Abstract
G protein-coupled receptors (GPCRs) represent one of the largest membrane protein families that participate in various physiological and pathological activities. Accumulating structural evidences have revealed how GPCR activation induces conformational changes to accommodate the downstream G protein or β-arrestin. Multiple GPCR functional assays have been developed based on Förster resonance energy transfer (FRET) and bioluminescence resonance energy transfer (BRET) sensors to monitor the conformational changes in GPCRs, GPCR/G proteins, or GPCR/β-arrestin, especially over the past two decades. Here, we will summarize how these sensors have been optimized to increase the sensitivity and compatibility for application in different GPCR classes using various labeling strategies, meanwhile provide multiple solutions in functional assays for high-throughput drug screening.
Highlights
Gprotein-coupled receptors (GPCRs) represent one of the largest membrane receptor superfamily, which is encoded by approximately 3% of human genes and over 800 members (Klabunde and Hessler, 2002; Fredriksson et al, 2003; Pin et al, 2019)
Ligand binding to class C GPCR leads to the closure of Venus Flytrap domain (VFT), triggering the conformational change in the cysteine-rich domain or stalk domain, further rearranging the transmembrane domain (TM) from inactive interface to TM6/TM6 active interface, which is similar in class C GPCR homodimers such as metabotropic glutamate receptor type 2 (Xue et al, 2015), mGlu5 (Koehl et al, 2019), and calcium sensing receptor (CaSR) (Liu et al, 2020), or heterodimer, like metabotropic γ-aminobutyric acid receptors (GABAB receptor) (Xue et al, 2019; Mao et al, 2020; PapasergiScott et al, 2020; Park et al, 2020; Shaye et al, 2020)
There are two main types of biosensors for studying the kinetics of GPCR/β-arrestin signal based on bioluminescence resonance energy transfer (BRET) and Förster resonance energy transfer (FRET): intermolecular sensors used for monitoring GPCR/β-arrestin dynamic interactions and intramolecular sensors used for measuring β-arrestin conformational rearrangement (Table 1; Bertrand et al, 2002; Charest and Bouvier, 2003; Krasel et al, 2005)
Summary
Gprotein-coupled receptors (GPCRs) represent one of the largest membrane receptor superfamily, which is encoded by approximately 3% of human genes and over 800 members (Klabunde and Hessler, 2002; Fredriksson et al, 2003; Pin et al, 2019). Measuring the proximity change between Gα and Gβγ subunits through BRET assay (Figure 3B), can reflect the G protein heterotrimer states and activation of GPCRs (Galés et al, 2006).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
