Signal transduction and ligand specificity of the human monocyte chemoattractant protein-1 receptor in transfected embryonic kidney cells.
We have examined the ligand specificity and signal transduction pathways of a recently cloned receptor for monocyte chemoattractant protein-1 (MCP-1). In human 293 cells stably transfected with the MCP-1 receptor, MCP-1 bound specifically with high affinity (Kd = 260 pM) and induced a rapid mobilization of calcium from intracellular stores. The closely related chemokines MIP-1 alpha, MIP-1 beta, RANTES, interleukin 8 (IL-8), and Gro-alpha were inactive at concentrations as high as 300 nM. Activation of the MCP-1 receptor potently inhibited adenylyl cyclase with an IC50 = 90 pM. Activation of the MIP-1 alpha/RANTES receptor also mediated inhibition of adenylyl cyclase activity but with a different pharmacological profile: MIP-1 alpha (110 pM, IC50), RANTES (140 pM), MIP-1 beta (10 nM), and MCP-1 (820 nM). Mobilization of intracellular calcium and inhibition of adenylyl cyclase were blocked by pertussis toxin, suggesting that the MCP-1 receptor coupled to G alpha i. These results demonstrate that the MCP-1 receptor binds and signals in response to picomolar concentrations of MCP-1 in a highly specific manner. Signaling was manifested as mobilization of intracellular calcium and inhibition of adenylyl cyclase and was mediated by a pertussis toxin-sensitive G-protein(s).
Myers
S J
SJ
Gladstone Institute of Cardiovascular Disease, San Francisco, California 94141-9100.
Wong
L M
LM
Charo
I F
IF
D000067956:Adenylyl Cyclase Inhibitors; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D018932:Chemokine CCL2; D002630:Chemotactic Factors / Q000378:metabolism*; D016207:Cytokines / Q000494:pharmacology*; D004622:Embryo, Mammalian; D006801:Humans; D007457:Iodine Radioisotopes; D007668:Kidney; D007700:Kinetics; D008024:Ligands; D008222:Lymphokines / Q000494:pharmacology; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013379:Substrate Specificity; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism
D000067956:Adenylyl Cyclase Inhibitors; C515334:CCR2 protein, human; D018932:Chemokine CCL2; D002630:Chemotactic Factors; D016207:Cytokines; D007457:Iodine Radioisotopes; D008024:Ligands; D008222:Lymphokines; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine; D011994:Recombinant Proteins; D010738:Type C Phospholipases; D002118:Calcium