Characterization of ZO-2 as a MAGUK family member associated with tight as well as adherens junctions with a binding affinity to occludin and alpha catenin.
ZO-2, a member of the MAGUK family, was thought to be specific for tight junctions (TJs) in contrast to ZO-1, another MAGUK family member, which is localized at TJs and adherens junctions (AJs) in epithelial and nonepithelial cells, respectively. Mouse ZO-2 cDNA was isolated, and a specific polyclonal antibody was ... generated using corresponding synthetic peptides as antigens. Immunofluorescence microscopy with this polyclonal antibody revealed that, similarly to ZO-1, in addition to TJs in epithelial cells, ZO-2 was also concentrated at AJs in nonepithelial cells such as fibroblasts and cardiac muscle cells lacking TJs. When NH2-terminal dlg-like and COOH-terminal non-dlg-like domains of ZO-2 (N-ZO-2 and C-ZO-2, respectively) were separately introduced into cultured cells, N-ZO-2 was colocalized with endogenous ZO-1/ZO-2, i.e. at TJs in epithelial cells and at AJs in non-epithelial cells, whereas C-ZO-2 was distributed along actin filaments. Consistently, occludin as well as alpha catenin directly bound to N-ZO-2 as well as the NH2-terminal dlg-like portion of ZO-1 (N-ZO-1) in vitro. Furthermore, immunoprecipitation experiments revealed that the second PDZ domain of ZO-2 was directly associated with N-ZO-1. These findings indicated that ZO-2 forms a complex with ZO-1/occludin or ZO-1/alpha catenin to establish TJ or AJ domains, respectively.
Mesh Terms:
Animals, Antibodies, Cells, Cultured, Cloning, Molecular, Cytoskeletal Proteins, DNA, Complementary, Membrane Proteins, Mice, Phosphoproteins, Protein Binding, Subcellular Fractions, Tight Junctions, alpha Catenin
Animals, Antibodies, Cells, Cultured, Cloning, Molecular, Cytoskeletal Proteins, DNA, Complementary, Membrane Proteins, Mice, Phosphoproteins, Protein Binding, Subcellular Fractions, Tight Junctions, alpha Catenin
J. Biol. Chem.
Date: Feb. 26, 1999
PubMed ID: 10026224
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