title: The serine phosphatase SerB of Porphyromonas gingivalis suppresses IL-8 production by dephosphorylation of NF-κB RelA/p65.
abstract: Porphyromonas gingivalis is a major pathogen in severe and chronic manifestations of periodontal disease, which is one of the most common infections of humans. A central feature of P. gingivalis pathogenicity is dysregulation of innate immunity at the gingival epithelial interface, including suppression of IL-8 production by epithelial cells. NF-κB is a transcriptional regulator that controls important aspects of innate immune responses, and NF-κB RelA/p65 homodimers regulate transcription of IL8. Phosphorylation of the NF-κB p65 subunit protein on the serine 536 residue affects nuclear translocation and transcription of target genes. Here we show that SerB, a haloacid dehalogenase (HAD) family serine phosphatase secreted by P. gingivalis, is produced intracellularly and can specifically dephosphorylate S536 of p65 in gingival epithelial cells. A P. gingivalis mutant lacking SerB was impaired in dephosphorylation of p65 S536, and ectopically expressed SerB bound to p65 and co-localized with p65 in the cytoplasm. Ectopic expression of SerB also resulted in dephosphorylation of p65 with reduced nuclear translocation in TNF-α-stimulated epithelial cells. In contrast, the p105/50 subunit of NF-κB was unaffected by SerB. Co-expression of a constitutively active p65 mutant (S536D) relieved inhibition of nuclear translocation. Both the activity of the IL8 promoter and production of IL-8 were diminished by SerB. Deletion and truncation mutants of SerB lacking the HAD-family enzyme motifs of SerB were unable to dephosphorylate p65, inhibit nuclear translocation or abrogate IL8 transcription. Specific dephosphorylation of NF-κB p65 S536 by SerB, and consequent inhibition of nuclear translocation, provides the molecular basis for a bacterial strategy to manipulate host inflammatory pathways and repress innate immunity at mucosal surfaces.
authors: Center for Oral Health and Systemic Disease, School of Dentistry, University of Louisville, Louisville, Kentucky, United States of America.
authors: Hiroki
authors: H
authors: Takeuchi
authors: Takanori
authors: T
authors: Hirano
authors: Sarah E
authors: SE
authors: Whitmore
authors: Ichijiro
authors: I
authors: Morisaki
authors: Atsuo
authors: A
authors: Amano
authors: Richard J
authors: RJ
authors: Lamont
mesh_terms: D021581:Active Transport, Cell Nucleus; D002460:Cell Line; D004847:Epithelial Cells / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D016966:Porphyromonas gingivalis / Q000201:enzymology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D016209:Interleukin-8; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; C489548:NFKB1 protein, human; C498143:RELA protein, human; D051996:Transcription Factor RelA; D010749:Phosphoprotein Phosphatases
references: Cell Signal. 2010 Sep;22(9):1282-90
references: 20363318
references: Infect Immun. 1998 Apr;66(4):1660-5
references: 9529095
references: Infect Immun. 2008 Jun;76(6):2420-7
references: 18391005
references: Biochem Biophys Res Commun. 2003 Feb 7;301(2):583-90
references: 12565903
references: Nature. 1997 Aug 7;388(6642):548-54
references: 9252186
references: Science. 1993 Mar 26;259(5103):1912-5
references: 8096091
references: Cell. 2007 Nov 30;131(5):927-39
references: 18045535
references: Cell Microbiol. 2012 Apr;14(4):577-88
references: 22212282
references: J Immunol. 2004 May 15;172(10):6336-44
references: 15128824
references: J Biol Chem. 2004 Jun 18;279(25):26115-25
references: 15073170
references: Nat Rev Immunol. 2008 Nov;8(11):837-48
references: 18927578
references: Mol Cell Biol. 2000 Feb;20(4):1436-47
references: 10648628
references: Microbes Infect. 2008 Feb;10(2):122-8
references: 18280195
references: J Dent Res. 2012 Oct;91(10):914-20
references: 22935673
references: Infect Immun. 2006 Jan;74(1):594-601
references: 16369016
references: Infect Immun. 1995 Oct;63(10):3878-85
references: 7558295
references: Proc Natl Acad Sci U S A. 2006 Jul 18;103(29):11027-32
references: 16832066
references: Mol Microbiol. 2010 Dec;78(5):1232-45
references: 21091507
references: Biochem J. 1999 Apr 15;339 ( Pt 2):223-6
references: 10191250
references: Immunol Rev. 2012 Mar;246(1):125-40
references: 22435551
references: Analyst. 2001 Jan;126(1):52-7
references: 11205512
references: EMBO J. 2000 Jun 1;19(11):2580-91
references: 10835356
references: Nat Immunol. 2011 Jul 19;12(8):695-708
references: 21772278
references: Periodontol 2000. 2004;35:53-74
references: 15107058
references: Cell Microbiol. 2012 Feb;14(2):155-67
references: 22044780
references: Annu Rev Immunol. 2009;27:693-733
references: 19302050
references: Cell Microbiol. 1999 Nov;1(3):215-23
references: 11207554
references: Mol Cell Biol. 2006 Jan;26(2):457-71
references: 16382138
references: Structure. 2000 Apr 15;8(4):419-28
references: 10801482
references: Mol Cell Biol. 2001 Feb;21(4):1024-35
references: 11158290
references: Proc Natl Acad Sci U S A. 1992 Sep 1;89(17):8145-9
references: 1518839
references: Proteomics. 2007 Dec;7(23):4323-37
references: 17979175
references: Infect Immun. 2010 Nov;78(11):4560-9
references: 20805334
references: J Dent Res. 2012 Sep;91(9):816-20
references: 22772362
references: Nat Immunol. 2011 Apr;12(4):335-43
references: 21399639
references: J Immunol. 2003 Jun 1;170(11):5630-5
references: 12759443
references: Mol Cell Biol. 1993 Oct;13(10):6137-46
references: 8413215
references: J Biol Chem. 2002 Oct 11;277(41):38168-78
references: 12140289
references: Proc Natl Acad Sci U S A. 2010 Oct 5;107(40):17333-8
references: 20855622
references: Cell Host Microbe. 2011 Nov 17;10(5):497-506
references: 22036469
references: Nature. 2009 Jul 23;460(7254):520-4
references: 19561593
references: Cell. 1997 Oct 17;91(2):243-52
references: 9346241
references: J Biol Chem. 2005 Oct 14;280(41):34538-47
references: 16105840
references: J Clin Periodontol. 2010 Jan;37(1):24-9
references: 20096064