The promiscuous chemokine binding profile of the Duffy antigen/receptor for chemokines is primarily localized to sequences in the amino-terminal domain.
The Duffy antigen (DARC) is a promiscuous chemokine receptor that also binds Plasmodium vivax. DARC belongs to a family of heptahelical chemokine receptors that includes specific (IL-8RA) and shared (IL-8RB) IL-8 receptors. Ligand binding specificity of IL-8 receptors was localized to the amino-terminal extracellular (E1) domain. To determine the basis for promiscuous chemokine binding by DARC, a chimeric receptor composed of the E1 domain of DARC and hydrophobic helices and loops from IL-8RB (DARCe1/IL-8RB) was constructed. Scatchard analysis of stable transfectants demonstrated that the DARCe1/IL-8RB chimeric receptor bound IL-8 and melanoma growth stimulating activity (MGSA) with KD values almost identical to the native receptors. The hybrid receptor also bound RANTES, MCP-1, and MGSA-E6A (which binds DARC, but not IL-8RB), but not MIP-1 alpha, similarly to DARC. Ligand binding to DARC transfectants was unaltered by anti-Fy3, but inhibited by Fy6, which binds an epitope in the E1 domain. The epitope recognized by Fy3 was localized to the third extracellular loop by analysis of insect cells expressing chimeric receptors composed of complementary portions of DARC and IL-8RB. These findings implicate the E1 domain of DARC in multispecific chemokine binding.
Lu
Z H
ZH
Department of Pathology, Henry Vogt Cancer Research Institute, University of Louisville, Kentucky 40292, USA.
Wang
Z X
ZX
Horuk
R
R
Hesselgesser
J
J
Lou
Y C
YC
Hadley
T J
TJ
Peiper
S C
SC
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000953:Antigens, Protozoan; D001483:Base Sequence; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D054360:Chemokine CXCL1; D018925:Chemokines / Q000378:metabolism*; D019743:Chemokines, CXC; D002630:Chemotactic Factors / Q000378:metabolism; D017931:DNA Primers; D004375:Duffy Blood-Group System / Q000378:metabolism*; D006133:Growth Substances / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D008969:Molecular Sequence Data; D010966:Plasmodium vivax; D016133:Polymerase Chain Reaction; D017433:Protein Structure, Secondary; D015800:Protozoan Proteins; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
C473745:ACKR1 protein, human; D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; C475829:CXCL1 protein, human; D002352:Carrier Proteins; D054360:Chemokine CXCL1; D018925:Chemokines; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D017931:DNA Primers; D004375:Duffy Blood-Group System; C066001:Duffy antigen binding protein, Plasmodium; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D015800:Protozoan Proteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins