Characterization of chimeric proteins constructed from human epidermal growth factor (EGF) and the Drosophila EGF-receptor antagonist argos

The Drosophila argos protein is a natural ligand antagonist of Drosophila EGF receptor (DER), but does not interact with the human EGF receptor (EGFR). With a view to generating a corresponding EGFR antagonist, we, have designed five chimeric proteins featuring selected characteristic parts of argos within the framework of the human EGF ligand. These chimeras were expressed in bacteria, purified, refolded and characterized. We tested their ability to bind to EC;FR, to effect receptor tyrosine phosphorylation and to inhibit EGF-induced EGFR phosphorylation.