Figure 8.

Requirement for different domains for localization of α-catenin to β-catenin to the cell surface or cell adhesion sites. A) Confocal images of the ME180 cells transduced with full-length α-catenin or α-catenin lacking the actin (α-Δactin) or β-catenin (α-Δβ-cat) domains, each fused with HA tag to facilitate detection. Cells were stained for HA tag (red) and actin phalloidin (green). Cell nuclei were stained with Hoechst (blue). View: ×63. Scale bars = 20 μm. B) Lateral images were formed by maximum-intensity projection from confocal z-stack images. C) Model for JNK-mediated cell adhesion. Binding of α-catenin to β-catenin requires JNK and is necessary for transportation of α-catenin to the cell surface. Upon JNK inhibition, the AJ complex translocates to cell-cell adhesion sites; α-catenin leaves the AJ complex and associates with actin, possibly contributing to actin-bundle formation and strengthening cell adhesion.