title: The protein-tyrosine phosphatase SHP-1 binds to and dephosphorylates p120 catenin.
abstract: A prominent tyrosine-phosphorylated protein of approximately 100 kDa (designated pp100) in epidermal growth factor (EGF)-stimulated A431 cells was found to be a main interaction partner of the protein-tyrosine phosphatase SHP-1 in pull-down experiments with a glutathione S-transferase-SHP-1 fusion protein. Binding was largely mediated by the N-terminal SH2 domain of SHP-1 and apparently direct and independent from the previously described association of SHP-1 with the activated EGF receptor. pp100 was partially purified and identified by mass spectrometric analysis of tryptic fragments, partial amino acid sequencing, and use of authentic antibodies as the 3A isoform of the Armadillo repeat protein superfamily member p120 catenin (p120(ctn)). Different p120(ctn) isoforms expressed in human embryonal kidney 293 cells, exhibited differential binding to SHP-1 that correlated partly with the extent of EGF-dependent p120(ctn) tyrosine phosphorylation. Despite strong phosphorylation, p120(ctn) isoforms 3B and 3AB bound, however, less readily to SHP-1. SHP-1 associated transiently with p120(ctn) in EGF-stimulated A431 cells stably transfected with a tetracycline-responsive SHP-1 expression construct, and p120(ctn) exhibited elevated phosphorylation upon a tetracycline-mediated decrease in the SHP-1 level. Functions of p120(ctn), which are regulated by tyrosine phosphorylation, may be modulated by the described SHP-1-p120(ctn) interaction.
authors.affiliation: Research Unit "Molecular Cell Biology," Klinikum der Friedrich-Schiller-Universität Jena, Drackendorfer Strasse 1, D-07747 Jena, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Keilhack
authors.forename: U
authors.initials: U
authors.lastname: Hellman
authors.forename: J
authors.initials: J
authors.lastname: van Hengel
authors.forename: F
authors.initials: F
authors.lastname: van Roy
authors.forename: J
authors.initials: J
authors.lastname: Godovac-Zimmermann
authors.forename: F D
authors.initials: FD
authors.lastname: Böhmer
mesh_terms: D051177:Catenins; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D004815:Epidermal Growth Factor / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008970:Molecular Weight; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D018909:src Homology Domains; D000095002:Delta Catenin
chemical_list: D051177:Catenins; D015815:Cell Adhesion Molecules; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D004815:Epidermal Growth Factor; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D000095002:Delta Catenin; C000722347:CTNND1 protein, human