In the 1960s several groups reported the isolation and preliminary genetic mapping of Escherichia coli strains tolerant towards the action of colicins. These pioneering studies kick-started two new fields in bacteriology; one centred on how bacteriocins like colicins exploit the Tol (or more commonly Tol-Pal) system to kill bacteria, the other on the physiological role of this cell envelope-spanning assembly. The following half century has seen significant advances in the first of these fields whereas the second has remained elusive, until recently. Here, we review work that begins to shed light on Tol-Pal function in Gram-negative bacteria. What emerges from these studies is that Tol-Pal is an energised system with fundamental, interlinked roles in cell division – coordinating the re-structuring of peptidoglycan at division sites and stabilising the connection between the outer membrane and underlying cell wall. This latter role is achieved by Tol-Pal exploiting the proton motive force to catalyse the accumulation of the outer membrane peptidoglycan associated lipoprotein Pal at division sites while simultaneously mobilising Pal molecules from around the cell. These studies begin to explain the diverse phenotypic outcomes of tol-pal mutations, point to other cell envelope roles Tol-Pal may have and raise many new questions.

中文翻译：

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Tol-Pal 在革兰氏阴性菌中的多种作用。

在 1960 年代，几个小组报告了大肠杆菌菌株的分离和初步遗传图谱。与大肠杆菌素的作用不同。这些开创性的研究开启了细菌学的两个新领域。一个集中在像大肠杆菌素这样的细菌素如何利用 Tol（或更常见的 Tol-Pal）系统杀死细菌，另一个集中在这种跨越细胞包膜的组件的生理作用上。在接下来的半个世纪里，第一个领域取得了重大进展，而第二个领域一直难以捉摸，直到最近。在这里，我们回顾了开始阐明革兰氏阴性菌中 Tol-Pal 功能的工作。从这些研究中得出的结论是，Tol-Pal 是一个充满活力的系统，在细胞分裂中具有基本的、相互关联的作用——协调分裂部位肽聚糖的重组，并稳定外膜和下面的细胞壁之间的连接。后一种作用是通过 Tol-Pal 利用质子动力来催化外膜肽聚糖相关脂蛋白 Pal 在分裂部位的积累，同时从细胞周围调动 Pal 分子来实现的。这些研究开始解释不同的表型结果tol-pal突变，指出 Tol-Pal 可能具有的其他细胞包膜作用，并提出了许多新问题。