Laboratoire de Chimie Bactérienne, CNRS UMR 7283, Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, Marseille, France.
PLoS Biol. 2013 Dec;11(12):e1001728. doi: 10.1371/journal.pbio.1001728. Epub 2013 Dec 10.
Eukaryotic cells utilize an arsenal of processive transport systems to deliver macromolecules to specific subcellular sites. In prokaryotes, such transport mechanisms have only been shown to mediate gliding motility, a form of microbial surface translocation. Here, we show that the motility function of the Myxococcus xanthus Agl-Glt machinery results from the recent specialization of a versatile class of bacterial transporters. Specifically, we demonstrate that the Agl motility motor is modular and dissociates from the rest of the gliding machinery (the Glt complex) to bind the newly expressed Nfs complex, a close Glt paralogue, during sporulation. Following this association, the Agl system transports Nfs proteins directionally around the spore surface. Since the main spore coat polymer is secreted at discrete sites around the spore surface, its transport by Agl-Nfs ensures its distribution around the spore. Thus, the Agl-Glt/Nfs machineries may constitute a novel class of directional bacterial surface transporters that can be diversified to specific tasks depending on the cognate cargo and machinery-specific accessories.
真核细胞利用一系列连续的运输系统将生物大分子运送到特定的亚细胞位置。在原核生物中，这种运输机制仅被证明可以介导滑行运动，这是一种微生物表面迁移的形式。在这里，我们表明，粘细菌 Agl-Glt 机械的运动功能是由一类多功能细菌转运蛋白的最近专业化产生的。具体来说，我们证明 Agl 运动马达是模块化的，并且在孢子形成过程中与滑行机械（Glt 复合物）的其余部分分离，以结合新表达的 Nfs 复合物，这是 Glt 的密切同源物。在这种关联之后，Agl 系统将 Nfs 蛋白有方向地运输到孢子表面周围。由于主要的孢子外壳聚合物在孢子表面的离散部位分泌，因此 Agl-Nfs 的运输确保了其在孢子周围的分布。因此，Agl-Glt/Nfs 机械装置可能构成一类新型的定向细菌表面转运蛋白，可根据同源货物和机械特定配件的不同而多样化到特定任务。
