title: Insights into the function of YciM, a heat shock membrane protein required to maintain envelope integrity in Escherichia coli.
abstract: The cell envelope of Gram-negative bacteria is an essential organelle that is important for cell shape and protection from toxic compounds. Proteins involved in envelope biogenesis are therefore attractive targets for the design of new antibacterial agents. In a search for new envelope assembly factors, we screened a collection of Escherichia coli deletion mutants for sensitivity to detergents and hydrophobic antibiotics, a phenotype indicative of defects in the cell envelope. Strains lacking yciM were among the most sensitive strains of the mutant collection. Further characterization of yciM mutants revealed that they display a thermosensitive growth defect on low-osmolarity medium and that they have a significantly altered cell morphology. At elevated temperatures, yciM mutants form bulges containing cytoplasmic material and subsequently lyse. We also discovered that yciM genetically interacts with envC, a gene encoding a regulator of the activity of peptidoglycan amidases. Altogether, these results indicate that YciM is required for envelope integrity. Biochemical characterization of the protein showed that YciM is anchored to the inner membrane via its N terminus, the rest of the protein being exposed to the cytoplasm. Two CXXC motifs are present at the C terminus of YciM and serve to coordinate a redox-sensitive iron center of the rubredoxin type. Both the N-terminal membrane anchor and the C-terminal iron center of YciM are important for function.
authors.affiliation: de Duve Institute, Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Valérie
authors.initials: V
authors.lastname: Nicolaes
authors.forename: Hayat
authors.initials: H
authors.lastname: El Hajjaji
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Davis
authors.forename: Charles
authors.initials: C
authors.lastname: Van der Henst
authors.forename: Matthieu
authors.initials: M
authors.lastname: Depuydt
authors.forename: Pauline
authors.initials: P
authors.lastname: Leverrier
authors.forename: Abram
authors.initials: A
authors.lastname: Aertsen
authors.forename: Vincent
authors.initials: V
authors.lastname: Haufroid
authors.forename: Sandrine
authors.initials: S
authors.lastname: Ollagnier de Choudens
authors.forename: Xavier
authors.initials: X
authors.lastname: De Bolle
authors.forename: Natividad
authors.initials: N
authors.lastname: Ruiz
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Collet
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001433:Bacteriolysis; D002462:Cell Membrane / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D010450:Endopeptidases / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D006358:Hot Temperature; D007501:Iron / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008853:Microscopy; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D011485:Protein Binding; D025941:Protein Interaction Mapping; D016415:Sequence Alignment
chemical_list: D003470:Culture Media; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C586514:YciM protein, E coli; D007501:Iron; D010450:Endopeptidases; C454699:EnvC protein, E coli