The final, formatted version of the article will be published soon.
ORIGINAL RESEARCH article
Front. Pharmacol.
Sec. Experimental Pharmacology and Drug Discovery
Volume 15 - 2024 |
doi: 10.3389/fphar.2024.1455231
Receptor activity modifying protein modulation of parathyroid hormone-1 receptor function and signalling
Provisionally accepted- The University of Sheffield, Sheffield, England, United Kingdom
Receptor activity-modifying proteins (RAMPs) are known to modulate the pharmacology and function of several G protein-coupled receptors (GPCRs), including the parathyroid hormone 1 receptor (PTH1R). However, the precise effects of different RAMPs on PTH1R signalling and trafficking remain poorly understood. Here we investigated the impact of RAMP2 and RAMP3 on PTH1R function using a range of PTH-and PTH-related protein (PTHrP)-derived ligands.FRET imaging revealed that PTH1R preferentially interacts with RAMP2 and, to a lesser extent, RAMP3, but not RAMP1. Interestingly, RAMP3 co-expression resulted in reduced cell surface expression of PTH1R, suggesting a potential role in receptor trafficking or internalization. The presence of RAMP2 significantly enhanced PTH1R-mediated cAMP accumulation, β-arrestin recruitment, and calcium signalling in response to PTH (1-34), PTHrP (1-34), PTH (1-84), and the PTH (1-17) analogue ZP2307. In contrast, RAMP3 co-expression attenuated or completely abolished those responses.We found that full-length PTHrP analogues, PTHrP (1-108) and PTHrP (1-141), exhibited lower potency and efficacy than PTHrP (1-34) in activating PTH1R. RAMP2 significantly increased potency and/or efficacy when compared to PTH1R alone cells, while RAMP3 significantly reduced these responses. Antibody-capture scintillation proximity assays demonstrated that RAMP2 differentially modulates G protein activation by PTH1R in a ligand-dependent manner, with PTH (1-34) and PTHrP (1-34) inducing distinct patterns of G protein subtype activation.These findings highlight the complex role of RAMPs in regulating PTH1R signalling and trafficking, revealing differential effects of RAMP2 and RAMP3 on receptor function. The data suggest that targeting the PTH1R/RAMP2 complex may be a promising strategy for developing novel bone anabolic therapies by leveraging biased agonism and functional selectivity.
Keywords: Parathyroid hormone receptor-1 (PTH1R), parathyroid hormone (PTH), Parathyroid hormone-related protein (PTHrP), Receptor-activity-modifying protein (RAMP), biased agonism
Received: 26 Jun 2024; Accepted: 03 Sep 2024.
Copyright: © 2024 Avgoustou, Jailani, Desai, Roberts, Stothard, Lilley, Skerry and Richards. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Timothy M Skerry, The University of Sheffield, Sheffield, S10 2TN, England, United Kingdom
Gareth O Richards, The University of Sheffield, Sheffield, S10 2TN, England, United Kingdom
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.