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.
Fuchs
M
M
Department of Molecular Biology, Max-Planck-Institut für Biochemie, Am Klopferspitz 18A, 82152 Martinsried, Federal Republic of Germany.
Müller
T
T
Lerch
M M
MM
Ullrich
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001135:Armadillos; D001483:Base Sequence; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000378:metabolism; D018076:DNA, Complementary; D051180:Desmoplakins; D005786:Gene Expression Regulation; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators; D014407:Tumor Cells, Cultured; D051176:beta Catenin; D051185:gamma Catenin
C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D051180:Desmoplakins; D007527:Isoenzymes; C495292:JUP protein, human; C495293:Jup protein, mouse; D015534:Trans-Activators; D051176:beta Catenin; D051185:gamma Catenin; D017027:Protein Tyrosine Phosphatases