title: A two-component system regulates gene expression of the type IX secretion component proteins via an ECF sigma factor.
abstract: The periodontopathogen Porphyromonas gingivalis secretes potent pathogenic proteases, gingipains, via the type IX secretion system (T9SS). This system comprises at least 11 components; however, the regulatory mechanism of their expression has not yet been elucidated. Here, we found that the PorY (PGN_2001)-PorX (PGN_1019)-SigP (PGN_0274) cascade is involved in the regulation of T9SS. Surface plasmon resonance (SPR) analysis revealed a direct interaction between a recombinant PorY (rPorY) and a recombinant PorX (rPorX). rPorY autophosphorylated and transferred a phosphoryl group to rPorX in the presence of Mn(2+). These results demonstrate that PorX and PorY act as a response regulator and a histidine kinase, respectively, of a two component system (TCS), although they are separately encoded on the chromosome. T9SS component-encoding genes were down-regulated in a mutant deficient in a putative extracytoplasmic function (ECF) sigma factor, PGN_0274 (SigP), similar to the porX mutant. Electrophoretic gel shift assays showed that rSigP bound to the putative promoter regions of T9SS component-encoding genes. The SigP protein was lacking in the porX mutant. Co-immunoprecipitation and SPR analysis revealed the direct interaction between SigP and PorX. Together, these results indicate that the PorXY TCS regulates T9SS-mediated protein secretion via the SigP ECF sigma factor.
authors.affiliation: Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.|Division of Frontier Life Science, Department of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kadowaki
authors.affiliation: Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.
authors.forename: Hideharu
authors.initials: H
authors.lastname: Yukitake
authors.affiliation: Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Naito
authors.affiliation: Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Sato
authors.affiliation: Department of Microbiology, Tokyo Dental College, Tokyo 101-0061, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kikuchi
authors.affiliation: Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.|Department of Pediatric Dentistry, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kondo
authors.affiliation: Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.
authors.forename: Mikio
authors.initials: M
authors.lastname: Shoji
authors.affiliation: Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D058947:Bacterial Secretion Systems / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D010766:Phosphorylation; D016966:Porphyromonas gingivalis / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D012808:Sigma Factor / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D012808:Sigma Factor