T2R106 knockdown impaired quinine mediated ERK/S6 signaling activation. (A) Expression of phospho-ERK (p-ERK) and phospho-S6 (p-S6) proteins in shScramble cells by Western blot; (B) Quantification of p-ERK and p-S6 protein expression; (C) Expression of p-ERK and p-S6 proteins in shT2R106 cells by Western blot; and (D) Quantification of p-ERK and p-S6 protein expression. Control and T2R106 knockdown mouse preadipocytes were serum starved for 2 h with HBSS, cells were then treated with 20 µM quinine for the indicated time. Cell lysates were then used for immunoblotting for ERK, p-ERK, S6 and p-S6 by Western blot (* p < 0.05, ** p < 0.01, *** p < 0.001, indicated fold change compared with 0 min).