Fig. 2. Role of IQGAP1 in the regulation of E-cadherin-mediated cell-cell adhesion. When the amount of activated Rac1 increases, Rac1 interacts with IQGAP1, thereby crosslinking actin filaments. Under these conditions, IQGAP1 does not bind to ß-catenin and cannot dissociate -catenin from the cadherin-catenin complex, leading to strong adhesion. By contrast, when the amounts of inactivated Rac1 increases, IQGAP1 is freed from Rac1 and interacts with ß-catenin to dissociate -catenin from the cadherin-catenin complex. This results in weak adhesion.