G protein-selective GPCR conformations measured using FRET sensors in a live cell suspension fluorometer assay

Ansley Semack, Rabia U Malik, Sivaraj Sivaramakrishnan

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Fӧrster resonance energy transfer (FRET)-based studies have become increasingly common in the investigation of GPCR signaling. Our research group developed an intra-molecular FRET sensor to detect the interaction between Gα subunits and GPCRs in live cells following agonist stimulation. Here, we detail the protocol for detecting changes in FRET between the β2-adrenergic receptor and the Gαs C-terminus peptide upon treatment with 100 μM isoproterenol hydrochloride as previously characterized1. Our FRET sensor is a single polypeptide consisting serially of a full-length GPCR, a FRET acceptor fluorophore (mCitrine), an ER/K SPASM (systematic protein affinity strength modulation) linker, a FRET donor fluorophore (mCerulean), and a Gα C-terminal peptide. This protocol will detail cell preparation, transfection conditions, equipment setup, assay execution, and data analysis. This experimental design detects small changes in FRET indicative of proteinprotein interactions, and can also be used to compare the strength of interaction across ligands and GPCR-G protein pairings. To enhance the signal-to-noise in our measurements, this protocol requires heightened precision in all steps, and is presented here to enable reproducible execution.

Original languageEnglish (US)
Article numbere54696
JournalJournal of Visualized Experiments
Volume2016
Issue number115
DOIs
StatePublished - Sep 10 2016

Keywords

  • Agonist-driven signaling
  • ER/K SPASM linker
  • FRET
  • GPCR signaling
  • HEK-293
  • Issue 115
  • Live cell
  • MCerulean
  • MCitrine
  • Molecular biology

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