Characterization of the nutrient assimilation pathways in M. tuberculosis

项目总结/摘要 MTB利用宿主来源的脂质来促进发病，这是这种细胞内 病原体在感染期间，Mtb输入和代谢宿主脂质以通过产生以下物质来支持发病机制： 能量，ii）中心代谢中间体，或iii）聚酮毒性脂质。虽然结核分枝杆菌的代谢途径 降解或处理脂质的酶是复杂的，并含有多余的酶，即细菌Mce脂质转运蛋白 似乎对专用脂质底物具有特异性。 这项工作的目的1提出采用遗传和生物化学方法来鉴定和表征新的 Mtb中脂肪酸输入所需的基因/蛋白质虽然可以理解Mce 1进口脂肪酸， 这种转运蛋白的底物特异性是未知的。因此，我们打算定义底物和生化 Mce 1底物特异性的基础。我们的初步研究表明，结核分枝杆菌转运的脂肪酸前体， 通过Mce 1的免疫信号脂质，我们在这里包括研究，以评估是否清除这种免疫脂质 Mtb的前体影响免疫反应。 目的2提出鉴定和表征所有Mce转运蛋白共有的蛋白亚基， 是结核分枝杆菌中脂质输入所必需的。我们已经确定，LucA是需要的Mce 1和Mce 4介导的 转运蛋白和LucA稳定这些转运蛋白复合物。这些研究试图描述这种情况的基础 传送器稳定类似地，MceG是Mce 1和Mce 4介导的转运所必需的，我们打算 了解MceG如何稳定并与Mce 1相互作用。我们会用基因方法让卢卡沉默， MceG在慢性感染小鼠内的Mtb中，并量化细菌适应性以确定治疗潜力 有可能阻断这些蛋白质的药物。

Project Summary / Abstract Mtb utilizes host-derived lipids to promote pathogenesis and this is a defining feature of this intracellular pathogen. During infection Mtb imports and metabolizes host lipids to support pathogenesis by producing: i) energy, ii) central metabolic intermediates, or iii) polyketide virulence lipids. While the metabolic pathways in Mtb that degrade or process lipids are complex and contain redundant enzymes, the bacterial Mce lipid transporters appear to be specific for dedicated lipid substrates. Aim 1 of this work proposes to employ genetic and biochemical approaches to identify and characterize novel gene/proteins required for fatty acid import in Mtb. While it is understood that Mce1 imports fatty acids, the substrate specificity of this transporter is unknown. Therefore, we intend to define substrates and the biochemical basis of Mce1 substrate specificity. Our preliminary studies indicate that Mtb transports fatty acid precursors of immune signaling lipids via Mce1 and we include here studies to evaluate if scavenging of this immune lipid precursors by Mtb impacts the immune response. Aim 2 proposes to identify and characterize protein subunits that are shared by all the Mce transporters and are required for lipid import in Mtb. We have determined that LucA is required for Mce1- and Mce4-mediated transport and LucA stabilizes these transporter complexes. These studies seek to characterize the basis for this transporter stabilization. Similarly, MceG is required for Mce1- and Mce4-mediated transport and we intend to understand how MceG stabilizes and interacts with Mce1. We will use a genetic approach to silence LucA and MceG in Mtb within chronically infected mice and quantify bacterial fitness to determine the therapeutic potential of drugs that potentially block these proteins.