A structure-activity analysis of the cloned rat and human Y4 receptors for pancreatic polypeptide

We cloned and expressed the rat Y4 receptor for pancreatic polypeptide (PP). Structure-activity profiles derived from 125I-PP binding assays and [cAMP] radioimmunoassays reveal a selective receptor interaction with rat PP vs. neuropeptide Y (NPY) or peptide YY (PYY). Rat and human Y4 receptor clones share 75% amino acid identity. Based on [cAMP] radioimmunoassay, the human Y4 receptor exhibits a less selective interaction with rat PP vs. NPY or PYY and a greater dependence on N-terminal PP residues, relative to rat Y4. Differences in sequence and structure-activity profiles suggest the rat be used with caution to model human Y4 receptor function.