Two Plasmodium rhomboid proteases preferentially cleave different adhesins implicated in all invasive stages of malaria.
Two Plasmodium rhomboid proteases preferentially cleave different adhesins implicated in all invasive stages of malaria.
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DOI：
10.1371/journal.ppat.0020113
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发表时间：
2006-10
期刊：
影响因子：
6.7
通讯作者：
Urban S
中科院分区：
文献类型：
--
作者：
Baker RP;Wijetilaka R;Urban S
疟疾病原体对宿主细胞的侵袭取决于寄生虫的跨膜粘附素，这些粘附素会吸引宿主细胞受体。粘附素必须在寄生虫进入细胞之前释放，但是加工酶仍然难以捉摸。最近的工作表明，弓形虫菱形内膜蛋白酶TGROM5催化了这种必不可少的裂解。但是，疟原虫不会编码直接的TGROM5同源物。我们检查了当前认为在异源测定中被模型和菱形质量蛋白酶侵入的14粒恶性疟原虫的加工。虽然大多数粘附素都含有芳香的跨膜残基，但不能被非寄生虫菱形蛋白裂解，包括果蝇rhomboid-1，恶性疟原虫菱形rhomboid蛋白（PFROM）4（PFE0340C）能够有效地处理这些粘附素有效地处理这些粘附素，并显示出新颖的介质性。相反，PFROM1（PF11_0150）与其他生物体的菱形蛋白酶共享特异性，并且是唯一能够裂解顶端膜抗原1（AMA1）的PFROM1（AMA1）。因此，PFROM 1和/或4能够裂解多种粘附素，包括陷阱，CTRP，MTRAP，PFF0800C，EBA-175，BAEBL，JESEBL，JESEBL，MAEBL，AMA1，RH1，RH2A，RH2A，RH2B和RH4和RH4，但不是PTRAMP和CLEAVAGE，以及裂解和裂解在粘附素跨膜结构域上。交换BAEBL和AMA1之间的跨膜区域切换了这两个底物的Pfrom 1和4的相对偏好。我们的分析表明，pfrom 1和4具有不同底物特异性的功能，共同构成Tgrom5对切割多种粘附素的特异性。这是对疟原虫蛋白酶的首次酶促分析，并表明Pfrom在脊椎动物宿主和蚊子载体中都参与了疟疾生命周期的所有侵入性阶段。
疟疾是一种毁灭性的全球疾病，遭受了全球10％以上人口的10％，每年占1至300万人的生命。疟原虫疟原虫对宿主细胞的侵袭最终要求酶释放寄生虫和宿主细胞之间的密切接触，但尚未鉴定出这些酶。先前发现，菱形酶参与了相关病原体弓形虫的过程。目前的工作检查了菱形酶的活性，并揭示了两种晶状体菱形酶可以在入侵期间介导寄生虫和宿主细胞膜之间接触的目前已知的蛋白质最多（即使不是全部）蛋白质。这两种菱形酶对不同靶蛋白具有不同的特异性，但是可以一起处理所有类似的弓形虫菱形酶可以单独加工的蛋白质。该分析表明，菱形酶可能对于寄生虫通过人和蚊子宿主中不同途径侵袭宿主细胞的能力至关重要，因此为治疗或控制疟疾的毁灭性作用提供了一种新的治疗靶标。
Invasion of host cells by the malaria pathogen Plasmodium relies on parasite transmembrane adhesins that engage host-cell receptors. Adhesins must be released by cleavage before the parasite can enter the cell, but the processing enzymes have remained elusive. Recent work indicates that the Toxoplasma rhomboid intramembrane protease TgROM5 catalyzes this essential cleavage. However, Plasmodium does not encode a direct TgROM5 homolog. We examined processing of the 14 Plasmodium falciparum adhesins currently thought to be involved in invasion by both model and Plasmodium rhomboid proteases in a heterologous assay. While most adhesins contain aromatic transmembrane residues and could not be cleaved by nonparasite rhomboid proteins, including Drosophila Rhomboid-1, Plasmodium falciparum rhomboid protein (PfROM)4 (PFE0340c) was able to process these adhesins efficiently and displayed novel substrate specificity. Conversely, PfROM1 (PF11_0150) shared specificity with rhomboid proteases from other organisms and was the only PfROM able to cleave apical membrane antigen 1 (AMA1). PfROM 1 and/or 4 was thus able to cleave diverse adhesins including TRAP, CTRP, MTRAP, PFF0800c, EBA-175, BAEBL, JESEBL, MAEBL, AMA1, Rh1, Rh2a, Rh2b, and Rh4, but not PTRAMP, and cleavage relied on the adhesin transmembrane domains. Swapping transmembrane regions between BAEBL and AMA1 switched the relative preferences of PfROMs 1 and 4 for these two substrates. Our analysis indicates that PfROMs 1 and 4 function with different substrate specificities that together constitute the specificity of TgROM5 to cleave diverse adhesins. This is the first enzymatic analysis of Plasmodium rhomboid proteases and suggests an involvement of PfROMs in all invasive stages of the malaria lifecycle, in both the vertebrate host and the mosquito vector. Malaria is a devastating global disease that afflicts over 10% of the world's population, claiming between 1 and 3 million lives annually. Invasion of host cells by the malaria parasite Plasmodium ultimately requires enzymes to release close contacts made between the parasite and host cell, but these enzymes have not been identified. Rhomboid enzymes were previously found to be involved in this process in the related pathogen Toxoplasma. The present work examined the activity of Plasmodium rhomboid enzymes, and revealed that two Plasmodium rhomboid enzymes can cleave most, if not all, of the proteins currently known to mediate contacts between the parasite and host-cell membranes during invasion. The two rhomboid enzymes had different specificities for the different target proteins, but together could process all of the proteins that the similar Toxoplasma rhomboid enzyme could process alone. This analysis suggests that rhomboid enzymes may be essential for the ability of the parasite to invade host cells through different pathways both in the human and mosquito hosts, and therefore offers a possible new therapeutic target to explore for treating or controlling the devastating effects of malaria.
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影响因子：
4.9
作者：
Conseil, V;Soête, M;Dubremetz, JF
通讯作者：
Dubremetz, JF
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9.6
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作者：
Alexander, David L.;Arastu-Kapur, Shirin;Boothroyd, John C.
通讯作者：
Boothroyd, John C.