Functional differences between monocyte chemotactic protein-1 receptor A and monocyte chemotactic protein-1 receptor B expressed in a Jurkat T cell.
The monocyte chemotactic protein-1 (MCP-1) receptor (MCP-1R) is expressed on monocytes, a subpopulation of memory T lymphocytes, and basophils. Two alternatively spliced forms of MCP-1R, CCR2A and CCR2B, exist and differ only in their carboxyl-terminal tails. To determine whether CCR2A and CCR2B receptors function similarly, Jurkat T cells were stably transfected with plasmids encoding the human CCR2A or CCR2B gene. Nanomolar concentrations of MCP-1 induced chemotaxis in the CCR2B transfectants that express high, intermediate, and low levels of MCP-1R. Peak chemotactic activity was shifted to the right as receptor number decreased. Five-fold more MCP-1 was required to initiate chemotaxis of the CCR2A low transfectant, but the peak of chemotaxis was similar for the CCR2A and CCR2B transfectants expressing similar numbers of receptors. MCP-1-induced chemotaxis was sensitive to pertussis toxin, implying that both CCR2A and CCR2B are G(i)alpha protein coupled. MCP-1 induced a transient Ca(2+) flux in the CCR2B transfectant that was partially sensitive to pertussis toxin. In contrast, MCP-1 did not induce Ca(2+) flux in the CCR2A transfectant. Since MCP-1 can stimulate chemotaxis of the CCR2A transfectant without inducing Ca(2+) mobilization, Ca(2+) flux may not be required for MCP-1-induced chemotaxis in the Jurkat transfectants. These results indicate that functional differences exist between the CCR2A and CCR2B transfectants that can be attributed solely to differences in the carboxyl-terminal tail.
Sanders
S K
SK
Department of Molecular Biology, Pfizer Global Research and Development, Ann Arbor Laboratories, Ann Arbor, MI 48105, USA. Sheila.Sanders@pfizer.com
Crean
S M
SM
Boxer
P A
PA
Kellner
D
D
LaRosa
G J
GJ
Hunt
S W
SW
D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism; D020013:Calcium Signaling / Q000235:genetics / Q000276:immunology; D018932:Chemokine CCL2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte / Q000235:genetics / Q000276:immunology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D007457:Iodine Radioisotopes; D019169:Jurkat Cells / Q000276:immunology* / Q000378:metabolism*; D037342:Pertussis Toxin; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D054390:Receptors, CCR2; D019707:Receptors, Chemokine / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
C515334:CCR2 protein, human; D018932:Chemokine CCL2; D007457:Iodine Radioisotopes; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; D010566:Virulence Factors, Bordetella; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D037342:Pertussis Toxin; D002118:Calcium