Department of Biology, Boston College, Chestnut Hill, MA, United States.
Nuffield Department of Clinical Laboratory Science, University of Oxford John Radcliffe Hospital, Oxford, United Kingdom.
Front Cell Infect Microbiol. 2022 Apr 29;12:882166. doi: 10.3389/fcimb.2022.882166. eCollection 2022.
The Apicomplexa are famously named for their apical complex, a constellation of organelles at their apical end dedicated to invasion of their host cells. In contrast, at the other end of the cell, the basal complex (BC) has been overshadowed since it is much less prominent and specific functions were not immediately obvious. However, in the past decade a staggering array of functions have been associated with the BC and strides have been made in understanding its structure. Here, these collective insights are supplemented with new data to provide an overview of the understanding of the BC in . The emerging picture is that the BC is a dynamic and multifunctional complex, with a series of (putative) functions. The BC has multiple roles in cell division: it is the site where building blocks are added to the cytoskeleton scaffold; it exerts a two-step stretch and constriction mechanism as contractile ring; and it is key in organelle division. Furthermore, the BC has numerous putative roles in 'import', such as the recycling of mother cell remnants, the acquisition of host-derived vesicles, possibly the uptake of lipids derived from the extracellular medium, and the endocytosis of micronemal proteins. The latter process ties the BC to motility, whereas an additional role in motility is conferred by Myosin C. Furthermore, the BC acts on the assembly and/or function of the intravacuolar network, which may directly or indirectly contribute to the establishment of chronic tissue cysts. Here we provide experimental support for molecules acting in several of these processes and identify several new BC proteins critical to maintaining the cytoplasmic bridge between divided parasites. However, the dispensable nature of many BC components leaves many questions unanswered regarding its function. In conclusion, the BC in is a dynamic and multifunctional structure at the posterior end of the parasite.
顶复门生物因它们的顶端复合器而得名，该细胞器位于虫体的顶端，是专门用于入侵宿主细胞的一组细胞器。相比之下，在细胞的另一端，基底复合器（BC）则黯然失色，因为它不太明显，其特定功能也不那么明显。然而，在过去的十年中，人们发现了基底复合器的一系列惊人的功能，并在理解其结构方面取得了进展。在这里，这些综合的见解得到了新数据的补充，为我们提供了一个对 中基底复合器的理解的概述。新的研究结果表明，基底复合器是一个动态的多功能复合体，具有一系列（推测的）功能。基底复合器在细胞分裂中具有多种作用：它是细胞骨架支架添加构建块的部位；它作为收缩环发挥两步拉伸和收缩机制；它在细胞器分裂中起着关键作用。此外，基底复合器在“输入”方面有许多推测的作用，例如母细胞残余物的回收、宿主来源的囊泡的获取、可能来自细胞外介质的脂质的摄取以及微线蛋白的内吞作用。这后一个过程将基底复合器与运动联系起来，而肌球蛋白 C 赋予了它在运动中的另一个作用。此外，基底复合器作用于囊内网络的组装和/或功能，这可能直接或间接地有助于慢性组织包囊的建立。在这里，我们为参与这些过程的几种分子提供了实验支持，并确定了几种新的基底复合器蛋白，这些蛋白对维持分裂寄生虫之间的细胞质桥至关重要。然而，许多基底复合器成分的非必需性使得其功能仍然存在许多问题尚未解决。总之， 中的基底复合器是寄生虫后端的一个动态的多功能结构。
