title: Ligand binding induces a conformational change in epidermal growth factor receptor dimers.
abstract: The activation of the epidermal growth factor receptor (EGFR) kinase requires ligand binding to the extracellular domain (ECD). Previous reports demonstrate that the EGFR-ECD can be crystallized in two conformations - a tethered monomer or, in the presence of ligand, an untethered back-to-back dimer. We use Biosensor analysis to demonstrate that even in the monomeric state different C-terminal extensions of both truncated (EGFR(1-501))-ECD and full-length EGFR(1-621)-ECD can change the conformation of the ligand-binding site. The binding of a monoclonal antibody mAb806, which recognizes the dimer interface, to the truncated EGFR(1-501)-Fc fusion protein is reduced in the presence of ligand, consistent with a change in conformation. On the cell surface, the presence of erythroblastosis B2 (erbB2) increases the binding of mAb806 to the EGFR. The conformation of the erbB2: EGFR heterodimer interface changes when the cells are treated with epidermal growth factor (EGF). We propose that ligand induces kinase-inactive, pre-formed EGFR dimers and heterodimers to change conformation leading to kinase-active tetramers, where kinase activation occurs via an asymmetric interaction between EGFR dimers.
authors.affiliation: Ludwig Institute for Cancer Research Melbourne - Parkville Branch, Australia.
authors.forename: Francesca
authors.initials: F
authors.lastname: Walker
authors.forename: Julie
authors.initials: J
authors.lastname: Rothacker
authors.forename: Christine
authors.initials: C
authors.lastname: Henderson
authors.forename: Edouard C
authors.initials: EC
authors.lastname: Nice
authors.forename: Bruno
authors.initials: B
authors.lastname: Catimel
authors.forename: Hui-Hua
authors.initials: HH
authors.lastname: Zhang
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Scott
authors.forename: Michael F
authors.initials: MF
authors.lastname: Bailey
authors.forename: Suzanne G
authors.initials: SG
authors.lastname: Orchard
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Adams
authors.forename: Zhanqi
authors.initials: Z
authors.lastname: Liu
authors.forename: Thomas P J
authors.initials: TP
authors.lastname: Garrett
authors.forename: Andrew H A
authors.initials: AH
authors.lastname: Clayton
authors.forename: Antony W
authors.initials: AW
authors.lastname: Burgess
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D015374:Biosensing Techniques; D002460:Cell Line; D019281:Dimerization; D000939:Epitopes / Q000737:chemistry; D066246:ErbB Receptors / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D057809:HEK293 Cells; D006801:Humans; D007700:Kinetics; D008024:Ligands; D051379:Mice; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D005456:Fluorescent Dyes; D008024:Ligands; D066246:ErbB Receptors