Mechanisms of membrane homeostasis through protein and lipid transport

通过蛋白质和脂质运输实现膜稳态的机制

• 批准号: 10544025
• 负责人: TODD R GRAHAM
• 金额: $ 48.72万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10544025
• 关键词: ATP phosphohydrolase; Apoptotic; Binding; Biochemical Genetics; Biological; Blood coagulation; Cardiovascular Diseases; Cell fusion; Cell membrane; Cells; Coat Protein Complex I; Cytokinesis; Defect; Endosomes; Eukaryota; Eukaryotic Cell; Excision; Family; Glucosylceramides; Golgi Apparatus; Homeostasis; Immune; Lecithin; Life; Link; Lipids; Liver diseases; Lysosomes; Marketing; Mediating; Membrane; Membrane Proteins; Molecular Genetics; Morphogenesis; Non-Insulin-Dependent Diabetes Mellitus; Nutrient; Obesity; Organelles; Pathogenesis; Pathologic; Pathology; Pathway interactions; Pharmaceutical Preparations; Phosphatidylethanolamine; Phosphatidylserines; Post-Translational Protein Processing; Process; Proteins; Pump; Research; Role; Signal Transduction; Sphingolipids; Structure; System; Ubiquitination; Vesicle; Viral; extracellular; genetic approach; hearing impairment; human disease; improved; lipid transport; membrane assembly; membrane biogenesis; nervous system disorder; protein protein interaction; protein transport

Project Summary/Abstract Eukaryotic cells must maintain a specific protein and lipid composition of the plasma membrane and all of the internal membrane-bound organelles in order to function normally. Even though membrane biogenesis is crucial for life, mechanisms for establishing the composition and organization of membranes remain poorly understood. We study how membrane asymmetry is established, a fundamental feature of the eukaryotic cell plasma membrane defined by the enrichment of phosphatidylserine and phosphatidylethanolamine within the cytosolic leaflet, while sphingolipids and phosphatidylcholine are typically enriched in the extracellular leaflet of the bilayer. Regulated exposure of PS and PE on the extracellular leaflet contributes to cell signaling, cytokinesis, blood clotting, cell-cell fusion, apoptotic cell corpse removal and host-viral interactions. Membrane asymmetry is driven by type IV P-type ATPases (P4-ATPases), which are a large family of flippases that pump lipids from the extracellular leaflet to the cytosolic leaflet of the membrane bilayer. The P4-ATPase subfamily is highly conserved among eukaryotes and these transporters have been implicated in pathological conditions such as obesity-linked type 2 diabetes, cardiovascular disease, liver disease, hearing loss, immune deficiency, and severe neurological disease. In addition, P4-ATPases are critical components of the vesicle-mediated protein trafficking machinery within the Golgi complex and endosomal system. Through their role in protein trafficking, P4-ATPases help control the precise protein composition of the plasma membrane, Golgi complex endosomes and lysosomes. The proposed studies will determine how the P4-ATPases recognize and transport their lipid substrates to establish membrane asymmetry using structural, biochemical and molecular genetic approaches. These structure/function studies will include how P4-ATPase activity is regulated by post- translational modification and protein-protein interactions. We will also probe the cellular requirements for transport of specific substrate lipids, like glucosylceramide and phosphatidylserine, on cell morphogenesis, fungal pathogenesis, nutrient signaling, and protein trafficking. For the latter studies, we will probe how P4- ATPases help drive vesicle-mediated protein transport with a focus on carriers formed by COPI and retromer. Atypical roles for ubiquitination in the P4-ATPase- and COPI-dependent transport pathways will also be defined. In total, these studies should lead to a much better understanding of how P4-ATPases exert their essential function, and will be invaluable to our ability to understand and ultimately treat pathologies associated with P4-ATPase deficiency.

项目摘要/摘要 真核细胞必须维持质膜的特定蛋白质和脂质组成以及所有 内部膜结合的细胞器以正常功能。即使膜生物发生是 生命的关键，建立膜组成和组织的机制仍然很差 理解。我们研究如何建立膜不对称，这是真核细胞的基本特征 质膜由磷脂酰甲酯和磷脂酰乙醇胺的富集定义 胞质小叶，而鞘脂和磷脂酰胆碱通常富含在细胞外小叶中 双层。 PS和PE在细胞外小叶上的调节暴露有助于细胞信号传导， 细胞因子，血液凝结，细胞 - 细胞融合，凋亡细胞尸体的去除和宿主病毒相互作用。膜 不对称性是由IV型P型ATPases（P4-ATPases）驱动的，它们是一个大型的flippase家族 脂质从细胞外小叶到膜双层的胞质小叶。 P4-ATPase亚家族是 在真核生物和这些转运蛋白的高度保守与病理条件有关 例如肥胖2型糖尿病，心血管疾病，肝病，听力丧失，免疫缺陷， 和严重的神经疾病。此外，P4-ATP酶是囊泡介导的关键成分 高尔基体复合物和内体系统中的蛋白质运输机制。通过它们在蛋白质中的作用 贩运，P4-ATP酶有助于控制质膜的精确蛋白质组成，Golgi复合物 内体和溶酶体。拟议的研究将确定P4-ATP酶如何识别和 使用结构，生化和分子运输其脂质底物以建立膜不对称 遗传方法。这些结构/功能研究将包括P4-ATPase活性如何受到后的调节 翻译修饰和蛋白质 - 蛋白质相互作用。我们还将探测细胞要求 特异性底物脂质（如葡萄糖基酰胺和磷脂酰丝氨酸）在细胞形态发生上的转运， 真菌发病机理，营养信号传导和蛋白质运输。对于后者的研究，我们将探测P4- ATP酶有助于驱动囊泡介导的蛋白质转运，重点是由COPI和缩回剂形成的载体。 在P4-ATPase和COPI依赖性传输途径中泛素化的非典型作用也将是 定义。总的来说，这些研究应该可以更好地了解P4-ATP酶如何施加其 必不 与P4-ATPase缺乏症。