MIF interacts with CXCR7 to promote receptor internalization, ERK1/2 and ZAP-70 signaling, and lymphocyte chemotaxis

FASEB J. 2015 Nov;29(11):4497-511. doi: 10.1096/fj.15-273904. Epub 2015 Jul 2.


Macrophage migration-inhibitory factor (MIF) is a pleiotropic cytokine with chemokine-like functions and is a mediator in numerous inflammatory conditions. Depending on the context, MIF signals through 1 or more of its receptors cluster of differentiation (CD)74, CXC-motif chemokine receptor (CXCR)2, and CXCR4. In addition, heteromeric receptor complexes have been identified. We characterized the atypical chemokine receptor CXCR7 as a novel receptor for MIF. MIF promoted human CXCR7 internalization up to 40%, peaking at 50-400 nM and 30 min, but CXCR7 internalization by MIF was not dependent on CXCR4. Yet, by coimmunoprecipitation, fluorescence microscopy, and a proximity ligation assay, CXCR7 was found to engage in MIF receptor complexes with CXCR4 and CD74, both after ectopic overexpression and in endogenous conditions in a human B-cell line. Receptor competition binding and coimmunoprecipitation studies combined with sulfo-SBED-biotin-transfer provided evidence for a direct interaction between MIF and CXCR7. Finally, we demonstrated MIF/CXCR7-mediated functional responses. Blockade of CXCR7 suppressed MIF-mediated ERK- and zeta-chain-associated protein kinase (ZAP)-70 activation (from 2.1- to 1.2-fold and from 2.5- to 1.6-fold, respectively) and fully abrogated primary murine B-cell chemotaxis triggered by MIF, but not by CXCL12. B cells from Cxcr7(-/-) mice exhibited an ablated transmigration response to MIF, indicating that CXCR7 is essential for MIF-promoted B-cell migration. Our findings provide biochemical and functional evidence that MIF is an alternative ligand of CXCR7 and suggest a functional role of the MIF-CXCR7 axis in B-lymphocyte migration.

Keywords: CD74; chemokine; chemokine receptor; cytokine; receptor complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B-Lymphocytes / cytology
  • B-Lymphocytes / metabolism*
  • Cell Line, Tumor
  • Chemokine CXCL12 / genetics
  • Chemokine CXCL12 / metabolism
  • Chemotaxis / physiology*
  • Humans
  • Intramolecular Oxidoreductases / genetics
  • Intramolecular Oxidoreductases / metabolism*
  • MAP Kinase Signaling System / physiology*
  • Macrophage Migration-Inhibitory Factors / genetics
  • Macrophage Migration-Inhibitory Factors / metabolism*
  • Mice
  • Mitogen-Activated Protein Kinase 1 / genetics
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / genetics
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Receptors, CXCR / genetics
  • Receptors, CXCR / metabolism*
  • Receptors, CXCR4 / genetics
  • Receptors, CXCR4 / metabolism
  • ZAP-70 Protein-Tyrosine Kinase / genetics
  • ZAP-70 Protein-Tyrosine Kinase / metabolism*


  • ACKR3 protein, human
  • CXCL12 protein, human
  • CXCR4 protein, human
  • CXCR4 protein, mouse
  • Chemokine CXCL12
  • Cmkor1 protein, mouse
  • Cxcl12 protein, mouse
  • Macrophage Migration-Inhibitory Factors
  • Receptors, CXCR
  • Receptors, CXCR4
  • ZAP-70 Protein-Tyrosine Kinase
  • ZAP70 protein, human
  • Zap70 protein, mouse
  • MAPK1 protein, human
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Intramolecular Oxidoreductases
  • MIF protein, human
  • Mif protein, mouse