A 16-Residue Peptide Fragment of Macrophage Migration Inhibitory Factor, MIF-(50–65), Exhibits Redox Activity and Has MIF-like Biological Functions

• Published in: The Journal of biological chemistry 2003-09, Vol.278 (36), p.33654-33671
• Main Authors: Nguyen, Mai Tuyet, Beck, Jürgen, Lue, Hongqi, Fünfzig, Helge, Kleemann, Robert, Koolwijk, Pieter, Kapurniotu, Aphrodite, Bernhagen, Jürgen
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Amino Acid Motifs; Amino Acid Sequence; Animals; Biotinylation; Catalysis; Cell Cycle Proteins - metabolism; Cell Division; Cells, Cultured; Chromatography, High Pressure Liquid; Circular Dichroism; Cyclin-Dependent Kinase Inhibitor p27; Cysteine - chemistry; Disulfides - chemistry; Endocytosis; Endothelium, Vascular - cytology; Glutathione - chemistry; Glutathione - metabolism; Humans; Inflammation; JAB1 protein; Kinetics; Macrophage Migration-Inhibitory Factors - chemistry; Mass Spectrometry; Mice; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases - metabolism; Molecular Sequence Data; Oxidation-Reduction; Oxygen - metabolism; Peptides - chemistry; Phosphorylation; Protein Binding; Protein Conformation; Serine - chemistry; Signal Transduction; Sulfhydryl Compounds - chemistry; Time Factors; Tumor Suppressor Proteins - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M301735200

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 β-turn conformation comparable with that of β-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 β-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.