Characterization of two high affinity human interleukin-8 receptors.
Interleukin 8 (IL-8) and melanocyte growth-stimulatory activity/gro (MGSA) are structurally related proinflammatory cytokines that are chemoattractants and activators of neutrophils. Recently, cDNA clones encoding a high affinity IL-8 receptor (IL-8R-A) and a "low affinity" IL-8 receptor (IL-8R-B) have been isolated from human cDNA libraries. These two receptors have 77% amino acid identity and are members of the G protein-coupled superfamily of receptors with seven transmembrane domains. We have expressed these two receptors in mammalian cells and find that in this system both receptors bind IL-8 with high affinity (Kd approximately 2 nM). The receptor affinities differ for MGSA, however. IL-8R-A binds MGSA with low affinity (Kd approximately 450 nM); IL-8R-B binds MGSA with high affinity (Kd approximately 2 nM). The transfected cells respond to ligand binding with a transient increase in the intracellular Ca2+ concentration. A Ca2+ response is found for IL-8R-A following the binding of IL-8; no response is found for MGSA. A Ca2+ response for IL-8R-B follows the binding of both ligands. Blot hybridization with oligonucleotide probes specific for the two receptors shows that mRNA for both receptors is present in human neutrophils. Analysis of IL-8 and MGSA binding data on neutrophils as well as Ca2+ response and desensitization data shows that the presence of these two IL-8 receptors on the cell surface can account for the profile of these two ligands on neutrophils.
Lee
J
J
Department of Molecular Biology, Genentech, Inc., South San Francisco, California 94080.
Horuk
R
R
Rice
G C
GC
Bennett
G L
GL
Camerato
T
T
Wood
W I
WI
D000595:Amino Acid Sequence; D001483:Base Sequence; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors / Q000378:metabolism / Q000494:pharmacology; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D015723:Gene Library; D006133:Growth Substances / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8 / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009504:Neutrophils / Q000276:immunology; D015345:Oligonucleotide Probes; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger; D011971:Receptors, Immunologic / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D023062:Receptors, Interleukin-8A; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
C475829:CXCL1 protein, human; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D023062:Receptors, Interleukin-8A; D011994:Recombinant Proteins; D011061:Poly A; D012313:RNA; D002118:Calcium