GSK682753A dose-dependently inhibits EBI2 with an IC50of 53.6 nM. GSK682753A inhibits ERK phosphorylation, GTPγS binding, and cAMP-response element-binding protein activation with similar potency.GSK682753 is a selective and highly potent inverse agonist for murine as well as human EBI2 with inhibition of G protein-dependent signals as well as signals that are probably G protein-independent.?In cAMP-response element-binding protein-based reporter and guanosine5'-3-O-(thio)-triphosphate (GTPγS) binding assays, the potency of this compound is 2.6-53.6 nM, and its inhibitory efficacy is 75%.