FATTY ACID TRANSPORT--STRUCTURAL AND CELL BIOLOGY

脂肪酸是人体细胞的基本营养物质，但也是几种常见疾病的核心因素，包括心肌缺血、糖尿病和肥胖症。缺血事件后FA水平的急剧升高扰乱了与膜相关的功能，如收缩、兴奋性、节律和细胞活力。慢性升高的酸度可能是II型糖尿病的直接致病因素。不太常见的脂肪酸氧化遗传性疾病，如肾上腺脑白质营养不良(ALD)，其特征是特定脂肪酸、超长链饱和脂肪酸(VLCFA)的积累。本项目使用结构生物学和细胞生物学的最新方法，通过差示扫描量热法、13C核磁共振和荧光光谱描述脂肪酸结合相互作用的结构和动态方面，以及脂肪酸在血浆、细胞膜和血清白蛋白中的运输，并通过新的13C核磁共振方法研究VLCFA在ALD患者细胞中的代谢命运。第二个目标决定了细胞内脂肪酸和脂结合蛋白(FABP)溶液中完整的三级结构，这些结构为阐明蛋白质动力学和配体结合的分子细节提供了基础。将研究脂肪酸代谢的直接产物等不太丰富的配体的结合，以阐明FABP的新的潜在功能。第三个目的是研究脂肪酸在膜中的运输，并检验脂肪酸通过脂双层、被动扩散和蛋白质介导的转运蛋白运输的两个主要假说。这一目标将使用荧光探针的组合来量化细胞内脂肪酸运输的吸附和跨膜移动步骤。我们对脂肪酸的基本和复杂的物理相互作用和性质的研究将为解释脂肪酸在生理系统中的行为和描绘它们在人类疾病中的确切作用提供不可或缺的知识。

Fatty acids are essential nutrients of human cells but are also central players, if not causative agents, in several common diseases, including myocardial ischemia, diabetes and obesity. Acutely elevated leels of FA following an ischemic event disturb membrane-related functions such as contraction, excitability, rhythm and cell viability. Chronically elevated acids may be a direct causative agent in type II diabetes. Less common genetic disorders of fatty acid oxidation such as adrenoleukodystrophy (ALD) are characterized by accumulation of specific fatty acids, very long chain saturated fatty acids (VLCFA). This project uses state-of-the- art methods in both structural and cell biology to describe structural and dynamic aspects of fatty acid binding interactions and transport in plasma, cell membranes, and serum albumin by differential scanning calorimetry and 13C NMR and fluorescence spectroscopy, and studies the metabolic fate of VLCFA in cells of ALD patients by novel 13C NMR approaches. The second aim determines the complete tertiary structure in solution of intracellular fatty acid and lipid binding proteins (FABP); these structures provide a basis for elucidating molecular details of protein dynamics and ligand binding. Binding of less abundant ligands such as immediate products of fatty acid metabolism will be studied to elucidate new potential functions of FABP. The third aim studies the transport of fatty acids in membranes and tests both major hypotheses of fatty acid transport through the lipid bilayer, passive diffusion and protein-mediated transporter. This aim will use a combination of fluorescence probes to quantitative the adsorption and transmembrane movement steps of fatty acid transport in cells. Our studies of the fundamental and complex physical interactions and properties of fatty acids will prove indispensable knowledge for interpreting the behavior of fatty acids in physiological systems and delineating their precise roles in human diseases.