The a-catenin gene encodes a 102kDa protein that links E-cadherin to the actin cytoskeleton. The amino terminus of a-catenin contains the actin-binding domain essential for linking the cadherin-catenin complex to the cytoskeleton (Beavon, 2000). The cytoplasmic components of the adherens junctions are necessary for linking cadherins to actin (Takeichi, 1991). The association of cadherins with the cytoskeleton is mediated via either a-actinin (Nieset et al., 1997; Knudsen et al., 1995) or vinculin (Hazan et al., 1997a; Weiss et al., 1998; Watabe-Uchi-da, 1998). a-Catenin is also known to interact with ZO-1 (Itoh et al., 1997). a-catenin associates with either ß-catenin or y-catenin in adherens junctions, but does not form a complex in desmosomes where y-catenin is bound to desmosomal cadherins and desmoplakin, another desmosomal protein. Therefore, a-catenin links E-cadherin-catenin proteins to the cy-toskeleton at adherens junctions, but not at desmosomes. This would suggest that a-cateinin may contribute to the stability of the E-cadherin-catenin complex in normal tissues. Recent studies have suggested that a-catenin is the best prognostic marker for prostate cancer specific survival (van Oort et al., 2007).

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