Fig. 4: Involvement of neutral phenylalanine and tyrosine residues in proton sensing.
From: Molecular mechanism of pH sensing and activation in GPR4 reveals proton-mediated GPCR signaling
a–c Detailed interactions of phenylalanine residues in GPR4 complexes. The GPR4–Gs complexes are colored blue (pH 6.5) and green (pH 7.4), respectively. The GPR4–Gq complex at pH 7.4 is colored salmon. d–f Detailed interactions of tyrosine residues in GPR4 complexes. Polar interactions are marked by orange dashed lines. g Effects of mutations on GPR4-induced cAMP accumulation. Colors are shown as indicated. The original data are provided in Supplementary Fig. S9. Values are shown as means ± SEM from three independent experiments. h Conformation distribution under pH 6.0 and pH 8.0. The side-chain minimal distance distributions of E170ECL2–Y762.63 (upper) and E170ECL2–Y983.33 (lower) are shown.
