Related Experiment Video

Updated: Jul 18, 2026

G Protein-selective GPCR Conformations Measured Using FRET Sensors in a Live Cell Suspension Fluorometer Assay
09:12

G Protein-selective GPCR Conformations Measured Using FRET Sensors in a Live Cell Suspension Fluorometer Assay

Published on: September 10, 2016

Conformation state-sensitive antibodies to G-protein-coupled receptors

Achla Gupta1, Fabien M Décaillot, Ivone Gomes

  • 1Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, New York 10029, USA.

The Journal of Biological Chemistry
|December 7, 2006
PubMed

Insights

New antibodies targeting the N-terminal region of micro-opioid receptors can detect conformational changes upon activation. These tools help study receptor dynamics and identify potential therapeutics for various G-protein-coupled receptors.

Area of Science:

  • Pharmacology
  • Biochemistry
  • Molecular Biology

Background:

  • G-protein-coupled receptors (GPCRs) undergo conformational changes upon activation.
  • The extracellular N-terminal region of GPCRs is hypothesized to change conformation during activation.

Purpose of the Study:

  • To generate and characterize antibodies targeting specific regions of the micro-opioid receptor N-terminus.
  • To investigate if these antibodies can detect activation-dependent conformational changes in GPCRs.
  • To explore the utility of these antibodies in studying receptor dynamics and identifying novel therapeutics.

Main Methods:

  • Generation of region-specific antibodies against the N-terminal tail of micro-opioid receptors.
  • Assessing antibody binding to activated versus non-activated receptors.
  • Investigating the effect of G-protein coupling blockers and deglycosylation on antibody recognition.
  • Utilizing antibodies to differentiate between micro-opioid receptor ligands with varying efficacies.
  • Probing the spatio-temporal dynamics of endogenous receptors in vivo using antibody binding.
  • Applying the antibody generation strategy to other GPCRs coupled to different G proteins.

Main Results:

  • Antibodies targeting the midportion of the N-terminal tail enhanced recognition of activated micro-opioid receptors.
  • This enhanced recognition was abolished by blocking G-protein coupling or deglycosylation.
  • Antibodies accurately differentiated ligands based on their efficacies.
  • Peripheral morphine administration induced a time-dependent increase in antibody binding in specific brain regions, indicating in vivo applicability.
  • The strategy was successfully applied to diverse GPCRs, including delta-opioid, CB1 cannabinoid, alpha(2A)-adrenergic, beta(2)-adrenergic, and AT1 angiotensin receptors.

Conclusions:

  • The N-terminal region of mu-opioid receptors undergoes activation-dependent conformational changes detectable by region-specific antibodies.
  • These conformation-specific antisera are valuable tools for studying GPCR dynamics, ligand characterization, and identifying molecules of therapeutic interest.
  • This approach offers a novel strategy for investigating differential conformational states across various GPCRs.

More Related Videos

Visualizing the Conformational Dynamics of Membrane Receptors Using Single-Molecule FRET10:59

Visualizing the Conformational Dynamics of Membrane Receptors Using Single-Molecule FRET

Published on: August 17, 2022

A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators07:41

A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators

Published on: February 20, 2018

Related Concept Videos

G Protein-coupled Receptors01:15

G Protein-coupled Receptors

G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
G Protein-coupled Receptors01:15

G Protein-coupled Receptors

G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
Transducer Mechanism: G Protein–Coupled Receptors01:30

Transducer Mechanism: G Protein–Coupled Receptors

G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs.
GPCRs are also called heptahelical, 7TM, or...
G-protein Coupled Receptors01:21

G-protein Coupled Receptors

G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
G-protein Coupled Receptors01:21

G-protein Coupled Receptors

G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
Activation and Inactivation of G Proteins01:22

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...