Subcellular localization of beta-catenin is regulated by cell density.
It is generally accepted that subcellular distribution of beta-catenin regulates its function. Membrane-bound beta-catenin mediates cell-cell adhesion, whereas elevation of the cytoplasmic and nuclear pool of the protein is associated with an oncogenic function. Although the role of beta-catenin in transformed cells is relatively well characterized, little is known about its importance in proliferation and cell-cycle control of nontransformed epithelial cells. Using different approaches we show that in human keratinocytes (HaCaT) beta-catenin is distributed throughout the cells in subconfluent, proliferating cultures. In contrast, beta-catenin is nearly exclusively located at the plasma membrane in confluent, contact-inhibited cells. Hence, we demonstrate for the first time that beta-catenin is translocated from the cytoplasm to the plasma membrane in response to high cell density. We conclude that beta-catenin plays an important role in proliferation and mediating contact-inhibition by changing intracellular localization.
Dietrich
Cornelia
C
Institute of Toxicology, Johannes Gutenberg University, Obere Zahlbacherstrasse 67, 55131 Mainz, Germany. cdietric@mail.uni-mainz.de
Scherwat
Julia
J
Faust
Dagmar
D
Oesch
Franz
F
D015820:Cadherins / Q000096:biosynthesis; D002455:Cell Division; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003260:Contact Inhibition; D003598:Cytoskeletal Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000378:metabolism; D051180:Desmoplakins; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015603:Keratinocytes / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D021381:Protein Transport; D015534:Trans-Activators; D051176:beta Catenin
C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; D015534:Trans-Activators; D051176:beta Catenin