A MORN1-associated HAD phosphatase in the basal complex is essential for Toxoplasma gondii daughter budding.
A MORN1-associated HAD phosphatase in the basal complex is essential for Toxoplasma gondii daughter budding.
复制标题
DOI：
10.1111/cmi.12574
复制
发表时间：
2016-08
影响因子：
3.4
通讯作者：
Gubbels MJ
中科院分区：
文献类型：
--
作者：
Engelberg K;Ivey FD;Lin A;Kono M;Lorestani A;Faugno-Fusci D;Gilberger TW;White M;Gubbels MJ
顶复门寄生虫通过几种出芽机制进行复制，其中两个充分表征的例子是弓形虫endodyplasma和疟原虫endodyplasmodium。出芽的完成需要由基部复合体的收缩驱动的新生子芽向基部末端逐渐变细。这种收缩不是由任何已知的细胞分裂相关的收缩机制执行，为了揭示不寻常的基础复合物的新成分，我们用其主要支架蛋白TgMORN 1进行了酵母双杂交筛选。在这里，我们报告了一个保守的蛋白与卤酸脱卤酶（HAD）磷酸酶结构域，以下命名为HAD 2a，确定了酵母双杂交。HAD 2a已经在体外证明了酶活性，定位于新生的子芽，并在其收缩期间与MORN 1共定位于基底复合物。弓形虫中HAD 2a的条件性敲除干扰基础复合物组装，这导致不完全的胞质分裂和连体子体，最终导致破坏的增殖。在疟原虫，我们进一步证实了本地化的HAD 2a直系同源物的基础复合体对结束的同源生殖。总之，我们的工作突出了一个重要的作用，这种HAD磷酸酶在apicomplexan出芽，并建议差异磷酸化的基础复合物的结构和/或收缩功能的调节机制。
Apicomplexan parasites replicate by several budding mechanisms with two well-characterized examples being Toxoplasma endodyogeny and Plasmodium schizogony. Completion of budding requires the tapering of the nascent daughter buds toward the basal end, driven by contraction of the basal complex. This contraction is not executed by any of the known cell division associated contractile mechanisms and in order to reveal new components of the unusual basal complex we performed a yeast two-hybrid screen with its major scaffolding protein, TgMORN1. Here we report on a conserved protein with a haloacid dehalogenase (HAD) phosphatase domain, hereafter named HAD2a, identified by yeast two-hybrid. HAD2a has demonstrated enzyme-activity in vitro, localizes to the nascent daughter buds and co-localizes with MORN1 to the basal complex during its contraction. Conditional knockout of HAD2a in Toxoplasma interferes with basal complex assembly, which leads to incomplete cytokinesis and conjoined daughters that ultimately results in disrupted proliferation. In Plasmodium, we further confirmed localization of the HAD2a ortholog to the basal complex toward the end of schizogony. In conclusion, our work highlights an essential role for this HAD phosphatase across apicomplexan budding and suggests a regulatory mechanism of differential phosphorylation on the structure and/or contractile function of the basal complex.