Linking molecular affinity and cellular specificity in cadherin-mediated adhesion

Area of Science:

• Cell Biology
• Biophysics
• Developmental Biology

Background:

• Cell-cell adhesion is crucial for tissue formation and is largely mediated by cadherin proteins.
• In vitro assays for cadherin-mediated cell sorting have produced inconsistent results, highlighting a gap in understanding the molecular basis of cell patterning.
• The relationship between molecular binding affinities and macroscopic cell adhesive specificity remains unclear.

Purpose of the Study:

• To investigate the molecular basis of cadherin-mediated cell patterning by measuring dimerization affinities.
• To establish a connection between molecular binding free energies and cellular adhesive specificity.
• To elucidate how closely related cadherins mediate distinct cell behaviors.

Main Methods:

• Quantification of N-cadherin and E-cadherin dimerization affinities.
• Application of a theoretical framework linking molecular affinities to cell-cell adhesive specificity.

Main Results:

• N-cadherin exhibits higher homodimerization affinity compared to E-cadherin.
• The heterophilic binding affinity between N-cadherin and E-cadherin is intermediate between their respective homophilic binding affinities.
• Observed cell aggregation patterns can be explained by the measured differences in cadherin dimerization affinities.

Conclusions:

• Graded differences in homophilic and heterophilic cadherin binding affinities directly influence homotypic cell patterning.
• Closely related cadherin proteins can drive highly specific cellular adhesive behaviors through distinct binding characteristics.
• This work provides a molecular framework for understanding cadherin-mediated cell sorting and tissue organization.