Chasen Nathan M, Asady Beejan, Lemgruber Leandro, Vommaro Rossiane C, Kissinger Jessica C, Coppens Isabelle, Moreno Silvia N J
Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA.
Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA.
mSphere. 2017 May 17;2(3). doi: 10.1128/mSphere.00027-17. eCollection 2017 May-Jun.
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 that is related to the recently described η-class CA found in . 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. mutant tachyzoites lacking display a growth and invasion phenotype 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. is an intracellular pathogen that infects humans and animals. The pathogenesis of 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 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.
碳酸酐酶相关蛋白（CARPs）先前被描述为与α-碳酸酐酶（α-CAs）密切相关的无催化活性蛋白。这些CARPs在动物（包括脊椎动物和无脊椎动物）和病毒中以独立蛋白或其他蛋白的结构域形式存在。我们在此报告在单细胞生物中鉴定出一种新的CARP（TgCA_RP），它与最近在[具体生物]中描述的η类碳酸酐酶相关。TgCA_RP在其C末端经翻译后修饰，带有糖基磷脂酰肌醇锚定，这对其在细胞内速殖子中的定位很重要。通过使用特异性抗体的免疫荧光和免疫电子显微镜证明，该蛋白定位于成熟速殖子的整个棒状体泡以及分裂中的速殖子新生棒状体的外膜。缺乏[具体物质]的突变速殖子表现出一种生长和侵袭表型，并且具有非典型的棒状体形态。这些突变体在小鼠模型中也表现出毒力降低。我们的结果表明TgCA_RP在棒状体的生物发生中起重要作用。[具体病原体]是一种感染人类和动物的细胞内病原体。[具体病原体]的发病机制与其裂解周期有关，裂解周期始于速殖子侵入宿主细胞并从特化细胞器分泌蛋白质。一旦进入宿主细胞，寄生虫会形成一个寄生泡（PV）并在其中分裂。棒状体是特化的分泌细胞器，含有多种蛋白质，其中许多在侵袭过程中被分泌。这些蛋白质不仅在寄生虫与宿主的初始相互作用中起重要作用，而且在寄生泡的形成以及宿主细胞的修饰中也起重要作用。我们在此报告鉴定出一种新的[具体病原体]碳酸酐酶相关蛋白（TgCA_RP），它定位于成熟速殖子的棒状体。TgCA_RP对棒状体的形态以及寄生虫的侵袭和生长很重要。TgCA_RP对寄生虫的毒力也至关重要。我们认为TgCA_RP在棒状体的生物发生中起作用。
