abLIM3 is a novel component of adherens junctions with actin-binding activity

The interactions of adhesion molecules with dense actin filaments via cytoplasmic plaque proteins are crucial for the adhesive function of adherens junctions (AJs) in epithelial and endothelial cells. Using localization-based expression cloning, we identified abLIM3, a member of the actin-binding LIM (abLIM) protein family, as a component of the junctional complex. Immunolocalization studies revealed that abLIM3 was localized at AJs in limited cell types, including hepatocytes, bronchial epithelial cells, mesothelial cells and endothelial cells lining muscular tissues. Deletion mutant analyses in cultured cells showed that the C-terminal dematin-like domain of abLIM3, which bound to actin filaments in vitro, was colocalized with phalloidin-stained filamentous actin, whereas the N-terminal LIM domains of abLIM3 were sufficient for recruitment to cell-cell contacts. These results suggest that abLIM3 is involved in anchoring LIM domain-binding components of AJs to circumferential actin bundles in specific cell types.