Catenins

mammalian protein found in Homo sapiens

thumb|350px|Interactions of structural proteins at a cadherin-based adherens junction. The exact means by which [[cadherins are linked to actin filaments is still under investigation.]]

Plakoglobin, also known as junction plakoglobin or gamma-catenin, is a protein that in humans is encoded by the JUP gene. Plakoglobin is a member of the catenin protein family and homologous to β-catenin. Plakoglobin is a cytoplasmic component of desmosomes and adherens junctions structures located within intercalated discs of cardiac muscle that function to anchor sarcomeres and join adjacent cells in cardiac muscle. Mutations in plakoglobin are associated with arrhythmogenic right ventricular dysplasia.

α-Catenin (alpha-catenin) functions as the primary protein link between cadherins and the actin cytoskeleton. It has been reported that the actin binding proteins vinculin and α-actinin can bind to alpha-catenin. It has been suggested that alpha-catenin does not bind with high affinity to both actin filaments and the E-cadherin-beta-catenin complex at the same time. It has been observed that when α-catenin is not in a molecular complex with β-catenin, it dimerizes and functions to regulate actin filament assembly, possibly by competing with Arp2/3 protein. However, a protein complex including

δ-Catenin is a subfamily of catenin proteins with ten armadillo-repeats and includes the proteins catenin delta-1 and catenin delta-2. Catenin delta-2 is expressed in the brain where it is important for normal cognitive development. Like β-catenin and γ-catenin, δ-catenins seem to interact with presenilins. These catenin-presenilin interaction have implications for cadherin function and regulation of cell-to-cell adhesion.