Catenin are distinct peripheral cytosolic proteins, α, β, and γ -catenin (102 kDa, 94 kDa and 86 kDa, respectively) are found in varying abundance in many developing and adult tissues. Within its conserved regions, α-catenin shows 30% identity to vinculin, a protein found mainly in focal cell-cell and cell substrate adhesions.
Catenins bind, directly or indirectly, to the conserved cytoplasmic tail domain of the cell-adhesion cadherins. Cadherins are transmembrane cell surface glycoprotein molecules that mediate calcium-dependent intercellular interactions and are important for tissue morphogenesis. Catenins link E-cadherin to other integral membrane proteins such as Na+ /K+ -ATPase, or to cytoplasmic proteins such as fodrin, ankyrin, sarcoma (Src) and Yes kinases and are modulated by Wnt-1 protooncogene. They are considered good candidates for mediating transduction of cell-cell contact positional signals to the cell interior. α-Catenin appears to be capable of interacting with N-cadherin and P-cadherin. Absence of α-catenin is found in certain tumor cell lines. Frequent reduction of α-catenin levels in human carcinomas of the esophagus, stomach and colon is also reported. Prostate cancer development appears to be correlated with α-catenin gene deletions.
