The cellular levels of Ca2+ ions after ligand (C10ORF99) stimulation of the indicated GPR15 receptors painted turtle, coelacanth, and Asian bony tongue GPR15). A plasmid encoding human NTSR1 and the parental pcDNA plasmid were transfected as positive and negative controls, respectively. The fold-change in calcium levels was calculated based on the fluorescence intensity (excitation and emission wavelengths: 490 and 520 nm, respectively). Calcium RLU (relative light unit) fold was calculated using no stimulation data as standard value. 