A model of GAG/MIP-2/CXCR2 interfaces and its functional effects.
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.
Departments of Pharmacology, Yale University School of Medicine, New Haven, CT 06520-8066, USA.
Deepa
D
Rajasekaran
Camille
C
Keeler
Mansoor A
MA
Syed
Matthew C
MC
Jones
Jeffrey K
JK
Harrison
Dianqing
D
Wu
Vineet
V
Bhandari
Michael E
ME
Hodsdon
Elias J
EJ
Lolis
D000409:Alanine / Q000235:genetics; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002478:Cells, Cultured; D054426:Chemokine CXCL2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002634:Chemotaxis, Leukocyte; D018360:Crystallography, X-Ray; D004187:Disaccharides / Q000737:chemistry; D005260:Female; D006025:Glycosaminoglycans / Q000737:chemistry* / Q000378:metabolism; D006493:Heparin / Q000031:analogs & derivatives / Q000737:chemistry; D006801:Humans; D008168:Lung / Q000166:cytology / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D009154:Mutation; D009504:Neutrophils / Q000276:immunology / Q000502:physiology; D019906:Nuclear Magnetic Resonance, Biomolecular; D010529:Peritoneal Cavity / Q000166:cytology; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D023063:Receptors, Interleukin-8B / Q000737:chemistry* / Q000378:metabolism
D054426:Chemokine CXCL2; C404915:Cxcl2 protein, mouse; D004187:Disaccharides; D006025:Glycosaminoglycans; D023063:Receptors, Interleukin-8B; C464536:heparin disaccharide; D006493:Heparin; D000409:Alanine