Bauer Sarah T, McQueeney Kelley E, Patel Terral, Morris Meredith T
Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, 29634.
Department of Pharmacology, University of Virginia, 409 Lane Road, Charlottesville, Virginia, 22908.
J Eukaryot Microbiol. 2017 Jan;64(1):97-105. doi: 10.1111/jeu.12343. Epub 2016 Jul 18.
Trypanosoma brucei is the causative agent of diseases that affect 30,000-50,000 people annually. Trypanosoma brucei harbors unique organelles named glycosomes that are essential to parasite survival, which requires growth under fluctuating environmental conditions. The mechanisms that govern the biogenesis of these organelles are poorly understood. Glycosomes are evolutionarily related to peroxisomes, which can proliferate de novo from the endoplasmic reticulum or through the growth and division of existing organelles depending on the organism and environmental conditions. The effect of environment on glycosome biogenesis is unknown. Here, we demonstrate that the glycosome membrane protein, TbPex13.1, is localized to glycosomes when cells are cultured under high glucose conditions and to the endoplasmic reticulum in low glucose conditions. This localization in low glucose was dependent on the presence of a C-terminal tripeptide sequence. Our findings suggest that glycosome biogenesis is influenced by extracellular glucose levels and adds to the growing body of evidence that de novo glycosome biogenesis occurs in trypanosomes. Because the movement of peroxisomal membrane proteins is a hallmark of ER-dependent peroxisome biogenesis, TbPex13.1 may be a useful marker for the study such processes in trypanosomes.
布氏锥虫是一种每年影响3万至5万人的疾病的病原体。布氏锥虫含有名为糖体的独特细胞器，这些细胞器对寄生虫的生存至关重要，而寄生虫需要在波动的环境条件下生长。目前对这些细胞器生物发生的调控机制了解甚少。糖体在进化上与过氧化物酶体相关，过氧化物酶体可以根据生物体和环境条件从内质网重新增殖，或通过现有细胞器的生长和分裂来增殖。环境对糖体生物发生的影响尚不清楚。在这里，我们证明，当细胞在高糖条件下培养时，糖体膜蛋白TbPex13.1定位于糖体，而在低糖条件下则定位于内质网。这种在低糖条件下的定位依赖于C端三肽序列的存在。我们的研究结果表明，糖体生物发生受细胞外葡萄糖水平的影响，并为锥虫中发生从头糖体生物发生这一越来越多的证据增添了内容。由于过氧化物酶体膜蛋白的移动是内质网依赖性过氧化物酶体生物发生的一个标志，TbPex13.1可能是研究锥虫中此类过程的一个有用标记。
