Influence of K+-dependent membrane lipid composition on the expression of the kdpFABC operon in Escherichia coli.
The membrane-bound sensor kinase KdpD and the cytoplasmic response regulator KdpE regulate the expression of the kdpFABC operon coding for the high affinity potassium uptake system KdpFABC in Escherichia coli. The signal transduction cascade of this two component system is activated under K(+)-limiting conditions in the medium, but is less sensitive to high osmolality. In order to test whether K(+) limitation affects membrane phospholipid composition and whether this change affects kdpFABC expression, we analysed the phospholipid composition of E. coli under these conditions. Our measurements revealed that there is an increase in the cardiolipin (CL) content during the exponential growth phase at the expense of the zwitterionic phospholipid phosphatidylethanolamine. The higher anionic phospholipid content occurs along with an increase of transcriptional activity of the cls gene coding for CL synthase. Furthermore, in vivo studies with E. coli derivatives carrying mutations in genes coding for enzymes involved in phospholipid biosynthesis revealed that the increase in the anionic lipid composition enhances the expression rate of the kdpFABC operon. Finally, we show that kinase activity of KdpD is stimulated in its native membrane environment by fusion with liposomes of anionic, but reduced with liposomes of zwitterionic phospholipids.
Universität Osnabrück, Fachbereich Biologie/ Chemie, Abteilung Mikrobiologie, D- 49069 Osnabrück, Germany.
Maren
M
Schniederberend
Petra
P
Zimmann
Mikhail
M
Bogdanov
William
W
Dowhan
Karlheinz
K
Altendorf
D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry; D015964:Gene Expression Regulation, Bacterial; D008081:Liposomes / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009876:Operon; D010743:Phospholipids / Q000737:chemistry; D010766:Phosphorylation; D011188:Potassium / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017855:Transferases (Other Substituted Phosphate Groups) / Q000235:genetics / Q000378:metabolism; D022161:Transport Vesicles / Q000737:chemistry
D027682:Cation Transport Proteins; D029968:Escherichia coli Proteins; D005227:Fatty Acids; D008081:Liposomes; D008563:Membrane Lipids; D008565:Membrane Proteins; D010743:Phospholipids; D017855:Transferases (Other Substituted Phosphate Groups); C100091:cardiolipin synthetase; D000251:Adenosine Triphosphatases; C058166:potassium translocating Kdp-ATPase, E coli; D011188:Potassium