Host manipulation by the Mycobacterium tuberculosis phosphatase PtpB

描述(由申请人提供)：细菌毒力因子直接调节宿主-病原体的相互作用，从而提供工具来探索毒力机制和识别关键的宿主免疫功能。结核分枝杆菌(Mtb)能够通过对宿主的广泛操纵而在细胞内存活。结核分枝杆菌产生两种分泌的毒力因子磷酸酶，即PtPA和PtpB。PtpB是结核分枝杆菌在宿主体内生存所必需的，但其分子功能尚不清楚。我们现在发现PtpB不是先前假设的蛋白质酪氨酸磷酸酶，而是与脂类磷酸酶有很强的相似性，这为确定PtpB底物(S)和功能提供了新的实验途径。为了了解PtpB是如何介导Mtb在感染宿主中存活的，我们将通过底物捕获来确定PtpB的宿主底物，以及使用遗传和化学PtpB敲除来鉴定脂质组学和转录组学。结合这些全球方法，我们将广泛捕捉PtpB对细胞的影响，并确定PtpB依赖于宿主脂质的变化。总之，这些研究为通过基本毒力因子PtpB理解结核分枝杆菌宿主操纵提供了一条新的途径。由于PtpB正在成为一种新的治疗靶点，这些研究也将为推进药物先导提供框架。

DESCRIPTION (provided by applicant): Bacterial virulence factors directly mediate host-pathogen interactions, thus providing tools to probe virulence mechanisms and to identify key host immune functions. Mycobacterium tuberculosis (Mtb) is able to survive intracellularly through extensive manipulation of the host. Mtb produces two secreted virulence factor phosphatases, PtpA and PtpB. PtpB is essential for the survival of Mtb in the host, but its molecular functions are unknown. We now show that PtpB is not a protein tyrosine phosphatase as previously assumed, but has strong similarity to lipid phosphatases, offering novel experimental routes to define PtpB substrate(s) and function. To understand how PtpB mediates Mtb survival in an infected host, we will identify the host substrates of PtpB by substrate trapping, as well as lipidomics and transcriptomics using genetic and chemical PtpB knockouts. Combining these global approaches, we will broadly capture PtpB's effect on the cell and identify PtpB-dependent changes in host lipids. Together, these studies offer a new route towards the understanding of Mtb host manipulation through the essential virulence factor PtpB. Because PtpB is emerging as a novel therapeutic target, these studies will also provide the framework for advancing drug leads.