IDENTIFICATION OF PLAKOGLOBIN DOMAINS REQUIRED FOR ASSOCIATION WITH N-CADHERIN AND ALPHA-CATENIN

Cadherins are calcium-dependent, cell surface glycoproteins involved i n cell cell adhesion. To function in cell-cell adhesion, the transmemb rane cadherin molecule must be associated with the cytoskeleton via cy toplasmic proteins known as catenins. Three catenins, alpha-catenin, b eta-catenin, and gamma-catenin (also known as plakoglobin), have been identified, The domain of the cadherin molecule important for its inte raction with the catenins has been mapped to the COOH-terminal 70 amin o acids, but less is known about regions of the catenins that allow th em to associate with one another or with the cadherin molecule, In thi s study we have transfected carboxyl-terminal deletions of plakoglobin into the human fibrosarcoma HT-1080 and used immunofluorescence local ization and co-immunoprecipitation to map the regions of plakoglobin t hat allow it to associate with N-cadherin and with alpha-catenin. Plak oglobin is an armadillo family member containing 13 weakly similar int ernal repeats. These data show that the alpha-catenin-binding region m aps within the first repeat and the N-cadherin binding region maps wit hin repeats 7 and 8.