cateninbinding

Catenin binding refers to the network of molecular interactions formed by the catenin family proteins and their partner proteins. Catenins are multifunctional adapters that participate in cell–cell adhesion and intracellular signaling. The principal catenins involved in binding are beta-catenin, alpha-catenin, gamma-catenin (also known as plakoglobin), and related family members such as p120-catenin. Binding events recruit catenins to cadherin complexes at the cell membrane or enable their roles in transcriptional regulation, depending on context and localization.

In adherens junctions, classical cadherins bind beta-catenin or gamma-catenin at their cytoplasmic tails. This beta- or gamma-catenin then connects to alpha-catenin, which associates with the actin cytoskeleton, either directly or through auxiliary proteins like vinculin under mechanical tension. p120-catenin interacts with the juxtamembrane region of cadherins, stabilizing the adhesion complex and modulating cadherin turnover. These binding interactions create cohesive cell–cell junctions essential for tissue integrity and morphogenesis.

Beyond adhesion, beta-catenin participates in signaling. In the absence of Wnt signaling, beta-catenin is part of a destruction complex that marks it for degradation. When signaling is active, beta-catenin accumulates in the cytoplasm and translocates to the nucleus, where it binds TCF/LEF transcription factors to regulate target genes. This transcriptional role is another form of catenin binding with important developmental and homeostatic outcomes.

Regulation of catenin binding involves phosphorylation, ubiquitination, and mechanical forces, which modulate complex stability, subcellular localization, and degradation. Dysregulation of catenin binding is implicated in developmental disorders and cancer, particularly through altered Wnt/beta-catenin signaling or compromised cell–cell adhesion.