title: A 16-residue peptide fragment of macrophage migration inhibitory factor, MIF-(50-65), exhibits redox activity and has MIF-like biological functions.
abstract: Macrophage migration inhibitory factor (MIF) is a cytokine that participates in the host inflammatory response. A Cys-Xaa-Xaa-Cys (CXXC)-based thiol-protein oxidoreductase activity of MIF is associated with certain biological functions. Peptides spanning the CXXC region of thiol-protein oxidoreductases retain some biochemical properties of the full-length protein. We report on the characterization of CXXC-spanning MIF-(50-65) and its serine variant, C57S/C60S-MIF-(50-65). Following disulfide-mediated cyclization, MIF-(50-65) adapted a beta-turn conformation comparable with that of beta-turn-containing cyclo-57,60-[Asp57,Dap60]MIF-(50-65). MIF-(50-65) had a redox potential E'0 of -0.258 V and formed mixed disulfides with glutathione and cysteine. MIF-(50-65) but not C57S/C60S-MIF-(50-65) had oxidoreductase activity in vitro. Intriguingly, MIF-(50-65) exhibited MIF-like cellular activities. The peptide but not its variant had glucocorticoid overriding and proliferation-enhancing activity and stimulated ERK1/2 phosphorylation. MIF-(50-65) and its variant bound to the MIF-binding protein JAB1 and enhanced cellular levels of p27Kip1. As the peptide and its variant were endocytosed at similar efficiency, sequence 50-65 appears sufficient for the JAB1-related effects of MIF, whereas other activities require CXXC. Cyclo-57,60-[Asp57,Dap60]MIF-(50-65) activated ERK1/2, indicating that CXXC-dependent disulfide and beta-turn formation is associated with an activity-inducing conformation. We conclude that CXXC and sequence 50-65 are critical for the activities of MIF. MIF-(50-65) is a surprisingly short sequence with MIF-like functions that could be an excellent molecular template for MIF therapeutics.
authors.affiliation: Division of Biochemistry and Molecular Cell Biology, Institute of Biochemistry, University Hospital RWTH Aachen, D-52074 Aachen, Germany.
authors.forename: Mai Tuyet
authors.initials: MT
authors.lastname: Nguyen
authors.forename: Jürgen
authors.initials: J
authors.lastname: Beck
authors.forename: Hongqi
authors.initials: H
authors.lastname: Lue
authors.forename: Helge
authors.initials: H
authors.lastname: Fünfzig
authors.forename: Robert
authors.initials: R
authors.lastname: Kleemann
authors.forename: Pieter
authors.initials: P
authors.lastname: Koolwijk
authors.forename: Aphrodite
authors.initials: A
authors.lastname: Kapurniotu
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bernhagen
mesh_terms: D016475:3T3 Cells; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D019921:Biotinylation; D002384:Catalysis; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D050760:Cyclin-Dependent Kinase Inhibitor p27; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry; D004705:Endocytosis; D004730:Endothelium, Vascular / Q000166:cytology; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007249:Inflammation; D007700:Kinetics; D008263:Macrophage Migration-Inhibitory Factors / Q000737:chemistry*; D013058:Mass Spectrometry; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013997:Time Factors; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D004220:Disulfides; D008263:Macrophage Migration-Inhibitory Factors; D010455:Peptides; D013438:Sulfhydryl Compounds; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D012694:Serine; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D005978:Glutathione; D003545:Cysteine; D010100:Oxygen