Uncoupling of the allosteric signalling network in the β₁-adrenergic receptor by a negative allosteric modulator.
6 affiliations
- 1Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK.
- 2Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK.
- 3Department of Biotechnology & Microbiology, Kannur University, Kannur, 670 661, Kerala, India.
- 4Department of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, Kuwait City, 13060, Kuwait.
- 5Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK. [email protected].
- 6Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK. [email protected].
Abstract
Allosteric modulation is a fundamental aspect of G protein-coupled receptor (GPCR) regulation where molecules that bind to alternative sites outside the orthosteric pocket alter agonist-induced signalling responses. The advantages of allosteric modulators over traditional orthosteric agonists have positioned them as highly promising therapeutic agents. GPCRs exist in tuneable equilibria between multiple functional states, yet the ways in which allosteric modulators reshape these equilibria remain incompletely understood. Here we characterise how changes to the allosteric signalling network influence the conformational dynamics of the β₁-adrenergic receptor (β₁AR) through mutations at the E1303.41 position or using the negative allosteric modulator, AS408. Both act through a known transmembrane (TM)3-TM4-TM5 site, reducing signalling to similar extents, but through distinct molecular mechanisms as revealed by pharmacological assays, MD simulations, and solution nuclear magnetic resonance spectroscopy. E1303.41 mutations reduce agonist-stimulated signalling as a side chain-dependent rheostat, shifting receptor equilibria to populate states with weaker G protein affinities. In contrast, AS408 uncouples the intracellular region of β₁AR from the influence of the orthosteric pocket and reduces G protein coupling by adoption of an alternative signalling-incompetent intracellular surface arrangement. Our investigations emphasise the relevance of mechanistic understanding in drug development and the importance of dynamics in GPCR allostery.
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BibTeX
@article{harman2026uncoupling,
title = {{Uncoupling of the allosteric signalling network in the β₁-adrenergic receptor by a negative allosteric modulator.}},
author = {Thomas H Harman and Timothy Noel and Ali Nokhbehzaim and Abigail Pearce and Andrew J Y Jones and Anjana Saji and Matthew Harris and Venkat S Vege and Aneesh Chandran and Pierre Leroy and Suleiman Al-Sabah and Graham Ladds and Daniel Nietlispach},
journal = {Nature communications},
year = {2026},
month = sep,
doi = {10.1038/s41467-026-77802-8},
url = {https://europepmc.org/article/MED/42897158},
note = {CC BY},
}
RIS
TY - JOUR
TI - Uncoupling of the allosteric signalling network in the β₁-adrenergic receptor by a negative allosteric modulator.
AU - Thomas H Harman
AU - Timothy Noel
AU - Ali Nokhbehzaim
AU - Abigail Pearce
AU - Andrew J Y Jones
AU - Anjana Saji
AU - Matthew Harris
AU - Venkat S Vege
AU - Aneesh Chandran
AU - Pierre Leroy
AU - Suleiman Al-Sabah
AU - Graham Ladds
AU - Daniel Nietlispach
PY - 2026
DA - 2026/09/18
JO - Nature communications
DO - 10.1038/s41467-026-77802-8
UR - https://europepmc.org/article/MED/42897158
AB - Allosteric modulation is a fundamental aspect of G protein-coupled receptor (GPCR) regulation where molecules that bind to alternative sites outside the orthosteric pocket alter agonist-induced signalling responses. The advantages of allosteric modulators over traditional orthosteric agonists have positioned them as highly promising therapeutic agents. GPCRs exist in tuneable equilibria between multiple functional states, yet the ways in which allosteric modulators reshape these equilibria remain incompletely understood. Here we characterise how changes to the allosteric signalling network influence the conformational dynamics of the β₁-adrenergic receptor (β₁AR) through mutations at the E1303.41 position or using the negative allosteric modulator, AS408. Both act through a known transmembrane (TM)3-TM4-TM5 site, reducing signalling to similar extents, but through distinct molecular mechanisms as revealed by pharmacological assays, MD simulations, and solution nuclear magnetic resonance spectroscopy. E1303.41 mutations reduce agonist-stimulated signalling as a side chain-dependent rheostat, shifting receptor equilibria to populate states with weaker G protein affinities. In contrast, AS408 uncouples the intracellular region of β₁AR from the influence of the orthosteric pocket and reduces G protein coupling by adoption of an alternative signalling-incompetent intracellular surface arrangement. Our investigations emphasise the relevance of mechanistic understanding in drug development and the importance of dynamics in GPCR allostery.
SN - 2041-1723
ER -