Novel Roles for Lysophospholippids in Eukaryotic Membrane Biogenesis and Turnover

溶血磷脂在真核细胞膜生物发生和周转中的新作用

• 批准号: 7883195
• 负责人: DENNIS R. VOELKER
• 金额: $ 30.89万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7883195
• 关键词: ATP phosphohydrolase; Acylation; Acyltransferase; Address; Apoptotic; Arachidonic Acids; Benign recurrent intrahepatic cholestasis; Biochemical; Biochemistry; Cell Signaling Process; Cell membrane; Cells; Cellular biology; Complement; Defect; Development; Drosophila genus; Eicosanoids; Elements; Enzyme Gene; Enzymes; Eukaryota; Eukaryotic Cell; Family; Family member; Functional disorder; Gene Family; Genes; Genetic; Glycerophospholipids; Goals; Hand; Human; Lecithin; Lesion; Link; Lipids; Liver diseases; Lysophospholipids; Male Sterility; Mammalian Cell; Membrane; Metabolism; Molecular; Pathway interactions; Phagocytes; Phosphatidylethanolamine; Phosphatidylserines; Phospholipids; Play; Polyunsaturated Fatty Acids; Process; Progressive intrahepatic cholestasis; Property; Proteins; Reaction; Role; Signal Transduction; Skeleton; Sterility; System; Transmembrane Transport; Work; Yeasts; base; enzyme activity; human disease; in vivo; lipid transport; member; membrane biogenesis; novel; phosphatidylethanolamine; public health relevance; tool; uptake; yeast genetics

DESCRIPTION (provided by applicant): Lysophospholipids constitute a class of membrane glycerophospholipids that are rapidly transported and metabolized by many eukaryotic cells ranging from yeast to humans. We have recently identified two yeast transporters for the major lysophospholipids found throughout the eukaryotic world, lyso- phosphatidylethanolamine (lyso-PtdEtn) and lyso-phosphatidylcholine (lyso-PtdCho). The yeast lyso-PtdEtn and lyso-PtdCho transporters are also the same molecules implicated in regulating the plasma membrane asymmetry of phosphatidylserine and phosphatidylethanolamine. The metazoan forms of these transporters play crucial roles in signaling the apoptotic status of target cells to phagocytes. Defects in the function of the mammalian transporters are linked to primary familial intrahepatic cholestasis and benign recurrent intrahepatic cholestasis in humans. Genetic and biochemical work in yeast reveals that additional lyso-PtdCho and lyso-PtdEtn transporters remain to be identified. The first specific aim of this proposal will focus on identifying the genes for the remaining yeast lysophospholipid transporters and characterizing them biochemically. The second specific aim will capitalize upon the powerful tools of yeast genetics to structurally define the mechanistic basis by which the yeast and mammalian transporters recognize their substrates and introduce them into the transport channel. Subsequent to uptake by yeast and mammalian cells, lyso-PtdCho and lyso-PtdEtn are metabolized to their diacyl counterparts, PtdCho and PtdEtn, by acyltransferase enzymes. Although the enzyme activities have been known for more than 40 years, our recent work in yeast provided the first definition of the genes executing these reactions. The yeast gene ALE1 is the founding member of a family represented in multiple eukaryotes that is involved in acylating lysophospholipids with di-unsaturated and polyunsaturated fatty acids. In the third specific aim we will use the power of yeast genetics to elucidate the biochemical activities and functions of the metazoan acyltransferases belonging to the ALE1-family. Genetic studies already reveal that lesions in Drosophila ALE1-family genes cause developmental defects and male sterility. Studies in humans reveal defects in ALE1-family genes cause developmental defects of the hands and skeleton and also produce male sterility. The biochemical studies in yeast will be complemented by detailed studies in mammalian cells examining the role of ALE1-family members as regulators of arachidonic acid mobilization for the synthesis of eicosanoids. In summary, the work in this proposal will define major genetic and biochemical aspects of lysophospholipid transport and metabolism that are intimately associated with fundamental processes of cell biology whose dysfunction leads to serious human disease. PUBLIC HEALTH RELEVANCE: The focus of this proposal is upon genes and enzymes involved in transport and metabolism of a class of lipids known as lysophospholipids. Dysfunction of genes involved in lysophospholipid transport is known to cause the liver diseases Progressive Familial Intrahepatic Cholestasis and Benign Recurrent Intrahepatic Cholestasis. Dysfunction of genes involved in the metabolism of lysophospholipids is linked to developmental abnormalities of the hands and sterility in humans. The goals of this project are to understand the mechanistic biochemistry of how lysophospholipid transport occurs and how the lipids are metabolized.

描述（由申请人提供）：溶物磷脂构成一类膜甘油磷脂，这些膜是由许多从酵母到人类的真核细胞迅速运输和代谢的。我们最近已经确定了在整个真核世界中发现的主要溶物磷脂的两个酵母菌转运蛋白，即溶菌 - 磷脂酰乙醇胺（lyso-ptdetn）和溶血磷脂酰胆碱（lyso-ptdcho）。酵母液溶剂-PTDETN和LYSO-PTDCHO转运蛋白也是与调节磷脂酰甲酯和磷脂酰乙醇胺的质膜不对称性有关的分子。这些转运蛋白的后生形式在信号靶细胞对吞噬细胞的凋亡状态中起着至关重要的作用。哺乳动物转运蛋白功能的缺陷与人类的主要家族性肝内胆汁淤积和良性复发性肝内胆汁淤积有关。酵母中的遗传和生化工作表明，其他溶血杆和溶血杆菌转运蛋白仍有待鉴定。该提案的第一个具体目的将集中在识别其余酵母溶物磷脂转运蛋白的基因，并以生化为特征。第二个特定目的将利用酵母遗传学的强大工具在结构上定义酵母和哺乳动物转运蛋白识别其底物并将其引入运输渠道的机理基础。在酵母和哺乳动物细胞摄取之后，将溶血杆菌和溶血杆菌与酰基转移酶一起代谢其二酰基对应物，ptdcho和ptdetn。尽管酶活性已闻名已有40多年了，但我们最近在酵母中的工作提供了执行这些反应的基因的第一个定义。酵母基因ALE1是在多个真核生物中代表的家族的创始成员，该家族与糖基溶磷脂有关，具有二糖磷脂，具有二不饱和和多不饱和脂肪酸。在第三个特定目的中，我们将利用酵母遗传学的能力来阐明属于ALE1家族的后生酰酰基转移酶的生化活性和功能。遗传学研究已经表明，果蝇中的ale1家族基因的病变会导致发育缺陷和雄性不育。人类研究揭示了ALE1家族基因的缺陷会导致手和骨骼的发育缺陷，还会产生雄性不育。哺乳动物细胞中的详细研究将补充酵母中的生化研究，这些研究研究了ALE1家庭成员作为蛛网膜酸动员的调节剂在合成类花生酸酯中的作用。总而言之，该提案中的工作将定义溶血磷脂转运和代谢的主要遗传和生化方面，这些方面与细胞生物学的基本过程密切相关，其功能障碍会导致严重的人类疾病。公共卫生相关性：该提案的重点放在一类称为溶血磷脂的脂质的运输和代谢的基因和酶上。众所周知，参与溶物磷脂转运的基因的功能障碍会导致肝脏疾病进行性家族性肝内胆汁淤积和良性复发性肝内胆汁淤积。与溶血磷脂代谢有关的基因功能障碍与手的发育异常和人类无菌性有关。该项目的目标是了解溶血磷脂运输方式以及脂质如何代谢的机械生物化学。