title: Activation of the Rcs signal transduction system is responsible for the thermosensitive growth defect of an Escherichia coli mutant lacking phosphatidylglycerol and cardiolipin.
abstract: The lethal effect of an Escherichia coli pgsA null mutation, which causes a complete lack of the major acidic phospholipids, phosphatidylglycerol and cardiolipin, is alleviated by a lack of the major outer membrane lipoprotein encoded by the lpp gene, but an lpp pgsA strain shows a thermosensitive growth defect. Using transposon mutagenesis, we found that this thermosensitivity was suppressed by disruption of the rcsC, rcsF, and yojN genes, which code for a sensor kinase, accessory positive factor, and phosphotransmitter, respectively, of the Rcs phosphorelay signal transduction system initially identified as regulating the capsular polysaccharide synthesis (cps) genes. Disruption of the rcsB gene coding for the response regulator of the system also suppressed the thermosensitivity, whereas disruption of cpsE did not. By monitoring the expression of a cpsB'-lac fusion, we showed that the Rcs system is activated in the pgsA mutant and is reverted to a wild-type level by the rcs mutations. These results indicate that envelope stress due to an acidic phospholipid deficiency activates the Rcs phosphorelay system and thereby causes the thermosensitive growth defect independent of the activation of capsule synthesis.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Science, Saitama University, Saitama, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shiba
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Aono
authors.forename: Takashi
authors.initials: T
authors.lastname: Kiuchi
authors.forename: Jin
authors.initials: J
authors.lastname: Kusaka
authors.forename: Kouji
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hara
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology*; D002308:Cardiolipins / Q000502:physiology*; D004926:Escherichia coli / Q000254:growth & development* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000502:physiology*; D009097:Multienzyme Complexes / Q000502:physiology*; D010715:Phosphatidylglycerols / Q000502:physiology*; D010749:Phosphoprotein Phosphatases / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013696:Temperature; D014157:Transcription Factors; D017855:Transferases (Other Substituted Phosphate Groups) / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D002308:Cardiolipins; D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; D010715:Phosphatidylglycerols; C489568:RcsB protein, E coli; D014157:Transcription Factors; C489728:rcsC protein, E coli; C078611:rcsF protein, E coli; C074889:RcsB protein, Bacteria; D011494:Protein Kinases; D017855:Transferases (Other Substituted Phosphate Groups); C020676:CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase; D010749:Phosphoprotein Phosphatases