A model of GAG/MIP-2/CXCR2 interfaces and its functional effects

Biochemistry. 2012 Jul 17;51(28):5642-54. doi: 10.1021/bi3001566. Epub 2012 Jul 2.

Abstract

MIP-2/CXCL2 is a murine chemokine related to human chemokines that possesses the Glu-Leu-Arg (ELR) activation motif and activates CXCR2 for neutrophil chemotaxis. We determined the structure of MIP-2 to 1.9 Å resolution and created a model with its murine receptor CXCR2 based on the coordinates of human CXCR4. Chemokine-induced migration of cells through specific G-protein coupled receptors is regulated by glycosaminoglycans (GAGs) that oligomerize chemokines. MIP-2 GAG-binding residues were identified that interact with heparin disaccharide I-S by NMR spectroscopy. A model GAG/MIP-2/CXCR2 complex that supports a 2:2 complex between chemokine and receptor was created. Mutants of these disaccharide-binding residues were made and tested for heparin binding, in vitro neutrophil chemotaxis, and in vivo neutrophil recruitment to the mouse peritoneum and lung. The mutants have a 10-fold decrease in neutrophil chemotaxis in vitro. There is no difference in neutrophil recruitment between wild-type MIP-2 and mutants in the peritoneum, but all activity of the mutants is lost in the lung, supporting the concept that GAG regulation of chemokines is tissue-dependent.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Alanine / genetics
  • Animals
  • Bronchoalveolar Lavage Fluid / cytology
  • Cells, Cultured
  • Chemokine CXCL2 / chemistry*
  • Chemokine CXCL2 / genetics
  • Chemokine CXCL2 / metabolism
  • Chemotaxis, Leukocyte
  • Crystallography, X-Ray
  • Disaccharides / chemistry
  • Female
  • Glycosaminoglycans / chemistry*
  • Glycosaminoglycans / metabolism
  • Heparin / analogs & derivatives
  • Heparin / chemistry
  • Humans
  • Lung / cytology
  • Lung / immunology
  • Mice
  • Mice, Inbred BALB C
  • Models, Molecular
  • Mutation
  • Neutrophils / immunology
  • Neutrophils / physiology
  • Nuclear Magnetic Resonance, Biomolecular
  • Peritoneal Cavity / cytology
  • Protein Binding
  • Protein Conformation
  • Protein Multimerization
  • Receptors, Interleukin-8B / chemistry*
  • Receptors, Interleukin-8B / metabolism

Substances

  • Chemokine CXCL2
  • Cxcl2 protein, mouse
  • Disaccharides
  • Glycosaminoglycans
  • Receptors, Interleukin-8B
  • heparin disaccharide
  • Heparin
  • Alanine