Signaling GPI-phosphlipase C of a Trypanosome

锥虫的 GPI-磷脂酶 C 信号传导

基本信息

批准号：
8072926
负责人：
KOJO A. MENSA-WILMOT
金额：
$ 1.72万
依托单位：
UNIVERSITY OF GEORGIA
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-05-24 至 2010-08-15
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Endocytosis and cell signaling are important for viability of eukaryotes. In Trypanosoma brucei, little is known about cell signaling because the major receptors studied in model eukaryotes are unrecognizable in the parasite genome. T. brucei has a glycosylphosphatidylinositol-phospholipase C (GPI-PLC) whose biological function(s) of GPI-PLC have been elusive. We found recently that GPI-PLC stimulates endocytosis of transferrin up to 500%, and that enzyme activity is needed for this physiological effect. Therefore, we hypothesized that a cleavage product of GPI-PLC would be sufficient to stimulate endocytosis. Consistent with this concept, exogenous diacylglycerol (DAG) promoted endocytosis in the parasite. Thus, T. brucei has receptors for DAG that regulate endocytosis. Our long-term goals are to delineate the components and evaluate the physiological significance of DAG signaling in T. brucei. Towards these goals, we describe approaches for identification of DAG-binding proteins (TbDAGBPs). In Specific Aim 1, we will (i) clone and characterize TbDAGBPs predicted from bioinformatic analysis; (ii) use conventional chromatography to purify TbDAGBPs; and (iii) screen a cDNA expression library for TbDAGBPs. In Specific Aim 2, effectors that link DAG signaling to the endocytic system will be identified, by knocking down expression of TbDAGBPs, and testing whether the TbDAGBP-deficient T. brucei lose ability to stimulate endocytosis in response to DAG. These studies will lead to discovery of novel DAG binding proteins because the C1-domain used in vertebrates for recognition of DAG is not detectable in the genome of T. brucei. Trypanosomes cause diseases that affect millions of people world-wide. Work described in this proposal may lead to discovery of new signaling pathways that may be targeted for treatment of human African trypanosomiasis.

描述（由申请人提供）：内吞作用和细胞信号传导对于真核生物的生存能力很重要。在布鲁氏锥虫瘤中，对细胞信号传导知之甚少，因为在寄生虫基因组中，模型真核生物中研究的主要受体无法识别。 T. brucei具有糖基磷脂酰肌醇 - 磷脂酶C（GPI-PLC），其GPI-PLC的生物学功能难以捉摸。我们最近发现，GPI-PLC刺激转铁蛋白的内吞作用高达500％，并且这种生理作用需要酶活性。因此，我们假设GPI-PLC的切割产物足以刺激内吞作用。与这个概念一致，外源二酰基甘油（DAG）促进了寄生虫的内吞作用。因此，布鲁氏菌具有调节内吞作用的DAG受体。我们的长期目标是描述组件并评估T. Brucei中DAG信号的生理意义。朝向这些目标，我们描述了鉴定DAG结合蛋白（TBDAGBPS）的方法。在特定的目标1中，我们将（i）克隆并表征来自生物信息学分析预测的TBDAGBP；（ii）使用常规色谱法净化tbdagbps；（iii）筛选用于tbdagbps的cDNA表达式库。在特定的目标2中，将通过击倒tbdagbps的表达来确定将DAG信号传导与内吞系统联系起来的效应子，并测试Brucei缺乏TBDAGBP的T. brucei是否失去了刺激内吞作用的能力，以响应DAG。这些研究将导致发现新型DAG结合蛋白，因为在Brucei的基因组中无法检测到用于识别DAG的脊椎动物的C1域。锥虫会引起影响全球数百万人的疾病。该提案中描述的工作可能导致发现可能针对人类非洲锥虫病治疗的新信号通路。