Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
Mol Microbiol. 2019 Jan;111(1):46-64. doi: 10.1111/mmi.14138. Epub 2018 Nov 28.
Dynamin-related proteins (Drps) are involved in diverse processes such as organelle division and vesicle trafficking. The intracellular parasite Toxoplasma gondii possesses three distinct Drps. TgDrpC, whose function remains unresolved, is unusual in that it lacks a conserved GTPase Effector Domain, which is typically required for function. Here, we show that TgDrpC localizes to cytoplasmic puncta; however, in dividing parasites, TgDrpC redistributes to the growing edge of the daughter cells. By conditional knockdown, we determined that loss of TgDrpC stalls division and leads to rapid deterioration of multiple organelles and the IMC. We also show that TgDrpC interacts with proteins that exhibit homology to those involved in vesicle transport, including members of the adaptor complex 2. Two of these proteins, a homolog of the adaptor protein 2 (AP-2) complex subunit alpha-1 and a homolog of the ezrin-radixin-moesin (ERM) family proteins, localize to puncta and associate with the daughter cells. Consistent with the association with vesicle transport proteins, re-distribution of TgDrpC to the IMC during division is dependent on post-Golgi trafficking. Together, these results support that TgDrpC contributes to vesicle trafficking and is critical for stability of parasite organelles and division.
动力相关蛋白(Drps)参与多种过程,如细胞器分裂和囊泡运输。细胞内寄生虫刚地弓形虫拥有三种不同的 Drps。TgDrpC 的功能尚未解决,它的独特之处在于缺乏保守的 GTPase 效应结构域,而该结构域通常是其功能所必需的。在这里,我们表明 TgDrpC 定位于细胞质斑点;然而,在分裂的寄生虫中,TgDrpC 重新分布到子细胞的生长边缘。通过条件性敲低,我们确定 TgDrpC 的缺失会使分裂停滞,并导致多个细胞器和 IMC 的迅速恶化。我们还表明,TgDrpC 与具有囊泡运输同源性的蛋白相互作用,包括衔接蛋白复合物 2 的成员。这些蛋白中的两种,衔接蛋白 2(AP-2)复合物亚基α-1 和 ezrin-radixin-moesin(ERM)家族蛋白的同源物,定位于斑点并与子细胞相关联。与囊泡运输蛋白的关联一致,TgDrpC 在分裂过程中重新分布到 IMC 依赖于高尔基体后运输。这些结果共同表明,TgDrpC 有助于囊泡运输,对于寄生虫细胞器和分裂的稳定性至关重要。