- 作者: Li-Saung Ai; Sheau-Fen Lee; Steve S.L.Chen; Fang Liao
- 作者服務機構: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, ROC
- 中文摘要: --
- 英文摘要: The CC chemokine receptor 6 (CCR6) is selectively ex-pressed on memory T cells, B cells, and dendritic cellsand appears to be involved in the initiation of a memoryimmune response. The only chemokine ligand for CCR6is CCL20/MIP-3 . In the present study, we attempted todefine the extracellular domains (ECDs) of CCR6 respon-sible for CCL20/MIP-3 binding using a domain-swap-ping approach in which the ECDs of CCR6 were substi-tuted with the corresponding CCR5 domains to generatevarious CCR6/CCR5 chimeras. These chimeras weretested for receptor expression, ligand binding, and func-tional activity as evaluated by calcium flux and chemo-taxis. All chimeras showed respectable surface expres-sion; however only one, substituted with extracellularloop 1 from CCR5, showed reduced functional activity.The general failure of functionality of the CCR6/CCR5 chi-meras may imply that characteristics of each ECD arecritical for coordination among all the ECDs of CCR6.Additionally, of interest, a chimera containing all of theECDs from CCR5 in the context of CCR6 neither re-sponded to CCR5 ligands nor served as a coreceptor formacrophage-tropic HIV-1. These results suggest that notonly ECDs but also transmembrane and intracellulardomains of CCR5 are involved in both ligand binding andcoreceptor activity.
- 中文關鍵字: --
- 英文關鍵字: --