Membrane Interaction of Mycobacterium tuberculosis Virulence Factors

结核分枝杆菌毒力因子的膜相互作用 项目总结 据估计，结核分枝杆菌(Mtb)是一种传染性和空气传播的细菌病原体， 感染了世界三分之一的人口，每年造成100-200万人死亡。人们认为最初的结核分枝杆菌 感染发生在肺泡巨噬细胞中。结核分枝杆菌内化到吞噬小体中，在那里它穿透 吞噬体膜，并移位到胞浆中进行复制和在细胞间传播。这个 胞浆易位被认为是结核分枝杆菌发病的重要机制。两株结核分枝杆菌毒力 6-kDal早期抗原靶蛋白(MtbESAT6)和10-kDal培养滤液蛋白(MtbCFP10)是 作为一种异二聚体从结核分枝杆菌分泌出来，并被认为在结核分枝杆菌胞质中起着重要作用 易位。ESAT-6或CFP-10的基因敲除会导致胞质有缺陷的易位和 毒性减弱。我们最近的研究表明，MtbESAT-6具有酸性-pH依赖性的孔- 形成结核分枝杆菌胞质转位和毒力所需的活性。然而，分子 控制MtbESAT-6孔形成和异二聚体解离的机制尚不清楚。在现在 提案中，我们将使用各种生化、显微、结构和细胞方法来探索 MtbESAT-6孔隙形成的动态过程，确定了孔隙复合体的结构。我们还将 研究MtbESAT-6的N-α-乙酰化在酸化诱导的异二聚体解离中的作用 MtbESAT-6与膜相互作用的先决条件。在这项拨款提案中设计的研究旨在 填补我们对结核分枝杆菌感染过程中依赖于MtbESAT-6的分子事件的了解的关键空白 在肺泡巨噬细胞和其他吞噬细胞中。从拟议研究中获得的知识将有助于 开发防治结核病的新对策、疗法和疫苗。 好了！

Title: Membrane interaction of Mycobacterium tuberculosis virulence factors PROJECT SUMMARY It is estimated that Mycobacterium tuberculosis (Mtb), a contagious and airborne bacterial pathogen, infects one-third of the world population and causes 1-2 million deaths each year. It is believed that initial Mtb infection occurs in alveolar macrophages. Mtb is internalized into the phagosome, where it penetrates the phagosomal membrane and translocates into the cytosol for replicating and cell-to-cell spreading. The cytosolic translocation is regarded as an important mechanism of Mtb pathogenesis. Two Mtb virulence factors, namely 6-kDal early antigenic target (MtbESAT6) and 10-kDal culture filtrate protein (MtbCFP10), are secreted out of Mtb as a heterodimer and have been implicated to play an essential role in Mtb cytosolic translocation. Genetic knockout of either esat-6 or cfp-10 results in defective cytosolic translocation and attenuated virulence. Our recent studies have suggested that MtbESAT-6 has an acidic-pH dependent pore- forming activity that is required for Mtb cytosolic translocation and virulence. However, the molecular mechanisms governing MtbESAT-6 pore formation and heterodimer dissociation are not clear. In the present proposal, using a variety of biochemical, microscopic, structural and cellular approaches, we will probe the dynamic process of MtbESAT-6 pore formation and determine the structure of the pore complex. We will also investigate the role of Nα-acetylation of MtbESAT-6 in acidification-induced heterodimer dissociation, a prerequisite for MtbESAT-6 to interact with the membrane. Studies designed in this grant proposal are aimed to fill the critical gap in our understanding of the MtbESAT-6-dependent molecular events during Mtb infection in alveolar macrophages and other phagocytes. Knowledge obtained from the proposed studies will facilitate the development of novel countermeasures, therapeutics and vaccines, against tuberculosis. !