title: Biochemical and immunological characterization of Toxoplasma gondii macrophage migration inhibitory factor.
abstract: Macrophage migration inhibitory factor (MIF) is a proinflammatory molecule in mammals that, unusually for a cytokine, exhibits tautomerase and oxidoreductase enzymatic activities. Homologues of this well conserved protein are found within diverse phyla including a number of parasitic organisms. Herein, we produced recombinant histidine-tagged Toxoplasma gondii MIF (TgMIF), a 12-kDa protein that lacks oxidoreductase activity but exhibits tautomerase activity with a specific activity of 19.3 μmol/min/mg that cannot be inhibited by the human MIF inhibitor ISO-1. The crystal structure of the TgMIF homotrimer has been determined to 1.82 Å, and although it has close structural homology with mammalian MIFs, it has critical differences in the tautomerase active site that account for the different inhibitor sensitivity. We also demonstrate that TgMIF can elicit IL-8 production from human peripheral blood mononuclear cells while also activating ERK MAPK pathways in murine bone marrow-derived macrophages. TgMIF may therefore play an immunomodulatory role during T. gondii infection in mammals.
authors: Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, Scotland, United Kingdom.
authors: Caroline
authors: C
authors: Sommerville
authors: Julia M
authors: JM
authors: Richardson
authors: Roderick A M
authors: RA
authors: Williams
authors: Jeremy C
authors: JC
authors: Mottram
authors: Craig W
authors: CW
authors: Roberts
authors: James
authors: J
authors: Alexander
authors: Fiona L
authors: FL
authors: Henriquez
mesh_terms: D000818:Animals; D018360:Crystallography, X-Ray; D006801:Humans; D016209:Interleukin-8 / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008263:Macrophage Migration-Inhibitory Factors / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008264:Macrophages / Q000276:immunology / Q000378:metabolism / Q000469:parasitology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014122:Toxoplasma / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014123:Toxoplasmosis / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: C508606:CXCL8 protein, human; D016209:Interleukin-8; D008263:Macrophage Migration-Inhibitory Factors; D015800:Protozoan Proteins
keywords: Biochemistry; Cell Signaling; Cellular Immune Response; Crystallography; Enzyme Kinetics; Immunology; Macrophages; Mammalian Macrophage Migration Inhibitory Factor; Parasite; Toxoplasma