Phosphatidic acid and N-acylphosphatidylethanolamine form membrane domains in Escherichia coli mutant lacking cardiolipin and phosphatidylglycerol.
The pgsA null Escherichia coli strain, UE54, lacks the major anionic phospholipids phosphatidylglycerol and cardiolipin. Despite these alterations the strain exhibits relatively normal cell division. Analysis of the UE54 phospholipids using negativeion electrospray ionization mass spectrometry resulted in identification of a new anionic phospholipid, N-acylphosphatidylethanolamine. Staining with the fluorescent dye 10-N-nonyl acridine orange revealed anionic phospholipid membrane domains at the septal and polar regions. Making UE54 null in minCDE resulted in budding off of minicells from polar domains. Analysis of lipid composition by mass spectrometry revealed that minicells relative to parent cells were significantly enriched in phosphatidic acid and N-acylphosphatidylethanolamine. Thus despite the absence of cardiolipin, which forms membrane domains at the cell pole and division sites in wild-type cells, the mutant cells still maintain polar/septal localization of anionic phospholipids. These three anionic phospholipids share common physical properties that favor polar/septal domain formation. The findings support the proposed role for anionic phospholipids in organizing amphitropic cell division proteins at specific sites on the membrane surface.
Mileykovskaya
Eugenia
E
Department of Biochemistry and Molecular Biology, University of Texas, Medical School, Houston, Texas 77030. Electronic address: Eugenia.Mileykovskaya@uth.tmc.edu.
Ryan
Andrea C
AC
Department of Biochemistry, Duke University, Medical Center, Durham, North Carolina 27710.
Mo
Xi
X
Department of Biochemistry and Molecular Biology, University of Texas, Medical School, Houston, Texas 77030.
Lin
Chun-Chieh
CC
Department of Biochemistry and Molecular Biology, University of Texas, Medical School, Houston, Texas 77030.
Khalaf
Khaled I
KI
Department of Biochemistry and Molecular Biology, University of Texas, Medical School, Houston, Texas 77030.
Dowhan
William
W
Department of Biochemistry and Molecular Biology, University of Texas, Medical School, Houston, Texas 77030. Electronic address: William.Dowhan@uth.tmc.edu.
Garrett
Teresa A
TA
Department of Chemistry, Vassar College, Poughkeepsie, New York 12604. Electronic address: tegarrett@vassar.edu.
D002308:Cardiolipins / Q000235:genetics*; D002853:Chromatography, Liquid; D002855:Chromatography, Thin Layer; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins / Q000235:genetics; D008081:Liposomes; D009154:Mutation; D010712:Phosphatidic Acids / Q000378:metabolism*; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D010715:Phosphatidylglycerols / Q000235:genetics*; D021241:Spectrometry, Mass, Electrospray Ionization
D002308:Cardiolipins; D005456:Fluorescent Dyes; D008081:Liposomes; D010712:Phosphatidic Acids; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; D049452:Green Fluorescent Proteins; C483858:phosphatidylethanolamine