Identification of a novel intracellular interaction domain essential for Bves function

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Blood vessel epicardial substance (Bves) is a conserved integral membrane protein involved in cell adhesion.
• The molecular mechanisms regulating Bves adhesive properties and its functional domains were previously unidentified.

Purpose of the Study:

• To elucidate the molecular mechanism underlying Bves-mediated intercellular adhesion.
• To identify the specific domain and residues within Bves essential for its function.

Main Methods:

• Glutathione-S-transferase (GST) pull-down and SPOTs analyses were used to map the interaction domain.
• Site-directed mutagenesis was employed to investigate the role of specific lysine residues.
• Transfection of human corneal cells with wild-type and mutated Bves was performed to assess protein localization and cellular function.

Main Results:

• A novel intracellular interaction domain (amino acids 268-274) essential for Bves homodimerization and intercellular adhesion was identified.
• Lysines 272 and 273 were found to be critical for Bves homodimerization and cell adhesion.
• Expression of mutated Bves disrupted epithelial sheet formation, junctional protein localization (ZO-1, E-cadherin), and tight junction integrity, indicated by reduced transepithelial electrical resistance.
• Mutated Bves expression induced an epithelial-to-mesenchymal transition.

Conclusions:

• Bves homodimerization through its C-terminal intracellular domain is essential for maintaining epithelial cell adhesion and phenotype.
• This study reveals a critical regulatory mechanism for Bves function and its role in epithelial integrity.
• The findings highlight the importance of Bves in preventing epithelial-to-mesenchymal transition.