Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.
School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom.
PLoS Biol. 2021 Mar 11;19(3):e3001081. doi: 10.1371/journal.pbio.3001081. eCollection 2021 Mar.
The apical complex is the instrument of invasion used by apicomplexan parasites, and the conoid is a conspicuous feature of this apparatus found throughout this phylum. The conoid, however, is believed to be heavily reduced or missing from Plasmodium species and other members of the class Aconoidasida. Relatively few conoid proteins have previously been identified, making it difficult to address how conserved this feature is throughout the phylum, and whether it is genuinely missing from some major groups. Moreover, parasites such as Plasmodium species cycle through 3 invasive forms, and there is the possibility of differential presence of the conoid between these stages. We have applied spatial proteomics and high-resolution microscopy to develop a more complete molecular inventory and understanding of the organisation of conoid-associated proteins in the model apicomplexan Toxoplasma gondii. These data revealed molecular conservation of all conoid substructures throughout Apicomplexa, including Plasmodium, and even in allied Myzozoa such as Chromera and dinoflagellates. We reporter-tagged and observed the expression and location of several conoid complex proteins in the malaria model P. berghei and revealed equivalent structures in all of its zoite forms, as well as evidence of molecular differentiation between blood-stage merozoites and the ookinetes and sporozoites of the mosquito vector. Collectively, we show that the conoid is a conserved apicomplexan element at the heart of the invasion mechanisms of these highly successful and often devastating parasites.
顶复体复合物是顶复门寄生虫用于入侵的工具,而圆锥体是该器官的一个显著特征,在该门中普遍存在。然而,据信圆锥体在疟原虫和其他类锥体亚门成员中严重减少或缺失。以前相对较少鉴定到圆锥体蛋白,这使得难以确定该特征在整个门中是如何保守的,以及它是否真的从一些主要群体中缺失。此外,疟原虫等寄生虫经历 3 种入侵形式,并且圆锥体在这些阶段之间可能存在差异存在的可能性。我们应用空间蛋白质组学和高分辨率显微镜技术,对模型顶复体弓形虫中的圆锥体相关蛋白的组织进行了更全面的分子清单和理解。这些数据显示了圆锥体亚结构在整个顶复门(包括疟原虫)中的分子保守性,甚至在相关的肉足虫门(如 Chromera)和鞭毛藻类中也是如此。我们对疟疾模型 P. berghei 中的几种圆锥体复合物蛋白进行了标记和观察,发现其所有裂殖子形式都具有相同的结构,并证明了血期裂殖子与蚊媒的卵囊和子孢子之间存在分子分化。总的来说,我们表明圆锥体是一个保守的顶复体元件,是这些高度成功且常常具有破坏性的寄生虫入侵机制的核心。