Analysis of newly identified adhesin used by pathogenic Gram-negative bacteria

描述(由申请人提供)：这项建议的目的是表征在大多数革兰氏阴性致病动物细菌中发现的一种新的多价黏附分子(MAM7)。我们认为MAM7参与了细菌病原体与宿主细胞的最初接触。作为这类分子的代表，我们将使用副溶血性弧菌的MAM7蛋白来研究与宿主细胞的多价结合。副溶血性弧菌是一种新出现的病原体，通过食用生或未煮熟的海鲜而导致胃肠炎。我们观察到宿主细胞中肌动蛋白细胞骨架依赖于MAM7的变化。我们预测，MAM7的结合将触发细菌病原体产生更多的黏附因子。因此，作为我们的目标之一，我们希望揭示MAM7结合时细菌和宿主细胞中激活的信号机制。另一方面，我们希望了解MAM7与其两个宿主细胞受体--纤维连接蛋白和磷脂酸之间的生化相互作用。这些信息将对未来专注于MAM7抑制剂的研究非常有价值。最后，我们观察到表达MAM7的非致病细菌(BL21-MAM7)与宿主细胞的结合可以改善表达MAM7的革兰氏阴性病原菌的细胞毒性。我们有兴趣确定MAM7在多大程度上提供了比其他类型的细菌病原体更广泛的竞争优势，这些细菌病原体不表达MAM7，但表达其他类型的粘附素。总之，这些实验将使我们能够表征新发现的多价黏附分子MAM7，并将有助于阐明其作为一种竞争抑制剂对多种细菌病原体的价值。

DESCRIPTION (provided by applicant): The aim of this proposal is to characterize a newly multivalent adhesion molecule (MAM7) found in the majority of Gram-negative pathogenic animal bacteria. We propose that MAM7 is involved in the initial contact of bacterial pathogens with host cells. As a representative for this type of molecule, we will use the MAM7 protein from Vibrio parahaemolyticus, an emerging pathogen that causes gastroenteritis through consumption of raw or undercooked seafood, to study the multivalent binding to host cells. We observe MAM7 dependent changes in the actin cytoskeleton in host cells. We predict that binding of MAM7 will trigger the production of more adhesion factors in the bacterial pathogens. Thus as one of our aims, we would like to uncover the signaling machinery activated in the bacteria and the host cell upon binding of MAM7. In another aim, we would like to understand the biochemical interaction of MAM7 with its two host cell receptors, fibronectin and phosphatidic acid. This information will be extremely valuable for future studies focused on MAM7 inhibitors. Finally, we observe that binding of non-pathogenic bacteria expressing MAM7 (BL21-MAM7) to host cells ameliorates cytotoxicity of Gram-negative pathogens expressing MAM7. We are interested in determining how broadly MAM7 provides a competitive advantage over other types of bacterial pathogens that do not express MAM7 but other types of adhesins. Together, these experiments will allow us to characterize the newly identified multivalent adhesion molecule MAM7 and will help to elucidate its value as a competitive inhibitor for a wide variety of bacterial pathogens.