Screening of Ligands for Human GPCRs by the Use of Receptor-Gα Fusion Proteins

Research .............................................................................................42 2.3 Ligand Screening System for GPCRs Using Receptor-G

α

Fusion Proteins...............................................................................................42 2.3.1 Gene Construction for Receptor-G

α

Fusion Proteins .......................44 2.3.2

In vivo

Cell-Based Assay...................................................................49 2.3.3

In vitro

[

S]GT

γ

S Binding Assay.....................................................56 Acknowledgments....................................................................................................63 Abbreviations ...........................................................................................................63 References................................................................................................................63

G protein-coupled receptors (GPCRs) are integral proteins in the cell membranes; receive extracellular signals, such as light, odorants, and taste substances, as well as most hormones and neurotransmitters; and interact with and activate G proteins in the intracellular surface. GPCRs constitute one of the largest protein superfamilies and are targets for 30 to 60% of present drugs.