Regulation of pulmonary surfactant by the adhesion GPCR GPR116/ADGRF5 requires a tethered agonist-mediated activation mechanism
- Cincinnati Children's Hospital Medical Center, United States
- Novartis, Switzerland
- University of Cincinnati, United States
- Novartis, United States
Abstract
The mechanistic details of the tethered agonist mode of activation for the adhesion GPCR ADGRF5/GPR116 has not been completely deciphered. We set out to investigate the physiologic importance of autocatalytic cleavage upstream of the agonistic peptide sequence, an event necessary for NTF displacement and subsequent receptor activation. To examine this hypothesis, we characterized tethered agonist-mediated activation of GPR116 in vitro and in vivo. A knock-in mouse expressing a non-cleavable GPR116 mutant phenocopies the pulmonary 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 conserved amino acids for GPR116 activation in the tethered agonist sequence and in extracellular loops 2/3 (ECL2/3). We further highlight residues in transmembrane7 (TM7) that mediate stronger signaling in mouse versus human GPR116 and recapitulate these findings in a model supporting tethered agonist:ECL2 interactions for GPR116 activation.
Data availability
Source data for the modeling is provided (coordinates of the model)
Article and author information
Author details
Marie-Gabrielle Ludwig
Funding
National Heart, Lung and Blood Institute of the NIH (HL131634)
- Caterina Safina
- Bernard Pirard
This work was funded in part by the NIH grant listed above.
Ethics
Animal experimentation: All animal procedures were performed under protocols (AS2842_05_22; JPB) approved by the Institutional Animal Care and Use Committee of National Jewish Health in accordance with National Institutes of Health guidelines.
Copyright
© 2022, Bridges et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Regulation of pulmonary surfactant by the adhesion GPCR GPR116/ADGRF5 requires a tethered agonist-mediated activation mechanism
eLife 11:e69061.
https://doi.org/10.7554/eLife.69061
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