Glucose Sensing and Hexokinases in the African Trypanosome

项目总结/摘要 非洲锥虫布氏锥虫的感染性生命周期阶段完全依赖于糖酵解 生成ATP。寄生虫对动态环境线索作出反应，以调节这一途径。目标 本申请的目的是解决调节必需糖酵解酶T. 布鲁氏菌己糖激酶1和2，特别强调了解葡萄糖敏感的亚细胞 蛋白质的定位。我们已经证明了T.布鲁氏菌己糖激酶2， 迄今为止，认为其分布局限于称为糖体的过氧化物酶体样细胞器， 此外，生命周期依赖性糖体外定位。在血液中形成寄生虫， 在鞭毛中发现，而在昆虫阶段，该蛋白质被发现接近基体。我们 初步数据表明，定位是依赖于环境葡萄糖的可用性， 己糖激酶与线粒体的洗涤剂不溶性部分相关。使用异位 标记蛋白的表达和免疫化学与显微镜和生物化学的合作 方法，我们将确定所需的酶域的本地化。此外，我们将开始 解决葡萄糖依赖性定位所需的机制，特别关注 己糖激酶与寄生虫的关系。通过这些研究，针对葡萄糖的新方法 代谢，一个重要的寄生虫途径，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.