title: Rapid and transient activation of the ERK MAPK signalling pathway by macrophage migration inhibitory factor (MIF) and dependence on JAB1/CSN5 and Src kinase activity.
abstract: Macrophage migration inhibitory factor (MIF) is a 12.5 kD polypeptide that serves as a critical regulator of cell functions such as gene expression, proliferation or apoptosis. However, the signal transduction pathways through which MIF takes part in cellular regulation are only incompletely understood. MIF leads to CD74-dependent "sustained" activation of ERK1/2 MAPK, but MIF's role in "transient" ERK activation and the involved upstream pathways are unknown. Here we report that the transient ERK pathway was markedly activated by MIF. This effect involved the phosphorylation and activation of Raf-1, MEK, ERK, and Elk-1. Of note, rapid and transient ERK phosphorylation by MIF was measurable in MIF-deficient cells, suggesting that MIF acted in a non-autocrine fashion. Applying the inhibitor genistein, a tyrosine kinase (TPK) activity was identified as a critical upstream signalling event in MIF-induced transient ERK signalling. Experiments using the Src kinase inhibitor PP2 indicated that the involved TPK was a Src-type tyrosine kinase. A role for an upstream Src kinase was proven by applying Src-deficient cells which did not exhibit transient ERK activation upon treatment with MIF, but in which MIF-induced ERK signalling could be restored by re-expressing Src. Intriguingly, JAB1/CSN5, a signalosome component, cellular binding protein of MIF and regulator of cell proliferation and survival, had a marked, yet dual, effect on MIF-induced ERK signalling. JAB1 overexpression inhibited sustained, but not transient, ERK phosphorylation. By contrast, JAB1-knock-down by siRNA revealed that minimum JAB1 levels were necessary for transient activation of ERK by MIF. In conclusion, MIF rapidly and transiently activates the ERK pathway, an effect that has not been recognized previously. This signalling pathway involves the upstream activation of a Src-type kinase and is co-regulated by the cellular MIF binding protein JAB1/CSN5. Our study thus has unravelled a novel MIF-driven signalling pathway and an intricate regulatory system involving extra- and possibly intracellular MIF, and which likely critically participates in controlling cell proliferation and survival.
authors.affiliation: Department of Biochemistry and Molecular Cell Biology, Institute of Biochemistry, University Hospital of the RWTH Aachen, Pauwelsstrasse 30, D-52074 Aachen, Germany.
authors.forename: Hongqi
authors.initials: H
authors.lastname: Lue
authors.forename: Aphrodite
authors.initials: A
authors.lastname: Kapurniotu
authors.forename: Günter
authors.initials: G
authors.lastname: Fingerle-Rowson
authors.forename: Thierry
authors.initials: T
authors.lastname: Roger
authors.forename: Lin
authors.initials: L
authors.lastname: Leng
authors.forename: Michael
authors.initials: M
authors.lastname: Thiele
authors.forename: Thierry
authors.initials: T
authors.lastname: Calandra
authors.forename: Richard
authors.initials: R
authors.lastname: Bucala
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bernhagen
mesh_terms: D000818:Animals; D019898:Autocrine Communication; D000075686:COP9 Signalosome Complex; D002478:Cells, Cultured; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D048370:MAP Kinase Kinase 2 / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008263:Macrophage Migration-Inhibitory Factors / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008263:Macrophage Migration-Inhibitory Factors; D034741:RNA, Small Interfering; D019061:src-Family Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D010447:Peptide Hydrolases; C501488:COPS5 protein, human; D000075686:COP9 Signalosome Complex