Cadherine

Cadherin, sometimes spelled cadherine, refers to a family of calcium-dependent cell adhesion proteins found in animals. They mediate homophilic cell–cell adhesion and help maintain tissue structure, polarity, and morphogenesis. The standard spelling is cadherin; cadherine is a common misspelling.

Classical cadherins are single-pass transmembrane proteins with an extracellular region made up of multiple cadherin repeats. The extracellular domains require calcium ions to stabilize their rigid, extended conformation that supports adhesion between like cells. The cytoplasmic tail binds to catenin proteins, such as beta-catenin and p120-catenin, which link the cadherin to the actin cytoskeleton through alpha-catenin. This arrangement forms adherens junctions that connect cells within tissues.

Examples of classical cadherins include E-cadherin (CDH1) in epithelial tissues, N-cadherin (CDH2) in neural and mesenchymal tissues, and P-cadherin (CDH3) in the placenta; VE-cadherin (CDH5) is important in vascular endothelium. The cadherin family also includes non-classical cadherins such as protocadherins, which have diverse roles in the nervous system.

Functions of cadherins encompass regulating cell sorting during development, maintaining tissue boundaries, contributing to epithelial polarity, and guiding cell migration. Dysregulation of cadherin-mediated adhesion is linked to disease, most notably cancer, where loss of E-cadherin can promote epithelial-to-mesenchymal transition and metastatic spread. Inherited mutations in CDH1 are associated with hereditary diffuse gastric cancer and other syndromes. Regulation of cadherin adhesion involves transcriptional control, post-translational modifications, phosphorylation, and endocytosis.