The role of actin as a determinant of cell shape and virulence of the sexual blood stage of the malaria parasite, Plasmodium falciparum

恶性疟原虫是一种专性细胞内寄生虫，在撒哈拉以南非洲地区导致严重疟疾。寄生虫的传播依赖于有性血期配子体从人类到蚊子宿主的传播。恶性疟原虫配子体经历了显着的形态转化为细长的细胞，扭曲了宿主红细胞，并在人类血管系统中黏附。我们的研究旨在了解形态转化背后的分子机制。我们有证据表明，一种基于肌动蛋白的新型细胞骨架的组装和拆解是寄生虫变形能力的关键组成部分。我们建议描述肌动蛋白细胞骨架的特征，并描绘其与微管蛋白细胞骨架的“串扰”。我们认为，这些以前未被识别的细胞事件代表了一个新的脆弱的目标，以防止配子体传递。为了解决这些基本问题，我们提出了以下研究1。恶性疟原虫配子体中基于肌动蛋白的细胞骨架的功能和生化特征。肌动蛋白和微管蛋白结合蛋白的鉴定和鉴定，这些蛋白调节和促进配子体中细胞骨架结构之间的相互作用。描述导致镰刀形的机制及其对寄生虫隔离和传播的意义。我们将利用基因工程和生化抑制剂来揭示细胞骨架蛋白的功能。超分辨率光学显微镜将被用来探索寄生细胞骨架网络中荧光融合蛋白的时空组织。我们将使用互补蛋白质组学方法识别新的蛋白质，并全面表征它们在配子体中的调节功能。为此，我们将利用细胞计数法和微粒法来评估配子细胞的流变学参数，并模拟脾环境。需要对配子细胞细胞骨架有详细的了解，以描绘配子细胞生物学的关键机制，并确定有前景的干预策略。

Plasmodium falciparum is an obligate intracellular parasite that cause severe malaria in sub-Saharan Africa. Parasite spreading relies on transmission of sexual blood stage gametocytes from humans to the mosquito host. P. falciparum gametocytes undergo remarkable morphological transformation into elongated cells that distort the host red blood cell and cytoadhere in the human vasculature. Our research aims to understand the molecular mechanisms that underlie the morphological transformation. We have evidence that the assembly and disassembly of a novel actin-based cytoskeleton is a key component of the parasite's shape-shifting abilities. We propose to characterize the actin cytoskeleton and delineate its "cross-talk" with the tubulin cytoskeleton. We suggest that these previously unrecognised cellular events represent a novel vulnerable target to prevent gametocyte transmission. To address these fundamental questions we propose the following research.1. Functional and biochemical characterization of the actin-based cytoskeleton in P. falciparum gametocytes.2. Identification and characterization of actin- and tubulin-binding proteins that regulate and facilitate cross-talk between cytoskeleton structures in gametocytes.3. Delineation of mechanisms leading to the falciform shape and its implication for parasite sequestration and transmission.We will utilize genetic engineering and biochemical inhibitors to reveal the function of cytoskeletal proteins. Super-resolution optical microscopy will be employed to probe the spatial-temporal organization of fluorescent-fusion proteins in parasitic-cytoskeletal networks. We will identify novel proteins using complementary proteomic approaches and comprehensively characterize their modulatory function within the gametocyte. To this end we will utilize ektocytometry and microphiltration to assess rheological parameters of gametocytes and mimic the splenic environment.A detailed understanding of the gametocyte cytoskeleton is required to delineate key mechanisms of gametocyte cell biology and to define promising intervention strategies.