Investigating the Heteromerization of Metabotropic Glutamate Receptors using a Novel Single Molecule Imaging Method

Abstract

Metabotropic Glutamate Receptors (mGluRs) are a type of G-Protein Coupled Receptor (GPCR) which bind glutamate as a neurotransmitter and are found in neurons throughout the brain and peripheral tissues. mGluRs are known to function as stable homodimers, but recent evidence suggests that the formation of heteromeric complexes may also occur. Knowledge of the stoichiometry of these complexes in vivo is crucial for the development of pharmacological compounds designed to act on them. Here we investigate the complexes formed by mGluRs using various optical methods including Single Protein Recovery After Dilution (SPReAD), a novel single molecule imaging technique we have developed which utilizes VSV-G mediated cell fusion in order to dilute the concentration of fluorescently tagged molecules of interest. This enables in vivo imaging without introducing harsh detergents or altering the level of expression.