Laboratory for Microbiology, Faculty of Biology, Philipps University, 35043, Marburg, Germany.
Max Planck Fellow Group "Bacterial Cell Biology", Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.
Nat Commun. 2017 Nov 28;8(1):1817. doi: 10.1038/s41467-017-02015-z.
In bacteria, homologs of actin, tubulin, and intermediate filament proteins often act in concert with bacteria-specific scaffolding proteins to ensure the proper arrangement of cellular components. Among the bacteria-specific factors are the bactofilins, a widespread family of polymer-forming proteins whose biology is poorly investigated. Here, we study the three bactofilins BacNOP in the rod-shaped bacterium Myxococcus xanthus. We show that BacNOP co-assemble into elongated scaffolds that restrain the ParABS chromosome segregation machinery to the subpolar regions of the cell. The centromere (parS)-binding protein ParB associates with the pole-distal ends of these structures, whereas the DNA partitioning ATPase ParA binds along their entire length, using the newly identified protein PadC (MXAN_4634) as an adapter. The integrity of these complexes is critical for proper nucleoid morphology and chromosome segregation. BacNOP thus mediate a previously unknown mechanism of subcellular organization that recruits proteins to defined sites within the cytoplasm, far off the cell poles.
在细菌中，肌动蛋白、微管蛋白和中间丝蛋白的同源物通常与细菌特异性支架蛋白协同作用，以确保细胞成分的正确排列。在这些细菌特异性因子中，有一个广泛存在的聚合物形成蛋白家族，即 bactofilins，但其生物学功能尚未得到充分研究。在这里，我们研究了杆状细菌粘细菌中的三种 bactofilins BacNOP。我们表明，BacNOP 共同组装成长形支架，将 ParABS 染色体分离机制限制在细胞的亚极区。着丝粒（parS）结合蛋白 ParB 与这些结构的极远端末端结合，而 DNA 分区 ATP 酶 ParA 沿着它们的全长结合，使用新鉴定的蛋白 PadC（MXAN_4634）作为接头。这些复合物的完整性对于核形态和染色体分离的正常至关重要。因此，BacNOP 介导了一种以前未知的细胞质内特定蛋白质定位的亚细胞组织机制，该机制与细胞极远离的细胞质内特定位置有关。
