Bridges, James, Safina, Caterina, Pirard, Bernard, Brown, Kari, Alyssa, Filuta, Bouhelal, Rochdi, Patel, Sejal, Voshol, Johannes, Seuwen, Klaus, Miller, William and Ludwig, Marie-Gabrielle (2022) Activation of GPR116/ADGRF5 by its tethered ligand relies on key amino acids in extracellular loop 2 of the transmembrane region. ELife..

Abstract

Adhesion GPCRs are activated via a tethered agonist, revealed upon ligand binding to the N-terminal extracellular domains. The mechanistic details of this mode of activation has not been deciphered. We set out to investigate the physiologic importance of autocatalytic cleavage upstream of the agonistic peptide sequence and characterize tethered agonist-mediated activation of GPR116 in vitro and in vivo. A transgenic mouse expressing a non-cleavable GPR116 mutant phenocopies the pulmonary surfactant phenotype of GPR116 knock-out mice, demonstrating that tethered agonist-mediated receptor activation is indispensable for function in vivo. Using site-directed mutagenesis and species swapping approaches we identified key amino acids for GPR116 activation in the tethered agonist sequence and in extracellular loop 2/transmembrane 6 (ECL2/TM6) that are conserved in human and mouse. We further highlight residues in TM7 that mediate a stronger signaling in mouse versus human GPR116. We recapitulate these findings in a model supporting tethered agonist:ECL2 interactions for GPR116 activation.

Item Type:	Article
Date Deposited:	04 Feb 2026 00:45
Last Modified:	04 Feb 2026 00:45
URI:	https://oak.novartis.com/id/eprint/44478