title: Aerial development in Streptomyces coelicolor requires sortase activity.
abstract: Streptomyces coelicolor is a multicellular bacterium whose life cycle encompasses three differentiated states: vegetative hyphae, aerial hyphae and spores. Among the factors required for aerial development are the 'chaplins', a family of eight secreted proteins that coat the surface of aerial hyphae. Three chaplins (the 'long' chaplins, ChpA, B and C) possess an LAXTG-containing C-terminal sorting signal and are predicted sortase substrates. The five remaining 'short' chaplins are presumed to be associated with the cell surface through interactions with the long chaplins. We show here that two sortase enzymes, SrtE1 and SrtE2, cleave LAXTG-containing peptides at two distinct positions in vitro, and are required for cell wall anchoring of ChpC in vivo. srtE1/E2 double mutants are delayed in aerial hyphae formation, do not sporulate and fail to display all short chaplins on their aerial surfaces. Surprisingly, these mutant characteristics were not shared by a long chaplin mutant, which exhibited only modest delays in aerial development, leading us to revise the current model of chaplin-mediated aerial development. The sortase mutant phenotype, instead, appears to stem from an inability to transcribe aerial hyphae-specific genes, whose products have diverse functions. This suggests that sortase activity triggers an important, and previously unknown, developmental checkpoint.
authors.affiliation: Department of Biology and Institute for Infectious Disease Research, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Duong
authors.forename: David S
authors.initials: DS
authors.lastname: Capstick
authors.forename: Christina
authors.initials: C
authors.lastname: Di Berardo
authors.forename: Kim C
authors.initials: KC
authors.lastname: Findlay
authors.forename: Andrew
authors.initials: A
authors.lastname: Hesketh
authors.forename: Hee-Jeon
authors.initials: HJ
authors.lastname: Hong
authors.forename: Marie A
authors.initials: MA
authors.lastname: Elliot
mesh_terms: D019881:Aminoacyltransferases / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D016297:Mutagenesis, Site-Directed; D013171:Spores, Bacterial / Q000254:growth & development; D048372:Streptomyces coelicolor / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; C509824:sortase E; D019881:Aminoacyltransferases; D003546:Cysteine Endopeptidases