Association of human protein-tyrosine phosphatase kappa with members of the armadillo family.

We have identified a human receptor-like protein-tyrosine phosphatase (PTP) in the mammary carcinoma cell line SK-BR-3, which represents the human homolog of murine PTPkappa (Jiang, Y.-P., Wang, H., D'Eustachio, P., Musacchio, J. M., Schlessinger, J., and Sap, J. (1993) Mol. Cell. Biol. 13, 2942-2951) and was therefore termed hPTPkappa. We ...
show here that hPTPkappa expression is dependent on cell density and find it colocalized with two members of the arm family of proteins, beta-catenin and gamma-catenin/plakoglobin, at adherens junctions. Using both in vitro and in vivo binding assays, we demonstrate specific complex formation between endogenous hPTPkappa and beta- and gamma-catenin/plakoglobin. In addition, we present evidence that suggests that beta-catenin may represent a substrate for the catalytic activity of hPTPkappa. The identification of specific binding partners for this receptor-like PTP provides insight into the mechanisms of its biological action and suggests a role for hPTPkappa in the regulation of processes involving cell contact and adhesion such as growth control, tumor invasion, and metastasis.
Mesh Terms:
Amino Acid Sequence, Animals, Armadillos, Base Sequence, Cell Adhesion, Cell Adhesion Molecules, Cell Line, Cloning, Molecular, Cytoskeletal Proteins, DNA, Complementary, Desmoplakins, Gene Expression Regulation, Humans, Isoenzymes, Mice, Molecular Sequence Data, Protein Tyrosine Phosphatases, Sequence Homology, Amino Acid, Trans-Activators, Tumor Cells, Cultured, beta Catenin, gamma Catenin
J. Biol. Chem.
Date: Jul. 12, 1996
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