1. Determining the Effects of Differential Expression of GRKs and β-arrestins on CLR-RAMP Agonist Bias
- Author
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Pearce, Abigail, Redfern-Nichols, Theo, Harris, Matthew, Poyner, David R, Wigglesworth, Mark, Ladds, Graham, Pearce, Abigail [0000-0001-9845-0541], Harris, Matthew [0000-0002-7918-5735], Ladds, Graham [0000-0001-7320-9612], and Apollo - University of Cambridge Repository
- Subjects
genetic structures ,CLR ,Physiology ,FOS: Biological sciences ,Physiology (medical) ,signalling bias ,RAMPs ,internalisation ,GPCRs (G protein-coupled receptors) ,GRK (G protein receptor kinase) ,β-arrestins - Abstract
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.
- Published
- 2022