Ligand-induced EGF Receptor Oligomerization Is Kinase-dependent and Enhances Internalization

The current activation model of the EGF receptor (EGFR) predicts that binding of EGF results in dimerization and oligomerization of the EGFR, leading to the allosteric activation of the intracellular tyrosine kinase. Little is known about the regulatory mechanism of receptor oligomerization. In this...

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Bibliographic Details
Published in:The Journal of biological chemistry 2010-12, Vol.285 (50), p.39481-39489
Main Authors: Hofman, Erik G., Bader, Arjen N., Voortman, Jarno, van den Heuvel, Dave J., Sigismund, Sara, Verkleij, Arie J., Gerritsen, Hans C., van Bergen en Henegouwen, Paul M.P.
Format: Article
Language:English
Subjects:
Animals
Anisotropy
Cell Line, Tumor
EGF
EGF Receptor
Epidermal Growth Factor - chemistry
ErbB Receptors - chemistry
Fluorescence Resonance Energy Transfer (FRET)
Fluorescence Resonance Energy Transfer - methods
Humans
Kinetics
Ligands
Mice
NIH 3T3 Cells
Protein Assembly
Protein Binding
Protein Phosphorylation
Protein-Tyrosine Kinases - chemistry
Receptor Endocytosis
Signal Transduction
Spectrometry, Fluorescence - methods
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Summary:The current activation model of the EGF receptor (EGFR) predicts that binding of EGF results in dimerization and oligomerization of the EGFR, leading to the allosteric activation of the intracellular tyrosine kinase. Little is known about the regulatory mechanism of receptor oligomerization. In this study, we have employed FRET between identical fluorophores (homo-FRET) to monitor the dimerization and oligomerization state of the EGFR before and after receptor activation. Our data show that, in the absence of ligand, ∼40% of the EGFR molecules were present as inactive dimers or predimers. The monomer/predimer ratio was not affected by deletion of the intracellular domain. Ligand binding induced the formation of receptor oligomers, which were found in both the plasma membrane and intracellular structures. Ligand-induced oligomerization required tyrosine kinase activity and nine different tyrosine kinase substrate residues. This indicates that the binding of signaling molecules to activated EGFRs results in EGFR oligomerization. Induction of EGFR predimers or pre-oligomers using the EGFR fused to the FK506-binding protein did not affect signaling but was found to enhance EGF-induced receptor internalization. Our data show that EGFR oligomerization is the result of EGFR signaling and enhances EGFR internalization.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M110.164731