title: The ESX system in Bacillus subtilis mediates protein secretion.
abstract: Esat-6 protein secretion systems (ESX or Ess) are required for the virulence of several human pathogens, most notably Mycobacterium tuberculosis and Staphylococcus aureus. These secretion systems are defined by a conserved FtsK/SpoIIIE family ATPase and one or more WXG100 family secreted substrates. Gene clusters coding for ESX systems have been identified amongst many organisms including the highly tractable model system, Bacillus subtilis. In this study, we demonstrate that the B. subtilis yuk/yue locus codes for a nonessential ESX secretion system. We develop a functional secretion assay to demonstrate that each of the locus gene products is specifically required for secretion of the WXG100 virulence factor homolog, YukE. We then employ an unbiased approach to search for additional secreted substrates. By quantitative profiling of culture supernatants, we find that YukE may be the sole substrate that depends on the FtsK/SpoIIIE family ATPase for secretion. We discuss potential functional implications for secretion of a unique substrate.
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Huppert
authors.affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America.
authors.forename: Talia L
authors.initials: TL
authors.lastname: Ramsdell
authors.affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Chase
authors.affiliation: Thermo Fisher Scientific, BRIMS Unit, Cambridge, Massachusetts, United States of America.
authors.forename: David A
authors.initials: DA
authors.lastname: Sarracino
authors.affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Fortune
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America.
authors.forename: Briana M
authors.initials: BM
authors.lastname: Burton
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors