title: D-dopachrome tautomerase (D-DT or MIF-2): doubling the MIF cytokine family.
abstract: D-dopachrome tautomerase (D-DT) is a newly described cytokine and a member of the macrophage migration inhibitory factor (MIF) protein superfamily. MIF is a broadly expressed pro-inflammatory cytokine that regulates both the innate and the adaptive immune response. MIF activates the MAP kinase cascade, modulates cell migration, and counter-acts the immunosuppressive effects of glucocorticoids. For many cell types, MIF also acts as an important survival or anti-apoptotic factor. Circulating MIF levels are elevated in the serum in different infectious and autoimmune diseases, and neutralization of the MIF protein via antibodies or small molecule antagonists improves the outcome in numerous animal models of human disease. Recently, a detailed investigation of the biological role of the closely homologous protein D-DT, which is encoded by a gene adjacent to MIF, revealed an overlapping functional spectrum with MIF. The D-DT protein also is present in most tissues and circulates in serum at similar concentrations as MIF. D-DT binds the MIF cell surface receptor complex, CD74/CD44, with high affinity and induces similar cell signaling and effector functions. Furthermore, an analysis of the signaling properties of the two proteins showed that they work cooperatively, and that neutralization of D-DT in vivo significantly decreases inflammation. In this review, we highlight the similarities and differences between MIF and D-DT, which we propose to designate "MIF-2", and discuss the implication of D-DT/MIF-2 expression for MIF-based therapies.
authors.affiliation: Center of Integrated Protein Science Munich, Division of Clinical Pharmacology, LMU Munich, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Merk
authors.forename: Robert A
authors.initials: RA
authors.lastname: Mitchell
authors.forename: Stefan
authors.initials: S
authors.lastname: Endres
authors.forename: Richard
authors.initials: R
authors.lastname: Bucala
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence / Q000235:genetics; D004194:Disease; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008263:Macrophage Migration-Inhibitory Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008264:Macrophages / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data
chemical_list: D008263:Macrophage Migration-Inhibitory Factors; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase