EnP1, a microsporidian spore wall protein that enables spores to adhere to and infect host cells in vitro
EnP1, a microsporidian spore wall protein that enables spores to adhere to and infect host cells in vitro
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DOI：
10.1128/ec.00113-07
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发表时间：
2007-08-01
期刊：
影响因子：
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通讯作者：
Hayman, J. Russell
中科院分区：
文献类型：
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作者：
Southern, Timothy R.;Jolly, Carrie E.;Hayman, J. Russell
微孢子虫是孢子形成真菌病原体，其需要宿主细胞的细胞内环境进行繁殖。我们已经表明，属脑炎原虫的孢子坚持宿主细胞表面糖胺聚糖（GAG）在体外，这种坚持有助于调节感染过程。在本研究中，从E.发现兔和脑炎原虫与宿主细胞表面相互作用。氨基酸序列的分析揭示了多个肝素结合基序，这是已知的细胞外基质相互作用。重组EnP 1蛋白和纯化的EnP 1抗体均抑制孢子粘附，导致宿主细胞感染减少。此外，当通过定点诱变删除N-末端肝素结合基序时，消除了对粘附的抑制。我们的透射免疫电子显微镜显示，EnP 1是嵌入在微孢子虫的内生孢子和外孢子，并发现在极囊/锚定盘区域，该地区的外翻的极管被释放的高丰度。最后，通过使用宿主细胞结合测定，EnP 1显示结合宿主细胞表面，但不结合缺乏表面GAG的那些。总的来说，这些数据表明，鉴于其在内生孢子和外孢子中的表达，EnP 1是一种微孢子虫细胞壁蛋白，其可以在结构能力和调节体外宿主细胞粘附和感染中发挥作用。
Microsporidia are spore-forming fungal pathogens that require the intracellular environment of host cells for propagation. We have shown that spores of the genus Encephalitozoon adhere to host cell surface glycosaminoglycans (GAGs) in vitro and that this adherence serves to modulate the infection process. In this study, a spore wall protein (EnP1; Encephalitozoon cuniculi ECUO1_0820) from E. cuniculi and Encephalitozoon intestinalis is found to interact with the host cell surface. Analysis of the amino acid sequence reveals multiple heparin-binding motifs, which are known to interact with extracellular matrices. Both recombinant EnP1 protein and purified EnP1 antibody inhibit spore adherence, resulting in decreased host cell infection. Furthermore, when the N-terminal heparin-binding motif is deleted by site-directed mutagenesis, inhibition of adherence is ablated. Our transmission immunoelectron microscopy reveals that EnP1 is embedded in the microsporidial endospore and exospore and is found in high abundance in the polar sac/anchoring disk region, an area from which the everting polar tube is released. Finally, by using a host cell binding assay, EnP1 is shown to bind host cell surfaces but not to those that lack surface GAGs. Collectively, these data show that given its expression in both the endospore and the exospore, EnP1 is a microsporidian cell wall protein that may function both in a structural capacity and in modulating in vitro host cell adherence and infection.