Figure 1.

Schematic illustration of the sensor principle and the fusion protein library used to determine the best combination of proteins. The activation of the Gα_q pathway was probed by fusing complementary luciferase fragments to Gα_q and PLC-β3 (A). A fusion protein library was generated by fusing CBRC to Gα_q terminally and in three loop regions (numbers in parentheses denote amino acid positions) and by fusing CBRN either N-, or C-terminally to PLC-β3 (B). The different combinations of Gα_q and PLC-β3 fusion proteins were expressed in HEK293T cells, co-expressing the hH₁R. The relative increase in luminescence of cells stimulated with 10 µM histamine compared to unstimulated cells is shown for each combination (C). Data are presented as means ± SEM from three independent experiments, each performed in triplicate.