Structural and biophysical characterization of the interaction between intracellular pathogens and phagosome membranes

细菌可以被专业吞噬细胞吞噬。在吞噬小体内，不同的机制会导致细菌被杀死。然而，一些细菌物种能够在吞噬体内存活。这些细胞内细菌和吞噬体膜之间的相互作用是了解病原体如何在这个利基中生存的关键。除了蛋白质，脂类在这一过程中也起着至关重要的作用。然而，到目前为止，关于脂类组成和膜的物理化学性质的数据还很有限。我们想要描述亚细胞隔室的脂质体的特征，并根据吞噬小体成熟前阶段是否存在阻止吞噬小体成熟的细菌对它们进行比较。基于这些结果，我们将使用生物物理方法来研究生存的潜在分子机制。为此，我们将分析纯化的吞噬体膜以及由模仿吞噬体膜的明确定义的脂质成分组成的重组脂膜。特别是，来自分枝杆菌的糖脂海藻糖-二聚乙醇酸(TDM)和来自马红球菌的毒力相关蛋白A(VapA)的相互作用将使用这些系统进行详细的表征。

Bacteria can be ingested by professional phagocytes. Within the phagosome different mechanisms lead to a killing of the bacteria. However, some bacterial species are able to survive within the phagosome. The interaction between these intracellular bacteria and phagosome membranes is a key to understand how the pathogens survive in this niche. Besides proteins, lipids play an essential role in this process. However, up to now only limited data on the lipid composition and the physicochemical membrane properties are published. We want to characterize the lipidome of sub-cellular compartments and compare them depending on the absence or presence of bacteria which arrest phagosome maturation at a pre-phagolysosome stage. Based on these results, we will investigate the underlying molecular mechanisms of survival using biophysical approaches. For this, we will analyze purified phagosome membranes as well as reconstituted lipid membranes composed of well defined lipid compositions mimicking the phagosome membrane. In particular the interactions of the glycolipid trehalose-dimycolate (TDM) from Mycobacteria and of the virulence-associated protein A (VapA) from Rhodococcus equi will be characterized in detail using these systems.