Determining the Effects of Differential Expression of GRKs and β-arrestins on CLR-RAMP Agonist Bias.
Poyner, David R
Frontiers Media SA
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Pearce, A., Redfern-Nichols, T., Harris, M., Poyner, D. R., Wigglesworth, M., & Ladds, G. (2022). Determining the Effects of Differential Expression of GRKs and β-arrestins on CLR-RAMP Agonist Bias.. Front Physiol, 13 https://doi.org/10.3389/fphys.2022.840763
Signalling of the calcitonin-like receptor (CLR) is multifaceted, due to its interaction with receptor activity modifying proteins (RAMPs), and three endogenous peptide agonists. Previous studies have focused on the bias of G protein signalling mediated by the receptor and receptor internalisation of the CLR-RAMP complex has been assumed to follow the same pattern as other Class B1 G Protein-Coupled Receptors (GPCRs). Here we sought to measure desensitisation of the three CLR-RAMP complexes in response to the three peptide agonists, through the measurement of β-arrestin recruitment and internalisation. We then delved further into the mechanism of desensitisation through modulation of β-arrestin activity and the expression of GPCR kinases (GRKs), a key component of homologous GPCR desensitisation. First, we have shown that CLR-RAMP1 is capable of potently recruiting β-arrestin1 and 2, subsequently undergoing rapid endocytosis, and that CLR-RAMP2 and -RAMP3 also utilise these pathways, although to a lesser extent. Following this we have shown that agonist-dependent internalisation of CLR is β-arrestin dependent, but not required for full agonism. Overexpression of GRK2-6 was then found to decrease receptor signalling, due to an agonist-independent reduction in surface expression of the CLR-RAMP complex. These results represent the first systematic analysis of the importance of β-arrestins and GRKs in CLR-RAMP signal transduction and pave the way for further investigation regarding other Class B1 GPCRs.
Physiology, GPCRs (G protein-coupled receptors), signalling bias, CLR, β-arrestins, RAMPs, internalisation, GRK (G protein receptor kinase)
External DOI: https://doi.org/10.3389/fphys.2022.840763
This record's URL: https://www.repository.cam.ac.uk/handle/1810/336015