Starnes G Lucas, Coincon Mathieu, Sygusch Jurgen, Sibley L David
Department of Molecular Microbiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63130-1093, USA.
Cell Host Microbe. 2009 Apr 23;5(4):353-64. doi: 10.1016/j.chom.2009.03.005.
Apicomplexan parasites rely on actin-based motility to drive host cell invasion. Prior in vitro studies implicated aldolase, a tetrameric glycolytic enzyme, in coupling actin filaments to the parasite's surface adhesin microneme protein 2 (MIC2). Here, we test the essentiality of this interaction in host cell invasion. Based on in vitro studies and homology modeling, we generated a series of mutations in Toxoplasma gondii aldolase (TgALD1) that delineated MIC2 tail domain (MIC2t) binding function from its enzyme activity. We tested these mutants by complementing a conditional knockout of TgALD1. Mutations that affected glycolysis also reduced motility. Mutants only affecting binding to MIC2t had no motility phenotype, but were decreased in their efficiency of host cell invasion. Our studies demonstrate that aldolase is not only required for energy production but is also essential for efficient host cell invasion, based on its ability to bridge adhesin-cytoskeleton interactions in the parasite.
顶复门寄生虫依靠基于肌动蛋白的运动来驱动宿主细胞入侵。先前的体外研究表明,醛缩酶(一种四聚体糖酵解酶)参与将肌动蛋白丝与寄生虫的表面粘附素微线体蛋白2(MIC2)偶联。在此,我们测试了这种相互作用在宿主细胞入侵中的必要性。基于体外研究和同源建模,我们在刚地弓形虫醛缩酶(TgALD1)中产生了一系列突变,这些突变区分了MIC2尾部结构域(MIC2t)的结合功能与其酶活性。我们通过补充TgALD1的条件性敲除来测试这些突变体。影响糖酵解的突变也降低了运动性。仅影响与MIC2t结合的突变体没有运动表型,但其宿主细胞入侵效率降低。我们的研究表明,醛缩酶不仅是能量产生所必需的,而且基于其在寄生虫中桥接粘附素-细胞骨架相互作用的能力,对于高效的宿主细胞入侵也是必不可少的。