在成为代谢性疾病和癌症的引人注目的治疗靶点。结果是 将为ABHD5调节脂肪酸通量的具体机制提供新的见解 胞浆/LD界面。

Project Summary/Abstract Disruption of cellular neutral lipid metabolism promotes the progression of obesity, diabetes, fatty liver disease, and cancer. The long-term scientific goal of the project is to understand the molecular mechanisms that control lipid storage and mobilization in order to identify novel points for therapeutic intervention. ABHD5 regulates cellular lipid metabolism, including PNPLA2/ATGL, the rate-limiting triglyceride lipase in key metabolic tissues. Nonetheless, the mechanisms by which ABHD5, a protein lacking enzymatic activity, activates PNPLA2 (and other PNPLAs) remains an important mystery. We hypothesize that the remodeling of biological membranes is a general mechanism by which ABHD5 regulates enzyme access to membrane-delimited neutral lipid substrates. Mechanistically, we hypothesize that ligand binding stabilizes ABHD5 molecular and macromolecular conformations that target and alter membrane biophysical properties (tension and curvature) to allow the lipase access to specific substrates sequestered within lipid droplets (LDs). We will test this hypothesis using novel chemical probes of ABHD5 and informative genetic mutants in live adipocytes (Aim 1). We will directly assess the impact ABHD5 on the biophysical properties of membranes in model LD systems using an array of high resolution and high throughput approaches (Aim 2). These Aims are designed to be highly complementary and to provide strong cross- validation between experimental platforms. In addition, we present data demonstrating that ABHD5 is targeted to specific subcellular sites where LDs form upon fatty acid supplementation. Furthermore, the interaction of ABHD5 with PLIN5, driven by the ABHD5 ligand oleoyl-CoA, facilitates LD formation. Aim 3 will dissect the biochemical pathways promoted by ABHD5/PLIN5 complexes and, in concert with Aim 2, evaluate the impact of this interaction on the biophysical properties of model membranes. ABHD5 is emerging as a compelling therapeutic target for metabolic diseases and cancer. The results of this project will provide new insights into specific mechanisms by which ABHD5 regulates fatty acid flux at the cytosol/LD interface.