Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, IC-11 Ciudad Universitaria Puebla, Apdo. Postal 1622, C. P. 72000, Puebla, Pue, Mexico.
Curr Microbiol. 2024 Aug 17;81(10):311. doi: 10.1007/s00284-024-03835-1.
The two-component system GacS/A and the posttranscriptional control system Rsm constitute a genetic regulation pathway in Gammaproteobacteria; in some species of Pseudomonas, this pathway is part of a multikinase network (MKN) that regulates the activity of the Rsm system. In this network, the activity of GacS is controlled by other kinases. One of the most studied MKNs is the MKN-GacS of Pseudomonas aeruginosa, where GacS is controlled by the kinases RetS and LadS; RetS decreases the kinase activity of GacS, whereas LadS stimulates the activity of the central kinase GacS. Outside of the Pseudomonas genus, the network has been studied only in Azotobacter vinelandii. In this work, we report the study of the RetS kinase of A. vinelandii; as expected, the phenotypes affected in gacS mutants, such as production of alginates, polyhydroxybutyrate, and alkylresorcinols and swimming motility, were also affected in retS mutants. Interestingly, our data indicated that RetS in A. vinelandii acts as a positive regulator of GacA activity. Consistent with this finding, mutation in retS also negatively affected the expression of small regulatory RNAs belonging to the Rsm family. We also confirmed the interaction of RetS with GacS, as well as with the phosphotransfer protein HptB.
双组分系统 GacS/A 和转录后控制系统 Rsm 构成了γ变形菌中的遗传调控途径；在某些假单胞菌物种中，该途径是调节 Rsm 系统活性的多激酶网络 (MKN) 的一部分。在该网络中，GacS 的活性受其他激酶控制。研究最多的 MKN 之一是铜绿假单胞菌的 MKN-GacS，其中 GacS 受激酶 RetS 和 LadS 控制；RetS 降低 GacS 的激酶活性，而 LadS 则刺激中央激酶 GacS 的活性。在假单胞菌属之外，该网络仅在固氮菌中进行了研究。在这项工作中，我们报告了对固氮菌 RetS 激酶的研究；正如预期的那样，gacS 突变体中受影响的表型，如藻酸盐、聚羟基丁酸酯和烷基间苯二酚的产生以及游动运动，在 retS 突变体中也受到影响。有趣的是，我们的数据表明，固氮菌中的 RetS 作为 GacA 活性的正调节剂发挥作用。与这一发现一致，retS 突变也对属于 Rsm 家族的小调控 RNA 的表达产生负面影响。我们还证实了 RetS 与 GacS 以及磷酸转移蛋白 HptB 的相互作用。
