Busting the Breast Cancer with AstraZeneca’s Gefitinib

Figure 1

Binding specificities of EGFRs and preferred dimerization partners. EGFR 1, EGFR 2/HER2, EGFR 3, and EGFR 4 are represented by 1, 2, 3, and 4. Four categories of ligands bind to the EGFR family of receptors: epidermal growth factor (EGF), amphiregulin (AR), and transforming growth factor-α (TGFα) bind to EGFR-1; betacellulin (BTC), heparin binding epidermal growth factor (HB-EGF), and epiregulin (EREG) bind to EGFR1 and EGFR4; neuregulins, NRG-1 and NRG-2, bind to EGFR3 and EGFR4; and NRG-3 and NRG-4 bind to EGFR4. EGFR2 has no ligand binding [7, 25, 26], and EGFR 3 has a defective kinase (K) activity (red). After ligand binding, homo- or heterodimerization occurs. The most frequent heterodimers formed are EGFR2/EGFR4, EGFR1/EGFR4, and EGFR2/EGFR3 [27]. Adapted and modified from [22, 28].