title: Regulation of phospholipid synthesis in Escherichia coli by guanosine tetraphosphate.
abstract: Phospholipid synthesis has been reported to be subject to stringent control in Escherichia coli. We present evidence that demonstrates a strict correlation between guanosine tetraphosphate accumulation and inhibition of phospholipid synthesis. In vivo experiments designed to examine the pattern of phospholipid labeling with (32)P-inorganic phosphate and (32)P-sn-glycerol-3-phosphate suggest that regulation must occur at the glycerol-3-phosphate acyltransferase step. Assay of phospholipid synthesis by cell-free extracts and semipurified preparations revealed that guanosine tetraphosphate inhibits at least two enzymes specific for the biosynthetic pathway, sn-glycerol-3-phosphate acyltransferase as well as sn-glycerol-3-phosphate phosphatidyl transferase. These findings provide a biochemical basis for the stringent control of lipid synthesis as well as regulation of steady-state levels of phospholipid in growing cells.
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D001345:Autoradiography; D002250:Carbon Radioisotopes; D002474:Cell-Free System; D002855:Chromatography, Thin Layer; D003597:Cytosine Nucleotides; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism*; D005994:Glycerophosphates / Q000378:metabolism; D006150:Guanine Nucleotides / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008055:Lipids / Q000096:biosynthesis; D010710:Phosphates / Q000378:metabolism; D010714:Phosphatidylethanolamines; D010743:Phospholipids / Q000096:biosynthesis*; D010761:Phosphorus Radioisotopes; D010770:Phosphotransferases / Q000378:metabolism; D012329:RNA, Bacterial / Q000096:biosynthesis; D014316:Tritium
chemical_list: D000596:Amino Acids; D002250:Carbon Radioisotopes; D003597:Cytosine Nucleotides; D005994:Glycerophosphates; D006150:Guanine Nucleotides; D008055:Lipids; D010710:Phosphates; D010714:Phosphatidylethanolamines; D010743:Phospholipids; D010761:Phosphorus Radioisotopes; D012329:RNA, Bacterial; D014316:Tritium; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D000123:Acetyltransferases; D010770:Phosphotransferases