Fortin, Jean-PhilippeChinnapen, DanielBeinborn, MartinLencer, WayneKopin, Alan S.Araujo, Ronaldo2019-10-052011Fortin, Jean-Philippe, Daniel Chinnapen, Martin Beinborn, Wayne Lencer, and Alan S. Kopin. 2011. “Discovery of Dual-Action Membrane-Anchored Modulators of Incretin Receptors.” Edited by Ronaldo Araujo. PLoS ONE 6 (9): e24693. https://doi.org/10.1371/journal.pone.0024693.1932-6203http://nrs.harvard.edu/urn-3:HUL.InstRepos:41483368Background: The glucose-dependent insulinotropic polypeptide (GIP) and the glucagon-like peptide-1 (GLP-1) receptors are considered complementary therapeutic targets for type 2 diabetes. Using recombinant membrane-tethered ligand (MTL) technology, the present study focused on defining optimized modulators of these receptors, as well as exploring how local anchoring influences soluble peptide function. Methodology/Principal Findings: Serial substitution of residue 7 in membrane-tethered GIP (tGIP) led to a wide range of activities at the GIP receptor, with [G(7)]tGIP showing enhanced efficacy compared to the wild type construct. In contrast, introduction of G(7) into the related ligands, tGLP-1 and tethered exendin-4 (tEXE4), did not affect signaling at the cognate GLP-1 receptor. Both soluble and tethered GIP and GLP-1 were selective activators of their respective receptors. Although soluble EXE4 is highly selective for the GLP-1 receptor, unexpectedly, tethered EXE4 was found to be a potent activator of both the GLP-1 and GIP receptors. Diverging from the pharmacological properties of soluble and tethered GIP, the newly identified GIP-R agonists, (i.e. [G(7)]tGIP and tEXE4) failed to trigger cognate receptor endocytosis. In an attempt to recapitulate the dual agonism observed with tEXE4, we conjugated soluble EXE4 to a lipid moiety. Not only did this soluble peptide activate both the GLP-1 and GIP receptors but, when added to receptor expressing cells, the activity persists despite serial washes. Conclusions: These findings suggest that conversion of a recombinant MTL to a soluble membrane anchored equivalent offers a means to prolong ligand function, as well as to design agonists that can simultaneously act on more than one therapeutic target.en-USJournal Article2019-10-0510.1371/journal.pone.0024693