Extended Data Fig. 7: TAS2R14 activation by intracellular cmpd28.1.
From: Bitter taste receptor activation by cholesterol and an intracellular tastant
a, Close-up view of structures of cmpd28.1 in the allosteric site by aligning between TAS2R14–Gi1 and TAS2R14–Ggust. The ligands and interacting residues are shown as sticks. Hydrogen bonds are indicated as yellow dashed lines. b, Close-up view of the intracellular allosteric site of structures aligned between TAS2R14-Gi1 and TAS2R46-mGs/gust (PDB 7XP6). The labeling of the conserved residues of TAS2R46 compared to TAS2R14 was omitted for clarity. c, d, Structural superposition of TAS2R14-Gi1 with either NTSR1-Go (c) or PTH1R-Gs (d). The ligands bound to the intracellular allosteric sites were shown as sticks. e-g, Representative agonist-stimulated BRET2 assays upon no treatment (e), cholesterol depletion (f), and replenishment (g) using mutations at the allosteric site. h-j, Split luciferase biosensor cAMP inhibition assays for mutations of TAS2R14 at the allosteric site with a dose-response of cmpd28.1 (h), flufenamic acid (i), and aristolochic acid I (j). k-n, Substitution of L353 of Gα which interacts with cmpd28.1 with Alanine affects the coupling of TAS2R14 to Gαi1 (k) and Gαgust (l) as well as NTSR1 to Gαi1 (m) and Gαgust (n). Data represent mean ± s.e.m. of n = 3 biological replicates (e-n).