Related Experiment Video

Updated: Apr 28, 2026

Parallel Interrogation of β-Arrestin2 Recruitment for Ligand Screening on a GPCR-Wide Scale using PRESTO-Tango Assay
09:03

Parallel Interrogation of β-Arrestin2 Recruitment for Ligand Screening on a GPCR-Wide Scale using PRESTO-Tango Assay

Published on: March 10, 2020

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Phosphorylation site topology governs the functional dynamics of arrestin recruitment to GPCRs

Irene Coin1, Timo Müller1, Woojin Lee2

  • 1Leipzig University.

Research Square
|April 27, 2026
PubMed

Insights

G protein-coupled receptor (GPCR) signaling relies on β-arrestin binding, often through intracellular loops. This study reveals the structural basis of muscarinic acetylcholine receptor M2 (M2R) and β-arrestin interaction, highlighting the role of phosphorylation site topology.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Structural Biology

Background:

  • G protein-coupled receptors (GPCRs) mediate cellular responses via β-arrestin (arr) recruitment.
  • While C-terminal tails typically mediate arrestin binding, some GPCRs utilize third intracellular loops (ICL3) for this interaction.
  • Structural data on GPCR-arrestin complexes involving ICL3 are scarce, limiting understanding of arrestin engagement mechanisms.

Purpose of the Study:

  • To elucidate the structural mechanisms of β-arrestin engagement by GPCRs that lack canonical C-terminal tails.
  • To investigate the role of phosphorylation site topology in modulating GPCR-arrestin interactions.
  • To provide atomistic models of the muscarinic acetylcholine receptor M2 (M2R)-β-arrestin complex in living cells.

Main Methods:

  • Genetically encoded crosslinkers were used to study M2R-β-arrestin interactions in living cells.
  • Crosslinking data guided the construction of atomistic models of the M2R-β-arrestin complex.
  • Unbiased molecular dynamics simulations validated the derived structural models.

Main Results:

  • The M2R ICL3 interacts with a positively charged region on the β-arrestin N-domain.
  • The M2R core forms a dynamic interface with the β-arrestin central crest, crucial for binding.
  • Phosphorylation site location significantly impacts arrestin engagement, with C-terminal tails promoting stronger binding than ICL3.

Conclusions:

  • The study provides novel structural insights into GPCR-arrestin complexes mediated by ICL3.
  • The topology of the interaction interface, not just phosphorylation motifs, dictates arrestin coupling dynamics.
  • This work advances understanding of GPCR desensitization and alternative signaling pathways.

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