Screening β-arrestin recruitment for the identification of natural ligands for orphan G-protein-coupled receptors

J Biomol Screen. 2013 Jun;18(5):599-609. doi: 10.1177/1087057113475480. Epub 2013 Feb 8.


A variety of G-protein-coupled receptor (GPCR) screening technologies have successfully partnered a number of GPCRs with their cognate ligands. GPCR-mediated β-arrestin recruitment is now recognized as a distinct intracellular signaling pathway, and ligand-receptor interactions may show a bias toward β-arrestin over classical GPCR signaling pathways. We hypothesized that the failure to identify native ligands for the remaining orphan GPCRs may be a consequence of biased β-arrestin signaling. To investigate this, we assembled 10 500 candidate ligands and screened 82 GPCRs using PathHunter β-arrestin recruitment technology. High-quality screening assays were validated by the inclusion of liganded receptors and the detection and confirmation of these established ligand-receptor pairings. We describe a candidate endogenous orphan GPCR ligand and a number of novel surrogate ligands. However, for the majority of orphan receptors studied, measurement of β-arrestin recruitment did not lead to the identification of cognate ligands from our screening sets. β-Arrestin recruitment represents a robust GPCR screening technology, and ligand-biased signaling is emerging as a therapeutically exploitable feature of GPCR biology. The identification of cognate ligands for the orphan GPCRs and the extent to which receptors may exist to preferentially signal through β-arrestin in response to their native ligand remain to be determined.

Keywords: natural ligand; orphan G-protein–coupled receptor; β-arrestin recruitment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arrestins / metabolism*
  • CHO Cells
  • Cells, Cultured
  • Cricetinae
  • Cricetulus
  • Drug Discovery / methods
  • HEK293 Cells
  • High-Throughput Screening Assays / methods*
  • Humans
  • Ligands
  • Protein Binding / physiology
  • Receptors, G-Protein-Coupled / agonists*
  • Receptors, G-Protein-Coupled / metabolism
  • Saccharomyces cerevisiae
  • Small Molecule Libraries / analysis
  • beta-Arrestins


  • Arrestins
  • GPR35 protein, human
  • Ligands
  • Receptors, G-Protein-Coupled
  • Small Molecule Libraries
  • beta-Arrestins