N-cadherin cell-cell adhesion complexes are regulated by fibronectin matrix assembly

Area of Science:

• Cell Biology
• Extracellular Matrix Research
• Adhesion Complex Dynamics

Background:

• Fibronectin (FN) is crucial for extracellular matrix (ECM) assembly and tissue repair.
• Cell-ECM interactions regulate cell functions, while cell-cell and cell-ECM adhesion complexes coordinate tissue organization.
• N-cadherin-based adherens junctions are vital for tissue development and remodeling.

Purpose of the Study:

• To investigate how fibronectin matrix assembly influences N-cadherin-based adherens junctions.
• To identify molecular complexes involved in cell adhesion in the presence and absence of fibronectin.
• To elucidate the role of tensin in coordinating cell-cell and cell-matrix adhesion.

Main Methods:

• Utilized fibronectin-null mouse embryonic myofibroblasts.
• Analyzed the composition and organization of N-cadherin complexes.
• Investigated the recruitment and translocation of proteins like tensin and α5β1 integrins.

Main Results:

• Identified a novel quaternary complex (N-cadherin, β-catenin, tensin, actin) in fibronectin-deficient cells.
• Observed that N-cadherin ligation recruits tensin and α5β1 integrins in the absence of fibronectin.
• Demonstrated that fibronectin matrix assembly disrupts tensin-actin association with N-cadherin, decreases N-cadherin adhesion, and causes α5β1 integrin and tensin translocation.

Conclusions:

• Fibronectin matrix assembly significantly impacts the organization, composition, and function of N-cadherin adherens junctions.
• Tensin acts as a common cytoskeletal linker for both integrin- and cadherin-based adhesions.
• A novel mechanism involving α5β1 integrin translocation from cell-cell contacts to fibrillar adhesions coordinates cell-cell and cell-matrix adhesion during fibronectin assembly.