Calcium signaling in Mycobacterium tuberculosis

摘要 钙(Ca~(2+))是真核细胞中的一种主要信号机制，但虽然Ca~(2+)信号具有古老的 在细菌中，它的起源还不是很清楚。已有几种细菌被证明维持较低的细胞内浓度 Ca~(2+)浓度，这是真核生物钙信号转导的基础。此外，一些细菌的钙离子- 结合蛋白和可能的转运蛋白已被鉴定，表明细菌中存在钙离子。 类似于真核生物的信号系统。然而，关于细菌钙离子的许多基本问题 信号仍然存在，从维持钙离子梯度到钙离子触发，钙结合蛋白，钙存储， 最后探讨了钙离子浓度变化对细菌生理及发病机制的影响。使用 基于FRET的结核分枝杆菌(Mtb)钙报告系统，允许精确、实时 细胞内钙离子水平的测量，我们将探索这些关于钙离子信号转导的基本问题 山地车。我们将使用一种新的蛋白质组学方法，热蛋白质图谱，来全球检测钙结合蛋白 在Mtb。我们还鉴定了一种新的钙离子孔道蛋白，并将使用一种孔道蛋白基因敲除菌株来测试钙离子在 结核分枝杆菌的发病机制。我们将共同利用这些新工具来检验结核分枝杆菌维持钙离子的假设 类似于许多真核生物中的信号系统，并将开始剖析生理和 结核分枝杆菌钙稳态的致病意义。

ABSTRACT Calcium (Ca2+) is a major signaling mechanism in eukaryotic cells, but although Ca2+ signaling has ancient origins, it is not well understood in bacteria. Several bacteria have been shown to maintain a low intracellular Ca2+ concentration, which is the basis for Ca2+ signaling in eukaryotes. In addition, some bacterial Ca2+- binding proteins and putative transporters have been identified, suggesting the presence of a bacterial Ca2+ signaling system analogous to that in eukaryotes. However, many fundamental questions about bacterial Ca2+ signaling remain, from maintenance of Ca2+ gradients to Ca2+ triggers, Ca2+ binding proteins, Ca2+ storage, and finally the effects of changing Ca2+ concentrations on bacterial physiology and pathogenesis. Using a FRET-based Ca2+ reporter system in Mycobacterium tuberculosis (Mtb) that allows for precise, real time measuring of intracellular Ca2+ levels, we will explore these fundamental questions about Ca2+ signaling in Mtb. We will use a novel proteomic approach, thermal protein profiling, to globally detect Ca2+ binding proteins in Mtb. We also identified a novel Ca2+ porin and will use a porin knockout strain to test for the role of Ca2+ in Mtb pathogenesis. Together, we will leverage these new tools to test the hypothesis that Mtb maintains a Ca2+ signaling system analogous to that in many eukaryotes and will begin to dissect the physiologic and pathogenic implications of Ca2+ homeostasis in Mtb.