Abstract：
TmaR, the only known pole-localizer protein in Escherichia coli, was shown to cluster at the cell poles and control localization and activity of the major sugar regulator in a tyrosine phosphorylation-dependent manner. Here, we show that TmaR assembles by phase separation (PS) via heterotypic interactions with RNA in vivo and in vitro. An unbiased automated mutant screen combined with directed mutagenesis and genetic manipulations uncovered the importance of a predicted nucleic-acid-binding domain, a disordered region, and charged patches, one containing the phosphorylated tyrosine, for TmaR condensation. We demonstrate that, by protecting flagella-related transcripts, TmaR controls flagella production and, thus, cell motility and biofilm formation. These results connect PS in bacteria to survival and provide an explanation for the linkage between metabolism and motility. Intriguingly, a point mutation or increase in its cellular concentration induces irreversible liquid-to-solid transition of TmaR, similar to human disease-causing proteins, which affects cell morphology and division.
摘要：
TmaR,大肠杆菌中唯一已知的极点定位蛋白，显示在细胞两极聚集，并以酪氨酸磷酸化依赖性方式控制主要糖调节剂的定位和活性。这里,我们显示TmaR通过相分离（PS）通过体内和体外与RNA的异型相互作用进行组装。无偏的自动突变筛选结合定向诱变和遗传操作揭示了预测的核酸结合域的重要性。一个无序的区域，和带电的补丁，一个含有磷酸化的酪氨酸，用于TmaR冷凝。我们证明，通过保护鞭毛相关的转录本，TmaR控制鞭毛的产生，因此，细胞运动和生物膜形成。这些结果将细菌中的PS与存活联系起来，并为代谢和运动性之间的联系提供了解释。有趣的是，点突变或其细胞浓度的增加诱导TmaR的不可逆的液-固转变，类似于人类致病蛋白质，影响细胞形态和分裂。
