Bacterial osmoadaptation: coordination of osmoregulatory systems and their roles in cell growth

渗透压的变化导致水流过包裹活细胞的膜。 这种水通量会扰乱细胞结构和功能。 细胞通过调整称为有机渗透剂（氨基酸、糖等）的物质含量来做出反应。 这种“渗透调节”控制水流，以确保细胞保持适当的水合，稳定其内部机制，并支持其持续生长。 已经描述了调节细菌渗透物质含量的渗透调节机制。 现在我们的目标是了解大肠杆菌的渗透调节系统是如何协调的。 我们将检验以下假设。 首先，ProQ 蛋白是一种 RNA 伴侣，可调节编码渗透调节蛋白（包括 ProP 和 ProU）的基因。 其次，ProP 与其他基于膜的渗透调节蛋白聚集在大肠杆菌细胞的末端，呈杆状。 这种蛋白质聚集是由细胞膜和“细胞骨架”成分之间的特定相互作用产生的，对于有效的渗透调节和细胞生长是必要的。

Osmotic pressure changes cause water to flow across the membranes that encase living cells. Such water fluxes can perturb cell structures and functions. Cells respond by adjusting their content of substances called organic osmolytes (amino acids, sugars etc). This "osmoregulation" controls water flow to ensure that cells remain properly hydrated, to stabilize their internal machinery, and to support their continuing growth. The osmoregulatory machinery that modulates bacterial osmolyte content has been described. Now we aim to learn how the osmoregulatory systems of bacterium Escherichia coli are coordinated. We will test the following hypotheses. First, the ProQ protein is an RNA chaperone that regulates the genes encoding osmoregulatory proteins, including ProP and ProU. Second, ProP clusters with other membrane-based osmoregulatory proteins at the ends of E. coli cells, which are rod-shaped. This protein clustering, resulting from specific interactions among cell membrane and "cell skeleton" components, is necessary for effective osmoregulation and cell growth.