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.

项目概要/摘要 真核细胞必须维持质膜和所有细胞的特定蛋白质和脂质组成 内膜结合细胞器才能正常发挥功能。尽管膜生物发生是 对于生命至关重要，建立膜的组成和组织的机制仍然很差 明白了。我们研究膜不对称性是如何建立的，这是真核细胞的基本特征 质膜由磷脂酰丝氨酸和磷脂酰乙醇胺的富集定义 细胞质小叶，而鞘脂和磷脂酰胆碱通常富集在细胞外小叶中 双层。细胞外小叶上 PS 和 PE 的调节暴露有助于细胞信号传导， 胞质分裂、血液凝固、细胞-细胞融合、凋亡细胞尸体清除和宿主-病毒相互作用。膜 不对称性由 IV 型 P 型 ATP 酶 (P4-ATP 酶) 驱动，这是一大类翻转酶，可泵送 脂质从细胞外小叶到膜双层的胞质小叶。 P4-ATP酶亚家族是 在真核生物中高度保守，这些转运蛋白与病理条件有关 例如与肥胖相关的2型糖尿病、心血管疾病、肝脏疾病、听力损失、免疫缺陷、 以及严重的神经系统疾病。此外，P4-ATP 酶是囊泡介导的 高尔基复合体和内体系统内的蛋白质运输机制。通过它们在蛋白质中的作用 运输、P4-ATP酶有助于控制质膜、高尔基复合体的精确蛋白质组成 内体和溶酶体。拟议的研究将确定 P4-ATPase 如何识别和 利用结构、生化和分子转运其脂质底物以建立膜不对称性 遗传方法。这些结构/功能研究将包括 P4-ATP 酶活性如何通过后调节来调节。 翻译修饰和蛋白质-蛋白质相互作用。我们还将探讨以下方面的蜂窝需求 特定底物脂质（如葡萄糖神经酰胺和磷脂酰丝氨酸）对细胞形态发生的运输， 真菌发病机制、营养信号传导和蛋白质运输。对于后面的研究，我们将探讨 P4- ATP 酶有助于驱动囊泡介导的蛋白质转运，重点是 COPI 和逆转录体形成的载体。 泛素化在 P4-ATPase 和 COPI 依赖性转运途径中的非典型作用也将被 定义的。总的来说，这些研究应该能让我们更好地了解 P4-ATP 酶如何发挥其作用 的基本功能，对于我们理解和最终治疗相关病理的能力具有无价的价值 P4-ATP酶缺乏症。