研究発表を行った学会； 20th IUBMB International Congress
　　　２００６年６月１８日〜２３日 (Kyoto)
タイトル； The role of beta-catenin in the regulation of E-cadherin trafficking
発表者；福永　剛隆　氏
　　　（熊本大学　発生医学研究センター　初期発生分野）
Abstract；
Cadherin, an intercellular adhesion molecule, forms a cadherin/catenin complex with alpha-catenin and beta-catenin. beta -Catenin links E-cadherin via alpha -catenin to the actin cytoskeleton. It has been reported that plakoglobin, a close homologue of beta -catenin, has a similar function. Although the role of beta -catenin pertaining to the Wnt signaling pathway has been elucidated in some detail, much less is known concerning its role in the cadherin-mediated cell adhesion system.
F9 teratocarcinoma cells in which beta -catenin and/or plakoglobin genes are knocked-out were generated and investigated in an effort to define the role of beta -catenin and plakoglobin in cell adhesion. Loss of beta -catenin expression alone did not affect cadherin-mediated cell adhesion. Loss of both beta -catenin and plakoglobin expression severely affected the strong cell adhesion activity of cadherin. Internalization assays demonstrated that in the absence of beta -catenin and plakoglobin, E-cadherin was actively internalized from the cell surface.
Deletion mutation analysis demonstrated that the alpha -catenin-binding and cadherin-binding domains of beta -catenin are necessary and sufficient to restore strong cell adhesion activity. It also indicated that beta -catenin lacking the alpha -catenin-binding domain could support the stable expression and plasma membrane localization of E-cadherin independently from strong cell adhesion activity and cytoskeletal interactions. The present data indicated that beta -catenin and plakoglobin could be involved in cadherin-mediated cell-cell adhesion through the control of E-cadherin trafficking.