The Two-Component Signal Transduction System CopRS of Corynebacterium glutamicum Is Required for Adaptation to Copper-Excess Stress
- Publisher: Public Library of Science
(issn: 1932-6203, eissn: 1932-6203)
genetics [Bacterial Proteins] | Cellular Stress Responses | Bacterial Physiology | Protein Kinases | genetics [Gene Expression Regulation, Bacterial] | drug effects [Phosphorylation] | genetics [Adaptation, Physiological] | genetics [Nucleotide Motifs] | Base Sequence | Signaling in Cellular Processes | Binding Sites | drug effects [Corynebacterium glutamicum] | Biology | Signal Transduction | cytology [Corynebacterium glutamicum] | DNA, Bacterial | Mutation | DNA transcription | genetics [Protein Kinases] | Science | genetics [Genes, Bacterial] | Transmembrane Signaling | genetics [Signal Transduction] | Gene expression | Microbial Control | toxicity [Copper] | Bacterial Proteins | Research Article | Molecular cell biology | drug effects [Gene Expression Regulation, Bacterial] | genetics [Corynebacterium glutamicum] | genetics [DNA, Bacterial] | drug effects [Signal Transduction] | drug effects [Homeostasis] | drug effects [Adaptation, Physiological] | Bacteriology | genetics [Homeostasis] | genetics [Stress, Physiological] | Copper | genetics [Phosphorylation] | Microbiology | J | Medicine | protein-histidine kinase | metabolism [DNA, Bacterial] | metabolism [Protein Kinases] | Q | R | physiology [Corynebacterium glutamicum] | drug effects [Stress, Physiological] | metabolism [Bacterial Proteins]
Copper is an essential cofactor for many enzymes but at high concentrations it is toxic for the cell. Copper ion concentrations ≥50 µM inhibited growth of Corynebacterium glutamicum. The transcriptional response to 20 µM Cu(2+) was studied using DNA microarrays and revealed 20 genes that showed a ≥ 3-fold increased mRNA level, including cg3281-cg3289. Several genes in this genomic region code for proteins presumably involved in the adaption to copper-induced stress, e. g. a multicopper oxidase (CopO) and a copper-transport ATPase (CopB). In addition, this region includes the copRS genes (previously named cgtRS9) which encode a two-component signal transduction system composed of the histidine kinase CopS and the response regulator CopR. Deletion of the copRS genes increased the sensitivity of C. glutamicum towards copper ions, but not to other heavy metal ions. Using comparative transcriptome analysis of the ΔcopRS mutant and the wild type in combination with electrophoretic mobility shift assays and reporter gene studies the CopR regulon and the DNA-binding motif of CopR were identified. Evidence was obtained that CopR binds only to the intergenic region between cg3285 (copR) and cg3286 in the genome of C. glutamicum and activates expression of the divergently oriented gene clusters cg3285-cg3281 and cg3286-cg3289. Altogether, our data suggest that CopRS is the key regulatory system in C. glutamicum for the extracytoplasmic sensing of elevated copper ion concentrations and for induction of a set of genes capable of diminishing copper stress.