Inhibitors of Type III Secretion and Translocation in yersinia

多种革兰氏阴性杆菌，包括耶尔森氏菌、沙门氏菌、假单胞菌、志贺氏菌、 肠源性大肠埃希菌、乳杆菌和伯克霍尔德氏菌使用III型分泌系统(TTSS)进行转位 效应蛋白从细菌胞浆进入哺乳动物细胞。易位效应蛋白，称为YOPs 耶尔森氏菌，颠覆正常的寄主过程，促进病原菌的生存，从而TTSS发挥作用 在这些细菌的感染过程和毒力中起重要作用。TTS由一个底座组成，该底座 横跨细菌的内膜和外膜，一根针，从底部延伸到宿主细胞， 以及一个转运子，它被插入到宿主细胞膜中，YOPs被认为通过它旅行到 到达宿主细胞胞质。在耶尔森氏菌中，针主要由一种7kD蛋白质YscF组成，它 聚合成一条长管。这根针被认为是一条管道，将YOPS从 细菌连接到转运子，被认为是将信号从宿主细胞膜传导到TTSS碱基 当病原体与宿主细胞接触时。这些信号会触发Yop易位。尖端蛋白， LCRV，发现于针的远端。LCrV的一个功能是定位、组装和/或插入 转运子，进入质膜，这是YOP进入细胞的关键。两种蛋白质，YopB和 YopD由转位基因组成。这个提议的总体目标是理解分子间的相互作用。 在与哺乳动物细胞接触时转运YOPs所需的TTSS组件之间。我们 已鉴定出3个显性负YscF等位基因和8个抑制YOP易位的小分子。这些 将深入研究独特的突变体和化合物，作为了解所需分子的探针。 Yop易位到宿主细胞的相互作用。我们的工作假设是我们的抑制剂干扰了 YscF、LcrV、YopB和/或YopD之间的关键交互作用。了解易位的机制 和针头组装将支持干扰这些过程的新策略的开发，并 从而中和细菌的致病性。

Many gram negative bacterial pathogens, including Yersinia, Salmonella, Pseudomonas, Shigella, enteropathogenic E. coli, Chylamydia, and Burkholderia, use type III secretion systems (TTSS) to translocate effector proteins from the bacterial cytosol into mammalian cells. Translocated effector proteins, called Yops in Yersinia, subvert normal host processes to promote the survival of the pathogen, and thus TTSS play an essential role in the infectious process and virulence of these bacteria. TTSS are comprised of a base, which spans the inner and outer membranes of the bacteria, a needle, which extends from the base to the host cell, and a translocon, which is inserted into host cell membranes and through which Yops are thought to travel to reach host cell cytoplasm. In Yersinia, the needle is primarily composed of one 7kD protein, YscF, which polymerizes to form a long tube. The needle is thought to be a conduit for the passage of Yops from the bacteria to the translocon and is thought to conduct signals from the host cell membrane to the TTSS base when the pathogen comes in contact with a host cell. These signals trigger Yop translocation. A tip protein, LcrV, is found at the distal end of the needle. One function of LcrV is to position, assemble, and/or insert the translocon, into plasma membranes, which is essential for Yop delivery into cells. Two proteins, YopB and YopD comprise the translocon. The overall goals of this proposal are to understand the molecular interactions between TTSS components that are required for translocating Yops upon contact with mammalian cells. We have identified 3 dominant negative YscF alleles and 8 small molecules that inhibit Yop translocation. These unique mutants and compounds will be studied intensively as probes to understand the required molecular interactions for Yop translocation into host cells. Our working hypothesis is that our inhibitors interfere with critical interactions between YscF, LcrV, YopB and/or YopD. Understanding the mechanism of translocation and needle assembly will support the development of new strategies that interfere with these processes and thus neutralize the bacteria's pathogenecity.