MIF-chemokine receptor interactions in atherogenesis are dependent on an N-loop-based 2-site binding mechanism

FASEB J. 2011 Mar;25(3):894-906. doi: 10.1096/fj.10-168559. Epub 2010 Nov 24.


Macrophage migration inhibitory factor (MIF) is a cytokine that mediates inflammatory diseases. MIF promotes atherogenic leukocyte recruitment through a promiscuous, yet highly affine, interaction with CXCR2 and CXCR4. Binding to CXCR2 is dependent on a pseudo-(E)LR motif in MIF, but a second interaction site has been elusive. Here we identified an N-like loop in MIF, suggesting that MIF binding to CXCR2 follows the 2-site binding mode of bona fide chemokines. For MIF, the model predicts interactions between the N-like loop and the CXCR2 N domain (site 1) and pseudo-(E)LR and extracellular loops (ELs) of CXCR2 (site 2). Applying biophysical and peptide array analysis, we demonstrated an interaction between MIF and the CXCR2 N domain, which was pseudo-(E)LR independent. Peptide array analysis also indicated that the pseudo-(E)LR motif is responsible for MIF binding to EL2 and 3. Notably, peptides MIF-(40-49) and MIF-(47-56), representing N-like-loop-derived peptides, but not a scrambled control peptide, significantly blocked MIF/CXCR2 binding, MIF-mediated monocyte arrest under flow on aortic endothelial cells in vitro (IC(50): 1.24×10(-6) M), and MIF-dependent monocyte adhesion to atherosclerotic mouse carotid arteries in vivo. Thus, the N-like loop in MIF is critical for MIF's noncognate interaction with CXCR2 and proatherogenic functions. The 2-site binding model that explains chemokine receptor activation also applies to MIF.

MeSH terms

  • Animals
  • Aorta / cytology
  • Apolipoproteins E / genetics
  • Atherosclerosis / metabolism*
  • Atherosclerosis / pathology
  • Atherosclerosis / physiopathology
  • Binding Sites / physiology
  • Binding, Competitive / physiology
  • Circular Dichroism
  • Endothelial Cells / cytology
  • Endothelial Cells / physiology*
  • HEK293 Cells
  • Humans
  • Interleukin-8 / metabolism
  • Intramolecular Oxidoreductases / genetics
  • Intramolecular Oxidoreductases / metabolism*
  • Macrophage Migration-Inhibitory Factors / genetics
  • Macrophage Migration-Inhibitory Factors / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Monocytes / cytology
  • Protein Binding / physiology
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Receptors, Immunologic / chemistry
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / metabolism
  • Receptors, Interleukin-8B / chemistry*
  • Receptors, Interleukin-8B / genetics
  • Receptors, Interleukin-8B / metabolism*
  • Structure-Activity Relationship


  • Apolipoproteins E
  • CXCL8 protein, human
  • Interleukin-8
  • Macrophage Migration-Inhibitory Factors
  • Receptors, Immunologic
  • Receptors, Interleukin-8B
  • macrophage migration inhibitory factor receptor
  • Intramolecular Oxidoreductases
  • MIF protein, human
  • Mif protein, mouse