Expression of GPCRs in Drug Discovery and Structural Biology

Expression of GPCRs in Drug Discovery and Structural Biology

Speaker: Kenneth Lundstrom

Affiliation: PanTherapeutics, Lausanne, Switzerland

Host: Manuel T. Carrondo

Abstract:

G protein-coupled receptors (GPCRs) are targets for more than 50% of current drugs. GPCRs are involved in essential signal transduction events triggered by a variety of inducers such as amino acids, lipids, biogenic amines, nucleotides, nucleosides, hormones, peptides, light and odorants.  The effect includes development, proliferation, differentiation, cell survival, angiogenesis, cancer and susceptibility to viral infections. For this reason, GPCRs are involved in all major disease indications such as cardiovascular, metabolic, neurologic, neuro-psychiatric, infectious and oncologic diseases.

Modern drug discovery relies heavily on efficient compound screening methods and requires large quantities of receptor protein, which only can be provided through recombinant expression approaches. Alphavirus vectors, particularly Semliki Forest virus (SFV) vectors, have been proven suitable for GPCR expression due to their easy and rapid high-titer virus production, broad range of mammalian host cells and possibility for large-scale production. More than 100 GPCRs have been expressed from SFV vectors resulting in robust radioligand binding assays and demonstration of functional coupling to G proteins by intracellular Ca2+-release, inositol phosphate accumulation and cAMP stimulation. Gene function studies in primary neurons and hippocampal slice cultures have also been conducted. Large-scale production in suspension cultures in bioreactors and spinner flasks has directly supported drug screening programs and provided material for structural biology. In this context up to 10 mg receptor per liter was produced, which allowed purification and structural characterization.