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Affinity regulates spatial range of EGF receptor autocrine ligand binding
Ann DeWitt1, Tomoko Iida, Ho-Yan Lam
1Department of Chemical Engineering, Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139, USA.
Developmental Biology
|October 12, 2002
Summary
Cells can control Epidermal Growth Factor Receptor (EGFR) signaling localization by tuning ligand-receptor binding affinity. Lower affinity binding is less efficient for ligand capture when ligand production is limited, impacting spatial distribution.
Area of Science:
- Molecular Biology
- Cell Biology
- Biophysics
Background:
- Spatial localization of Epidermal Growth Factor Receptor (EGFR) signaling is crucial for embryonic development and tissue function.
- Ligand-receptor binding affinity is a proposed mechanism for regulating this spatial localization.
- Autocrine signaling, where ligands act on the same cells producing them, relies on precise spatial control.
Purpose of the Study:
- To computationally predict and experimentally validate how Epidermal Growth Factor Receptor (EGFR) binding affinity influences autocrine ligand capture versus diffusion.
- To investigate the role of ligand-receptor binding affinity in regulating spatial distribution of autocrine signaling.
- To determine if cells can modulate EGFR signaling localization by altering binding affinity under specific production rates.
Main Methods:
- Development of a computational model to simulate ligand capture efficiency based on binding affinity and production rates.
- Construction of cell lines expressing wild-type EGFR and either wild-type EGF or a low-affinity EGF mutant (EGF(L47M)).
- Experimental validation of model predictions using the engineered cell lines to assess ligand spatial distribution.
Main Results:
- The computational model predicted that lower affinity ligands are captured less efficiently when ligand production rate is low relative to receptor appearance rate.
- Experimental data confirmed this prediction, showing reduced local capture of the low-affinity EGF mutant.
- Cells demonstrated the ability to regulate ligand spatial distribution by altering ligand-receptor binding affinity when autocrine ligand production was limiting.
Conclusions:
- Ligand-receptor binding affinity is a key molecular determinant for controlling the spatial localization of autocrine Epidermal Growth Factor Receptor (EGFR) signaling.
- Cells can leverage differences in binding affinity to manage the spread and concentration of signaling molecules.
- This mechanism provides a regulatory mechanism for fine-tuning developmental and tissue patterning processes governed by EGFR signaling.