RRC ID 4979
Author Naseem R, Wann KT, Holland IB, Campbell AK.
Title ATP regulates calcium efflux and growth in E. coli.
Journal J. Mol. Biol.
Abstract Escherichia coli regulates cytosolic free Ca(2+) in the micromolar range through influx and efflux. Herein, we show for the first time that ATP is essential for Ca(2+) efflux and that ATP levels also affect generation time. A transcriptome analysis identified 110 genes whose expression responded to an increase in cytosolic Ca(2+) (41 elevated, 69 depressed). Of these, 3 transport proteins and 4 membrane proteins were identified as potential Ca(2+) transport pathways. Expression of a further 943 genes was modified after 1 h in growth medium containing Ca(2+) relative to time zero. Based on the microarray results and other predicted possible Ca(2+) transporters, the level of cytosolic free Ca(2+) was measured in selected mutants from the Keio knockout collection using intracellular aequorin. In this way, we identified a knockout of atpD, coding for a component of the F(o)F(1) ATPase, as defective in Ca(2+) efflux. Seven other putative Ca(2+) transport proteins exhibited normal Ca(2+) handling. The defect in the DeltaatpD knockout cells could be explained by a 70% reduction in ATP. One millimolar glucose or 1 mM methylglyoxal raised ATP in the DeltaatpD knockout cells to that of the wild type and restored Ca(2+) efflux. One millimolar 2,4-dinitrophenol lowered the ATP in wild type to that in the DeltaatpD cells. Under these conditions, a similar defect in Ca(2+) efflux in wild type was observed in DeltaatpD cells. Ten millimolar concentration of Ca(2+) resulted in a 30% elevation in ATP in wild type and was accompanied by a 10% reduction in generation time under these conditions. Knockouts of pitB, a potential Ca(2+) transporter, atoA, the beta subunit of acetate CoA-transferase likely to be involved in polyhydroxybutyrate synthesis, and ppk, encoding polyphosphate kinase, all indicated no defect in Ca(2+) efflux. We therefore propose that ATP is most likely to regulate Ca(2+) efflux in E. coli through an ATPase.
Volume 391(1)
Pages 42-56
Published 2009-8-7
DOI 10.1016/j.jmb.2009.05.064
PII S0022-2836(09)00646-9
PMID 19481094
MeSH 2,4-Dinitrophenol / pharmacology Adenosine Triphosphate / metabolism* Calcium / metabolism* Escherichia coli / growth & development Escherichia coli / metabolism Escherichia coli / physiology* Escherichia coli Proteins / genetics Gene Expression Profiling Gene Expression Regulation, Bacterial* Gene Knockout Techniques Membrane Proteins / deficiency Membrane Proteins / genetics Mutant Proteins / genetics Oligonucleotide Array Sequence Analysis Proton-Translocating ATPases / deficiency Transcription Factors / deficiency Transcription Factors / genetics Uncoupling Agents / pharmacology
IF 4.894
Times Cited 24
Prokaryotes E. coli CV-41(JM109) ME7986(MG1655) ME9062(BW25113)