Key phosphorylation sites in GPCRs orchestrate the contribution of β‐Arrestin 1 in ERK1/2 activation. (26th July 2020)

• Record Type: Journal Article
• Authors: Baidya, Mithu; Kumari, Punita; Dwivedi‐Agnihotri, Hemlata; Pandey, Shubhi; Chaturvedi, Madhu; Stepniewski, Tomasz Maciej; Kawakami, Kouki; Cao, Yubo; Laporte, Stéphane A; Selent, Jana; Inoue, Asuka; Shukla, Arun K
• Is Part Of: EMBO reports. Volume 21:Number 9(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-07-26
• Subjects: biased agonism -- cellular signaling -- ERK1/2 MAP kinase -- G protein‐coupled receptors -- β‐arrestins; Molecular biology -- Periodicals; Molecular Biology -- Periodicals; Molecular biology; Periodicals; 572.8
• DOI: 10.15252/embr.201949886
• Languages: English
• ISSNs: 1469-221X

Abstract

Abstract: β‐arrestins (βarrs) are key regulators of G protein‐coupled receptor (GPCR) signaling and trafficking, and their knockdown typically leads to a decrease in agonist‐induced ERK1/2 MAP kinase activation. Interestingly, for some GPCRs, knockdown of βarr1 augments agonist‐induced ERK1/2 phosphorylation although a mechanistic basis for this intriguing phenomenon is unclear. Here, we use selected GPCRs to explore a possible correlation between the spatial positioning of receptor phosphorylation sites and the contribution of βarr1 in ERK1/2 activation. We discover that engineering a spatially positioned double‐phosphorylation‐site cluster in the bradykinin receptor (B2 R), analogous to that present in the vasopressin receptor (V2 R), reverses the contribution of βarr1 in ERK1/2 activation from inhibitory to promotive. An intrabody sensor suggests a conformational mechanism for this role reversal of βarr1, and molecular dynamics simulation reveals a bifurcated salt bridge between this double‐phosphorylation site cluster and Lys 294 in the lariat loop of βarr1, which directs the orientation of the lariat loop. Our findings provide novel insights into the opposite roles of βarr1 in ERK1/2 activation for different GPCRs with a direct relevance to biased agonism and novel therapeutics. Synopsis: Distinct spatial positioning of key phosphorylation sites in different GPCRs plays a decisive role in the contribution of β‐arrestin 1 in agonist‐induced ERK1/2 activation. These findings have direct relevance for biased agonism, and for designing GPCR‐targeted novel therapeutics. Spatial distribution of GPCR phosphorylation sites governs the role of β‐arrestin 1 in ERK1/2 activation. Engineering spatially positioned receptor phospho‐sites can reverse the role of β‐arrestin 1 in ERK1/2 activation. A key salt‐bridge interaction between the receptor and β‐arrestin 1 directs the lariat loop orientation in β‐arrestin 1. Abstract : Distinct spatial positioning of key phosphorylation sites in different GPCRs plays a decisive role in the contribution of β‐arrestin 1 in agonist‐induced ERK1/2 activation. These findings have direct relevance for biased agonism, and for designing GPCR‐targeted novel therapeutics.