Identification of CCR6, the specific receptor for a novel lymphocyte-directed CC chemokine LARC.
Liver and activation-regulated chemokine (LARC) is a recently identified CC chemokine that is expressed mainly in the liver. LARC functions as a selective chemoattractant for lymphocytes that express a class of receptors specifically binding to LARC with high affinity. To identifiy the receptor for LARC, we examined LARC-induced calcium mobilization in cells stably expressing five CC chemokine receptors (CCR1-CCR5) and five orphan seven-transmembrane receptors. LARC specifically induced calcium flux in K562 cells as well as 293/EBNA-1 cells stably expressing an orphan receptor GPR-CY4. LARC induced migration in 293/EBNA-1 cells stably expressing GPR-CY4 with a bi-modal dose-response curve. LARC fused with secreted alkaline phosphatase (LARC-SEAP) bound specifically to Raji cells stably expressing GPR-CY4 with a Kd of 0.9 nM. Only LARC but not five other CC chemokines (MCP-1, RANTES, MIP-1alpha, MIP-1beta, and TARC) competed with LARC-SEAP for binding to GPR-CY4. By Northern blot analysis, GPR-CY4 mRNA was expressed mainly in spleen, lymph nodes, Appendix, and fetal liver among various human tissues. Among various leukocyte subsets, GPR-CY4 mRNA was detected in lymphocytes (CD4(+) and CD8(+) T cells and B cells) but not in natural killer cells, monocytes, or granulocytes. Expression of GPR-CY4 mRNA in CD4(+) and CD8(+) T cells was strongly up-regulated by IL-2. Taken together, GPR-CY4 is the specific receptor for LARC expressed selectively on lymphocytes, and LARC is a unique functional ligand for GPR-CY4. We propose GPR-CY4 to be designated as CCR6.
Baba
M
M
Shionogi Institute for Medical Science, 2-5-1 Mishima, Settsu-shi, Osaka 566, Japan.
Imai
T
T
Nishimura
M
M
Kakizaki
M
M
Takagi
S
S
Hieshima
K
K
Nomiyama
H
H
Yoshie
O
O
D001402:B-Lymphocytes / Q000502:physiology; D001667:Binding, Competitive; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D054418:Chemokine CCL20; D018925:Chemokines / Q000378:metabolism / Q000494:pharmacology*; D019742:Chemokines, CC; D002633:Chemotaxis; D003001:Cloning, Molecular; D006412:Hematopoietic Stem Cells; D006801:Humans; D007668:Kidney; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008214:Lymphocytes / Q000502:physiology*; D019402:Macrophage Inflammatory Proteins; D012333:RNA, Messenger / Q000096:biosynthesis; D054399:Receptors, CCR6; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine / Q000096:biosynthesis / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000494:pharmacology; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
C108355:CCL20 protein, human; C106311:CCR6 protein, human; D054418:Chemokine CCL20; D018925:Chemokines; D019742:Chemokines, CC; D019402:Macrophage Inflammatory Proteins; D012333:RNA, Messenger; D054399:Receptors, CCR6; D019707:Receptors, Chemokine; D018121:Receptors, Cytokine; D011993:Recombinant Fusion Proteins; D002118:Calcium