title: Inactive and active states of the interferon-inducible resistance GTPase, Irga6, in vivo.
abstract: Irga6, a myristoylated, interferon-inducible member of the immunity-related GTPase family, contributes to disease resistance against Toxoplasma gondii in mice. Accumulation of Irga6 on the T. gondii parasitophorous vacuole membrane is associated with vesiculation and ultimately disruption of the vacuolar membrane in a process that requires an intact GTP-binding domain. The role of the GTP-binding domain of Irga6 in pathogen resistance is, however, unclear. We provide evidence that Irga6 in interferon-induced, uninfected cells is predominantly in a GDP-bound state that is maintained by other interferon-induced proteins. However, Irga6 that accumulates on the parasitophorous vacuole membrane after Toxoplasma infection is in the GTP-bound form. We demonstrate that a monoclonal antibody, 10D7, specifically detects GTP-bound Irga6, and we show that the formation of the 10D7 epitope follows from a GTP-dependent conformational transition of the N terminus of Irga6, anticipating an important role of the myristoyl group on Irga6 function in vivo.
authors.affiliation: Department of Cell Genetics, Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
authors.forename: Natasa
authors.initials: N
authors.lastname: Papic
authors.forename: Julia P
authors.initials: JP
authors.lastname: Hunn
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Pawlowski
authors.forename: Jens
authors.initials: J
authors.lastname: Zerrahn
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Howard
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002460:Cell Line; D004789:Enzyme Activation; D000939:Epitopes / Q000276:immunology; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D014122:Toxoplasma / Q000187:drug effects / Q000201:enzymology / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D007371:Interferon-gamma; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases
references.citation: J Immunol. 1998 Dec 15;161(12):6715-23
references.pmid: 9862701
references.citation: J Biol Chem. 2002 Jun 28;277(26):23515-24
references.pmid: 11971904
references.citation: Proc Natl Acad Sci U S A. 2000 Jan 18;97(2):751-5
references.pmid: 10639151
references.citation: Biochemistry. 1997 Apr 15;36(15):4675-84
references.pmid: 9109679
references.citation: Proc Natl Acad Sci U S A. 2006 Sep 19;103(38):14092-7
references.pmid: 16959883
references.citation: Annu Rev Immunol. 1985;3:501-35
references.pmid: 2415142
references.citation: PLoS Pathog. 2005 Nov;1(3):e24
references.pmid: 16304607
references.citation: J Immunol. 2004 Jan 15;172(2):1163-8
references.pmid: 14707092
references.citation: EMBO J. 2008 Oct 8;27(19):2495-509
references.pmid: 18772884
references.citation: J Biol Chem. 1995 Nov 3;270(44):26707-14
references.pmid: 7592898
references.citation: Genome Biol. 2005;6(11):R92
references.pmid: 16277747
references.citation: J Exp Med. 2001 Jul 16;194(2):181-8
references.pmid: 11457893
references.citation: J Immunol. 2005 Dec 15;175(12):8165-72
references.pmid: 16339555
references.citation: Science. 2003 Oct 24;302(5645):654-9
references.pmid: 14576437
references.citation: J Biol Chem. 1997 Apr 18;272(16):10639-45
references.pmid: 9099712
references.citation: J Immunol. 2007 Aug 1;179(3):1814-24
references.pmid: 17641048
references.citation: Cell. 1998 Oct 16;95(2):237-48
references.pmid: 9790530
references.citation: EMBO J. 1986 Feb;5(2):409-13
references.pmid: 2423325
references.citation: Biochim Biophys Acta. 1963 May 14;71:377-91
references.pmid: 18421828
references.citation: J Immunol. 1969 Nov;103(5):1132-42
references.pmid: 4900519
references.citation: J Immunol. 2008 May 1;180(9):6237-45
references.pmid: 18424746
references.citation: Mol Cell. 2004 Sep 10;15(5):727-39
references.pmid: 15350217
references.citation: Annu Rev Cell Dev Biol. 2007;23:579-611
references.pmid: 17506703
references.citation: J Immunol. 2004 Aug 15;173(4):2594-606
references.pmid: 15294976
references.citation: Infect Immun. 2001 Sep;69(9):5573-6
references.pmid: 11500431
references.citation: J Biol Chem. 2003 Aug 1;278(31):29336-43
references.pmid: 12732635
references.citation: Infect Immun. 2005 Jun;73(6):3278-86
references.pmid: 15908352
references.citation: Proc Natl Acad Sci U S A. 2005 Jul 26;102(30):10658-63
references.pmid: 16020528
references.citation: J Exp Med. 2006 Sep 4;203(9):2063-71
references.pmid: 16940170
references.citation: Immunity. 2005 Feb;22(2):163-73
references.pmid: 15723805
references.citation: Nature. 1995 Mar 9;374(6518):190-2
references.pmid: 7877694
references.citation: FEBS Lett. 1979 Nov 1;107(1):198-202
references.pmid: 499541