title: Polymorphism and ligand dependent changes in human glucagon-like peptide-1 receptor (GLP-1R) function: allosteric rescue of loss of function mutation.
abstract: The glucagon-like peptide-1 receptor (GLP-1R) is a key physiological regulator of insulin secretion and a major therapeutic target for the treatment of type II diabetes. However, regulation of GLP-1R function is complex with multiple endogenous peptides that interact with the receptor, including full-length (1-37) and truncated (7-37) forms of GLP-1 that can exist in an amidated form (GLP-1(1-36)NH₂ and GLP-1(7-36)NH₂) and the related peptide oxyntomodulin. In addition, the GLP-1R possesses exogenous agonists, including exendin-4, and the allosteric modulator, compound 2 (6,7-dichloro-2-methylsulfonyl-3-tert-butylaminoquinoxaline). The complexity of this ligand-receptor system is further increased by the presence of several single nucleotide polymorphisms (SNPs) that are distributed across the receptor. We have investigated 10 GLP-1R SNPs, which were characterized in three physiologically relevant signaling pathways (cAMP accumulation, extracellular signal-regulated kinase 1/2 phosphorylation, and intracellular Ca²⁺ mobilization); ligand binding and cell surface receptor expression were also determined. We demonstrate both ligand- and pathway-specific effects for multiple SNPs, with the most dramatic effect observed for the Met¹⁴⁹ receptor variant. At the Met¹⁴⁹ variant, there was selective loss of peptide-induced responses across all pathways examined, but preservation of response to the small molecule compound 2. In contrast, at the Cys³³³ variant, peptide responses were preserved but there was attenuated response to compound 2. Strikingly, the loss of peptide function at the Met¹⁴⁹ receptor variant could be allosterically rescued by compound 2, providing proof-of-principle evidence that allosteric drugs could be used to treat patients with this loss of function variant.
authors: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.
authors: Cassandra
authors: C
authors: Koole
authors: Denise
authors: D
authors: Wootten
authors: John
authors: J
authors: Simms
authors: Celine
authors: C
authors: Valant
authors: Laurence J
authors: LJ
authors: Miller
authors: Arthur
authors: A
authors: Christopoulos
authors: Patrick M
authors: PM
authors: Sexton
references: Neuropharmacology. 2011 Jan;60(1):24-35
references: 20637785
references: J Clin Endocrinol Metab. 2001 Aug;86(8):3717-23
references: 11502801
references: Diabetes. 1995 Sep;44(9):1126-31
references: 7657039
references: Neuropsychopharmacology. 2010 Mar;35(4):855-69
references: 19940843
references: Mol Pharmacol. 2010 Sep;78(3):456-65
references: 20547734
references: Regul Pept. 2005 Aug 15;130(1-2):1-6
references: 15975668
references: J Pharmacol Exp Ther. 2010 Jan;332(1):274-80
references: 19841474
references: J Neurochem. 2005 Jun;93(6):1603-15
references: 15935077
references: J Clin Endocrinol Metab. 1995 Mar;80(3):952-7
references: 7883856
references: J Biol Chem. 2010 Jan 15;285(3):1989-2002
references: 19915011
references: FEBS Lett. 1985 Aug 19;188(1):81-4
references: 4018272
references: Diabetes. 2008 Mar;57(3):584-93
references: 18025410
references: Diabetologia. 1993 Aug;36(8):741-4
references: 8405741
references: Cell Metab. 2006 Mar;3(3):153-65
references: 16517403
references: Diabetes Care. 2002 Aug;25(8):1398-404
references: 12145241
references: Endocrinology. 1984 Jul;115(1):102-5
references: 6376068
references: Mol Pharmacol. 2007 Aug;72(2):463-76
references: 17525129
references: J Med Chem. 2000 May 4;43(9):1664-9
references: 10794683
references: Gastroenterology. 2007 May;132(6):2131-57
references: 17498508
references: Diabetes Res Clin Pract. 2004 Oct;66(1):63-9
references: 15364163
references: Proc Natl Acad Sci U S A. 2007 Jan 16;104(3):937-42
references: 17213325
references: J Biol Chem. 1993 Sep 15;268(26):19650-5
references: 8396143
references: Diabetologia. 1992 Apr;35(4):389-97
references: 1516769
references: Bioorg Med Chem Lett. 2007 Oct 1;17(19):5472-8
references: 17827014