Takemae Hitoshi, Kobayashi Kyousuke, Sugi Tatsuki, Han Yongmei, Gong Haiyan, Ishiwa Akiko, Recuenco Frances C, Murakoshi Fumi, Takano Ryo, Murata Yuho, Nagamune Kisaburo, Horimoto Taisuke, Akashi Hiroomi, Kato Kentaro
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, Japan; Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan.
Neurovirology Project, Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa, Setagaya-ku, Tokyo, Japan.
Parasitol Int. 2018 Apr;67(2):123-130. doi: 10.1016/j.parint.2017.10.008. Epub 2017 Nov 20.
Toxoplasma gondii rhoptry neck protein 4 (TgRON4) is a component of the moving junction, a key structure for host cell invasion. We previously showed that host cellular β-tubulin is a binding partner of TgRON4 in the invasion process. Here, to identify other binding partners of TgRON4 in the host cell, we examined the binding of TgRON4 to components of the host cell surface. TgRON4 binds to various mammalian cells, but this binding disappeared in glycosaminoglycan- and heparan sulfate-deficient CHO cells and after heparitinase treatment of mammalian cells. The C-terminal half of TgRON4 showed relatively strong binding to cells and heparin agarose. A glycoarray assay indicated that TgRON4 binds to heparin and modified heparin derivatives. Immunoprecipitation of T. gondii-infected CHO cell lysates showed that TgRON4 interacts with glypican 1 during Toxoplasma invasion. This interaction suggests a role for heparan sulfate in parasite invasion.
弓形虫棒状体颈部蛋白4（TgRON4）是移动连接的一个组成部分，移动连接是宿主细胞入侵的关键结构。我们之前表明宿主细胞β-微管蛋白是入侵过程中TgRON4的结合伴侣。在此，为了鉴定宿主细胞中TgRON4的其他结合伴侣，我们检测了TgRON4与宿主细胞表面成分的结合。TgRON4能与多种哺乳动物细胞结合，但这种结合在缺乏糖胺聚糖和硫酸乙酰肝素的CHO细胞中以及在对哺乳动物细胞进行肝素酶处理后消失。TgRON4的C端半段与细胞和肝素琼脂糖表现出相对较强的结合。糖芯片分析表明TgRON4能与肝素和修饰的肝素衍生物结合。对弓形虫感染的CHO细胞裂解物进行免疫沉淀显示，在弓形虫入侵过程中TgRON4与磷脂酰肌醇蛋白聚糖1相互作用。这种相互作用表明硫酸乙酰肝素在寄生虫入侵中发挥作用。
