LIBRARY SCREENING AS A STRATEGY TO CLONE DRUGS FOR G PROTEIN COUPLED RECEPTORS

摘要

The present invention is directed to a strategy to identify small peptides that activate any G protein coupled receptor (GPCR) or inactive any constitutively active GPCR by screening combinatorial peptide libraries. The invention comprises expressing a peptide of a peptide library tethered to a GPCR of interest in a cell, and monitoring the cell to determine whether the peptide is an agonist or negative antagonist of the GPCR of interest. The peptide is tethered to the GPCR by replacing the amino terminus of the GPCR with the amino terminus of a self-activating receptor, and replacing the natural peptide ligand present in the amino terminus with the library peptide. In one embodiment for discovery of agonists, a ligand of the self-activating receptor is used to cleave the resulting amino terminus to expose the peptide of the peptide library. In another embodiment for discovery of agonists or negative antagonists, the GPCR construct ends in the peptide so the peptide is always exposed. Preferably, the self-activating receptor is the thrombin receptor and the ligand of the self-activating receptor is thrombin.