Tengganu Isadonna F, Padilla Luisa F Arias, Lopez Jonathan Munera, Liu Jun, Brown Peter T, Murray John M, Hu Ke
bioRxiv. 2023 Aug 3:2023.04.23.538011. doi: 10.1101/2023.04.23.538011.
Motility is essential for apicomplexan parasites to infect their hosts. In a three-dimensional (3-D) environment, the apicomplexan parasite moves along a helical path. The cortical microtubules, which are ultra-stable and spirally arranged, have been considered to be a structure that guides the long-distance movement of the parasite. Here we address the role of the cortical microtubules in parasite motility, invasion, and egress by utilizing a previously generated mutant (dubbed "TKO") in which these microtubules are destabilized in mature parasites. We found that the cortical microtubules in ~ 80% of the non-dividing (i.e. daughter-free) TKO parasites are much shorter than normal. The extent of depolymerization is further exacerbated upon commencement of daughter formation or cold treatment, but parasite replication is not affected. In a 3-D Matrigel matrix, the TKO mutant moves directionally over long distances, but along trajectories significantly more linear (i.e. less helical) than those of wild-type parasites. Interestingly, this change in trajectory does not impact either movement speed in the matrix or the speed and behavior of the parasite's entry into and egress from the host cell.
运动能力对于顶复门寄生虫感染宿主至关重要。在三维（3-D）环境中，顶复门寄生虫沿螺旋路径移动。皮质微管超稳定且呈螺旋状排列，被认为是引导寄生虫长距离移动的结构。在此，我们通过利用先前产生的一种突变体（称为“TKO”）来研究皮质微管在寄生虫运动、入侵和逸出中的作用，在这种突变体中，这些微管在成熟寄生虫中不稳定。我们发现，约80%的非分裂（即无子代）TKO寄生虫中的皮质微管比正常的短得多。在子代形成开始或冷处理后，解聚程度进一步加剧，但寄生虫复制不受影响。在3-D基质胶基质中，TKO突变体可长距离定向移动，但沿着的轨迹比野生型寄生虫的轨迹明显更直（即螺旋性更小）。有趣的是，这种轨迹变化既不影响其在基质中的移动速度，也不影响寄生虫进入和离开宿主细胞的速度及行为。
