Figure 3. Functional expression of the Schistosoma mansoni SmGPR-3 receptor in yeast.
(A) The full-length SmGPR-3 cDNA was expressed in Saccharomyces cerevisae strain YEX108 and grown in selective leu/histidine-deficient (leu−/his−) medium containing 2×10−4 M of each biogenic amine or vehicle (no drug control, ND). Yeast cells transformed with empty plasmid were used as a negative control (mock). Receptor activation was quantified from measurements of yeast growth in relative fluorescence units (RFU), using an Alamar blue fluorescence assay. The results are the means ± S.E.M. of 5–6 independent clones, each assayed in triplicate. The following biogenic amines were tested: adrenaline (A), noradrenaline (NA), dopamine (DA), epinine (EPN), serotonin (5-hydroxytryptamine, 5HT), octopamine (OA), tyramine (TA) and histamine (HA). (B) Functional assays were repeated with the same SmGPR-3-expressing yeast strain and variable concentrations of DA (△) or EPN (□). The mock control was tested with DA (•). EC50 values for DA and EPN are 3.10×10−5 M and 2.85×10−5 M, respectively. The data are the means ± S.E.M. of two experiments, each in triplicate.