Essential function of a putative glycosyltransferase in P. falciparum

项目摘要 人类疟疾的致命形式是由细胞内寄生虫恶性疟原虫引起的，这种寄生虫 每年造成近45万人死亡。这些寄生虫的感染导致约2.5亿人感染 每年。然而，没有有效的疟疾疫苗，这种寄生虫已经获得了 对临床上使用的所有抗疟疾药物产生抗药性。此外，这些耐药菌株正在蔓延 在世界各地。因此，确定寄生虫使用的基本可用药途径是至关重要的。 在人类宿主细胞内生长。其中一个知之甚少但却必不可少的途径就是修饰 通过糖分子或多聚糖对寄生虫蛋白质的作用。在其他模式生物中，这一过程是必不可少的 对于蛋白质的功能，主要发生在分泌途径中。关于疟原虫的最新研究 已表明几种寄生虫表面配体的葡聚糖修饰在寄生虫中起着至关重要的作用 在蚊子媒介内的传播及其发展。但人们对这种功能知之甚少，如果有的话。 在临床重要的恶性疟原虫红细胞内生长过程中糖化作用的变化。我们最近 发现了一种假定的糖基转移酶，它是一种存在于 内质网。为了研究它在寄生虫生长的红细胞内阶段中的作用，我们 产生了这种蛋白质的条件突变。我们假设，糖基转移酶的功能 该蛋白在恶性疟原虫红细胞内生长过程中起着重要作用。我们的预赛 数据显示，这种蛋白质对人体红细胞内寄生虫的生长是必不可少的，并且是必需的 在红细胞内生命周期结束时，子体寄生虫从宿主细胞中流出。vbl.使用 细胞、生物化学和遗传学方法，我们将定义该基因的功能 女儿寄生虫。推测的糖基转移酶活性对寄生虫生存的重要性 接受测试。拟议的研究将使用重组酶来确定这一酶的活性 糖基转移酶。基于邻近效应的生物素化方法与质谱学的结合 将被用来确定相互作用物以及假定的底物。这个项目的成功将揭示 寄生虫在人类红血球中用于无性扩张的新的和必要的糖基化途径 血细胞。

Project Summary The lethal form of human malaria is caused by the intracellular parasite Plasmodium falciparum, which causes nearly 450,000 deaths every year. Infection by these parasites results in ~250 million infections each year. However, there are no effective vaccines against malaria and the parasite has gained resistance to all antimalarial drugs used in the clinic. Further, these drug-resistant strains are spreading throughout the world. Therefore, it is crucial to identify essential druggable pathways used by the parasite to grow within human host cells. One such poorly understood but essential pathway is the modification of parasite proteins by sugar molecules or glycans. In other model organisms, this process is essential for protein function and mostly occurs in the secretory pathway. Recent work in Plasmodium parasites has shown that glycan modification of several parasite surface ligands play an essential role in parasite transmission and its development within the mosquito vector. But little is known about the function, if any, of glycosylation during the clinically important intraerythrocytic growth of P. falciparum. We recently identified a putative glycosyltransferase as an essential interactor of a heat shock protein residing in the endoplasmic reticulum. To study its function during the intraerythrocytic stages of parasite growth, we generated conditional mutants for this protein. We hypothesize that the glycosyltransferase function of this protein plays an essential function during intraerythrocytic growth of P. falciparum. Our preliminary data show that this protein is essential for parasite growth within human red blood cells and is required for the egress of daughter parasites from the host cell at the end of the intraerythrocytic life cycle. Using cellular, biochemical, and genetic approaches, we will define the function of this gene during egress of daughter parasites. The essentiality of the putative glycosyltransferase activity for parasite survival will be tested. The proposed studies will use recombinant enzyme to define the enzymatic activity of this glycosyltransferase. Proximity-dependent biotinylation approaches combined with mass spectrometry will be used to identify interactors as well as putative substrates. The success of this project will reveal novel and essential glycosylation pathways used by the parasite for asexual expansion in human red blood cells.