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 Drosoph ila EGF receptor (DER), but does not interact with the human EGF recep tor (EGFR). With a view to generating a corresponding EGFR antagonist, we, have designed five chimeric proteins featuring selected character istic parts of argos within the framework of the human EGF ligand. The se chimeras were expressed in bacteria, purified, refolded and charact erized. We tested their ability to bind to EC;FR, to effect receptor t yrosine phosphorylation and to inhibit EGF-induced EGFR phosphorylatio n.