RT Journal Article
SR Electronic
T1 A Hydrogen-Bonded Polar Network in the Core of the Glucagon-Like Peptide-1 Receptor is a Fulcrum for Biased Agonism: Lessons from Class B Crystal Structures.
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP mol.115.101246
DO 10.1124/mol.115.101246
A1 Denise M. Wootten
A1 Christopher A Reynolds
A1 Cassandra Koole
A1 Kevin J Smith
A1 Juan C Mobarec
A1 John Simms
A1 Tezz Quon
A1 Thomas Coudrat
A1 Sebastian G.B. Furness
A1 Laurence J Miller
A1 Arthur Christopoulos
A1 Patrick Sexton
YR 2015
UL http://molpharm.aspetjournals.org/content/early/2015/12/23/mol.115.101246.abstract
AB The glucagon-like peptide 1 (GLP-1) receptor is a class B G protein-coupled receptor (GPCR) that is a key target for treatments for type II diabetes and obesity. This receptor, like other class B GPCRs, displays biased agonism, though the physiological significance of this is yet to be elucidated. Previous work has implicated R2.60190, N3.43240, Q7.49394 and H6.52363 as key residues involved in peptide-mediated biased agonism (Wootten et al., 2013a), with R2.60190, N3.43240 and Q7.49394 predicted to form a polar interaction network. In this study, we used novel insight gained from recent crystal structures of the transmembrane domains of the glucagon and corticotropin releasing factor 1 (CRF1) receptors to develop improved models of the GLP-1 receptor that predict additional key molecular interactions with these amino acids. We have introduced E6.53364A, N3.43240Q, Q7.49394N and N3.43240Q/ Q7.49394N mutations to probe the role of predicted H-bonding and charge-charge interactions in driving cAMP, calcium or ERK signaling. A polar interaction between E6.53364 and R2.60190 was predicted to be important for GLP-1- and exendin-4-, but not oxyntomodulin-mediated cAMP formation and also ERK1/2 phosphorylation. In contrast, Q7.49394, but not R2.60190/ E6.53364 was critical for calcium mobilisation for all three peptides. Mutation of N3.43240 and Q7.49394 had differential effects on individual peptides providing evidence for molecular differences in activation transition. Collectively, this work expands our understanding of peptide-mediated signaling from the GLP-1 receptor and the key role that the central polar network plays in these events.