title: A comprehensive study on the immunological reactivity of the Hsp90 molecular chaperone.
abstract: Periodontitis is a chronic infectious disease, Porphyromonas gingivalis being the most implicated pathogen. In the present study, we investigated the role of P. gingivalis HtpG (PgHtpG), a bacterial ortholog of mammalian Hsp90, in the growth of P. gingivalis and also assessed the immunological cross-reactivity of the members of the Hsp90 family. Antiserum against rat liver Hsp90 potently reacted with yeast Hsp90, called Hsc82, and also weakly with human Hsp90 (hHsp90) and human mitochondrial paralog Trap1, but did not react with PgHtpG, Escherichia coli HtpG, or human endoplasmic reticulum paralog Grp94. Moreover, among 19 monoclonal antibodies raised against hHsp90, nine cross-reacted with yeast Hsc82, and one with human Grp94, but none bound to PgHtpG or E. coli HtpG. Among them, three mAbs that strongly reacted with yeast Hsc82 recognized Asn(291)-Ile(304), a conserved region of the family protein. The polyclonal antibody raised against a peptide, Met(315)-Glu(328), of human Grp94, which corresponded to the conserved region of hHsp90, cross-reacted with hHsp90, but not with other Hsp90-family members. Thus, although mammalian Hsp90 shares some immunological reactivity with yeast Hsc82, human Grp94, and human Trap1, it is considerably distinct from its bacterial ortholog, HtpG. Disruption of the P. gingivalis htpG gene neither affected bacterial survival nor altered the sensitivity of P. gingivalis to various forms of stress.
authors.affiliation: Division of Oral and Maxillofacial Surgery, Department of Developmental and Reconstructive Medicine, Course of Medical and Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kawano
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kobayakawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Fukuma
authors.forename: Hideharu
authors.initials: H
authors.lastname: Yukitake
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Mikio
authors.initials: M
authors.lastname: Shoji
authors.forename: Koji
authors.initials: K
authors.lastname: Nakayama
authors.forename: Akio
authors.initials: A
authors.lastname: Mizuno
authors.forename: Takashi
authors.initials: T
authors.lastname: Takagi
authors.forename: Takayuki K
authors.initials: TK
authors.lastname: Nemoto
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D001426:Bacterial Proteins / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D004926:Escherichia coli / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000276:immunology; D018841:HSP90 Heat-Shock Proteins / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008565:Membrane Proteins / Q000276:immunology; D009154:Mutation; D016966:Porphyromonas gingivalis / Q000187:drug effects / Q000254:growth & development / Q000276:immunology; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; C092306:TRAP1 protein, human; C018551:glucose-regulated proteins; C066720:HtpG protein, bacteria; D006861:Hydrogen Peroxide