HUMAN NEUROPEPTIDE Y1 RECEPTOR EXPRESSED IN ESCHERICHIA-COLI RETAINS ITS PHARMACOLOGICAL PROPERTIES

The coding region of the gene for the human neuropeptide Y (NPY) Y1 receptor was fused to the maltose binding protein gene, Expression of this transcription unit, after derepression with isopropyl beta-D-thiogalactopyranoside, was evidenced by the appearance of a protein of higher molecular weight, as well as the native maltose binding protein, both of which were inmunoreactive with anti-maltose binding protein antibodies, Specific [I-125]Npy binding activity was found associated mainly with the inner bacterial membrane fraction, suggesting that the receptor is correctly folded in this membrane. Competition binding experiments using NPY Y1- and Y2-specific ligands clearly exhibited a NPY Y1 specific pharmacological profile with K-d values indistinguishable from those of the native receptor. These results suggest that the membrane environment required by the human NPY Y1 receptor for specific high-affinity ligand binding is conserved in this heterologous bacterial system and can be used for detailed analyses of ligand-receptor interaction and drug screening.