CELL CYCLE DYNAMICS OF THE TRYPANOSOME FLAGELLAR POCKET

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 我们正在努力了解非洲锥虫和它们的宿主之间的关系。我们的方法是追求分子和细胞的理解“鞭毛口袋”（FP），锥虫细胞表面的特化，围绕鞭毛从寄生虫表面突出的地方。 这是所有锥虫胞内和胞吐的部位，因此它在这种寄生虫避免宿主获得性免疫反应攻击的策略中发挥作用。我们正在使用电子断层扫描技术进行结构研究，分辨率约为6纳米的3-D。我们的工作是围绕最近的发现，即人类LDL的一个组成部分，ApoL 1，是细胞毒性的一些非洲锥虫，但不是其他人，差异取决于蛋白质，是特定于他们的内吞系统。 初步结果表明，这种细胞毒性因子在FP处进入锥虫，但不知何故导致细胞溶解和死亡。我们预计这种杀死锥虫的方法可以用于医疗目的。了解血清因子对物种特异性和广谱锥虫杀灭的机制，应有助于深入了解宿主-寄生虫生物学，并有助于评估预防性治疗的新途径。因此，我们使用电子断层扫描检查FP的T。Brucei等人发现FP相关的膜组分包括网格蛋白包被的囊泡、微管蛋白和各种各样的膜结合区室。 收集了11张双轴断层图像的数据，以3D重建这些隔间。 我们现在正致力于开发标记技术，将表征所有的内吞途径，包括那些从哺乳动物血清内化细胞毒性因子。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are working to understand the relationships between African trypanosomes and their hosts. Our approach is to pursue a molecular and cellular understanding of the "Flagellar Pocket" (FP), a specialization of the trypanosome cell surface that surrounds the place where the flagellum protrudes from the parasite's surface. This is the site of all trypanosome endo- and exocytosis, so it plays a role in this parasite's strategies for avoiding attack by the host's acquired immune response. We are using electron tomography to pursue structural studies at about 6 nm resolution in 3-D. Our work is organized around the recent finding that a component of human LDL, ApoL1, is cytotoxic to some African trypanosomes but not others, the difference depending on a protein that is specific to their endocytic systems. Preliminary results suggest that this cytotoxic factors enters trypanosomes at the FP but somehow lead to cell lysis and death. We anticipate that this way of killing trypanosomes could be exploited for medical purposes. An understanding of mechanisms for both species-specific and broad-spectrum trypanosome killing by serum factors should provide insight into host-parasite biology and will assist in assessing novel routes to preventative treatments. We have therefore used electron tomography to examine the FP of T. brucei and found that FP-associated membrane components include clathrin-coated vesicles, tubulins, and a wide variety of membrane-bounded compartments. Data for 11 dual-axis tomograms have been collected to reconstruct these compartments in 3D. We are now working to develop labeling techniques that will characterize all the endocytic pathways, including those that internalize cytotoxic factors from mammalian serum.