Istituto Superiore di Sanità, Dipartimento di Malattie Infettive, Rome, Italy.
Istituto Superiore di Sanità, Servizio Grandi Strumentazioni e Core Facilities, Rome, Italy.
Mol Cell Proteomics. 2020 Dec;19(12):1986-1997. doi: 10.1074/mcp.RA120.002212. Epub 2020 Sep 3.
, the malaria parasite, undergoes a complex life cycle alternating between a vertebrate host and a mosquito vector of the genus In red blood cells of the vertebrate host, multiplies asexually or differentiates into gamete precursors, the male and female gametocytes, responsible for parasite transmission. Sexual stage maturation occurs in the midgut of the mosquito vector, where male and female gametes egress from the host erythrocytes to fuse and form a zygote. Gamete egress entails the successive rupture of two membranes surrounding the parasite, the parasitophorous vacuole membrane and the erythrocyte plasma membrane. In this study, we used the rodent model parasite to design a label-free quantitative proteomic approach aimed at identifying gender-related proteins differentially released/secreted by purified mature gametocytes when activated to form gametes. We compared the abundance of molecules secreted by wild type gametocytes of both genders with that of a transgenic line defective in male gamete maturation and egress. This enabled us to provide a comprehensive data set of egress-related molecules and their gender specificity. Using specific antibodies, we validated eleven candidate molecules, predicted as either gender-specific or common to both male and female gametocytes. All of them localize to punctuate, vesicle-like structures that relocate to cell periphery upon activation, but only three of them localize to the gametocyte-specific secretory vesicles named osmiophilic bodies. Our results confirm that the egress process involves a tightly coordinated secretory apparatus that includes different types of vesicles and may put the basis for functional studies aimed at designing novel transmission-blocking molecules.
疟原虫，经历一个复杂的生命周期，在脊椎动物宿主和蚊子媒介的属之间交替。在脊椎动物宿主的红细胞中，无性繁殖或分化成配子前体，即雄性和雌性配子体，负责寄生虫的传播。性阶段成熟发生在蚊子媒介的中肠，在这里雄性和雌性配子从宿主红细胞中逸出融合形成合子。配子逸出需要连续破坏包围寄生虫的两层膜，即寄生泡膜和红细胞质膜。在这项研究中，我们使用啮齿动物模型寄生虫来设计一种无标记定量蛋白质组学方法，旨在鉴定纯化成熟配子体在被激活形成配子时，性别相关的蛋白质的差异释放/分泌。我们比较了野生型雌雄配子体分泌的分子丰度与雄配子体成熟和逸出缺陷的转基因系的丰度。这使我们能够提供与逸出相关的分子及其性别特异性的全面数据集。使用特异性抗体，我们验证了十一个候选分子，它们被预测为雌雄配子体特异性或雌雄配子体共有的。它们都定位于点状、囊泡样结构，在激活时迁移到细胞外周，但只有三种定位于称为嗜锇体的配子体特异性分泌囊泡。我们的结果证实，逸出过程涉及一个紧密协调的分泌装置，包括不同类型的囊泡，并可能为旨在设计新型传播阻断分子的功能研究奠定基础。
