Cadherins and Catenins: Role in Signal Transduction and Tumor Progression

Cadherins are transmembrane cell–cell adhesion molecules which are connected to the cytoskeleton by association with the cytoplasmic proteins, α-, β-, and γ-catenin (plakoglobin). β-catenin has an additional role in the wnt signal transduction pathway in which it transmitts signals to the cell nucleus in complexes with transcription factors of the LEF-1/TCF family. The cell adhesion function of the epithelial E-cadherin is frequently disturbed in carcinomas either by downregulation or by mutation of the E-cadherin/catenin genes. The signaling function of β-catenin is activated in tumors by mutations of β-catenin or of the tumor suppressor gene product APC. In this review I will give an introduction to the structure and function of the cadherin/catenin complex and summarize findings which support a decisive role of these components in the development of cancer.