title: Dead-end intermediates in the enterobacterial common antigen pathway induce morphological defects in Escherichia coli by competing for undecaprenyl phosphate.
abstract: Bacterial morphology is determined primarily by the architecture of the peptidoglycan (PG) cell wall, a mesh-like layer that encases the cell. To identify novel mechanisms that create or maintain cell shape in Escherichia coli, we used flow cytometry to screen a transposon insertion library and identified a wecE mutant that altered cell shape, causing cells to filament and swell. WecE is a sugar aminotransferase involved in the biosynthesis of enterobacterial common antigen (ECA), a non-essential outer membrane glycolipid of the Enterobacteriaceae. Loss of wecE interrupts biosynthesis of ECA and causes the accumulation of the undecaprenyl pyrophosphate-linked intermediate ECA-lipid II. The wecE shape defects were reversed by: (i) preventing initiation of ECA biosynthesis, (ii) increasing the synthesis of the lipid carrier undecaprenyl phosphate (Und-P), (iii) diverting Und-P to PG synthesis or (iv) promoting Und-P recycling. The results argue that the buildup of ECA-lipid II sequesters part of the pool of Und-P, which, in turn, adversely affects PG synthesis. The data strongly suggest there is competition for a common pool of Und-P, whose proper distribution to alternate metabolic pathways is required to maintain normal cell shape in E. coli.
authors.affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Jorgenson
authors.affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
authors.forename: Suresh
authors.initials: S
authors.lastname: Kannan
authors.affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Laubacher
authors.affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
authors.forename: Kevin D
authors.identifier: http://orcid.org/0000-0003-1760-281X
authors.initials: KD
authors.lastname: Young
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D053858:Metabolic Networks and Pathways; D009154:Mutation; D011106:Polyisoprenyl Phosphates / Q000378:metabolism*; D000637:Transaminases / Q000235:genetics / Q000378:metabolism; D014538:Uridine Diphosphate N-Acetylmuramic Acid / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D029968:Escherichia coli Proteins; D011106:Polyisoprenyl Phosphates; D014538:Uridine Diphosphate N-Acetylmuramic Acid; C017286:enterobacterial common antigen; C069249:muramyl-NAc-(pentapeptide)pyrophosphoryl-undecaprenol; C009621:undecaprenyl phosphate; D000637:Transaminases; C000608766:WecE protein, E coli