Altered cell adhesion activity by pervanadate due to the dissociation of alpha-catenin from the E-cadherin.catenin complex.
Leukemia cells (K562) that grow as non-adhesive single cells and have no endogenous cadherin were transfected with an E-cadherin expression vector, and cell clones stably expressing E-cadherin on their surface were established. The expression of E-cadherin induced the up-regulation of catenins, and E-cadherin became associated with catenins. The transfected cells grew as floating aggregates. Cell aggregation was Ca2+-dependent and was inhibited by E-cadherin antibodies. The aggregates dissociated into single cells on the addition of pervanadate. Pervanadate caused a dramatic augmentation of the phosphorylation of E-cadherin, beta-catenin, and gamma-catenin (plakoglobin), but alpha-catenin was not detectably phosphorylated. After pervanadate treatment, beta-catenin and gamma-catenin migrated more slowly on gel electrophoresis, suggesting changes in their conformations due to eventual changes in their phosphorylation levels. In the treated cells, a significant amount of alpha-catenin was dissociated from the E-cadherin.catenin complex. Aggregates of cells expressing an E-cadherin chimeric molecule covalently linked with alpha-catenin were not dissociated on pervanadate treatment, supporting the idea that the dissociation of alpha-catenin from the complex underlies the observed E-cadherin dysfunction.
Ozawa
M
M
Department of Biochemistry, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan. mozawa@med2.kufm.kogoshima-u.ac.jp
Kemler
R
R
D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D006801:Humans; D011233:Precipitin Tests; D011485:Protein Binding / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014638:Vanadates / Q000494:pharmacology*; D051178:alpha Catenin
C495273:CTNNA1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D011993:Recombinant Fusion Proteins; D051178:alpha Catenin; C076715:pervanadate; D014638:Vanadates