Epidermal growth factor receptor (EGFR)–ErbB receptor tyrosine kinase 3 (ErbB3) heterodimer interface (EGFR–ErbB3 interface)

The Epidermal growth factor receptor (EGFR)–ErbB receptor tyrosine kinase 3 (ErbB3) heterodimer interface is a critical structural site for the formation of a potent signaling complex within the ErbB family (UniProt P00533, P21860). While ErbB3 possesses minimal intrinsic kinase activity, its heterodimerization with EGFR allows EGFR to trans-phosphorylate the C-terminal tail of ErbB3, creating docking sites for the p85 subunit of PI3K (Schaefer et al., Cancer Cell, 2011). This interaction is a major driver of the PI3K/Akt survival pathway, which is frequently implicated in oncogenesis and the development of resistance to standard EGFR-targeted therapies (Yonesaka et al., Nature Medicine, 2011). In many cancers, such as non-small cell lung cancer and colorectal cancer, the upregulation of ErbB3 or its ligand, neuregulin, compensates for EGFR inhibition, making the heterodimer interface a high-priority therapeutic target (Wheeler et al., Oncogene, 2008). Drugs targeting this interface, including bispecific antibodies like duligotuzumab, aim to simultaneously block ligand binding and prevent the physical association of the two receptors. By disrupting this specific protein-protein interaction, these therapies can overcome bypass signaling mechanisms that lead to drug resistance. Consequently, targeting the EGFR–ErbB3 interface offers a sophisticated approach to treating aggressive or resistant epithelial malignancies. Clinical development of these agents focuses on patients whose tumors exhibit high levels of both receptors or specific ligand-driven activation (ClinicalTrials.gov).

Other names

HER1–HER3 interfaceErbB1–ErbB3 interfaceEGFR–HER3 heterodimer interfaceEGFR–ErbB3 complex

The mechanism of action involves the use of bispecific antibodies to simultaneously bind the extracellular domains of EGFR and ErbB3, sterically hindering their dimerization and preventing the ligand-induced activation of downstream signaling pathways, particularly the PI3K/Akt axis (Schaefer et al., Cancer Cell, 2011).