Proellocks Nicholas I, Kovacevic Svetozar, Ferguson David J P, Kats Lev M, Morahan Belinda J, Black Casilda G, Waller Karena L, Coppel Ross L
NHMRC Program in Malaria, Department of Microbiology, Monash University, Vic. 3800, Australia.
Int J Parasitol. 2007 Sep;37(11):1233-41. doi: 10.1016/j.ijpara.2007.03.013. Epub 2007 Apr 19.
Apicomplexan parasites are characterised by the presence of specialised organelles, such as rhoptries, located at the apical end of invasive forms that play an important role in invasion of the host cell and formation of the parasitophorous vacuole. In this study, we have characterised a novel Plasmodium falciparum rhoptry protein, Pf34, encoded by a single exon gene located on chromosome 4 and expressed as a 34kDa protein in mature asexual stage parasites. Pf34 is expressed later in the life cycle than the previously described rhoptry protein, Rhoptry Associated Membrane Antigen (RAMA). Orthologues of Pf34 are present in other Plasmodium species and a potential orthologue has also been identified in Toxoplasma gondii. Indirect immunofluorescence assays show that Pf34 is located at the merozoite apex and localises to the rhoptry neck. Pf34, previously demonstrated to be glycosyl-phosphatidyl-inositol (GPI)-anchored [Gilson, P.R., Nebl, T., Vukcevic, D., Moritz, R.L., Sargeant, T., Speed, T.P., Schofield, L., Crabb, B.S. (2006) Identification and stoichiometry of GPI-anchored membrane proteins of the human malaria parasite Plasmodium falciparum. Mol. Cell. Proteomics 5, 1286-1299.], is associated with parasite-derived detergent-resistant microdomains (DRMs). Pf34 is carried into the newly invaded ring, consistent with a role for Pf34 in the formation of the parasitophorous vacuole. Pf34 is exposed to the human immune system during infection and is recognised by human immune sera collected from residents of malaria endemic areas of Vietnam and Papua New Guinea.
顶复门寄生虫的特征是存在特化的细胞器,如位于侵袭性虫体顶端的棒状体,这些细胞器在宿主细胞入侵和寄生泡形成中起重要作用。在本研究中,我们鉴定了一种新型的恶性疟原虫棒状体蛋白Pf34,它由位于4号染色体上的单外显子基因编码,在成熟无性阶段的寄生虫中表达为34kDa的蛋白。Pf34在生命周期中的表达时间比先前描述的棒状体蛋白——棒状体相关膜抗原(RAMA)要晚。Pf34的直系同源物存在于其他疟原虫物种中,并且在刚地弓形虫中也鉴定出了一个潜在的直系同源物。间接免疫荧光分析表明,Pf34位于裂殖子顶端,并定位于棒状体颈部。Pf34先前已被证明是糖基磷脂酰肌醇(GPI)锚定的[吉尔森,P.R.,内布尔,T.,武克切维奇,D.,莫里茨,R.L.,萨金特,T.,斯皮德,T.P.,斯科菲尔德,L.,克拉布,B.S.(2006年)人类疟原虫恶性疟原虫GPI锚定膜蛋白的鉴定和化学计量。《分子与细胞蛋白质组学》5,1286 - 1299。],与寄生虫来源的耐去污剂微区(DRMs)相关。Pf34被带入新入侵的环状体,这与Pf34在寄生泡形成中的作用一致。Pf34在感染期间暴露于人体免疫系统,并被从越南和巴布亚新几内亚疟疾流行地区居民采集的人体免疫血清所识别。