PDF(Pubmed)
Abstract：
Cytokinetic abscission marks the final stage of cell division, during which the daughter cells physically separate through the generation of new barriers, such as the plasma membrane or cell wall. While the contractile ring plays a central role during cytokinesis in bacteria, fungi and animal cells, the process diverges in Apicomplexa. In Toxoplasma gondii, two daughter cells are formed within the mother cell by endodyogeny. The mechanism by which the progeny cells acquire their plasma membrane during the disassembly of the mother cell, allowing daughter cells to emerge, remains unknown. Here we identify and characterize five T. gondii proteins, including three protein phosphatase 2A subunits, which exhibit a distinct and dynamic localization pattern during parasite division. Individual downregulation of these proteins prevents the accumulation of plasma membrane at the division plane, preventing the completion of cellular abscission. Remarkably, the absence of cytokinetic abscission does not hinder the completion of subsequent division cycles. The resulting progeny are able to egress from the infected cells but fail to glide and invade, except in cases of conjoined twin parasites.
摘要：
细胞动力学脱落标志着细胞分裂的最后阶段，在此期间，子细胞通过产生新的屏障物理分离，如质膜或细胞壁。虽然收缩环在细菌的胞质分裂过程中起着核心作用，真菌和动物细胞,该过程在Apicomplex中发散。在弓形虫中，两个子细胞在母细胞内通过内分泌形成。子代细胞在母细胞拆卸过程中获得质膜的机制，允许子细胞出现，仍然未知。在这里，我们鉴定并表征了五种弓形虫蛋白，包括三个蛋白磷酸酶2A亚基，在寄生虫划分过程中表现出明显的动态定位模式。这些蛋白质的个体下调阻止了细胞膜在分裂平面的积累，防止细胞脱落的完成。值得注意的是,细胞动力学脱落的缺失并不妨碍后续分裂周期的完成.产生的后代能够从感染的细胞中排出，但无法滑行和入侵，除了连体双胞胎寄生虫的情况。
