Axin directly interacts with plakoglobin and regulates its stability.
Plakoglobin is homologous to beta-catenin. Axin, a Wnt signal negative regulator, enhances glycogen synthase kinase (GSK)-3beta-dependent phosphorylation of beta-catenin and stimulates the degradation of beta-catenin. Therefore, we examined the effect of Axin on plakoglobin stability. Axin formed a complex with plakoglobin in COS cells and SW480 cells. Axin directly bound to plakoglobin, and this binding was inhibited by beta-catenin. Axin promoted GSK-3beta-dependent phosphorylation of plakoglobin. Furthermore, overexpression of Axin down-regulated the level of plakoglobin in SW480 cells. These results suggest that Axin regulates the stability of plakoglobin by enhancing its phosphorylation by GSK-3beta and that Axin may act on beta-catenin and plakoglobin in similar manners.
Kodama
S
S
Department of Biochemistry, Hiroshima University School of Medicine, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
Ikeda
S
S
Asahara
T
T
Kishida
M
M
Kikuchi
A
A
D000818:Animals; D060466:Axin Protein; D019556:COS Cells; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051180:Desmoplakins; D007700:Kinetics; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012097:Repressor Proteins; D015534:Trans-Activators; D014162:Transfection; D051176:beta Catenin; D051185:gamma Catenin
D060466:Axin Protein; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; D011506:Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D051176:beta Catenin; D051185:gamma Catenin; D020928:Mitogen-Activated Protein Kinases