title: Antitoxin MqsA helps mediate the bacterial general stress response.
abstract: Although it is well recognized that bacteria respond to environmental stress through global networks, the mechanism by which stress is relayed to the interior of the cell is poorly understood. Here we show that enigmatic toxin-antitoxin systems are vital in mediating the environmental stress response. Specifically, the antitoxin MqsA represses rpoS, which encodes the master regulator of stress. Repression of rpoS by MqsA reduces the concentration of the internal messenger 3,5-cyclic diguanylic acid, leading to increased motility and decreased biofilm formation. Furthermore, the repression of rpoS by MqsA decreases oxidative stress resistance via catalase activity. Upon oxidative stress, MqsA is rapidly degraded by Lon protease, resulting in induction of rpoS. Hence, we show that external stress alters gene regulation controlled by toxin-antitoxin systems, such that the degradation of antitoxins during stress leads to a switch from the planktonic state (high motility) to the biofilm state (low motility).
authors.affiliation: Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA.
authors.forename: Xiaoxue
authors.initials: X
authors.lastname: Wang
authors.forename: Younghoon
authors.initials: Y
authors.lastname: Kim
authors.forename: Seok Hoon
authors.initials: SH
authors.lastname: Hong
authors.forename: Qun
authors.initials: Q
authors.lastname: Ma
authors.forename: Breann L
authors.initials: BL
authors.lastname: Brown
authors.forename: Mingming
authors.initials: M
authors.lastname: Pu
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Tarone
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Benedik
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Peti
authors.forename: Rebecca
authors.initials: R
authors.lastname: Page
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Wood
mesh_terms: D000992:Antitoxins / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D018441:Biofilms; D004268:DNA-Binding Proteins / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D010933:Plankton; D049070:Protease La / Q000378:metabolism; D012808:Sigma Factor / Q000096:biosynthesis / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics
chemical_list: D000992:Antitoxins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C555039:MqsA protein, E coli; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D049070:Protease La