Role of very long chain fatty acids in protein quality control and membrane homeostasis

极长链脂肪酸在蛋白质质量控​​制和膜稳态中的作用

• 批准号: 10456096
• 负责人: John W Hanna
• 金额: $ 35.8万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10456096
• 关键词: Acyl Coenzyme A; Address; Area; Cells; Cellular biology; Ceramides; Coenzyme A; Complex; Conceptions; Data; Defect; Development; Diabetes Mellitus; Diazepam Binding Inhibitor; Disease; Drosophila genus; Endoplasmic Reticulum; FAT gene; Functional disorder; Genes; Homeostasis; Insulin Resistance; Lead; Lecithin; Ligase; Lipids; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; Mediator of activation protein; Membrane; Metabolic; Neurodegenerative Disorders; Obesity; Parkinson Disease; Pathway interactions; Play; Property; Proteins; Publishing; Quality Control; Role; Signal Transduction; Stress; Structure; Testing; Thick; Toxic effect; Very Long Chain Fatty Acid; Work; Yeasts; alpha synuclein; base; biological adaptation to stress; desaturase; fascinate; fatty acid metabolism; fluidity; human disease; insight; lipid disorder; lipid metabolism; lipidomics; loss of function; luminal membrane; misfolded protein; mutant; programs; protein misfolding; proteostasis; response; sensor; synuclein

Project Summary/Abstract Cells have developed complex stress responses to identify and eliminate misfolded proteins. An exciting development in recent years has been the recognition that lipid homeostasis is critical for protein quality control. The Unfolded Protein Response (UPR) senses misfolded proteins in the endoplasmic reticulum and orchestrates a broad program of cellular remodeling to address this threat. Various defects in lipid metabolism trigger the UPR, and the UPR in turn controls the expression of some lipid metabolic genes. Furthermore, in contrast to the canonical luminal signaling mechanism for misfolded proteins, recent work indicates the presence of a second sensor pathway that detects defects in the ER membrane ("bilayer stress"). The functional properties of membranes (e.g. thickness, fluidity, curvature) are largely determined by their compositions. Far from early conceptions of membranes as static or inert structures, we now understand that membranes are highly dynamic and capable of altering their compositions in response to changing cellular conditions/needs. This proposal focuses on a poorly understood group of lipids known as very long chain fatty acids (VLCFAs) which are relatively unabundant but perform critical functions. We hypothesize that VLCFAs play key roles in protein quality control and membrane homeostasis. To inhibit VLCFA utilization, we have studied a mutant of the major VLCFA CoA synthetase, Fat1. Our preliminary data indicate that Fat1 plays an important role in ER homeostasis, and its loss triggers compensatory induction of the UPR. To understand the basis for this effect, we carried out a mass spectrometry-based lipidomic analysis. Remarkably, the fat1Δ mutant showed a dramatic increase in membrane saturation which is a known inducer of the UPR. This effect is mediated, at least in part, via partial loss of function of Ole1, the sole fatty acyl desaturase in yeast. In Aim 1, we will determine the mechanism by which VLCFAs regulate membrane homeostasis and the UPR. Recent data implicate membrane saturation as a key determinant of alpha-synuclein toxicity, which is responsible for Parkinson's disease. Our data indicate that Fat1 is an important regulator of synuclein toxicity. In Aim 2, we will determine mechanism by which VLCFAs regulate synuclein toxicity in yeast and Drosophila. Completion of this proposal is expected to provide both basic and disease-oriented mechanistic insight into this emerging but fundamental area of cell biology.

项目总结/摘要 细胞已经发展出复杂的应激反应来识别和消除错误折叠的蛋白质。一个令人兴奋 近年来的发展已经认识到脂质体内平衡对于蛋白质质量控制是关键的。 未折叠蛋白质反应（UPR）检测内质网中错误折叠的蛋白质， 一个广泛的细胞重塑计划来应对这一威胁。脂质代谢的各种缺陷触发了 UPR，而UPR反过来又控制一些脂质代谢基因的表达。此外，与 错误折叠蛋白质的典型管腔信号传导机制，最近的工作表明存在第二个 检测ER膜中的缺陷（“双层应力”）的传感器通路。的功能特性 膜的特性（例如厚度、流动性、曲率）在很大程度上由其组成决定。远远早于 将膜视为静态或惰性结构的概念，我们现在了解到膜是高度动态的 并且能够响应变化的细胞条件/需要而改变它们的组成。这项建议 重点关注一组知之甚少的脂质，称为极长链脂肪酸（VLCFAs）， 不丰富，但执行关键功能。我们假设VLCFA在蛋白质质量控制中起关键作用 和膜内稳态。为了抑制VLCFA的利用，我们研究了主要VLCFA CoA的突变体 合成酶，脂肪1。我们的初步数据表明，Fat 1在ER稳态中起着重要作用，它的丢失 触发对普遍定期审议的补偿性诱导。为了了解这种效应的基础，我们进行了一次质量分析。 基于光谱的脂质组学分析。值得注意的是，fat 1 Δ突变体显示出膜蛋白的显著增加， 饱和，这是一个已知的诱导剂的UPR。这种效应至少部分是通过部分功能丧失来介导的 Ole 1是酵母中唯一的脂肪酰去饱和酶。在目标1中，我们将确定VLCFA 调节膜稳态和UPR。最近的数据暗示膜饱和度作为一个关键的决定因素 α-突触核蛋白的毒性，这是负责帕金森氏症。我们的数据表明，Fat 1是一种 突触核蛋白毒性的重要调节剂。在目标2中，我们将确定VLCFA调节的机制， 酵母和果蝇中突触核蛋白毒性。完成这一建议，预计将提供基本的， 以疾病为导向的机制洞察这一新兴的，但细胞生物学的基本领域。