title: BopC is a type III secreted effector protein of Burkholderia pseudomallei.
abstract: Burkholderia pseudomallei, the causative agent of melioidosis, exploits the Bsa type III secretion system (T3SS) to deliver effector proteins into host cells. These effectors manipulate host cell functions; thus, contributing to the ability of the bacteria to evade the immune response and cause disease. Only two Bsa-secreted effectors have been conclusively identified to date. Here, we report the identification of the third B. pseudomallei type III secreted effector protein, designated BopC. BopC is encoded by the bpss1516 gene abutting bpss1517, which encodes its putative chaperone. The genes are located in the close proximity to the bsa T3SS gene cluster of B. pseudomallei K96243 (Fig. 1). BopC was secreted into culture supernatant by the wild-type B. pseudomallei strain, but its secretion was abolished in the bsaZ T3SS mutant. Using pull down and co-purification assays, we confirmed that BopC interacts with its putative chaperone, BPSS1517, in vitro. Furthermore, the first 20 N-terminal amino acids of BopC were found to be sufficient to mediate the T3SS-dependent translocation of a reporter protein from a heterologous enteropathogenic Escherichia coli host into mammalian cells. Finally, bopC mutant was found to be less invasive than the wild-type strain in the epithelial cells.
authors.affiliation: Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sunsiree
authors.initials: S
authors.lastname: Muangman
authors.forename: Sunee
authors.initials: S
authors.lastname: Korbsrisate
authors.forename: Veerachat
authors.initials: V
authors.lastname: Muangsombut
authors.forename: Varintip
authors.initials: V
authors.lastname: Srinon
authors.forename: Natalie Lazar
authors.initials: NL
authors.lastname: Adler
authors.forename: Gunnar N
authors.initials: GN
authors.lastname: Schroeder
authors.forename: Gad
authors.initials: G
authors.lastname: Frankel
authors.forename: Edouard E
authors.initials: EE
authors.lastname: Galyov
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016957:Burkholderia pseudomallei / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D002460:Cell Line; D004847:Epithelial Cells / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics; D017353:Gene Deletion; D017930:Genes, Reporter; D006801:Humans; D018832:Molecular Chaperones / Q000378:metabolism; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; D037521:Virulence Factors