title: Regulation of biofilm components in Salmonella enterica serovar Typhimurium by lytic transglycosylases involved in cell wall turnover.
abstract: In Salmonella enterica serovar Typhimurium, a biofilm mode of growth known as the rdar morphotype is regulated by several networks which sense multiple environmental signals. The transcriptional regulator CsgD is the major target for these regulatory pathways. In this study, we show that two lytic transglycosylases of family I, MltE and MltC, in combination increase CsgD expression and rdar morphotype. MltE and MltC, which share a highly similar transglycosylase SLT domain, work redundantly to regulate CsgD at the transcriptional and posttranscriptional levels. The effect of MltE and MltC on CsgD levels was independent of the known regulatory pathways that sense cell envelope stress. These findings reveal, for the first time, a specific function of lytic transglycosylases in S. Typhimurium and suggest the existence of a new signaling pathway that links cell wall turnover to biofilm formation.
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, FE28017177, Stockholm, Sweden.
authors.forename: Claudia
authors.initials: C
authors.lastname: Monteiro
authors.forename: Xin
authors.initials: X
authors.lastname: Fang
authors.forename: Irfan
authors.initials: I
authors.lastname: Ahmad
authors.forename: Mark
authors.initials: M
authors.lastname: Gomelsky
authors.forename: Ute
authors.initials: U
authors.lastname: Römling
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000235:genetics / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D016695:Glycosyltransferases