T_m as a function of ligand concentration.

T_m was measured by CPM assay for SEC purified S1P₁ (control) and GPR3 in the presence of the of the inverse GPR3 agonist AF64394. Monomers of both receptor derivatives were isolated in buffer composed of 50 mM Tris pH 7.5; 150 mM NaCl; 0.5 mg/ml DDM; 0.01 mg/ml CHS. The values of GPR3 were fitted with a logistic function to determine the inflection point.