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Updated: May 9, 2026
Studying the Stoichiometry of Epidermal Growth Factor Receptor in Intact Cells using Correlative Microscopy
Published on: September 11, 2015
Single molecular dissection of the ligand binding property of epidermal growth factor receptor
Jing Zhang1, Huiqing Liu, Rong Zhu
1State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
Abstract:
The understanding of ligand binding interactions is an important component of understanding the fundamental mechanism of receptor function. In this study, the binding abilities of EGF and TGF-α to EGFR on human bladder cancer (T24) cells were investigated by single molecular force spectroscopy (SMFS) based on atomic force microscopy (AFM). By approaching the specifically functionalized AFM tips to the T24 cell surface and subsequent retraction, specific unbinding events of the EGF/EGFR complexes and TGF-α/EGFR complexes were investigated. Further, the unbinding forces and the kinetic off rate constants that govern the bond stabilities were calculated through varying the external mechanic forces applied. Meanwhile, the distances from the energy minimum to the transition states along the separation paths of the EGF/EGFR complexes and TGF-α/EGFR complexes were deduced. This study at single-molecule level may enrich our understanding of the ligand binding properties of EGFR and provide some new information to the development of improved EGFR inhibitors. In addition, the results present new insight into the study of the energy landscape of the dissociation of ligand-EGFR system.
Insights
This study used atomic force microscopy to investigate how epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-α) bind to epidermal growth factor receptors (EGFR) on bladder cancer cells, revealing key binding dynamics.
Area of Science:
- Biochemistry
- Cell Biology
- Biophysics
Background:
- Ligand binding interactions are crucial for understanding receptor function.
- Epidermal Growth Factor Receptor (EGFR) is implicated in human bladder cancer.
- Investigating ligand-EGFR interactions at the single-molecule level provides fundamental insights.
Purpose of the Study:
- To investigate the binding abilities of EGF and TGF-α to EGFR on human bladder cancer (T24) cells.
- To analyze the unbinding forces and kinetic off-rate constants of EGF/EGFR and TGF-α/EGFR complexes.
- To deduce energy landscape parameters for ligand-EGFR dissociation.
Main Methods:
- Single-molecule force spectroscopy (SMFS) utilizing atomic force microscopy (AFM).
- Functionalized AFM tips were used to probe T24 cell surfaces.
- Analysis of specific unbinding events, unbinding forces, and kinetic off-rate constants.
Main Results:
- Quantified unbinding forces and kinetic off-rate constants for EGF/EGFR and TGF-α/EGFR interactions.
- Deduced distances from energy minimum to transition states for complex dissociation.
- Provided single-molecule level data on ligand-EGFR binding properties.
Conclusions:
- The study enriches the understanding of EGFR ligand binding properties at the single-molecule level.
- Findings may inform the development of improved EGFR inhibitors for bladder cancer.
- Presents new insights into the energy landscape of ligand-EGFR dissociation.
