Epidermal growth factor receptor is an essential component in E-cadherin force-transduction complexes

This thesis focuses on the structural functional analysis of E-cadherin and EGFR interaction and their role in mediating E-cadherin mechanotransduction. E-cadherin serves as molecular Velcro in epithelial cells to maintain epithelial homeostasis. Despite passively bearing mechanical stress at cell-cell junctions, E-cadherin has been shown to actively respond to force to reinforce junction stability. However, classical E-cadherin mechanotransduction lacks sufficient information for force-induced biochemical signaling. In this dissertation, I focus on the role of E-cadherin/EGFR complexes in mediating force-responsive biochemical signaling in regulating junctional reinforcement. In Chapter 2, I focus on investigating the necessary region on E-cadherin required for EGFR binding. Studies revealed that the intracellular and transmembrane regions of E-cadherin were insufficient for EGFR binding. Further Co-IP and super-resolution results identified the extracellular domain 4 (EC4) as a critical binding domain for EGFR. Supporting these, Gastric cancer germline E-cadherin missense mutations near the EC4 domain impaired EGFR binding. Chapter 3 addressed the fundamental question of whether E-cadherin could initiate mechanotransduction signaling without EGFR physical complexes. Well-characterized E-cadherin mechanotransduction signatures, including adaptive cell stiffening, actin and vinculin recruitment at stressed junctions, were analyzed with E-cadherin mutants. The results demonstrated that without E-cadherin/EGFR physical complexes, cells were unable to activate EGFR and integrin in response to force, resulting in a lack of cellular stiffening and actin and vinculin remodeling at stressed junctions. Importantly, activation of integrin in E-cadherin mutant cells rescued E-cadherin mechanotransduction features, indicating a downstream role of integrin in the E-cadherin mechano-signaling pathway. In dense cultures, E-cadherin suppresses EGFR-mediated proliferation. I also studied how the hetero receptor regulates epithelial proliferation. Results revealed that E-cadherin mutants that uncouple EGFR displayed less effective inhibition of EGFR at confluency when treated with EGF. Notably, WT E-cadherin expressing cells displayed tension-dependent proliferation such that increased substrate rigidity correlated with higher proliferation rates. In contrast, cells expressing EGFR uncoupling E-cadherin mutants displayed higher proliferation than wild-type E-cadherin cells at all EGFR concentrations. Moreover, the substrate had no significant influence on proliferation for these mutant cells. These results provide direct evidence that E-cadherin and EGFR associate through extracellular domains to form a force-sensitive switch that regulates tension-dependent cell proliferation and intercellular junction mechanics.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Zou, Yubo

Contributors dc:contributor

• Leckband, Deborah
• Sokac, Anna
• Brieher, William
• Zhang, Kai

• Epidermal growth factor receptor, E-cadherin, Mechanotransduction

Statement dc:rights

• Copyright 2025 Yubo Zou

Language dc:language

en

Handle dc:identifier

https://hdl.handle.net/2142/132621

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/132621