Direct observation of Gα13 and Gαq activation by different GPCRs.

<p>Normalized ratio-metric FRET traces of HeLa cells transfected with the Gq sensor (grey line) or the G13.2 sensor (black line) (dotted lines depict 95% CI). (A) As a control, cells expressing only the Gq (<i>n</i> = 37) or G13.2 (<i>n</i> = 20) sensor were measured. Agonists were sequentially added after 50s, 150s and 230s of imaging. (B) Ratio traces of cells transfected with an untagged LPA2 receptor next to the Gαq (<i>n</i> = 13 (out of 60 in total)) or the Gα13.2 (<i>n</i> = 14 (out of 37 in total)), stimulated at t = 50s. (C) Ratio traces of cells transfected with AngiotensinII type 1 receptor-P2A-mCherry next to the Gαq (<i>n</i> = 22) or the Gα13.2 (<i>n</i> = 9) sensor, stimulated at t = 50s. (D) Ratio traces of cells transfected with an untagged kiss-receptor next to the Gαq (<i>n</i> = 13) or the Gα13.2 (<i>n</i> = 30) sensor, stimulated at t = 50s (indicated with the arrowhead).