Screening β-Arrestin Recruitment for the Identification of Natural Ligands for Orphan G-Protein–Coupled Receptors

• Published in: Journal of biomolecular screening Vol. 18; no. 5; pp. 599 - 609
• Main Authors: Southern, Craig, Cook, Jennifer M., Neetoo-Isseljee, Zaynab, Taylor, Debra L., Kettleborough, Catherine A., Merritt, Andy, Bassoni, Daniel L., Raab, William J., Quinn, Elizabeth, Wehrman, Tom S., Davenport, Anthony P., Brown, Andrew J., Green, Andrew, Wigglesworth, Mark J., Rees, Steve
• Format: Journal Article
• Language: English
• Published: United States 01.06.2013
• Subjects: Animals; Arrestins - metabolism; beta-Arrestins; Cells, Cultured; CHO Cells; 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; β-arrestin recruitment; natural ligand; orphan G-protein–coupled receptor
• ISSN: 2472-5552; 1552-454X
• DOI: 10.1177/1087057113475480

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.