Bordes Patricia, Genevaux Pierre
Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France.
Front Mol Biosci. 2021 May 17;8:691399. doi: 10.3389/fmolb.2021.691399. eCollection 2021.
Toxin-antitoxin (TA) systems are small genetic elements composed of a noxious toxin and a counteracting cognate antitoxin. Although they are widespread in bacterial chromosomes and in mobile genetic elements, their cellular functions and activation mechanisms remain largely unknown. It has been proposed that toxin activation or expression of the TA operon could rely on the degradation of generally less stable antitoxins by cellular proteases. The resulting active toxin would then target essential cellular processes and inhibit bacterial growth. Although interplay between proteases and TA systems has been observed, evidences for such activation cycle are very limited. Herein, we present an overview of the current knowledge on TA recognition by proteases with a main focus on the major human pathogen , which harbours multiple TA systems (over 80), the essential AAA + stress proteases, ClpC1P1P2 and ClpXP1P2, and the Pup-proteasome system.
毒素-抗毒素（TA）系统是由一种有害毒素和一种起中和作用的同源抗毒素组成的小型遗传元件。尽管它们广泛存在于细菌染色体和可移动遗传元件中，但其细胞功能和激活机制在很大程度上仍不清楚。有人提出，TA操纵子的毒素激活或表达可能依赖于细胞蛋白酶对通常不太稳定的抗毒素的降解。产生的活性毒素随后会靶向细胞的基本过程并抑制细菌生长。尽管已观察到蛋白酶与TA系统之间的相互作用，但这种激活循环的证据非常有限。在此，我们概述了目前关于蛋白酶识别TA的知识，主要关注主要的人类病原体，该病原体含有多个TA系统（超过80个）、必需的AAA + 应激蛋白酶ClpC1P1P2和ClpXP1P2以及Pup-蛋白酶体系统。
