title: The proteolytic activation of the relNEs (ssr1114/slr0664) toxin-antitoxin system by both proteases Lons and ClpP2s/Xs of Synechocystis sp. PCC 6803.
abstract: The proteolytic regulation of toxin-antitoxin (TA) systems has been well studied in Escherichia coli but remains unclear in other bacteria. A chromosomal gene pair ssr1114/slr0664, named relNEs, of Synechocystis sp. PCC 6803 forms a TA system belonging to rel family. Here, we used E. coli strain BL21 (DE3) as a host to characterize the proteolytic regulation of relNEs. The proteases of this strain could not degrade the antitoxin RelN, and the ectopic production of the ATP-dependant protease Lons or ClpP2s/Xs of Synechocystis sp. PCC6803 did not affect E. coli growth. Either Lons or ClpP2s/Xs was able to degrade RelN resulting in growth arrest of E. coli due to the activation of RelEs's toxicity, and the presence of RelEs could protect RelN to a certain extent against Lons and ClpP2s/Xs. Our observations suggest that both Lons and ClpP2s/Xs are responsible for RelN proteolysis in the native host under certain conditions. RelN is the first protein substrate identified for cyanobacterial ATP-dependent proteases.
authors: Department of Environment Sciences, School of Environment, Jiangsu University, Xuefu Road, Zhenjiang, 212013 Jiangsu, China. 306502@ujs.edu.cn
authors: Degang
authors: D
authors: Ning
authors: Sen
authors: S
authors: Ye
authors: Biao
authors: B
authors: Liu
authors: Jianing
authors: J
authors: Chang
mesh_terms: D000992:Antitoxins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D011499:Protein Processing, Post-Translational; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism*
chemical_list: D000992:Antitoxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; C119658:ClpP2 protein, bacteria; D012697:Serine Endopeptidases