Augmentation of adherens junction formation in mesenchymal cells by co-expression of N-CAM or short-term stimulation of tyrosine-phosphorylation.
Adherens-type junctions (AJ) are specialized intercellular contacts, mediated by cadherins and characterized by the association with actin filaments through a vinculin- and catenin-rich submembrane plaque. We describe here two mechanisms which potentiate AJ formation in mesenchymal cells. These include the augmentation of AJ by the co-expression of another adhesion molecule, namely NCAM, and the stimulation of tyrosine phosphorylation. These effects were obtained in NIH-3T3 cells, which, under normal conditions, have poor cadherin- and vinculin-containing intercellular junctions. The transfection of these cells with cDNA encoding the 140kD NCAM resulted in the extensive formation of cadherin- and vinculin-rich AJ, demonstrating a cooperativity between the two junctional systems. AJ could also be induced in 3T3, and in CEF and COS cells, upon a brief exposure to H2O2/vanadate, which elevates cellular levels of phosphotyrosine due to inhibition of tyrosine-specific phosphatases. This induction was, however, transient since prolonged exposure to H2O2/vanadate resulted in an overall destruction of AJ and detachment of cells from each other and from the extracellular matrix. AJ formation appears, therefore, to be modulated by a variety of factors including the level of expression of its intrinsic components, the cooperative effect of other adhesion molecules, and by tyrosine-phosphorylation.
Michalides
R
R
Department of Tumor Biology, The Netherlands Cancer Institute, Amsterdam.
Volberg
T
T
Geiger
B
B
D016475:3T3 Cells; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D002642:Chick Embryo; D002522:Chlorocebus aethiops; D018076:DNA, Complementary / Q000235:genetics; D005109:Extracellular Matrix / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007365:Intercellular Junctions / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D010766:Phosphorylation; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology; D016596:Vinculin / Q000378:metabolism
D015820:Cadherins; D015816:Cell Adhesion Molecules, Neuronal; D018076:DNA, Complementary; D016596:Vinculin; D014638:Vanadates; D014443:Tyrosine; D006861:Hydrogen Peroxide