title: Responses of Pseudomonas putida to Zinc Excess Determined at the Proteome Level: Pathways Dependent and Independent of ColRS.
abstract: Zinc is an important micronutrient for bacteria, but its excess is toxic. Recently, the ColRS two-component system was shown to detect and respond to zinc excess and to contribute to zinc tolerance of Pseudomonas putida. Here, we applied a label-free whole-cell proteome analysis to compare the zinc-induced responses of P. putida and colR knockout. We identified dozens of proteins that responded to zinc in a ColR-independent manner, among others, known metal efflux systems CzcCBA1, CzcCBA2, CadA2 and CzcD. Nine proteins were affected in a ColR-dependent manner, and besides known ColR targets, four new candidates for ColR regulon were identified. Despite the relatively modest ColR-dependent changes of wild-type, colR deficiency resulted in drastic proteome alterations, with 122 proteins up- and 62 down-regulated by zinc. This zinc-promoted response had remarkable overlap with the alternative sigma factor AlgU-controlled regulon in P. aeruginosa. The most prominent hallmark was a high induction of alginate biosynthesis proteins and regulators. This response likely alleviates the zinc stress, as the AlgU-regulated alginate regulator AmrZ was shown to contribute to zinc tolerance of colR knockout. Thus, the ColRS system is important for zinc homeostasis, and in its absence, alternative stress response pathways are activated to support the zinc tolerance.
authors: Institute of Molecular and Cell Biology, University of Tartu , Tartu 51010, Estonia.
authors: Karl
authors: K
authors: Mumm
authors: Institute of Molecular and Cell Biology, University of Tartu , Tartu 51010, Estonia.
authors: Kadi
authors: K
authors: Ainsaar
authors: Institute of Technology, University of Tartu , Tartu 50411, Estonia.
authors: Sergo
authors: S
authors: Kasvandik
authors: Institute of Technology, University of Tartu , Tartu 50411, Estonia.
authors: Tanel
authors: T
authors: Tenson
authors: Institute of Molecular and Cell Biology, University of Tartu , Tartu 51010, Estonia.
authors: Rita
authors: R
authors: Hõrak
mesh_terms: D000464:Alginates; D004361:Drug Tolerance; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D020723:Glucuronic Acid / Q000096:biosynthesis; D006603:Hexuronic Acids; D053858:Metabolic Networks and Pathways; D020543:Proteome / Q000032:analysis* / Q000187:drug effects; D016958:Pseudomonas putida / Q000737:chemistry / Q000187:drug effects*; D015398:Signal Transduction; D015032:Zinc / Q000494:pharmacology*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020543:Proteome; D020723:Glucuronic Acid; D015032:Zinc
keywords: ColRS two-component system; Pseudomonas putida; proteomic response; stress response; zinc excess