Institute of Biochemistry, Goethe University Frankfurt, Frankfurt am Main, Germany.
Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States.
J Mol Biol. 2021 Aug 6;433(16):166968. doi: 10.1016/j.jmb.2021.166968. Epub 2021 Mar 30.
Potassium ion homeostasis is essential for bacterial survival, playing roles in osmoregulation, pH homeostasis, regulation of protein synthesis, enzyme activation, membrane potential adjustment and electrical signaling. To accomplish such diverse physiological tasks, it is not surprising that a single bacterium typically encodes several potassium uptake and release systems. To understand the role each individual protein fulfills and how these proteins work in concert, it is important to identify the molecular details of their function. One needs to understand whether the systems transport ions actively or passively, and what mechanisms or ligands lead to the activation or inactivation of individual systems. Combining mechanistic information with knowledge about the physiology under different stress situations, such as osmostress, pH stress or nutrient limitation, one can identify the task of each system and deduce how they are coordinated with each other. By reviewing the general principles of bacterial membrane physiology and describing the molecular architecture and function of several bacterial K-transporting systems, we aim to provide a framework for microbiologists studying bacterial potassium homeostasis and the many K-translocating systems that are still poorly understood.
钾离子稳态对于细菌的生存至关重要，在渗透调节、pH 稳态、蛋白质合成调控、酶激活、膜电位调节和电信号传导中发挥作用。为了完成如此多样化的生理任务，毫不奇怪，单个细菌通常编码几种钾离子摄取和释放系统。为了了解每个单独蛋白质的作用以及这些蛋白质如何协同工作，了解其功能的分子细节非常重要。人们需要了解这些系统是主动运输离子还是被动运输离子，以及是什么机制或配体导致单个系统的激活或失活。将机械信息与不同应激情况下（如渗透压应激、pH 应激或营养限制）的生理学知识相结合，可以确定每个系统的任务，并推断它们彼此之间是如何协调的。通过回顾细菌膜生理学的一般原理，并描述几种细菌 K 转运系统的分子结构和功能，我们旨在为研究细菌钾离子稳态和许多仍知之甚少的 K 转运系统的微生物学家提供一个框架。
