Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802.
Department of Chemistry, The Pennsylvania State University, University Park, PA 16802.
Proc Natl Acad Sci U S A. 2018 Dec 18;115(51):13009-13014. doi: 10.1073/pnas.1814042115. Epub 2018 Dec 3.
To meet their purine demand, cells activate the de novo purine biosynthetic pathway and transiently cluster the pathway enzymes into metabolons called purinosomes. Recently, we have shown that purinosomes were spatially colocalized with mitochondria and microtubules, yet it remained unclear as to what drives these associations and whether a relationship between them exist. Here, we employed superresolution imaging methods to describe purinosome transit in the context of subcellular localization. Time-resolved imaging of purinosomes showed that these assemblies exhibit directed motion as they move along a microtubule toward mitochondria, where upon colocalization, a change in purinosome motion was observed. A majority of purinosomes colocalized with mitochondria were also deemed colocalized with microtubules. Nocodazole-dependent microtubule depolymerization resulted in a loss in the purinosome-mitochondria colocalization, suggesting that the association of purinosomes with mitochondria is facilitated by microtubule-directed transport, and thereby supporting our notion of an interdependency between these subcellular components in maximizing purine production through the de novo purine biosynthetic pathway.
为了满足嘌呤需求，细胞激活从头合成途径，并将途径酶短暂聚集到称为嘌呤体的代谢物中。最近，我们已经表明嘌呤体与线粒体和微管在空间上共定位，但尚不清楚是什么驱动了这些关联，以及它们之间是否存在关系。在这里，我们采用超分辨率成像方法来描述细胞内定位背景下嘌呤体的转运。嘌呤体的时分辨成像显示，这些组装体在沿着微管向线粒体移动时表现出定向运动，在共定位时，观察到嘌呤体运动发生变化。大多数与线粒体共定位的嘌呤体也被认为与微管共定位。微管的长春花碱依赖性解聚导致嘌呤体-线粒体共定位的丧失，表明嘌呤体与线粒体的关联是由微管定向运输介导的，从而支持了我们的观点，即这些细胞内成分通过从头合成途径最大限度地产生嘌呤具有相互依存性。
