Understanding the role of malaria red blood cell binding proteins in invasion and host specificity

人畜共患的猿类疟疾寄生虫诺氏疟原虫是东南亚发病率和死亡率的一个重要和新出现的原因。间日疟原虫是密切相关的，具有相同的入侵途径，是全球疟疾的第二大原因。间日疟原虫感染人类，而诺氏疟原虫可感染人类和猕猴，这一灵长类宿主对疟疾控制构成极大挑战。众所周知，允许寄生虫侵入红细胞（红细胞）的蛋白质是毒力和宿主细胞易感性的重要决定因素，因此对了解宿主范围至关重要。该项目旨在了解Duffy结合蛋白（DBP）的作用，DBP是一种疟疾寄生虫蛋白，需要结合和侵入红细胞。虽然我们知道DBP与人红细胞上的DARC受体的结合对于诺氏疟原虫（PkDBPa）和间日疟原虫（PvDBP）的侵袭至关重要，但我们不知道这种结合的作用，也不知道包括磷酸化和蛋白水解加工在内的各种蛋白质修饰如何促进其功能。我们率先在诺氏疟原虫中使用同源物替代方法来研究间日疟原虫同源物的功能，为直接比较PkDBPa和PvDBP如何影响入侵和支撑宿主范围提供了一个平台。该项目将使用尖端的bar - seq方法来研究表达DBP变异的寄生虫，比较Pv和PkDBP结构域的功能作用、翻译后修饰、配体-受体相互作用（Moon Lab，LSHTM）。结构和生化研究将用于检查DBPorthologues如何与DARC受体相互作用（Higgins实验室，牛津）。这也将通过群体遗传学来了解这些关键相互作用域的多态性程度（Campino实验室，LSHTM）。最后，学生将使用入侵的荧光活细胞成像实时研究这些过程，获得关于这些蛋白质如何促进入侵和定义宿主特异性的新见解。

The zoonotic simian malaria parasite P. knowlesi, is a significant and emerging causeof morbidity and mortality in South-East Asia. P. vivax is closely-related, sharesinvasion pathways, and is the second biggest cause of malaria globally. Whilst P. vivaxonly infects humans, P. knowlesi can infect both humans and macaques, and thisprimate reservoir presents an extreme challenge for malaria control. Proteins thatallow the parasite to invade red blood cells (RBCs) are known to be importantdeterminants of virulence and host cell susceptibility, thus critical to understandinghost-range. The project aims to understand the role of the Duffy binding protein (DBP),a malaria parasite protein which is required to bind and invade RBCs. Whilst we knowbinding of DBP to the DARC receptor on human RBCs is essential for invasion of both P.knowlesi (PkDBPa) and P. vivax (PvDBP), we do not know what this binding does, norhow various protein modifications including phosphorylation and proteolytic processingcontribute to its function. We have pioneered orthologue replacement approaches in P.knowlesi to study functions of orthologues from P. vivax- providing a platform todirectly compare how PkDBPa and PvDBP affect invasion and underpin host range. Theproject will dissect the functional role of domains, posttranslational modifications,ligand-receptor interactions comparatively across both Pv and PkDBP using cuttingedgeBar-Seq approaches to study pooled parasite expressing DBP variants (Moon Lab,LSHTM). Structural and biochemical studies will be used to examine how DBPorthologues interact with the DARC receptor (Higgins Lab, Oxford). This will also beinformed by population genetics to understand the extent of polymorphisms in thesekey interacting domains (Campino Lab, LSHTM). Finally, the student will usefluorescent live-cell imaging of invasion to study these processes in real time, gainingnew insights into how these proteins facilitate invasion and define host specificity.