Functional characterization of striated fiber assemblins in malaria parasites

项目总结 疟疾是全世界疾病和死亡的一个重要原因，其中大多数死亡是由 恶性疟原虫感染。人类疟疾的症状和体征是无性繁殖的结果。 寄生虫在人类红细胞中的复制。在这一临床重要的血液期，恶性疟原虫 寄生虫通过分裂分裂--在这个过程中产生几个子细胞的成分 在一个共同的细胞质内，然后分裂，同步的细胞质分裂，产生个体 入侵的女儿。侵袭性子代寄生虫，称为裂殖子，发生在 高保真，确保每个女儿都有一个细胞核和所需的细胞器。分子 这种高保真的核和细胞器分割的机制还没有完全被理解 疟原虫。 对相关Apicomplexan寄生虫弓形虫的研究发现了一个蛋白质家族，参考 如条纹纤维集合素(SFA)，对寄生虫细胞分裂至关重要。SFA的假设是 在分裂核的中心体和两个新形成的顶端之间形成联系 弓形虫内生过程中的子寄生虫。恶性疟原虫SFAs、PfSFA1和PfSFA1的同源基因 据报道，PfSFA2在全基因组转座子筛选中是必不可少的。与此形成对比的是 数据，我们证明了这两个蛋白是恶性疟原虫无性复制所必需的。基座 根据我们的初步数据，我们假设PfSFA1和PfSFA2在 寄生虫分割。在目前的方案中，我们将在一系列显微镜下测试这一假设 化验。此外，我们还将通过对寄生虫的鉴定来评估PfSFA1和PfSFA2的功能 诱导性基因敲除后的停滞和形态缺陷。为了更全面地了解 PfSFA1和PfSFA2的分子功能，我们将通过共同作用来确定蛋白质的直接相互作用。 免疫沉淀和通过邻近标记的间接或瞬时相互作用。通过确定健壮的 针对疟原虫SFAs的蛋白质相互作用网络，我们将为了解其 分子功能。我们假设SFAs蛋白对分段的组织至关重要 在恶性疟原虫的无性繁殖过程中。总而言之，拟议的研究将询问该功能 并直接确定它们在恶性疟原虫分割过程中的作用。

PROJECT SUMMARY Malaria is an important cause of illness and death worldwide, with most of these deaths resulting from Plasmodium falciparum infection. The signs and symptoms of human malaria results from the asexual replication of parasites in human red blood cells. During this clinically important blood stage, P. falciparum parasites divide by schizogony – a process wherein components for several daughter cells are produced within a common cytoplasm and then segmentation, a synchronized cytokinesis, produces individual invasive daughters. The generation of the invasive daughter parasites, known as merozoites, occurs with high fidelity, ensuring that each daughter has a single nucleus and the required organelles. The molecular mechanism underlying this high fidelity of nuclear and organellar partitioning is incompletely understood in Plasmodium. Studies in the related Apicomplexan parasite Toxoplasma gondii identified a family of proteins, referred to as striated fiber assemblins (SFAs), that are critical for parasite cell division. The SFAs are hypothesized to form a connection between the centrosome of dividing nuclei and the newly forming apical ends of the two daughter parasites during T. gondii endodyogeny. The P. falciparum orthologs of the SFAs, PfSFA1 and PfSFA2, have been reported to be dispensable in a genome-wide transposon screen. In contrast to this data, we demonstrate that these two proteins are essential for asexual replication in P. falciparum. Based on our preliminary data, we hypothesize that PfSFA1 and PfSFA2 localize to a filament-like structure during parasite segmentation. In the current proposal, we will test this hypothesize in a series of microscopy assays. Furthermore, we will also evaluate the function of PfSFA1 and PfSFA2 by characterizing parasite arrest and morphologic defects following inducible knockout. To gain a more complete understanding of the molecular functions of PfSFA1 and PfSFA2, we will determine the direct protein interactions by co- immunoprecipitation and the indirect or transient interactions by proximity labeling. By determining a robust protein interaction network for the Plasmodium SFAs, we will establish the foundation to understand their molecular function. We hypothesize that the SFAs proteins are critical for organization of segmentation during the asexual replication of P. falciparum. Together, the proposed studies will interrogate the function of these two essential proteins and directly identify their role during P. falciparum segmentation.