Fig. 3. Binding of soluble N-cadherin Fc to cell surface N-cadherin. Mutant or wild-type Fc fusion proteins were used to `stain' cell surface N-cadherin expressed by K562 transfectants. Binding was detected with FITC-labelled anti-Fc. The shaded profiles are negative controls using N-cadherin Fc with the mutation Asp134Ala. Results show that the affinity between wild-type cadherin molecules was too low to give detectable binding, whereas the interaction between Glu89Ala (E89A) and the Gly-Gly mutant (GG) gave strong staining.