A Glycosylphosphatidylinositol-Anchored Carbonic Anhydrase-Related Protein of Toxoplasma gondii Is Important for Rhoptry Biogenesis and Virulence.
A Glycosylphosphatidylinositol-Anchored Carbonic Anhydrase-Related Protein of Toxoplasma gondii Is Important for Rhoptry Biogenesis and Virulence.
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DOI：
10.1128/msphere.00027-17
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发表时间：
2017-05
期刊：
影响因子：
4.8
通讯作者：
Moreno SNJ
中科院分区：
文献类型：
--
作者：
Chasen NM;Asady B;Lemgruber L;Vommaro RC;Kissinger JC;Coppens I;Moreno SNJ
弓形虫是一种细胞内病原体，感染人类和动物。弓形虫的发病机制与其裂解周期有关，该周期始于速殖子侵入宿主细胞并从专门的细胞器分泌蛋白质。一旦进入宿主细胞，寄生虫就会产生一个寄生空泡（PV），并在那里分裂。棒状体是含有蛋白质的特化分泌细胞器，其中许多蛋白质在入侵期间分泌。这些蛋白质不仅在寄生虫和宿主之间的初始相互作用期间，而且在PV的形成和宿主细胞的修饰中具有重要作用。我们在这里报告的鉴定一个新的T。弓形虫碳酸酐酶相关蛋白（TgCA_RP）定位于成熟速殖子的棒状体。TgCA_RP对棒状体的形态及寄生虫的侵入和生长有重要作用。TgCA_RP对寄生虫毒力也至关重要。我们认为TgCA_RP在棒状体的生物发生中发挥作用。碳酸酐酶相关蛋白（Carbonic anhydrase-related proteins，CARP）是一种与α-碳酸酐酶（α-carbonic anhydrase，α-CA）密切相关的无催化活性蛋白。这些CARP在动物（脊椎动物和无脊椎动物）和病毒中作为独立的蛋白质或其他蛋白质的结构域被发现。本文报道了在单细胞弓形虫（Toxoplasma gondii）中发现的一种新的CARP（TgCA_RP），它与恶性疟原虫（Plasmodium falciparum）中发现的η类CA有关。TgCA_RP在其C末端被糖基化磷脂酰肌醇锚后修饰，这对于其在细胞内速殖子中的定位是重要的。该蛋白定位于整个棒状体球成熟速殖子和新生棒状体在分裂速殖子的外膜，如使用特异性抗体的免疫荧光和免疫电镜所示。缺乏TgCA_RP的弓形虫突变体速殖子在体外表现出生长和侵袭表型，并具有非典型的棒状体形态。突变体在小鼠模型中也表现出降低的毒力。结果表明，TgCA_RP在棒状体的生物发生中起着重要作用。重要性弓形虫是一种细胞内病原体，感染人类和动物。弓形虫的发病机制与其裂解周期有关，该周期始于速殖子侵入宿主细胞并从专门的细胞器分泌蛋白质。一旦进入宿主细胞，寄生虫就会产生一个寄生空泡（PV），并在那里分裂。棒状体是含有蛋白质的特化分泌细胞器，其中许多蛋白质在入侵期间分泌。这些蛋白质不仅在寄生虫和宿主之间的初始相互作用期间，而且在PV的形成和宿主细胞的修饰中具有重要作用。我们在这里报告的鉴定一个新的T。弓形虫碳酸酐酶相关蛋白（TgCA_RP）定位于成熟速殖子的棒状体。TgCA_RP对棒状体的形态及寄生虫的侵入和生长有重要作用。TgCA_RP对寄生虫毒力也至关重要。我们认为TgCA_RP在棒状体的生物发生中发挥作用。
Toxoplasma gondii is an intracellular pathogen that infects humans and animals. The pathogenesis of T. gondii is linked to its lytic cycle, which starts when tachyzoites invade host cells and secrete proteins from specialized organelles. Once inside the host cell, the parasite creates a parasitophorous vacuole (PV) where it divides. Rhoptries are specialized secretory organelles that contain proteins, many of which are secreted during invasion. These proteins have important roles not only during the initial interaction between parasite and host but also in the formation of the PV and in the modification of the host cell. We report here the identification of a new T. gondii carbonic anhydrase-related protein (TgCA_RP), which localizes to rhoptries of mature tachyzoites. TgCA_RP is important for the morphology of rhoptries and for invasion and growth of parasites. TgCA_RP is also critical for parasite virulence. We propose that TgCA_RP plays a role in the biogenesis of rhoptries. Carbonic anhydrase-related proteins (CARPs) have previously been described as catalytically inactive proteins closely related to α-carbonic anhydrases (α-CAs). These CARPs are found in animals (both vertebrates and invertebrates) and viruses as either independent proteins or domains of other proteins. We report here the identification of a new CARP (TgCA_RP) in the unicellular organism Toxoplasma gondii that is related to the recently described η-class CA found in Plasmodium falciparum. TgCA_RP is posttranslationally modified at its C terminus with a glycosylphosphatidylinositol anchor that is important for its localization in intracellular tachyzoites. The protein localizes throughout the rhoptry bulbs of mature tachyzoites and to the outer membrane of nascent rhoptries in dividing tachyzoites, as demonstrated by immunofluorescence and immunoelectron microscopy using specific antibodies. T. gondii mutant tachyzoites lacking TgCA_RP display a growth and invasion phenotype in vitro and have atypical rhoptry morphology. The mutants also exhibit reduced virulence in a mouse model. Our results show that TgCA_RP plays an important role in the biogenesis of rhoptries. IMPORTANCE Toxoplasma gondii is an intracellular pathogen that infects humans and animals. The pathogenesis of T. gondii is linked to its lytic cycle, which starts when tachyzoites invade host cells and secrete proteins from specialized organelles. Once inside the host cell, the parasite creates a parasitophorous vacuole (PV) where it divides. Rhoptries are specialized secretory organelles that contain proteins, many of which are secreted during invasion. These proteins have important roles not only during the initial interaction between parasite and host but also in the formation of the PV and in the modification of the host cell. We report here the identification of a new T. gondii carbonic anhydrase-related protein (TgCA_RP), which localizes to rhoptries of mature tachyzoites. TgCA_RP is important for the morphology of rhoptries and for invasion and growth of parasites. TgCA_RP is also critical for parasite virulence. We propose that TgCA_RP plays a role in the biogenesis of rhoptries.