Glucose Sensing and Hexokinases in the African Trypanosome

项目摘要/摘要 非洲布氏锥虫的感染生命周期阶段完全依赖糖酵解 用于生成ATP。寄生虫对动态的环境提示做出反应，以调节这一途径。目标是 这一应用的目的是解决调节必需的糖酵解酶T. Brucei己糖激酶1和2，特别强调了解葡萄糖敏感的亚细胞 蛋白质的定位。我们之前已经证明了布鲁氏锥虫己糖激酶2，这是 到目前为止，人们认为它的分布仅限于一种被称为糖体的过氧酶体样细胞器，它在 此外，还存在依赖生命周期的糖体外定位。在血液中形成寄生虫的蛋白质 是在鞭毛中发现的，而在昆虫阶段，该蛋白是在基体附近发现的。我们的 初步数据表明，定位取决于环境中葡萄糖的可获得性，并且 己糖激酶与线粒体中不溶于洗涤剂的部分有关。使用这两种异地 标记蛋白的表达及结合显微镜和生化的免疫化学 方法，我们将确定定位所需的酶结构域。此外，我们将开始 解决葡萄糖依赖定位所需的机制，并特别关注关联 与寄生虫线粒体结合的己糖激酶组。通过这些研究，靶向葡萄糖的新方法 新陈代谢，一种重要的寄生虫途径，将被确定。

PROJECT SUMMARY/ABSTRACT The infectious lifecycle stage of the African trypanosome, Trypanosoma brucei, relies exclusively on glycolysis for ATP generation. The parasite responds to dynamic environmental cues to regulate this pathway. The goal of this application is to resolve the mechanisms that regulate localization of the essential glycolytic enzymes, T. brucei hexokinase 1 and 2, with a particular emphasis on understanding the glucose-sensitive subcellular localization of the proteins. We have previously demonstrated that T. brucei hexokinase 2, which was heretofore believed to be limited in its distribution to a peroxisome-like organelle called the glycosome, has in addition a life-cycle dependent extra-glycosomal localization. In the bloodstream form parasites, the protein was found in the flagellum while in the insect stage the protein was found proximal to the basal bodies. Our preliminary data suggests that the localization is dependent on environmental glucose availability and that the hexokinases are associated with a detergent-insoluble fraction of the mitochondria. Using both ectopic expression of tagged proteins and immunochemistry in collaboration with microscopy and biochemical approaches, we will identify the enzyme domains that are required for localization. Additionally, we will begin to resolve the mechanisms required for glucose-dependent localization, with a particular focus on the association of the hexokinases with the parasite mitochondrion. Through these studies, new ways of targeting glucose metabolism, an essential parasite pathway, will be identified.