Background：

Atypical chemokine receptor that controls chemokine levels and localization via high-affinity chemokine binding that is uncoupled from classic ligand-driven signal transduction cascades， resulting instead in chemokine sequestration， degradation， or transcytosis. Also known as interceptor (internalizing receptor) or chemokine-scavenging receptor or chemokine decoy receptor. Has a promiscuous chemokine-binding profile， interacting with inflammatory chemokines of both the CXC and the CC subfamilies but not with homeostatic chemokines. Acts as a receptor for chemokines including CCL2， CCL5， CCL7， CCL11， CCL13， CCL14， CCL17， CXCL5， CXCL6， IL8/CXCL8， CXCL11， GRO， RANTES， MCP-1， TARC and also for the malaria parasites P.vivax and P.knowlesi. May regulate chemokine bioavailability and， consequently， leukocyte recruitment through two distinct mechanisms: when expressed in endothelial cells， it sustains the abluminal to luminal transcytosis of tissue-derived chemokines and thei