Extracellular loop 2 of the free Fatty Acid receptor 2 mediates allosterism of a phenylacetamide ago-allosteric modulator
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Extracellular loop 2 of the free Fatty Acid receptor 2 mediates allosterism of a phenylacetamide ago-allosteric modulator. / Smith, Nicola J; Ward, Richard J; Stoddart, Leigh A; Hudson, Brian D; Kostenis, Evi; Ulven, Trond; Morris, Joanne C; Tränkle, Christian; Tikhonova, Irina G; Adams, David R; Milligan, Graeme.
In: Molecular Pharmacology, Vol. 80, No. 1, 2011, p. 163-173.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Extracellular loop 2 of the free Fatty Acid receptor 2 mediates allosterism of a phenylacetamide ago-allosteric modulator
AU - Smith, Nicola J
AU - Ward, Richard J
AU - Stoddart, Leigh A
AU - Hudson, Brian D
AU - Kostenis, Evi
AU - Ulven, Trond
AU - Morris, Joanne C
AU - Tränkle, Christian
AU - Tikhonova, Irina G
AU - Adams, David R
AU - Milligan, Graeme
PY - 2011
Y1 - 2011
N2 - Allosteric agonists are powerful tools for exploring the pharmacology of closely related G protein-coupled receptors that have nonselective endogenous ligands, such as the short chain fatty acids at free fatty acid receptors 2 and 3 (FFA2/GPR43 and FFA3/GPR41, respectively). We explored the molecular mechanisms mediating the activity of 4-chloro-α-(1-methylethyl)-N-2-thiazolylbenzeneacetamide (4-CMTB), a recently described phenylacetamide allosteric agonist and allosteric modulator of endogenous ligand function at human FFA2, by combining our previous knowledge of the orthosteric binding site with targeted examination of 4-CMTB structure-activity relationships and mutagenesis and chimeric receptor generation. Here we show that 4-CMTB is a selective agonist for FFA2 that binds to a site distinct from the orthosteric site of the receptor. Ligand structure-activity relationship studies indicated that the N-thiazolyl amide is likely to provide hydrogen bond donor/acceptor interactions with the receptor. Substitution at Leu(173) or the exchange of the entire extracellular loop 2 of FFA2 with that of FFA3 was sufficient to reduce or ablate, respectively, allosteric communication between the endogenous and allosteric agonists. Thus, we conclude that extracellular loop 2 of human FFA2 is required for transduction of cooperative signaling between the orthosteric and an as-yet-undefined allosteric binding site of the FFA2 receptor that is occupied by 4-CMTB.
AB - Allosteric agonists are powerful tools for exploring the pharmacology of closely related G protein-coupled receptors that have nonselective endogenous ligands, such as the short chain fatty acids at free fatty acid receptors 2 and 3 (FFA2/GPR43 and FFA3/GPR41, respectively). We explored the molecular mechanisms mediating the activity of 4-chloro-α-(1-methylethyl)-N-2-thiazolylbenzeneacetamide (4-CMTB), a recently described phenylacetamide allosteric agonist and allosteric modulator of endogenous ligand function at human FFA2, by combining our previous knowledge of the orthosteric binding site with targeted examination of 4-CMTB structure-activity relationships and mutagenesis and chimeric receptor generation. Here we show that 4-CMTB is a selective agonist for FFA2 that binds to a site distinct from the orthosteric site of the receptor. Ligand structure-activity relationship studies indicated that the N-thiazolyl amide is likely to provide hydrogen bond donor/acceptor interactions with the receptor. Substitution at Leu(173) or the exchange of the entire extracellular loop 2 of FFA2 with that of FFA3 was sufficient to reduce or ablate, respectively, allosteric communication between the endogenous and allosteric agonists. Thus, we conclude that extracellular loop 2 of human FFA2 is required for transduction of cooperative signaling between the orthosteric and an as-yet-undefined allosteric binding site of the FFA2 receptor that is occupied by 4-CMTB.
U2 - 10.1124/mol.110.070789
DO - 10.1124/mol.110.070789
M3 - Journal article
VL - 80
SP - 163
EP - 173
JO - Molecular Pharmacology
JF - Molecular Pharmacology
SN - 0026-895X
IS - 1
ER -
ID: 189158930