Mechanism and physiology of DUF1222-assisted lipase maturation

描述（由申请方提供）：描述：脂蛋白脂肪酶（LPL）水解三酰甘油对正常脂质代谢至关重要。LPL没有新鉴定的跨膜蛋白脂肪酶成熟因子（LMF 1）就不能正确折叠和发挥功能。LMF 1基本上没有特征;事实上，它属于一个具有类似“未知功能域”（Duf 1222）的蛋白质家族。本项目的主要目的是研究LPL和LMF 1之间的相互作用。通过类比与LPL的结构特征相似的脂肪酶，我们提出LMF 1作为LPL的“私人折叠酶”。在目标1中，我将使用生物化学测定和细胞测定来确定为什么LPL需要折叠辅助以及LMF 1如何帮助LPL折叠。目的2包括LMF 1的膜拓扑结构和结构的分析。最后，目标3的重点是观察到许多人类病原体具有Duf 1222蛋白;因此，我将使用计算和生物化学方法来确定Duf 1222蛋白是否代表折叠酶-脂肪酶对的一半。在指导阶段，我将建立在我的初步观察，以开发一个模型LMF 1膜拓扑结构。此外，我将开始生化和结构分析的LMF-LPL相互作用，并开始初步工作的目标3。在独立阶段，我将继续LMF 1的结构分析，并将我的生化分析扩展到其他物种中的Duf 1222蛋白，以确定它们是否在脂质代谢中起重要作用。 公共卫生相关性：心血管疾病是发达国家的主要死亡原因，血甘油三酯升高是一个危险因素。LPL缺乏导致血液三酰甘油升高并干扰整体脂质代谢。LMF 1通过一个知之甚少的过程促进LPL活性，阐明这一机制将为开始改善LPL缺陷的一个原因提供基础。

DESCRIPTION (provided by applicant): Description: Hydrolysis of triacylglycerols by lipoprotein lipase (LPL) is essential for normal lipid metabolism. LPL does not fold and function properly without a newly identified, transmembrane protein, lipase maturation factor (LMF1). LMF1 is essentially uncharacterized; in fact it belongs to a family of proteins with a similar "domain of unknown function" (Duf1222). The major goal of this project is to investigate the interaction between LPL and LMF1. By analogy to lipases with structural characteristics similar to LPL, we propose that LMF1 acts as a "private foldase" for LPL. In Aim 1, I will use biochemical assays and assays in cells to determine why LPL needs folding assistance and how LMF1 helps LPL fold. Aim 2 consists of analysis of the membrane topology and structure of LMF1. Finally, Aim 3 focuses on the observation that many human pathogens have Duf1222 proteins; therefore I will use computational and biochemical approaches to determine if the Duf1222 protein represents one-half of a foldase-lipase pair. During the mentored phase, I will build on my preliminary observations to develop a model for LMF1 membrane topology. Additionally I will begin biochemical and structural analyses of the LMF-LPL interaction, and begin preliminary work on aim 3. For the independent phase, I will continue structural analysis of LMF1 and expand my biochemical analysis to Duf1222 proteins in other species to determine if they have important roles in lipid metabolism. PUBLIC HEALTH RELEVANCE: Relevance Cardiovascular disease is a leading cause of death in the developed world, and elevated blood triacylglycerol is a risk factor. LPL deficiency results in elevated blood triacylglycerol and disturbs overall lipid metabolism. LMF1 promotes LPL activity through a poorly understood process, and elucidation of this mechanism will provide a foundation to begin to ameliorate one cause of LPL deficiency.