Crystal structure of isolated domain III of the extracellular region of the epidermal growth factor receptor in complex with the Fab fragment of IMC-11F8
[EGFR_HUMAN] Defects in EGFR are associated with lung cancer (LNCR) [MIM:211980]. LNCR is a common malignancy affecting tissues of the lung. The most common form of lung cancer is non-small cell lung cancer (NSCLC) that can be divided into 3 major histologic subtypes: squamous cell carcinoma, adenocarcinoma, and large cell lung cancer. NSCLC is often diagnosed at an advanced stage and has a poor prognosis.
[EGFR_HUMAN] Receptor tyrosine kinase binding ligands of the EGF family and activating several signaling cascades to convert extracellular cues into appropriate cellular responses. Known ligands include EGF, TGFA/TGF-alpha, amphiregulin, epigen/EPGN, BTC/betacellulin, epiregulin/EREG and HBEGF/heparin-binding EGF. Ligand binding triggers receptor homo- and/or heterodimerization and autophosphorylation on key cytoplasmic residues. The phosphorylated receptor recruits adapter proteins like GRB2 which in turn activates complex downstream signaling cascades. Activates at least 4 major downstream signaling cascades including the RAS-RAF-MEK-ERK, PI3 kinase-AKT, PLCgamma-PKC and STATs modules. May also activate the NF-kappa-B signaling cascade. Also directly phosphorylates other proteins like RGS16, activating its GTPase activity and probably coupling the EGF receptor signaling to the G protein-coupled receptor signaling. Also phosphorylates MUC1 and increases its interaction with SRC and CTNNB1/beta-catenin.             Isoform 2 may act as an antagonist of EGF action.            
Publication Abstract from PubMed
Therapeutic anticancer strategies that target and inactivate the epidermal growth factor receptor (EGFR) are under intense study in the clinic. Here we describe the mechanism of EGFR inhibition by an antibody drug IMC-11F8. IMC-11F8 is a fully human antibody that has similar antitumor potency as the chimeric cetuximab/Erbitux and might represent a safer therapeutic alternative. We report the X-ray crystal structure of the Fab fragment of IMC-11F8 (Fab11F8) in complex with the entire extracellular region and with isolated domain III of EGFR. We compare this to our previous study of the cetuximab/EGFR interaction. Fab11F8 interacts with a remarkably similar epitope, but through a completely different set of interactions. Both the similarities and differences in binding of these two antibodies have important implications for the development of inhibitors that could exploit this same mechanism of EGFR inhibition.
Structural basis for EGF receptor inhibition by the therapeutic antibody IMC-11F8.,Li S, Kussie P, Ferguson KM Structure. 2008 Feb;16(2):216-27. PMID:18275813
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.