Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
Open Biol. 2013 Mar 27;3(3):130006. doi: 10.1098/rsob.130006.
Prior to bacterial cell division, the ATP-dependent polymerization of the cytoskeletal protein, ParA, positions the newly replicated origin-proximal region of the chromosome by interacting with ParB complexes assembled on parS sites located close to the origin. During the formation of unigenomic spores from multi-genomic aerial hyphae compartments of Streptomyces coelicolor, ParA is developmentally triggered to form filaments along the hyphae; this promotes the accurate and synchronized segregation of tens of chromosomes into prespore compartments. Here, we show that in addition to being a segregation protein, ParA also interacts with the polarity protein, Scy, which is a component of the tip-organizing centre that controls tip growth. Scy recruits ParA to the hyphal tips and regulates ParA polymerization. These results are supported by the phenotype of a strain with a mutant form of ParA that uncouples ParA polymerization from Scy. We suggest that the ParA-Scy interaction coordinates the transition from hyphal elongation to sporulation.
在细菌细胞分裂之前，细胞骨架蛋白 ParA 的 ATP 依赖性聚合通过与位于复制起点附近的 parS 位点上组装的 ParB 复合物相互作用，将新复制的染色体起始近端区域定位。在链霉菌单细胞孢子形成过程中，多基因组气生菌丝隔室中 ParA 被发育触发沿菌丝形成纤维；这促进了数十个染色体准确和同步地分配到孢子隔室中。在这里，我们表明，除了作为一种分离蛋白外，ParA 还与极性蛋白 Scy 相互作用，Scy 是控制顶端生长的顶端组织中心的一个组成部分。Scy 将 ParA 招募到菌丝顶端并调节 ParA 聚合。这些结果得到了一种具有突变形式 ParA 的菌株的表型的支持，该菌株将 ParA 聚合与 Scy 分离。我们认为，ParA-Scy 相互作用协调了从菌丝伸长到孢子形成的转变。
