Fig. 6: Characteristics of ICL2 in G protein coupling of GAL1R and GAL2R.
From: Molecular basis for allosteric agonism and G protein subtype selectivity of galanin receptors
Detailed interaction between ICL2 of GAL1R (a), μOR (b), and CCR6 (c) and the Gαi subunit. Detailed interaction between ICL2 of GAL2R (d), 5-HT2AR (e), and CCKAR (f) and the Gαq subunit. g Sequence alignment of ICL2 of GAL1R and other class A GPCRs primarily coupled to Gi heterotrimer. The positive-charged arginine in ICL2 of GAL1R (blue) and polar residue threonine in ICL2 of CCR6 and CXCR2 (purple) at 34.51 are highlighted. Hydrophobic residues at 34.54 in CCR6 and CXCR2, which substantially contribute to the receptor-Gi coupling, are indicated in green. The conserved hydrophobic residues in other listed class A GPCRs at 34.51 are highlighted in green. h Sequence alignment of ICL2 of GAL1R and other class A GPCRs primarily coupled to Gq heterotrimer. The conserved hydrophobic residues at 34.51 are highlighted in green. The positively charged residues at 34.54 and 34.55 are indicated in blue. The swapping effects of R14134.51 of GAL1R (i) and L13134.51 of GAL2R (j) on G protein-coupling activity. Data shown are mean ± S.E.M. of three (n = 3, i) or four (n = 4, j) independent experiments. Source data are provided as a Source Data file.
