PfNT2, a Permease of the Equilibrative Nucleoside Transporter Family in the Endoplasmic Reticulum of Plasmodium falciparum
PfNT2, a Permease of the Equilibrative Nucleoside Transporter Family in the Endoplasmic Reticulum of Plasmodium falciparum
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DOI：
10.1074/jbc.m110.118489
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发表时间：
2010-07-02
影响因子：
4.8
通讯作者：
Mamoun, Choukri Ben
中科院分区：
文献类型：
--
作者：
Downie, Megan J.;El Bissati, Kamal;Mamoun, Choukri Ben
专性细胞内疟疾寄生虫恶性疟原虫的生存和增殖需要从宿主中回收必需的嘌呤。此前的遗传学研究表明，寄生虫质膜嘌呤渗透酶PfNT1在所有自然产生的嘌呤核苷和核苷酸碱基跨寄生虫质膜的运输中起着至关重要的作用。在这里，我们描述了一种胞内渗透酶，PfNT2。PfNT2和PfNT1一样，是平衡核苷转运蛋白家族的成员。对含有绿色荧光蛋白或血凝素标记的PfNT2的转基因寄生虫的共聚焦和免疫电子显微镜分析表明，内质网定位。通过与内质网标记PfBiP的共定位，证实了这一定位。使用酵母作为替代系统，我们证明了将PfNT2靶向于缺乏质膜核苷转运体Fui1的Delta细胞的质膜，使其对有毒的核苷类似物5-氟尿苷具有敏感性。这项研究首次提供了顶端复合体寄生虫细胞内嘌呤渗透酶的证据，并提示了寄生虫内质网在疟疾感染过程中的一种新的生物学功能。
The survival and proliferation of the obligate intracellular malaria parasite Plasmodium falciparum require salvage of essential purines from the host. Genetic studies have previously shown that the parasite plasma membrane purine permease, PfNT1, plays an essential function in the transport of all naturally occurring purine nucleosides and nucleobases across the parasite plasma membrane. Here, we describe an intracellular permease, PfNT2. PfNT2 is, like PfNT1, a member of the equilibrative nucleoside transporter family. Confocal and immunoelectron microscopic analyses of transgenic parasites harboring green fluorescent protein- or hemagglutinin-tagged PfNT2 demonstrated endoplasmic reticulum localization. This localization was confirmed by colocalization with the endoplasmic reticulum marker PfBiP. Using yeast as a surrogate system, we show that targeting PfNT2 to the plasma membrane of fui1 Delta cells lacking the plasma membrane nucleoside transporter Fui1 confers sensitivity to the toxic nucleoside analog 5-fluorouridine. This study provides the first evidence of an intracellular purine permease in apicomplexan parasites and suggests a novel biological function for the parasite endoplasmic reticulum during malaria infection.