Hliscs Marion, Millet Coralie, Dixon Matthew W, Siden-Kiamos Inga, McMillan Paul, Tilley Leann
Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, Melbourne, Vic., 3010, Australia; Australian Research Council Centre of Excellence for Coherent X-ray Science, The University of Melbourne, Melbourne, Vic., 3010, Australia; School of Botany, The University of Melbourne, Melbourne, Vic., 3010, Australia.
Cell Microbiol. 2015 Feb;17(2):207-25. doi: 10.1111/cmi.12359. Epub 2014 Oct 31.
In preparation for transmission to its mosquito vector, Plasmodium falciparum, the most virulent of the human malaria parasites, adopts an unusual elongated shape. Here we describe a previously unrecognized actin-based cytoskeleton that is assembled in maturing P. falciparum gametocytes. Differential extraction reveals the presence of a highly stabilized population of F-actin at all stages of development. Super-resolution microscopy reveals an F-actin cytoskeleton that is concentrated at the ends of the elongating gametocyte but extends inward along the microtubule cytoskeleton. Formin-1 is also concentrated at the gametocyte ends suggesting a role in actin stabilization. Immunoelectron microscopy confirms that the actin cytoskeleton is located under the inner membrane complex rather than in the sub-alveolar space. In stage V gametocytes, the actin and microtubule cytoskeletons are reorganized in a coordinated fashion. The actin-depolymerizing agent, cytochalasin D, depletes actin from the end of the gametocytes, whereas the actin-stabilizing compound, jasplakinolide, induces formation of large bundles and prevents late-stage disassembly of the actin cytoskeleton. Long-term treatment with these compounds is associated with disruption of the normal mitochondrial organization and decreased gametocyte viability.
为了准备传播给其蚊媒，恶性疟原虫（人类疟原虫中最具毒性的一种）会呈现出一种不同寻常的细长形状。在这里，我们描述了一种以前未被认识的基于肌动蛋白的细胞骨架，它在成熟的恶性疟原虫配子体中组装。差异提取显示在发育的所有阶段都存在高度稳定的F-肌动蛋白群体。超分辨率显微镜揭示了一种F-肌动蛋白细胞骨架，它集中在伸长的配子体的末端，但沿着微管细胞骨架向内延伸。formin-1也集中在配子体末端，表明其在肌动蛋白稳定中发挥作用。免疫电子显微镜证实肌动蛋白细胞骨架位于内膜复合体下方，而不是在肺泡下空间。在V期配子体中，肌动蛋白和微管细胞骨架以协调的方式重新组织。肌动蛋白解聚剂细胞松弛素D从配子体末端耗尽肌动蛋白，而肌动蛋白稳定化合物茉莉酸内酯诱导形成大的束状结构并防止肌动蛋白细胞骨架在后期解体。用这些化合物进行长期处理与正常线粒体组织的破坏和配子体活力的降低有关。
