title: High levels of DegU-P activate an Esat-6-like secretion system in Bacillus subtilis.
abstract: The recently discovered Type VII/Esat-6 secretion systems seem to be widespread among bacteria of the phyla Actinobacteria and Firmicutes. In some species they play an important role in pathogenic interactions with eukaryotic hosts. Several studies have predicted that the locus yukEDCByueBC of the non-pathogenic, Gram-positive bacterium Bacillus subtilis would encode an Esat-6-like secretion system (Ess). We provide here for the first time evidences for the functioning of this secretion pathway in an undomesticated B. subtilis strain. We show that YukE, a small protein with the typical features of the secretion substrates from the WXG100 superfamily is actively secreted to culture media. YukE secretion depends on intact yukDCByueBC genes, whose products share sequence or structural homology with known components of the S. aureus Ess. Biochemical characterization of YukE indicates that it exists as a dimer both in vitro and in vivo. We also show that the B. subtilis Ess essentially operates in late stationary growth phase in absolute dependence of phosphorylated DegU, the response regulator of the two-component system DegS-DegU. We present possible reasons that eventually have precluded the study of this secretion system in the B. subtilis laboratory strain 168.
authors.affiliation: Centro de Patogénese Molecular-Unidade de Retrovírus e Infecções Associadas (CPM-URIA), Faculdade de Farmácia da Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Baptista
authors.forename: Hugo Condessa
authors.initials: HC
authors.lastname: Barreto
authors.forename: Carlos
authors.initials: C
authors.lastname: São-José
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002876:Chromosomes, Bacterial; D015964:Gene Expression Regulation, Bacterial; D056426:Genetic Loci; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D055503:Protein Multimerization; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; C066496:DegS protein, Bacteria; C066497:DegU protein, Bacteria