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Molecular mechanism of β-arrestin-2 pre-activation by phosphatidylinositol 4,5-bisphosphate

ABSTRACT: Phosphorylated residues of G protein-coupled receptors bind to the N-domain of arrestin, resulting in the release of its C-terminus. This induces further allosteric conformational changes, such as polar core disruption, alteration of interdomain loops, and domain rotation, which transform arrestins into the receptor-activated state. It is widely accepted that arrestin activation occurs by conformational changes propagated from the N- to the C-domain. However, recent studies have revealed that binding of phosphatidylinositol 4,5-bisphosphate (PIP2) to the C-domain transforms arrestins into a pre-active state. Here, we aimed to elucidate the mechanisms underlying PIP2-induced arrestin pre-activation. We compare the conformational changes of β-arrestin-2 upon binding of PIP2 or phosphorylated C-tail peptide of vasopressin receptor type 2 using hydrogen/deuterium exchange mass spectrometry (HDX-MS). Introducing point mutations on the potential routes of the allosteric conformational changes and analyzing these mutant constructs with HDX-MS reveals that PIP2-binding at the C-domain affects the back loop, which destabilizes the gate loop and βXX to transform β-arrestin-2 into the pre-active state.

SUBMITTER: Ms. Kiae Kim

PROVIDER: S-SCDT-10_1038-S44319-024-00239-X | biostudies-other |

REPOSITORIES: biostudies-other

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Molecular mechanism of β-arrestin-2 pre-activation by phosphatidylinositol 4,5-bisphosphate

Project description:Arrestins are a protein family that regulate G protein-coupled receptor (GPCR) signaling, with four distinct members in mammals (arrestin 1–4). Phosphorylated residues of G protein-coupled receptors bind to the N-domain of arrestin, resulting in C-terminus release. This induces further allosteric conformational changes, such as polar core disruption, alteration of interdomain loops, and domain rotation, which transform arrestins into the receptor-activated state. It is widely accepted that arrestin activation occurs by conformational changes propagated from the N- to the C-domain. However, recent studies have revealed that binding of phosphatidylinositol 4,5-bisphosphate (PIP2) to the C-domain transforms arrestins into an active state. In this study, we aimed to elucidate the mechanisms underlying PIP2-induced arrestin activation. We compared the conformational changes of β-arrestin-2 upon binding of PIP2 or phosphorylated C-tail peptide of vasopressin receptor type 2 (V2Rpp) using hydrogen/deuterium exchange mass spectrometry (HDX-MS). Introducing point mutations on the potential routes of the allosteric conformational changes and analyzing these mutant constructs with HDX-MS revealed that PIP2-binding at the C-domain affects the back loop, which destabilizes the gate loop and β-strand XX to transform β-arrestin-2 into the pre-active state.

2024-07-15 | PXD049391 | Pride

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