Involvement of AtoSC two-component system in Escherichia coli flagellar regulon

• Published in: Amino acids 2012-08, Vol.43 (2), p.833-844
• Main Authors: Theodorou, Marina C., Theodorou, Evaggelos C., Kyriakidis, Dimitrios A.
• Format: Article
• Language: English
• Subjects: Acetoacetates - chemistry; Amino Acid Substitution; Analytical Chemistry; Aspartic Acid - chemistry; Biochemical Engineering; Biochemistry; Biomedical and Life Sciences; Calcium - chemistry; Chemotactic Factors - chemistry; Chemotaxis - genetics; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Escherichia coli; Escherichia coli - genetics; Escherichia coli - physiology; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Flagella; Gene Expression Regulation, Bacterial; Gene Knockout Techniques; Glycerol - chemistry; Histamine - chemistry; Life Sciences; Neurobiology; Operon; Original Article; Phosphorylation; Protein Kinases - genetics; Protein Kinases - metabolism; Protein Processing, Post-Translational; Proteomics; Regulon; Serine - chemistry; Spermidine - chemistry
• ISSN: 0939-4451; 1438-2199
• DOI: 10.1007/s00726-011-1140-7

The AtoSC two-component system in Escherichia coli is a key regulator of many physiological processes. We report here the contribution of AtoSC in E. coli motility and chemotaxis. AtoSC locus deletion in Δ atoSC cells renders cells not motile or responsive against any chemoattractant or repellent independently of the AtoSC inducer’s presence. AtoSC expression through plasmid complemented the Δ atoSC phenotype. Cells expressing either AtoS or AtoC demonstrated analogous motility and chemotactic phenotypes as Δ atoSC cells, independently of AtoSC inducer’s presence. Mutations of AtoC phosphate-acceptor sites diminished or abrogated E. coli chemotaxis. trAtoC, the AtoC constitutive active form which lacks its receiver domain, up-regulated E. coli motility. AtoSC enhanced the transcription of the flhDC and fliAZY operons and to a lesser extent of the flgBCDEFGHIJKL operon. The AtoSC-mediated regulation of motility and chemotactic response required also the expression of the CheAY system. The AtoSC inducers enhanced the AtoSC-mediated motility and chemotaxis. Acetoacetate or spermidine further promoted the responses of only AtoSC-expressing cells, while Ca 2+ demonstrated its effects independently of AtoSC. Histamine regulated bacterial chemotaxis only in atoSC + cells in a concentration-dependent manner while reversed the AtoSC-mediated effects when added at high concentrations. The trAtoC-controlled motility effects were enhanced by acetoacetate or spermidine, but not by histamine. These data reveal that AtoSC system regulates the motility and chemotaxis of E. coli , participating in the transcriptional induction of the main promoters of the chemotactic regulon and modifying the motility and chemotactic phenotypes in an induction-dependent mechanism.