Division of Veterinary Infection Biology and Immunology, Department of Immunology and Cell Biology, Research Center Borstel, Parkallee 22, 23845, Borstel, Germany,
Parasitol Res. 2010 Apr;106(5):1085-102. doi: 10.1007/s00436-010-1747-8. Epub 2010 Feb 17.
Intracellular leukoproliferative Theileria are unique as eukaryotic organisms that transform the immune cells of their ruminant host. Theileria utilize the uncontrolled proliferation for rapid multiplication and distribution into host daughter cells. The parasite distribution into the daughter cells is accompanied by a tight association with the host cell mitotic apparatus. Since the molecular basis for this interaction is largely unknown, we investigated the possible involvement of the immunodominant Theileria annulata surface protein, TaSP, in the attachment of the parasite to host cell microtubule network. Confocal microscopic analyses showed co-localization of the TaSP protein with alpha-tubulin and reciprocal immuno-co-precipitation experiments demonstrated an association of TaSP with alpha-tubulin in vivo. In addition, the partially expressed predicted extracellular domain of TaSP co-localized with the mitotic spindle of dividing cells and was co-immunoprecipitated with alpha-tubulin in transiently transfected Cos-7 cells devoid of other T. annulata expressed proteins. Pull-down studies showed that there is a direct interaction between TaSP and polymerized microtubules. Analysis of the interaction of TaSP and host microtubulin during host cell mitosis indicated that TaSP co-localizes and interacts with the spindle poles, the mitotic spindle apparatus and the mid-body. Moreover, TaSP was demonstrated to be localized to the microtubule organizing center and to physically interact with gamma-tubulin. These data support the notion that the TaSP-microtubule interaction may be playing a potential role in parasite distribution into daughter host cells and give rise to the speculation that TaSP may be involved in regulation of microtubule assembly in the host cell.
细胞内白细胞增生性泰勒虫是独特的真核生物，它们会改变反刍动物宿主的免疫细胞。泰勒虫利用不受控制的增殖来快速繁殖并分布到宿主的子细胞中。寄生虫分布到子细胞伴随着与宿主细胞有丝分裂装置的紧密关联。由于这种相互作用的分子基础在很大程度上是未知的，我们研究了免疫显性的环形泰勒虫表面蛋白 TaSP 是否参与寄生虫与宿主细胞微管网络的附着。共聚焦显微镜分析显示 TaSP 蛋白与微管蛋白α共定位，并且免疫共沉淀实验证明 TaSP 在体内与微管蛋白α相关联。此外，部分表达的预测的 TaSP 细胞外结构域与正在分裂的细胞的有丝分裂纺锤体共定位，并与瞬时转染的 Cos-7 细胞中的微管蛋白α共沉淀，该细胞缺乏其他环形泰勒虫表达的蛋白质。下拉研究表明 TaSP 与聚合微管之间存在直接相互作用。在宿主细胞有丝分裂过程中分析 TaSP 与宿主微管蛋白的相互作用表明，TaSP 与纺锤极、有丝分裂纺锤体装置和中体共定位和相互作用。此外，还证明 TaSP 定位于微管组织中心，并与γ-微管蛋白发生物理相互作用。这些数据支持了这样的观点，即 TaSP-微管相互作用可能在寄生虫分布到子宿主细胞中发挥潜在作用，并引发了这样的推测，即 TaSP 可能参与宿主细胞微管组装的调节。
