PLOS Pathogens:西南大学科学家发现微孢子虫极管侵染相关受体蛋白

摘要 : 2017年4月20日，国际微生物学知名期刊《PLOS Pathogens》在线发表了重庆西南大学周泽阳研究组和美国阿尔伯特·爱因斯坦医学院Louis M. Weiss研究组合作的一篇研究论文，研究发现了微孢子虫极管侵染的机制。

2017年4月20日，国际微生物学知名期刊《PLOS Pathogens》在线发表了重庆西南大学周泽阳研究组和美国阿尔伯特·爱因斯坦医学院Louis M. Weiss研究组合作的一篇研究论文，研究发现了微孢子虫极管侵染的机制。这是百年来微孢子虫研究领域首次针对极管蛋白受体的原创性研究，对最终解析微孢子虫的侵染机制有重要作用。

微孢子虫是一类可以侵染家蚕、鱼类以及人类的病原体，会对养蚕业、渔业以及畜牧业造成重大损失，并对人类健康构成威胁。论文详述了微孢子虫极管蛋白4(PTP4)的鉴定及其与宿主表面受体蛋白——转铁蛋白受体1(TfR-1)的相互作用，提出微孢子虫的极管借助宿主TfR-1受体介导的内吞作用侵染宿主细胞的分子机制，将有助于为治疗家蚕、鱼类及人类相关病害找到方法。

原文链接：

The role of microsporidian polar tube protein 4 (PTP4) in host Cell infection

原文摘要：

Microsporidia have been identified as pathogens that have important effects on our health, food security and economy. A key to the success of these obligate intracellular pathogens is their unique invasion organelle, the polar tube, which delivers the nucleus containing sporoplasm into host cells during invasion. Due to the size of the polar tube, the rapidity of polar tube discharge and sporoplasm passage, and the absence of genetic techniques for the manipulation of microsporidia, study of this organelle has been difficult and there is relatively little known regarding polar tube formation and the function of the proteins making up this structure. Herein, we have characterized polar tube protein 4 (PTP4) from the microsporidium Encephalitozoon hellem and found that a monoclonal antibody to PTP4 labels the tip of the polar tube suggesting that PTP4 might be involved in a direct interaction with host cell proteins during invasion. Further analyses employing indirect immunofluorescence (IFA), enzyme-linked immunosorbent (ELISA) and fluorescence-activated cell sorting (FACS) assays confirmed that PTP4 binds to mammalian cells. The addition of either recombinant PTP4 protein or anti-PTP4 antibody reduced microsporidian infection of its host cells in vitro. Proteomic analysis of PTP4 bound to host cell membranes purified by immunoprecipitation identified transferrin receptor 1 (TfR1) as a potential host cell interacting partner for PTP4. Additional experiments revealed that knocking out TfR1, adding TfR1 recombinant protein into cell culture, or adding anti-TfR1 antibody into cell culture significantly reduced microsporidian infection rates. These results indicate that PTP4 is an important protein competent of the polar tube involved in the mechanism of host cell infection utilized by these pathogens.

doi:10.1371/journal.ppat.1006341

作者：周泽阳

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