Calcium channels blockers inhibit the signal transduction through the AtoSC system in Escherichia coli.
Verapamil, diltiazem and nifedipine are Ca(2+)-channel blockers used in cardiovascular diseases. We report here that the Escherichia coli AtoSC signaling is inhibited by those blockers. AtoSC two-component system plays a pivotal role in sophisticated signaling networks in E. coli regulating processes implicated in bacterial homeostasis and pathogenicity. The Ca(2+)-channel blockers abrogated the in vitro full-length AtoS kinase autophosphorylation. However, they demonstrated no effect on the AtoS cytoplasmic form autophosphorylation. AtoC protected AtoS from verapamil or diltiazem but not from nifedipine, when the two constituents formed complex. The blockers did not affect the AtoS≈P to AtoC phosphotransfer. The blockers-mediated AtoSC inhibition was verified in vivo on the atoDAEB expression, which was inhibited only in AtoSC-expressing bacteria upon acetoacetate. The AtoS and AtoC protein or their genes transcription levels were unaffected by the blockers. Blockers demonstrated differential effects in the regulation of both the cytosolic- and most potently the membrane-bound-cPHB. Extracellular Ca(2+) counteracted the verapamil-mediated effect on cPHB only in atoSC(+) cells. Extracellular Ca(2+) reversed the diltiazem-mediated cPHB decreases in cells of both genetic backgrounds, yet a Ca(2+)-concentration dependent reversion was observed only in the AtoSC-regulated cPHB. Nifedipine caused a more pronounced cPHB down-regulation that was not reversed by extracellular Ca(2+). The AtoSC signaling inhibition by Ca(2+)-channel blockers used for human treatment, and their differential effects on cPHB-formed Ca(2+)-channels, signify their implications in bacterial-host interactions through the two-component signaling and could stimulate the design of Ca(2+)-channels blockers derivatives acting as inhibitors of two-component systems.
Laboratory of Biochemistry, Department of Chemistry, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece. mtheod80@yahoo.com
Marina C
MC
Theodorou
Dimitrios A
DA
Kyriakidis
D000090:Acetoacetates / Q000378:metabolism; D000217:Acyltransferases / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009876:Operon / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D014158:Transcription, Genetic / Q000187:drug effects
D000090:Acetoacetates; C505587:AtoC protein, E coli; D002121:Calcium Channel Blockers; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D000217:Acyltransferases; C060970:poly-beta-hydroxybutyrate polymerase; D011494:Protein Kinases; C505586:AtoS protein, E coli; D002118:Calcium