Vibrio vulnificus toxin-receptor interactions

摘要 创伤弧菌是一种革兰氏阴性细菌，可引起严重威胁生命的感染。 人类在吃了贝类或在温暖的海水中游泳后。在美国，每年大约有200起病例 死亡率和发病率都很高。虽然与其他食源性疾病相比，病例数量较低 在病原体方面，患者的高死亡率给人类的生活和经济造成了巨大的负担。 由于气候危机，创伤弧菌感染的发病率正在上升，预计这一数字将会增加。最多的 创伤弧菌的显著毒力因子是一种5208氨基酸的MARTX家族毒素，它能将细胞毒效应递送到 细胞和这些效应器对小鼠模型的毒力是必不可少的。虽然广泛的信息是已知的 关于效应器的机制，人们对剩余的2800个氨基酸的蛋白质知之甚少。 毒素。已知这些区域既是从细菌分泌毒素的必要条件也是充分条件， 毒素与真核细胞表面的相互作用以及效应物在血浆中的移位 薄膜。该项目建议识别宿主细胞受体和宿主因子，这些因素是中毒使用所必需的 对在毒素的细胞溶解作用中幸存下来的突变细胞进行遗传筛选和选择。我们还将使用 基于结构功能的MARTX毒素I型分泌区鉴定方法 细菌，毒素与假定的表面受体结合，在质膜上形成一个孔， 并将效应物转移到真核细胞胞浆中。这项研究将增进我们对 MARTX毒素重复区的功能，有望影响我们对MARTX毒素重复区的理解 创伤弧菌感染过程中的病理生理。

ABSTRACT Vibrio vulnificus is a Gram-negative bacterial pathogen that causes severe life-threatening infections in humans after eating shellfish or swimming in warm seawater. In the US, there are about 200 cases annually with high rates of mortality and morbidity. While the number of cases is low compared to other food-borne pathogens, the high rates of death among patients exerts a significant burden on human life and the economy. This is expected to increase as incidence of V. vulnificus infections is rising due to the climate crisis. The most prominent virulence factor of V. vulnificus is a 5208 aa MARTX family toxin that delivers cytotoxic effectors to cells and these effectors are essential for virulence in a mouse model. While extensive information is known about the mechanisms of the effectors, very little is known about the remaining over 2800 aa of the protein toxin. These regions are known to be both necessary and sufficient for secretion of the toxin from the bacteria, interaction of the toxin with the eukaryotic cell surface, and translocation of the effectors across the plasma membrane. The project proposes to identify host cell receptors and host factors essential for intoxication using a genetic screen and selection for mutant cells that survive the cytolytic action of the toxin. We will also use a structure-function based approach to identify regions of the MARTX toxin essential for Type I secretion from the bacterium, binding of the toxin to a putative surface receptor, formation of a pore in the plasma membrane, and translocation of effectors to the eukaryotic cell cytosol. This study will advance our understanding of the function of the MARTX toxin repeat regions in detail and is expected to impact our understanding of pathophysiology during V. vulnificus infection.