cadherincatenin

Cadherin-catenin is a multiprotein complex that forms the core of adherens junctions, specialized sites of cell-cell adhesion in epithelial and certain mesenchymal tissues. Cadherins are calcium-dependent transmembrane adhesion receptors that engage in homophilic interactions with cadherins on adjacent cells. The intracellular domain of classical cadherins binds to catenins, forming a linkage to the actin cytoskeleton.

Core components include beta-catenin and gamma-catenin (also called plakoglobin) that bind to the cadherin cytoplasmic tail. Beta-catenin can associate with alpha-catenin, which binds F-actin and couples the complex to the cytoskeleton. The p120-catenin family binds to the proximal cytoplasmic region of cadherins and regulates cadherin stability and membrane localization. Additional catenins and plakophilins contribute to junctional organization in tissue-specific contexts.

Functionally, the complex provides strong, yet dynamic, cell-cell adhesion essential for tissue architecture and morphogenesis. It also acts as a signaling platform: beta-catenin participates in the Wnt signaling pathway, where cytoplasmic accumulation and nuclear translocation regulate transcription with TCF/LEF factors when Wnt signaling is active.

Regulation and clinical relevance: Cadherin-catenin interactions are governed by phosphorylation, endocytosis, and interactions with cytoskeletal regulators. Disruption of the complex, loss of E-cadherin, or mislocalization of beta-catenin is associated with impaired adhesion, epithelial-mesenchymal transition, and progression of cancers.