Takemae Hitoshi, Sugi Tatsuki, Kobayashi Kyousuke, Gong Haiyan, Ishiwa Akiko, Recuenco Frances C, Murakoshi Fumi, Iwanaga Tatsuya, Inomata Atsuko, Horimoto Taisuke, Akashi Hiroomi, Kato Kentaro
1] National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan [2] Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Sci Rep. 2013 Nov 12;3:3199. doi: 10.1038/srep03199.
Toxoplasma rhoptry neck protein 4 (TgRON4) is a component of the moving junction macromolecular complex that plays a central role during invasion. TgRON4 is exposed on the cytosolic side of the host cell during invasion, but its molecular interactions remain unclear. Here, we identified host cellular β-tubulin as a binding partner of TgRON4, but not Plasmodium RON4. Coimmunoprecipitation studies in mammalian cells demonstrated that the C-terminal 15-kDa region of β-tubulin was sufficient for binding to TgRON4, and that a 17-kDa region in the proximal C-terminus of TgRON4 was required for binding to the C-terminal region of β-tubulin. Analysis of T. gondii-infected lysates from CHO cells expressing the TgRON4-binding region showed that the C-terminal region of β-tubulin interacted with TgRON4 at early invasion step. Our results provide evidence for a parasite-specific interaction between TgRON4 and the host cell cytoskeleton in parasite-infected cells.
弓形虫棒状体颈部蛋白4（TgRON4）是移动连接大分子复合物的一个组成部分，在入侵过程中起核心作用。在入侵过程中，TgRON4暴露于宿主细胞的胞质侧，但其分子相互作用仍不清楚。在这里，我们鉴定出宿主细胞β-微管蛋白是TgRON4的结合伴侣，而不是疟原虫RON4的结合伴侣。在哺乳动物细胞中进行的免疫共沉淀研究表明，β-微管蛋白的C末端15 kDa区域足以与TgRON4结合，而TgRON4近端C末端的17 kDa区域是与β-微管蛋白C末端区域结合所必需的。对表达TgRON4结合区域的CHO细胞的弓形虫感染裂解物分析表明，β-微管蛋白的C末端区域在入侵早期与TgRON4相互作用。我们的结果为寄生虫感染细胞中TgRON4与宿主细胞细胞骨架之间的寄生虫特异性相互作用提供了证据。
