Intracellular trafficking of the mitochondrial targeting toxin VacA from Helicobacter pylori

幽门螺杆菌线粒体靶向毒素 VacA 的细胞内运输

基本信息

批准号：
9054794
负责人：
Steven R. Blanke
金额：
$ 22.9万
依托单位：
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-04-15 至 2017-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9054794
关键词：
Address Bacteria Bacterial Toxins Bacterial exotoxin Binding Biology Cell Death Cell Surface Proteins Cell Surface Receptors Cell membrane Cell surface Cells Cholera Toxin Chronic Clostridium difficile Complement Factor H Cytosol Cytotoxin Data Diphtheria Toxin Disease Effectiveness Employee Strikes Endoplasmic Reticulum Functional disorder Gastric ulcer Health Helicobacter pylori Human Infection Inner mitochondrial membrane Intervention Intoxication Ion Channel Ions Iron Knock-out Knowledge Magnetism Malignant Neoplasms Mediating Membrane Membrane Potentials Metabolic Methods Mitochondria Mitochondrial Proteins Modeling Modification Molecular Nature Outer Mitochondrial Membrane Paper Process Property Protein Import Proteins Proteome Salmonella typhimurium Staging Stomach Stomach Diseases Surface System Targeted Toxins Testing Time Toxin Vesicle Virulence Factors Work anthrax toxin base disorder risk enteropathogenic Escherichia coli insight killings knock-down longitudinal analysis mitochondrial dysfunction pathogen pathogenic bacteria trafficking uptake

项目摘要

DESCRIPTION (provided by applicant): This exploratory R21 application proposes studies to identify and characterize the mechanism by which the vacuolating cytotoxin (VacA), an important virulence factor produced by the human gastric pathogen Helicobacter pylori, targets mitochondria within intoxicated host cells. VacA is a membrane-channel forming toxin, which subsequent to binding the surface of host cells, is taken up from the plasma membrane into VacA- containing vesicles (VCVs), and subsequently targets the inner membrane of mitochondria, resulting in metabolic dysfunction and cell death. Here, we propose studies that challenge canonical models of host cell intoxication by intracellular-acting bacterial toxins, whic generally require the translocation of enzymatic active fragments from the endolysosomal system or endoplasmic reticulum to the cytosol prior to toxin- mediated modification of intracellular targets. Rather, subsequent to internalization, we propose that VacA is transported within VCVs to mitochondria, where the toxin is then directly transferred to mitochondria. However, the identity of VCV proteins important for VacA targeting/trafficking to mitochondria is difficult to predict, due in part to the fact that until very recently, mitochondria were not generlly thought to receive protein cargo from the endolysosomal system and, as a consequence, almost nothing is known about intracellular trafficking compartments destined for mitochondria. To address this gap in knowledge, we will evaluate the hypothesis that VacA-targeting of mitochondria requires remodeling of VacA-containing vesicles (VCVs) from early endosomal-like compartments to vesicles that are functionally competent for targeting and fusion with mitochondria. Using magnetic-based separation methods to isolate iron-enriched VCVs from cells at different stages of intoxication for proteome analysis, we will identify changes in VCV-associated proteins, and, characterize their functional importance for VacA targeting of mitochondria and mitochondrial dysfunction. These studies will provide the first detailed characterization of the host cell machinery that is important for mitochondrial targeting, and, contribute to our understanding of the fundamental biology underlying the modulation of host cells by VacA.

描述（应用程序提供）：此探索性R21应用提案研究，以识别和表征真空的细胞毒素（VACA）（VACA）是人类胃病原体幽门螺杆菌幽门螺杆菌产生的重要病毒因子，靶向intotoxoxylated宿主细胞内的线粒体。 VACA是一种形成毒素的膜通道，在结合宿主细胞表面之后，从质膜中将其接收到含Vaca-con-cova-含有蔬菜的蔬菜（VCV），然后靶向线粒体的内膜，导致代谢功能障碍和细胞死亡。在这里，我们提出的研究通过细胞内作用细菌毒素来挑战宿主细胞中毒的规范模型，这通常需要将酶的活性片段从内溶液体系统或内质网易位到内质网向细胞质，然后再介导了细胞内靶标的毒素。相反，在内部化之后，我们建议将VACA转运到VCV中到线粒体，然后将毒素直接转移到线粒体上。然而，很难预测，VCV蛋白的身份对于VACA靶向/运输到线粒体很重要，部分原因是，直到最近，直到最近，线粒体还没有被认为是从内溶血体系统中接收蛋白质货物的，因此，几乎尚未了解有关细胞内贩运的脑内贩运界限的销售限制性菌落菌落。为了解决这一知识的差距，我们将评估以下假设：线粒体的VACA靶向需要重塑含Vaca的蔬菜（VCV），从早期的内体室样室到具有功能胜任和融合与线粒体的功能胜任的蔬菜。使用基于磁性的分离方法将富含铁的VCV与中毒分析的不同阶段的细胞分离，我们将确定与VCV相关蛋白的变化，并表征它们对于线粒体靶向线粒体和线粒体功能障碍的功能重要性。这些研究将提供对宿主细胞机制的第一个详细表征，这对于线粒体靶向很重要，并有助于我们对VACA调节宿主细胞的基本生物学的理解。